Chapter 7e ● Workplace adaptation/recommendations 319 the end of the power stretcher head that receives its leverage by Antifatigue mats for jobs requiring insertion of a sharp pin directly into the floor. The stretcher prolonged standing adapter puts a hole in the carpet, underlying pad, and floor and cannot be used when installing carpet over concrete, but it To reduce body discomfort and fatigue, antifatigue mats have reduces the setup time for the power stretcher, is lightweight and been used in many industries. Many researchers have investi- inexpensive, and can be used in small spaces such as hallways gated the relationships between subjective measures, such as self- and closets (http://mctltd.com/StretchAdapter.htm). reported body discomfort, while working on different surfaces (such as an antifatigue mat) and objective measures, such as elec- The stretcher adapter also causes no structural damage as tromyography recording on the lower legs and back,35,40,47,48,74,79,140 can occur when a power stretcher is anchored against a wall in leg volume,28 movements of the ankle and center of pressure, the room being carpeted. Innovations like these are what is and other biomechanical parameters.28,40,47,48,74 Because of the pull needed (provided such devices are properly evaluated and found of gravity, prolonged standing may cause poor venous pump satisfactory) to relieve the carpet installer from the hazardous activity, which may cause leg edema and body discomfort.137 insults to the knee that have long been associated with this In addition, poor venous pump activity has been documented industry. as a result of prolonged standing on poor resilient surfaces.23 The effects of various standing surfaces on venous pump activ- Communication with trainers and safety specialists at carpen- ity were evaluated in some studies.21-23,102,103 The results have try and floor laying unions indicate that there is more emphasis shown that antifatigue mats with increased elasticity/stiffness on safety and safe work practices now than ever before. Workers can increase venous pump activity of the legs and reduce body also have better personal protective equipment such as knee discomfort.28 However, the range of values of elasticity/stiffness pads that protect the knee and lower leg (www.proknee.com), and energy absorption of the floor mats, which are shown to be cushioned insoles for work shoes, and even cushioned antifa- beneficial, have not been reported in the literature. tigue material that can be wrapped around any type of shoe (http://www.safetyseven.com/ergoflash.html). For carpet and Impact of contaminants on antifatigue floor installers there are improved tools that reduce fatigue and properties of floor mats physical trauma to the lower extremity such as automatic scrap- ers for ripping up existing flooring, carpet stretchers that can be In many working environments, such as automobile parts manu- activated with a lever instead of the knee (www.kneeless.com), facturing plants or food processing facilities, antislip and/or and double-headed mini–carpet stretchers that more easily and antifatigue mats are often contaminated with water, oil, or other quickly align seams for carpet that is glued to the floor. Nail guns fluids. The effectiveness of the antislip properties of antislip used by carpenters eliminate the fatigue of hammering and allow and/or antifatigue mats with different contaminations and the framing and trim work to be accomplished quickly and effi- reduction of body discomfort while performing a job task are ciently, which means less time spent in hazardous postures such not well documented in the literature. The effectiveness of the as kneeling and squatting. The experts say that a worker who is antislip property of mats is “qualified” by manufacturers as not fatigued will more likely take the time to work smartly and “good” slip resistance. This measure is not adequate for working safely. environments because the slip resistance of the mat is related to the shoe worn by the worker and the task being performed.29-31 According to one source, the traditional carpet stretcher is Furthermore, the presence of contaminants such as water and oil still used, but sparingly. One of the main recommendations of can modify an antifatigue mat’s mechanical properties, which the NIOSH carpet layer Alert83 was to more extensively use the have been reported to relieve postural fatigue due to prolonged power stretcher. At first this device was not commonly used by standing.28 Cham and Redfern28 reported that floor mats with carpet installers because it was cumbersome to use, expensive, increased elasticity, decreased energy absorption, and increased and time consuming to set up. Modern designs are lightweight stiffness are associated with lower levels of fatigue of the lower and easy to set up, and attachments exist that eliminate the need leg and the back area. However, repeated exposure to oil and/or to span the stretcher between opposite walls to stretch carpet water decreases the mat’s stiffness and elasticity, thereby com- (http://mctltd.com/StretchAdapter.htm). These improvements promising its antifatigue properties. Contaminants also reduce have made the power stretcher the tool of choice in most carpet the antislip properties. Previous studies from our laboratory installation jobs. showed that postural stability is significantly compromised during dynamic and semidynamic task performance on slippery It is widely believed that comparatively few injuries to the surfaces.27,28,30,31,71,135 lower extremity for carpenters and floor layers may be due to under-reporting. Despite improvements in tools and installation Limited studies109 from our laboratory also showed that methods, workers still place a priority on finishing jobs on leg muscle workload associated with bicycling significantly time. Sometimes cutting corners and overworking their bodies is (p < 0.007) impairs postural stability. Previous electromyographic needed to achieve these goals. The bottom line is that more studies51,80 have shown that pedaling activity uses predominately emphasis on safety and the availability of more safety and health the same muscle groups (hamstrings, triceps surae, gluteus information, such as the NIOSH carpet layer Alert, may have maximus, tibialis anterior, and quadriceps) that are needed to made a difference in the musculoskeletal health of building trade perform standing and walking activities. Seliga et al109 showed workers, but working smart and safe is a constant struggle that that postural sway length significantly increased with increasing must continually be reinforced. Ultimately, surveys of workers workload from 40 to 125 watts, implying postural instability. in controlled studies must be conducted to determine the true Therefore, when postural muscles are overworked for maintaining extent of any changes in the hazards of this type of work and the manner in which workers cope with it.
320 Chapter 7e ● Workplace-related lower extremity disorders upright balance on a slippery surface, it is reasonable to assume Such stiffening of subchondral bone has been found to be that with prolonged standing/walking on slippery surfaces, the associated with osteoarthritis, one type of degenerative musculo- postural muscles experience further fatigue and discomfort, caus- skeletal disease.45,94,97 ing potential postural instability and fall/near fall-related injuries. Based on the above discussion of the potential detrimental In a pilot study at an auto manufacturing plant, the effect of impact of heel strike–induced trauma of the knee joint, it is task performance on slippery surfaces (concrete and floor mats) reasonable to use a shock-absorbing type of material in the lower on body part pain/discomfort and slips and their association with extremities to dampen the incoming shock waves. The use of surface coefficient of friction was carried out by our research shoe inserts and insoles have been reported in the literature group.70 The results suggest that workers’ body pain or discom- to help minimize pain and discomfort associated with degenera- fort may be caused by the task characteristics or the combination tive disorders of the knee such as osteoarthritis. In our laboratory, of working on the slippery surface and the task characteristics. a study110 with 24 subjects (normal and osteoarthritic patients) Under these circumstances, there is a need to modify the mat’s was carried out to determine the impact of shoe insert (pad) in properties in such a way that it has a reduced rate of absorption of reducing heel strike–induced acceleration measured at the tibial a contaminant such as cutting fluid/oil/coolant and an increased tuberosity. The results showed that a shoe insert or pad reduced coefficient of friction value, while preserving the desired material the high-frequency heel strike force-induced shock waves over a properties associated with its antifatigue features. One such tech- larger frequency range as compared with that provided by the nique is to deposit plasma polymerized films onto the mats physiologic shock absorbers available in the human body when to vary the coefficient of friction and to control the uptake of a shoe insert was not used. cutting fluid/coolant/oil.118-121 Specialized shoe orthotics have been evaluated to determine The above literature review raises several questions regarding their effectiveness in minimizing osteoarthritis associated the floor mats used in industries where workers have to perform pain/discomfort.84 Kerrigan et al53 tested lateral-wedged (5 degrees) tasks during prolonged standing on mats contaminated with oil/ insoles and found them to be biomechanically effective in poten- coolant/cutting fluid: How do contaminants modify the mechan- tially reducing loading of the medial compartment in patients ical properties of the floor mats? Do contaminants detrimentally with knee osteoarthritis. In a study by Toda et al,123 two types of modify the antifatigue properties of the mats? Do antislip shoe inserts were evaluated. The effectiveness of a novel lateral mats provide proper frictional properties as well as antifatigue wedge insole with elastic strapping was compared with that properties? of a traditional shoe insert/insole in 90 female subjects with osteoarthritis of the knee in an 8-week study. The subjects Shoe inserts/insoles for jobs requiring wearing the novel lateral wedge insole with elastic strapping prolonged walking showed a significant improvement in their pain and decreased femorotibial angle and talar tilt (i.e., leading to valgus angulation Because walking and running give rise to heel strike–induced of the talus). For the traditional patients wearing shoe inserts forces in the musculoskeletal system, the transmission, absorp- such improvements were not found. Although Kerrigan et al,53 tion, and attenuation of energy that intakes to the skeleton due Toda et al,123 and others36 reported some beneficial effects of to heel strike are an important component of bone physiology the use of laterally wedged insoles, Maillefert et al76 did not and pathology.44,84,98,134 The human locomotion system, which show any pain relief from short-term (6 months) use of the shoe consists of natural shock absorbers (joints with viscoelastic insert in medial femorotibial osteoarthritic patients. In addition components, articular cartilage, meniscus, intervertebral disks, to the use of shoe inserts, there is some evidence in the literature trabecular bone, etc.), is subjected to constant insult not only regarding the role of exercise programs for minimizing insult during weight-lifting activities but also during normal daily to the knee joint. Oddis84 recommended use of isometric mus- activities such as walking and running.6,16,130,131 During heel cle strengthening of the quadriceps, which may act as the shock strike, the vertical force component acting on the foot is on the absorber for the injured knee. order of 1.5 times the body weight depending on walking veloc- ity.16,129 These force waves are gradually attenuated by the body’s Although studies of shoe inserts in osteoarthritic patients natural shock absorbers on their way toward the head. The have been well documented in the literature, there are a lack of process of force wave attenuation is the body’s natural way of data regarding the use of this form of intervention in occupa- protecting the vital organ, the brain. In healthy subjects, 70% tional populations. Finally, there is a need for research studies of the incoming shock waves are absorbed by the body’s natural where shoe inserts and specialized exercise programs can be shock absorbers before it reaches the forehead.7,16,44,130,133,134 tested as preventive tools in workers exposed to activities requiring Among all natural shock absorbers in the human body, the prolonged walking and standing. trabecular bone has the highest capacity (170 times higher than that provided by the cartilage) to attenuate incoming shock wave A two-part case study from an industry in associated with heel strike during walking and running.96 Previous workplace accommodations for an acute researchers have shown that such cumulative loading may give knee injury and subsequent chronic pain, rise to gradual fracture of subchondral bone trabeculae, which discomfort, and work restrictions through healing of the fracture actually renders the subchondral bone stiffer, thereby decreasing its shock-absorbing capacity.94,97,99,124 Case study part 1: Prevention of recurrence of a knee injury that resulted from a fall while
Chapter 7e ● Workplace adaptation/recommendations 321 descending a staircase and carrying a 24-pound Safety and ergonomic assessment power tool Recall that the worker had no history of knee or lower extremity The worker and task disorders and did not recall experiencing any significant slips, A right-handed 52-year-old man approximately five feet ten trips, or falls during his 18 years with the company. Also, he had inches tall and weighing about 210 pounds worked as a main- become very familiar with the facility and until this accident tenance and service technician for over 18 years for the same had not missed work as a result of an on-the-job mishap. Therefore, company. At the time of this writing, he was one of seven tech- the assessment of the safety hazards and ergonomic risk factors nicians performing roughly the same tasks. His job required began with the design and construction of the staircase at the spe- frequent walking throughout the facility and occasionally cific location of the accident according to the following criteria: ascending and descending staircases while carrying various tools 1. Standard conventional angle of stairway rise (slope), height and equipment that weighed from just a few pounds to nearly 40 pounds. He estimated that he typically climbed and descended of each step (riser), depth of each step (tread run), slip resist- staircases three to five times during each regular 8- to 10-hour ance of each tread and leading edge (nosing), and uniformity shift. The nature of the business and potential safety hazards throughout the entire flight of stairs per: required him to wear steel-toed boots with metatarsal arch pro- a. OSHA 29 CFR 1910.24 (e): Angle of stairway rise88 tection, a flame-resistant long-sleeved jacket, a hardhat, eye b. OSHA 29 CFR 1910.24 (f): Stair treads89 protection, and hearing protection. c. Lehmann65: Stairs of the following dimensions require the The facility where he worked was built in the early 1970s, least energy consumption and “seem to cause the fewest and it had not changed significantly over the next 30 years, accidents.”59 except for occasional cleaning, repairs, and minor alterations to i. Slope of 25-30 degrees the walking and working surfaces. Until the spring of 2001, this ii. Recommended formula: 2h + d = 630 mm (24.8 in); worker had no history of knee or lower extremity injuries or discomfort and could not recall experiencing any significant where h = height of riser and d = depth of tread slips, trips, or falls during his 18 years of service. He reported to d. Rapid Entire Body Assessment, REBA49 be “very familiar” with the facility and until the experience described below had not missed a day of work as a result of a Assessment results work-related mishap. However, according to the company’s Occupational Safety and Health Administration (OSHA) 200 logs, OSHA 29 CFR 1910.24 (e)88 states that fixed stairs shall be there had been three other lost-time injuries to three separate installed at angles to the horizontal (slope) of between 30 and workers resulting from slips, trips, and falls during the previous 50 degrees. The 43-degree slope of the staircase at the location 3 years. of the accident was in compliance with the standard. The accident and injury Table 7e.1 from the OSHA standard88 shows “riser” and “tread run” combinations that when uniform throughout the entire One afternoon in April 2001, the worker was returning to the flight of stairs, produce a stairway within the permissible range. tool crib after completing a job that required the use of a The table also shows the slope (angle to horizontal) produced powered chipping hammer to break concrete. He reported carry- by each combination and that each step of a stairway having a ing the tool, which weighed about 24 pounds, in his right hand 43-degree slope should have a “riser” of approximately 8-1/2 and walking at a moderate pace. He decided to cross over inches and a “tread run” of roughly 9 inches. OSHA 29 CFR a bridge that recently had been closed for repairs but had been 1910.24 (f) reemphasizes that the “risers” and “tread runs” shall reopened. He stated that he typically had crossed the bridge be uniform throughout any flight of stairs.89 many times in the past but that his regular path over the bridge had been altered for about 3 days while repairs to the Each of the seven steps that were being descended by the bridge were in progress. The bridge was constructed with seven worker at the time of the accident were measured as shown in metal steps up one side, a platform over and across some Table 7e.1 (accuracy ± 1/8 inch) and numbered from the top step mechanical equipment below, and seven metal steps down the to the bottom. The measurements show that the bottom three other side. The worker climbed up the first set of steps, crossed steps had rise dimensions that did not comply with Table 7e.1 of the platform, and while descending the other side, misjudged a the OSHA standard,88 and that the riser dimensions were not step, lost his balance at about the third step from the bottom and fell to the floor, dropping the power tool and feeling a sharp Table 7e.1 Stairway riser and tread run in case burning pain in his right knee. After the fall, he stood up study part 1 carefully and took a few steps toward the chipping hammer that had slid several feet across the floor, but he could not bear Step no. Riser (in inches) Tread run (in inches) the pain so he sat down on one of the steps and then called and waited for assistance. An emergency medical examination that 7 8-5/8 9-0 evening discovered a torn medial collateral ligament in his 6 8-1/2 9-0 right knee that would require surgical repair and 3 to 4 weeks of 5 8-1/2 8-7/8 lost work. 4 8-3/8 9-0 3 8-0 9-0 2 7-7/8 8-7/8 1 9-5/8 9-1/8
322 Chapter 7e ● Workplace-related lower extremity disorders uniform throughout the flight of stairs. Further investigation ● Score B (upper arms, lower arms, and wrist) = 1 (on a scale of revealed that steps 2 and 3 had been repaired because they had 1 to 12) become rusted and had partially broken loose from the metal frame. Steps 2 and 3 had been raised slightly and rewelded to ● Score C (combination of scores A and B from Table C) = 7 (on the frame, which shortened their riser dimensions by 5/8 and a scale of 1 to 12) 1/2 inch, respectively, consequently increasing the riser of step 1 by 1-1/8 inches. ● REBA score = 9 (on a scale of 1 to 15) ● = 7 (score C) + 1 (activity score: static load of carrying tool) OSHA 29 CFR 1910.24 (f) states,89 “all treads shall be reason- + 1 (activity score: action caused rapid large range in pos- ably slip-resistant and the nosings shall be of non-slip finish. tures or an unstable base) Welded bar grating treads without nosings are acceptable pro- viding the leading edge can be readily identified by personnel ● REBA action level = 3 (on a scale of 0 to 4) descending the stairway and provided the tread is serrated or is ● “High” risk level requiring action “necessary soon.” of definite non-slip design.” The treads of the stairway at the accident location were welded bar grating without nosings, and In retrospect, if REBA had been applied beforehand, it would their leading edges were not clearly identifiable. The tread was have identified the task as “high” risk in need of corrective action serrated and of nonslip design. soon, but a question remains: What would have, or should have, triggered the necessity for an assessment, since simply returning According to Lehmann,65 a staircase slope of 25-30 degrees a tool to the tool crib typically would not be considered a with uniform risers of 170 mm (roughly 6-5/8 inches) and tread particularly hazardous task? Answer: The repairs to the bridge runs of 290 mm (roughly 11-3/8 inches) requires the least energy should have prompted a safety inspection and an ergonomics consumption and seems “to cause the fewest accidents.” Lehmann’s assessment of the “changes” made to the walking and working recommendation for the most “efficient” riser and tread run surfaces over the bridge. dimensions can be expressed by the formula Conclusions and corrective actions 2h + d = 630 mm (24.8 in) As a result of the accident and injury and following the where h = height of riser and d = depth of tread. assessments according to OSHA 29 CFR 1910.24 (e) and (f), Steps 4 through 7 of the 43-degree-slope staircase where the Lehmann’s65 empirical data, and REBA, the following conclu- sions were made and corrective actions implemented: accident occurred had relatively uniform risers (h) of an average 1. The first three steps on the descending staircase of the bridge 8-1/2 inches and tread runs (d) of roughly 9-0 inches. Although the 43-degree slope fell within range of the 30-50 degrees spec- were replaced. The new risers were each 8-1/2 inches high and ified by OSHA, it exceeded the most efficient slope recom- the tread runs 9 inches deep (accuracy ±1/8 inch). A complete mended by Lehmann65 by 13 to 18 degrees. Also, substituting inspection of the entire bridge and staircase was performed, the 8.5 inches for “h” and 9.0 inches for “d” in the formula gives and an inspection schedule of all bridges and staircases the result 2(8.5) + 9.0 = 26.0 inches, which is 1.2 inches greater throughout the facility was developed. than the ideal. 2. The leading edges of all the steps at the bridge were made clearly identifiable using yellow and black diagonally striped Other assessment tools tape. A plan and schedule to identify unmarked steps and to apply tape as needed was implemented. Other ergonomics assessment tools that have been used previ- 3. The following long-term plans were made (Case Study Part 2 ously in the facility to identify risk factors related to the various covers the long-term accommodations in greater detail): types of injuries and discomforts reported by the workers are a. Reduce the slopes and change the risers and tread runs of the Rapid Upper Limb Assessment (RULA),78 the Rapid Entire Body Assessment (REBA),49 the Job Strain Index (JSI),82 and the the staircases at the location of the accident and through- Washington State Caution/Hazard Zones (WAC 296-62-051).136 out the facility to match Lehmann’s65 recommendations as Each of these tools focuses almost exclusively on the upper closely as possible. extremities, with the possible exception of REBA. Although b. Relocate the tool crib and strategically locate tool storage REBA does not address stresses to the lower extremities specifi- cabinets to minimize transit hazards (i.e., climbing and cally, it does include the effect of the legs in its postural analysis descending stairs), distances and times. of the entire body. Case study part 2: Accommodations for chronic REBA is a postural analysis tool developed especially for knee pain and work restrictions while walking, the type of unpredictable working postures found in health care while climbing stairs, and during static standing and other service industries.49 Because the working postures of subsequent to the knee injury described in case a maintenance and service technician are often unpredictable, study part 1 REBA was applied after the accident, in this particular case to determine the “action level” (i.e., risk level and action required) The worker and task of the task of “descending the staircase while carrying a 24-pound The 52-year-old maintenance and service technician described in tool.” The results of REBA are summarized below: the first part of this case study returned to his regular job in early ● Score A (trunk, neck, and legs) = 7 (on a scale of 1 to 12) June 2001, about 7 weeks after his knee injury. Although modi- fications had been made to the staircase that contributed to his ● = 4 + 2 (load/force: > 10 kg for the 24-lb tool) + 1 (load/ injury and to many of the other staircases to bring them into force: shock or rapid buildup of force from “misjudgment” of step)
Chapter 7e ● Workplace adaptation/recommendations 323 compliance with OSHA 29 CFR 1910.24 (fixed industrial stairs),91 him to reach maximum improvement in strength and range of the job still required the following physical activities: motion. ● Frequent walking on various surfaces; ● Ascending and descending staircases three to five times a day In summary, the opinions from the worker himself, the physi- cian of record, and the physical therapist provided the following while carrying tools; work restrictions for which reasonable accommodations were to ● Climbing portable and fixed ladders four to five times per be made during the first 6 to 8 weeks of his return to work (work restrictions to be reassessed after each 6- to 8-week period): week; 1. Walking is to be limited to 2 hours per day. ● Occasionally climbing on various machines and structures to 2. Static standing must not exceed 1 hour per day. 3. Staircases with slopes greater than 40 degrees are to be avoided. perform maintenance and service tasks; 4. Climbing portable and fixed ladders is to be restricted to ● Static standing on a concrete floor for up to an hour at a time; ● Occasionally crouching, once or twice a day, to work on low twice daily. 5. To prevent unexpected or unnatural loading of the knee level equipment. (i.e., twisting, lateral stress, hyperextension, extreme flexion, Also, the safety hazards in the plant had not changed; therefore etc.), the most obvious slip, trip, and fall hazards should be it was a requirement to wear full foot protection and all the identified and removed wherever practicable. personal protective equipment described in Case Study Part 1. 6. All crouching, squatting, kneeling, or any activity that requires the right knee to be flexed more than 90 degrees is to Modifications made and planned during be avoided. the worker’s absence 7. Climbing on structures without regulation steps, grab bars, walking platforms, and handrails must be avoided. During the injured worker’s 7-week absence, the first three steps 8. Jumping down from platforms or other structures is to be on the descending staircase of the bridge at the location of prohibited. the accident were replaced with steps of the correct design and dimensions. Inspections and repairs of the most frequently used Assessment methods and tools bridges and staircases throughout the facility were completed, and the leading edges of most of the steps were made clearly In addition to ensuring compliance to the above restrictions for identifiable using yellow and black diagonally striped tape. the injured worker, the following safety standards and ergonom- ics guidelines were to be enforced for the purpose of minimizing In addition to the above modifications, the following long- risk of injury (or reinjury) to any of the workers: term plans were made: 1. All staircases were to be equipped with railings and guards in 1. To reduce the slopes and change the risers and tread runs of compliance with OSHA 29 CFR 1910.23 (d)(1)(i) through (v).87 the staircases at the location of the accident and throughout 2. The most frequently used staircases were to be modified so the facility to match Lehmann’s65 formula as closely as possible. 2. To relocate the tool crib and strategically locate tool storage that the tread heights and depths fit as closely as possible the cabinets to minimize transit hazards, such as climbing and following formula recommended by Lehmann.65 According descending stairs while carrying tools and excessive walking to Kroemer and Grandjean,59 “stairs of these dimensions are distances and times. not only the most efficient but also seem to cause the fewest accidents.” Physical discomforts, limitation, and work restrictions 2h + d = 630 mm (24.8 in), where h = riser height and d = tread depth Upon returning to his job, the worker felt confident in his ability to perform the essential functions of the job and was relatively 3. All portable ladders were to comply with OSHA 29 CFR satisfied with the progress of his recovery. However, he reported 1910.25 (Portable wood ladders),91 and 1910.26 (Portable metal mild to moderate pain and occasional swelling and joint stiffness, ladders),92 and with 1910.27 (Fixed ladders).93 especially after walking for more than about 2 hours, standing for more than an hour, and especially after climbing stairs of slopes 4. All walking surfaces were to be inspected and brought into greater than about 40 degrees, climbing ladders more than twice compliance with OSHA 29 CFR 1910.22 (General requirements)86 daily, or crouching for more than a minute or two. regarding housekeeping and aisles and passageways. Postoperative medical reports from the physician of record Controls and interventions stated that the surgery to repair the medial collateral ligament in the right knee, as well as the subsequent recovery, had progressed Table 7e.2 shows the controls and interventions that were with no complications; however, some preexisting degenerative implemented over a period of approximately 90 days to facilitate joint disease (osteoarthritis) was discovered. The physician’s report compliance to the prescribed work restrictions, safety standards, placed restrictions on duration and frequency of walking, static and ergonomic recommendations. standing, climbing stairs and ladders, and crouching and stressed the importance of avoiding reinjury from a slip, trip, or fall. Three-year follow-up A written opinion and functional capacity evaluation from a In June 2004, a brief telephone interview of the injured worker was physical therapist stated that the worker had participated cooper- done to determine his condition and to check the current status atively in his rehabilitation program thus far and was progressing and effectiveness of the workplace modifications. In summary, reasonably well; however, it would take approximately 1 year for
324 Chapter 7e ● Workplace-related lower extremity disorders Table 7e.2 List of controls and interventions to facilitate compliance to work instructions, safety standards and ergonomic recommendations Restriction, standard, or guideline Control or intervention Walking < 2 hours per day An electric-powered cart was purchased for transportation across flat surfaces. The main tool crib was moved to a central location and three tool cabinets were placed near the three most Static standing < 1 hour per day Avoid staircase slopes > 40 degrees frequently visited work areas. Antifatigue matting was placed on the concrete floors in eight locations. Climbing ladders < twice daily Five adjustable-height standing support stools were placed where “standing work” was common. Eliminate slip, trip, and fall hazards, and all Five bridges with staircases were modified to comply with the formula 2h + d = 630 mm (24.8 in) which walking surfaces must comply with reduced their slopes from approximately 43 to about 35 degrees. All frequently used staircases with slopes 29 CFR 1910.2286 > 40 degrees that couldn’t be modified were marked accordingly. No crouching, squatting, or kneeling A mobile “cherry picker” was purchased for the maintenance and service department. A videotape of all walking surfaces throughout the facility was developed and presented to management and all No climbing on structures without steps, grab maintenance and surfaces technicians. A 1-year corrective action plan with monthly status checks was developed. bars, etc.; and no jumping down from A 2-hour training program in “preventing slips, trips, and falls” was given to all maintenance and service platforms technicians. Two large electric motors and one pump were raised from floor level to elbow height. Two standing support All staircases must have railings and guards stools were placed at these locations, and four adjustable “low stools” were placed near four machines per 29 CFR 1910.23 (d)(1)(i) through (v)87 where low-level work is performed regularly. Steps with slip-resistant treads, grab bars, and walking platforms were installed (welded) to two machines that Frequently used staircases should comply are climbed on regularly. with the formula, 2h + d = 630 mm Stairways < 44 inches wide were inspected to comply with: All ladders must comply with 29 CFR Both sides enclosed–hand rail on right side descending 1910.25, 26, and 2791-93 One side open–stair railing on open side Both sides open–stair railing on each side Stairways > 44 inches but < 88 inches wide were checked for compliance with: Hand rail on each enclosed side Stair railing on each open side Stairways ≥ 88 inches wide were checked for: Hand rail on each enclosed side Stair railing on each open side Intermediate stair railing midway Although the bridge and staircase at the accident location plus four other bridges in the main walkway of the facility had been made OSHA compliant since the accident, they were further modified to comply also with the Lehmann formula. For example, the average riser and tread depth of the 43-degree steps at the accident location were changed from 8-1/2 and 9 inches, respectively, to 7-1/4 and 10-1/4 inches, which reduced the slope to about 35 degrees and required the bridge to be lowered and the staircases to be lengthened. All ladders were inspected and required to be in good condition or otherwise removed from service and tagged. A 2-hour training program in ladder safety, including maintenance and utilization of ladders, was given to all maintenance and service technicians. the injured worker was still actively employed as a maintenance job, and the work of all the maintenance and service technicians, and service technician but in a more supervisory role. He esti- safer and less physically demanding. Since his accident in mated that his workload had been reduced approximately 20% April 2001 and following the implementation of the workplace to 30% since the time of his accident and shortly thereafter. His modifications described above, there have been no lost-time work restrictions have been lifted, but he still experiences occa- injuries reported from slips, trips, and falls according to the sional stiffness and discomfort in his right knee; however, OSHA 300 logs. Comparatively, during the 3 years before the he sincerely believes that the modifications to the bridges, accident described in this case study there had been three other stairways, and the other walking-working surfaces have made his lost time accidents from slips, trips, and falls.
Chapter 7e ● References 325 Summary and conclusions 16. Bhattacharya A, McCutcheon EP, Greenleaf JE, Shvartz E: Body acceleration distribution and uptake in man during running and jumping. J Appl Physiol This two-part case study describes workplace modifications 49(5):881-887, 1980. that were applied, in part 1, for the prevention of the recurrence of an acute injury resulting from a fall while descending a stair- 17. Bhattacharya A, Mueller M, Putz Anderson V: Quantification of traumatogenic factors case and, in part 2, to accommodate the subsequent long-term affecting the knees of carpet installers. Appl Ergonom 16:243-250, 1985. pain, discomfort, and work restrictions of the injured worker. The task that was being performed when the injury occurred was 18. Bhattacharya A, Putz Anderson V, Habes D: Preliminary guidelines for the assessed using the OSHA standard for walking-working surfaces, development of work practices procedures for carpet layer’s job. Presented at namely related to staircase design and construction and an The American Industrial Hygiene Conference, Las Vegas, Nevada, 1985. ergonomic formula that suggests an efficient and safe relationship between staircase riser, tread depth, and slope. An ergonomic 19. Bhattacharya A, Ramakrishanan HK, Habes D: Electromyographic patterns associated assessment of the task also was performed using the REBA tool. with carpet installation task. Ergonomics 29:1073-1084, 1986. Each assessment method discovered noncompliances and risk factors that were determined to be likely contributors to the 20. Bhattacharya A, Warren J, Teuschler J, Dimov M, Lemasters G: Development and accident. The workplace modifications were directed toward evaluation of a microprocessor based ergonomic dosimeter for evaluating carpentry correcting the noncompliances and eliminating or significantly tasks. Appl Ergonom 30:543-553, 1999. reducing the ergonomic risk factors that were identified. 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8C H A P T E R Ankle and Foot
8aC H A P T E R injuries comes from accounts of case studies, many of which report an injury rate but often fail to define accurately the Epidemiology of the population at risk. For instance, the prevalent idea that runners Ankle and Foot who over-pronate are at a greater risk for injury, as reported by James et al,67 was fostered by noting that 58 of their 180 patients Victor Valderrabano and Beat Hintermann had a pronated foot configuration. This study does not take into consideration the total number of people in the running popu- Acute and chronic injuries of the foot and ankle are among lation from whom this select group was derived who also pronate the most common injuries in the musculoskeletal system. Based but have not been injured. on 15,000 completed questionnaires by family shoe store customers, it was determined that 40% of the population in the Another liability of epidemiologic studies is their failure United States has foot problems, 12% of which have had surgery accurately to define the factor to be analyzed. Sport injury studies and 7% of which have been untreated.51 It has been reported that show significant variations in the definition of what constitutes for every 300 men working in heavy industry, 15 working days an injury. It is difficult, for example, to compare studies where per month are lost as a result of foot problems, 65% of which are an injury is anything that causes an athlete to require medical the result of trauma.31 The amount of athletically related injuries attention and lose time from participation15 with those that have is substantially increasing due to the aging population, the grow- much stricter definitions and classifications.62,132,134 The compar- ing popularity of recreational sports activity in our society, ison difficulties are increased further when different sports and the greater numbers of professional active athletes. In sports and participation levels are compared. There may be significant practice, however, it is often difficult to distinguish and strictly differences between the injury of a recreational runner and that separate work-related from recreation-related injuries. of a professional rugby player.26 In addition, elite and endurance athletes are characterized by the psychologic “iceberg” profile, The following general comments on the epidemiologic assess- which includes scores below the population average on mood ment of disorders and injuries to the foot and ankle are meant states such as tension, depression, anger, fatigue, and confusion to show the general problems and difficulties of attempting to along with above average scores on vigor.92 During years of hard reveal and compare data from a literature review. More detailed training, pain recognition and processing by the central nervous considerations about epidemiology are made separately for system may change. work-, military-, and sport-related injuries, although as mentioned earlier, strict differentiation between these activities is often not Finally, the homogeneity of the population being studied is possible. The number of athletically related injuries has grown important. This relates to such considerations as exposure to coincident with an enlarging search by the public for specialists injury, age and gender differences, preexisting injury, and other to provide the necessary treatment. Hence, it is not surprising variables that may significantly confound risk.27 Several studies that athletic-related injuries are at this time among the best inves- have demonstrated, for instance, that weekly running mileage is tigated. The knowledge gleaned from such specific studies has the single most critical factor affecting injury risk in the running contributed to a better understanding of injuries occurring dur- population.85,136 At distances of over 64 km (40 miles) per week, ing work and military service and has led to improvements in the injury rate seems to increase exponentially. Through all these equipment. Shoe construction and design, for example, have studies, other risk factors have not been confirmed. improved markedly due to the research activities of sport shoe companies. WORK-RELATED INJURIES METHODOLOGY OF EPIDEMIOLOGIC Epidemiology STUDIES: CRITICAL ASPECTS Attempts to characterize and quantify work-related injuries to One of the goals of preventive medicine is to reduce the health the foot and ankle are few. Jobs involving extensive manual risk of both occupational exposure and athletic participation material handling or vehicular operations are those most often through recognition and control of the risk factors. From the listed by employees with foot-related injuries. vantage point of careful epidemiologic study, it is possible to identify and quantify risk along with the incidence and preva- Etiology lence of injury for a given set of conditions.107 Work-related foot and ankle injuries have been associated To analyze epidemiologic data properly, it is critical for with falling from ladders;100 being struck by boxes, metal objects, the population being analyzed to be assiduously defined. Many or vehicles; being caught in, under, or between vehicles or studies of athletic injuries that have engendered prejudicial think- machinery;98 and having cut or laceration injuries. ing about injury causes are flawed because of their methodology.27 Most of the existing information on observed causes of athletic O’Sullivan et al100 showed that ladder fall injuries are associ- ated with foot fractures, the male gender (89%), a median length and hospital cost of 1 week and US$3950, respectively, and a median duration of disability and unemployment of 6 weeks. From a total of 990 work-related injuries to the foot, being struck accounted for 58% across occupational groups.98 Regardless of
332 Chapter 8a ● Epidemiology of the ankle and foot the industry group, metal items and vehicles were related to were in the tibial or femoral shaft, whereas only 8% occurred in 51% of all work-related foot injuries. Bazroy et al7 found 15% the tarsus and metatarsus. Excessive rates of stress fractures were of cuts and laceration injuries to the foot and ankle in a glass found also by other authors.13,14,47,114 bottle manufacturing plant. Significant risk factors were age (less than 30 years) and experience (less than 2 years). Technical Etiology factors responsible for injury were a hazardous work site in 37 cases (38.5%), inadequate protection with safety wear in Stress fractures (Fig. 8a.1) are common injuries sustained during 32 cases (33%), and proximity to machines in 14 cases (14.6%). military training. Improper advance physical preparation and Human factors identified were lack of protective wear in excessive physical demands during military service may cause 43 episodes (45%), overconfidence in 18 episodes (18.7%), and tim- most of these injuries to the foot and ankle.13,14,48,72 Typically, ing error while working with machines in 11 episodes (11.4%). fatigue fractures have been seen mostly in the first months of service, indicating an acute overuse injury of bones.114 Prevention In the past, pes planus or flatfeet have been a disqualifying To reduce the incidence of foot injuries, workers in many indus- factor for military service. Specific studies, however, have shown tries are required to wear safety footwear incorporating a steel- that those recruits with flat or pronated feet had no greater inci- toed cap. In Australia, an investigation of 321 workers employed dence of stress fracture than the normal population.49 Rudzki116 in a broad range of work activities and required to wear safety showed that abnormalities of the foot (pes planus, pes cavus, footwear revealed an extremely high percentage of subjects (91%) hallux valgus) were not significant factors in the development reporting one or more foot problems that were verified by a pro- of injury during recruit training. In contrast, another study, this fessionally trained podiatrist.84 Most of these subjects believed one involving Israeli military recruits, showed that those with that the safety footwear either caused the problem or adversely low arches had a higher incidence of metatarsal stress fractures affected an existing foot condition. The main shoe concerns than did those with higher ones, whereas the number of stress were excessive heat (65%), inflexible soles (52%), weight (48%), fractures of the tibia and femur was lower in low-arch than in and pressure from the steel-toed cap (47%). As the priority, safety high-arch feet.121 may obviously conflict with comfort. Ideally, knowledge would compromise with experience in choosing shoes for industry Heavy loads have been recognized as a risk factor for foot workers to allow the best possible supply of safety footwear. and ankle injuries during endurance exercises in the military. Reynolds et al105 reported that 36% of soldiers were injured dur- MILITARY-RELATED INJURIES ing a 161-km march over 5 days carrying an average load mass of 47 kg. In this study smoking and younger age (< 20 years) Epidemiology were independent risk factors for injuries. Lower limb injuries, mainly to the foot and ankle, are the most Other causes of military-related foot and ankle injuries are common injuries in military service. In a survey of 350 male cold weather injuries30,88,128 and inflammatory foot lesions.63 recruits of the Royal Australian Army Corps, Rudzki115 reported Milgrom et al88 showed evidence of cold weather being a risk an 80% rate of foot and ankle injuries. Among the U.S. Marine factor for Achilles paratendinitis. They explained that a fall in Corps, training-related initial injuries to the foot were found at temperature of the Achilles paratendon may increase the viscos- a rate of 3.0 new injuries per 1000 recruit-days.80 The highest ity of the lubricant, in turn increasing friction and risk for specific rates of injuries occurred with stress fractures to the foot Achilles paratendinitis. (0.56 per 1000 recruit-days), ankle sprains (0.53), and Achilles tendinitis (0.39). Prevention In a prospective study, Bush et al21 examined the epidemiology In general terms, “warming up” before exercising may be one of of blisters and their association with subsequent injuries in the most important factors in lowering acute foot and ankle 2130 male U.S. Marine Corps recruits, who experienced an injuries.88 Meticulous foot care such as skin and nail hygiene incidence of 2.05 blisters per 100 recruit-months. Recruits with may prevent infections and blisters. Furthermore, higher quality blisters were 50% more likely to experience an additional training- and ergonomics of shoes, insoles, and equipment may avoid related injury. In combination with other related injuries, blisters overload injuries effectively. resulted in 159 clinic visits, 103 days of assigned light duty, and 177 days lost from training. To determine the effect of appropriate shoe fit and training shoe type on the incidence of overuse injuries, the Israeli Defense Among an air assault division, foot and ankle injuries were Forces Medical Corps conducted a prospective study.38 Among the most prevalent and severe category of injury for combat unit infantry recruits, they found that three shoe widths for each shoe soldiers.39 In a 1-year period, the average combat unit soldier length size were necessary to adequately accommodate the sustained 0.16 foot injuries with an estimated 3.2 effective duty recruit population’s foot anatomy. Recruits compensated for days lost. A prospective study of 295 male Israeli military recruits the lack of available shoe widths by choosing larger shoe sizes, reported a 31% incidence of stress fractures,90 most of which (80%) which did not result in a higher incidence of overuse injuries. Switching to tennis sport shoes substantially reduced calcaneal stress fractures in military recruits.52 A study of South African
Chapter 8a ● Sport-related injuries 333 AB Figure 8a.1 Stress fracture metatarsal V (Jones fracture). (A) Stress fracture of the fifth metatarsal in a basketball athlete (symptoms: chronic pain on the lateral aspect of the midfoot and sport disability after 5 months of conservative treatment). (B) Surgical treatment with open reduction and internal fixation (intramedullary compression screw). military recruits reported a reduction in overuse injuries by If injury rates for the foot and ankle are determined from studies incorporating a shock-absorbing neoprene insole into the shoe performed for various sports (Table 8a.1), the magnitude of used in training.119 Surprisingly, however, no mid- to long-term the athletic injury problem can be estimated by multiplying studies have systematically assessed the effectiveness of footwear these rates by the number of participants in the given sport. improvements on soldier fitness. Obviously, some sports have an extremely high risk for injuries to the ankle or foot (Table 8a.1), whereas the injury rate is mini- SPORT-RELATED INJURIES mal in others, such as golf, boating, cycling, equestrian, fishing, parachuting, or bowling. Epidemiology Etiology Injuries to the lower extremities constitute most injuries in most sports, especially those involving running, jumping, and kicking. The risk of sustaining an injury in a given sport may depend on Twenty-five percent of 12,681 injuries in the top 19 most com- different factors such as velocity, exposure to other players or mon sports injuries seen in a multispecialty sports medicine obstacles, playing environment, training techniques, and equip- clinic occurred at the ankle and foot. The percentages of foot and ment. These are among some of the extrinsic factors, whereas ankle injuries varied substantially from sport to sport, as did the the individual’s physical and personality traits constitute the intrin- proportion of sprains versus overuse injuries at each location.46 sic factors.27 The factors most associated with injuries to the foot
334 Chapter 8a ● Epidemiology of the ankle and foot Table 8a.1 Foot and ankle injury rates in high-risk sports: a literature review Sport First author Year Skill level Ankle injury Foot injury Ballet Garrick43 1986 Various levels 17% 22% Basketball Henry56 1982 Professional 18% 6% Zelisko143 1982 Professional 19% 4% Dance Prebble104 1999 Various levels 33% NA Washington137 1978 Various levels 17% 15% Football Rovere112 1983 Students 22% 15% Ice hockey du Toit33 2001 Various levels F&A 33% Moretz91 1978 High school 31% 8% Sutherland127 1976 Amateur 0% 0% High School 0% 0% Mountaineering Park101 1980 College 7% 10% Orienteering McLennan86 1983 Professional 0% 0% Running Tomczak131 1989 Junior 4% 1% Johansson71 1986 NA 41% 8% Skating (ice) Hintermann60 1992 NA 40% 35% Snowboarding Gottlieb50 1980 Elite 26% 13% Soccer Temple129 1983 Various levels 24% 11% Marti85 1988 Recreational 19% 11% Squash/racquetball Walter136 1989 NA 26% 26% Volleyball Bishop12 1999 NA 30% 10% Smith123 1982 Recreational 15% 16% Brown18 1987 Professional 36% NA Pino103 1989 Age 11-19 yr 29% 8% Bladin15 1993 National males 8% 8% Bridges17 2003 Recreational 26% 3% Ekstrand34 1983 Various levels F&A 23% Nielsen95 1989 Various levels F&A 10% Berger-Vachon9 1986 Swedish senior division 17% 12% Woods141 2003 Various levels 36% 8% Berson10 1978 French amateur leagues 20% NA Soderstrom124 1982 Professional 11% NA Schafle117 1990 Recreational 21% 2% Solgard125 1995 NA 20% 7% National amateur 18% 6% Various levels 31% NA F&A, foot and ankle; NA, not available. Adapted from Clanton TO, Wood RM: Etiology of injury to the foot and ankle. In JC DeLee, D Drez, MD Miller, eds: Orthopaedic sports medicine—principles and practice. Philadelphia, 2003, W.B. Saunders, pp. 2224-2274. and ankle in sports include anatomic or biomechanical abnormal- and their coaches, although no reliable study has supported this ities, lack of flexibility, poor strength, muscle imbalance, type of assumption. Probably the most comprehensive study of running- shoe and/or use of orthoses, and type of playing surface.26,27 related injuries, the Ontario cohort study, showed that none of the anthropometric variables, such as femoral neck anteversion, Anatomic/biomechanical abnormalities knee and patella alignment, rearfoot valgus, pes cavus/planus, and running shoe wear pattern, was significantly related to risk.136 Various anatomic conditions have been frequently associated with athletic injuries: Alignment of the lower extremity and/or Foot and ankle injuries in dancing such as ankle sprains, fatigue over-pronation has been associated with injuries to the knee, fractures, or tendon ruptures have been related to poor technique ankle, and foot, and foot configuration has been associated and malalignment.19,32,66,82 Kinetic chain dysfunctions of the foot with stress fractures of the lower extremity (Fig. 8a.2). The belief have been described in dancers secondary to primary injuries.82 that runners who over-pronate initially have a higher risk of sustaining a running-related injury is still held by most runners Indeed, anatomic/biomechanical alterations appear to be causally related to injury. Busseuil et al and other reports have
Chapter 8a ● Sport-related injuries 335 Figure 8a.2 Foot and ankle overload injuries. Foot and ankle Ehlers-Danlos syndrome, and osteogenesis imperfecta. In certain overload injuries (stress fractures, tendonitis, and others) are very sports, however, high flexibility is needed. Ballet dancers, divers, common in endurance sports, as marathon running. (Picture: IronMan and gymnasts are particularly noted for the tremendous mobility Triathlon, Zürich, Switzerland, 2003.) in their feet and ankles that allows them to achieve maximum plantar flexion so that the foot is parallel to the lower leg. shown that hindfoot valgus correlates with a higher risk for foot Although such increased mobility has obvious advantages, an and ankle injuries.22,27,58 The use of inverting shoe orthotics in increased incidence of injury was noted in those ballet dancers athletes with over-pronation may significantly prevent overuse who have greater mobility.78 Alternatively, maximum plantar foot and ankle injuries.27,58,140 flexion can create posterior ankle pain from impingement. Flexibility and stability A pathologic increase in joint laxity, ankle instability27,62 is seen commonly in a few high-risk sports activities such as soccer, Lack of flexibility as a result of limited joint motion is a common basketball, orienteering, and others (Table 8a.1). Instability in cause of injuries to the foot and ankle. Restricted dorsiflexion the ankle joint can be classified as lateral, medial, or rotational at the ankle joint is a factor in the anterior ankle pain (soccer instability and as acute or chronic. Chronic ankle instability ankle) often seen in soccer players that is associated with anterior (CAI) has become very epidemiologically important in sports tibial osteophytes and/or a meniscoid lesion.37 Two different medicine and orthopedics in recent years, leading to increased hypotheses have been described to explain the formation of health care costs and risk of posttraumatic osteoarthrosis of talotibial osteophytes in the anterior ankle impingement syn- the ankle.53,54 It is well known that ankle sprains are among the drome: hyperplantar flexion vs. recurrent ball impact. In a bio- most common injuries occurring during sports activities,44 caused mechanical study, however, Tol et al130 supported the hypothesis in 85% of the cases by an inversion trauma.4 More than 23,000 that spur formation in anterior ankle impingement syndrome ankle sprains occur per day in the United States.74 Although is related to recurrent ball impact, which can be regarded as most of these ligamentous ankle injuries can be treated success- repetitive microtrauma to the anteromedial aspect of the ankle. fully with physical rehabilitation and nonoperative treatment, 20% to 40% of patients with ankle injuries go on to experience In addition, other problems around the foot and ankle, CAI and subsequent disability.16,40 including turf toe,25,111,138 bunions,6 midfoot strain and plantar fasciitis,5,28,108,109 ankle sprains,36,44,65 Achilles tendonitis,139 calf The most common predisposition factor for CAI seems to strains,1,34 and hyperpronation22,27,58 are believed to be due to be the history of having suffered an ankle sprain in the past.36,142 restricted ankle dorsiflexion. Although these conditions have The pathomechanism involved in CAI may be mechanical insta- been related to a tight Achilles tendon, however, no study has bility133 (posttraumatic ligament laxity, intraarticular pathologies, yet confirmed such an association. altered joint mechanics), functional instability40,41,57 (proprio- ception, neuromuscular control, or strength deficit), or a combi- A deficit of dorsiflexion at the first metatarsophalangeal joint, nation of both.133 Concerning the link between proprioception as is typically the case in hallux rigidus,83 has been related to turf and neuromuscular joint control, it has been demonstrated that toe injuries.25,138 Limitation of motion at the interphalangeal CAI leads to deficits in ankle proprioception, nerve conduction joint is often connected to deformities such as hammer toe or velocity, neuromuscular response times, postural control, and mallet toe and thus creates a problem.24 strength. Evidence suggests that alteration in muscle-spindle activity of the muscles stabilizing the ankle may be more impor- On the other hand, hypermobility can cause injury problems tant than altered articular mechanoreceptors.76 Strength reduc- also at the foot and ankle. The hypermobility syndrome has been tion for eversion and inversion has been described.55,73 described as a potential source of musculoskeletal symptoms.27 In most cases this syndrome has no association with connective Strength tissue disorders, including Down syndrome, Marfan syndrome, The belief that weak musculature predisposes an individual to sports injury has been supported by various studies. Soccer play- ers who sustained a minor injury during the preceding 2 months with subsequent inadequate rehabilitation and poor muscle strength had a 20% increase in risk for a more serious subsequent injury.34,36 Among 1139 young soccer players, 216 injuries, most involving the ankle joint, were observed during a summer training camp.3 The highest incidence of injury occurred in boys who were tall and had weak grip strength, which suggests that skeletally mature but muscularly weak players were at increased risk for injury as compared with their peers. Other studies concluded that strength differences of more than 10% between the right and left legs increases the risk for injury.8,20 This finding corre- sponds to the observation that the institution of a prophylactic program, including rehabilitation to the point that 90% of mus- cle strength had been regained, reduces the incidence of injury in soccer players by 75%.35 Other studies also have shown that improving strength can reduce the risk for reinjury.2,34
336 Chapter 8a ● Epidemiology of the ankle and foot Shoe wear and orthoses A shoe that is fitted improperly and overly high causes pressure-related pain at the site of bunions and bunionettes. Foot fixation on a playing surface resulting in abnormal torque As examples, one can see aggravation of a bunion in a metatarsus is the most commonly cited etiologic factor for noncontact primus varus or an accessory navicular from an ice skating boot injuries to the knee and ankle.27 Obviously dependent on the play- and irritation of the Achilles tendon from many varieties of ing surface, these injuries are often attributed to the shoe-surface shoe wear. It could be that local pressure at the heel may in some interface. This aspect is discussed in a later section. A B CD Figure 8a.3 Fracture of the lateral process of the talus (LPT): “snowboarder’s ankle.” The LPT fracture is a snowboarding-specific foot and ankle injury that can easily be missed by being considered a simple ankle sprain. The most frequent injury mechanism is a combination of axial impact, dorsiflexion, external rotation, and eversion. Early and appropriate treatment based on fracture type may determine the outcome. (A) Acute lesion with swelling and beginning hematoma. (B) Computed tomography with imaging of the displaced LPT fracture. (C) Intraoperative situs after removal of the LPT fragment (D) in preparation for internal fixation with two screws.
Chapter 8a ● References 337 cases produce retrocalcaneal bursitis.139 The painful irritation of Prevention the retrocalcaneal bursa often seen in runners and cross-country skiers,61 however, is likely to be caused less by an improperly As mentioned in the preceding section, analysis of risk factors fitted shoe heel than by friction resulting from gliding of the sometimes makes it possible to intervene in a way to reduce or tendon over the posterior calcaneal bone due to eversion-inversion eliminate the risk factor and thereby lower the risk for injury. movement of the calcaneus.61 When the shoe is too short, the This is indeed the aim of preventive sports medicine. Examples toes jam into the end and nail problems occur; a shoe that is too of such intervention include rule changes in football to eliminate loose allows the foot to slide, and blisters result. the “crackback” block102 and improved generations of synthetic grass and underpadding brought about by research into the A lack of cushioning and/or support by the shoe has relationship between artificial turf and injury.79,122 In softball and been implicated also as a specific factor in overuse injuries.96,97 baseball, interventions such as breakaway bases, batting helmets, Whereas some reports have shown beneficial effects of cushi- face shields on helmets, lighter mass balls, and teaching and oned shoes in reducing injuries,94,119 other studies have been less reiteration of the fundamentals of softball and baseball all have conclusive or have shown no benefit from increased shock been effective in preventing millions of injuries and billions absorption in either shoes or insoles.42,87,89 The authors hypothe- of dollars in health care costs each year in the United States.68 size that excessive cushioning can actually be an etiologic factor During a 3-year follow-up in junior elite cross-country skiers, the in injury by dampening the body’s own sensory feedback prevalence of overuse injuries to the lower extremity decreased mechanism coming from the plantar surface of the foot, a from 62% to 22% when individual shoe adaptations and/or “pseudo-neurotropic” effect that has been shown by other orthotic devices were made.59 Supervision by a doctor and phys- authors as well.110 iotherapist;35 reduction in muscle tightness;34 use of shock- absorbent insoles,94,119 orthotic devices,121 external support75 or The importance of proper shoe equipment is exemplified by prophylactic ankle taping;99 and injury prevention through bare- snowboarding over the last decades. 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Kaminski TW, Hartsell HD: Factors contributing to chronic ankle instability: a strength 1992. perspective. J Athl Train 37:394-405, 2002. 39. Fleming JL: One-year prevalence of lower extremity injuries among active duty military 74. Kannus P, Renstrom P: Treatment for acute tears of the lateral ligaments of the ankle: soldiers. Mil Med 153:476-478, 1988. operation, cast, or early controlled mobilization. J Bone Joint Surg Am 73:305-312, 40. Freeman MA: Instability of the foot after injuries to the lateral ligament of the ankle. 1991. J Bone Joint Surg Br 47:669-667, 1965. 75. Karlsson J, Andreasson GO: The effect of external ankle support in chronic lateral ankle 41. Freeman MA, Dean MR, Hanham IW: The etiology and prevention of functional joint instability. An electromyographic study. Am J Sports Med 20:257-261, 1992. instability of the foot. J Bone Joint Surg Br 47:678-685, 1965. 76. Khin MH, Ishii T, Sakane M, Hayashi K: Effect of anesthesia of the sinus tarsi on 42. Gardner LI Jr, Dziados JE, Jones BH, et al: Prevention of lower extremity stress peroneal reaction time in patients with functional instability of the ankle. Foot Ankle fractures: a controlled trial of a shock absorbent insole. Am J Public Health Int 20:554-559, 1999. 78:1563-1567, 1988. 77. Kirkpatrick DP, Hunter RE, Janes PC, Mastrangelo J, Nicholas RA: The snowboarder’s 43. Garrick JG: Ballet injuries. Med Probl Perform Arts 1:123-127, 1986. foot and ankle. Am J Sports Med 26:271-277, 1998. 44. Garrick JG: The frequency of injury, mechanism of injury, and epidemiology of ankle 78. Klemp P, Chalton D: Articular mobility in ballet dancers. A follow-up study after four sprains. Am J Sports Med 5:241-242, 1977. years. Am J Sports Med 17:72-75, 1989. 45. Garrick JG, Gillien DM, Whiteside P: The epidemiology of aerobic dance injuries. Am J 79. Levy IM, Skovron ML, Agel J: Living with artificial grass: a knowledge update. Part 1. Sports Med 14:67-72, 1986. Basic science. Am J Sports Med 18:406-412, 1990. 46. Garrick JG, Requa RK: The epidemiology of foot and ankle injuries in sports. Clin 80. Linenger JM, Shwayhat AF: Epidemiology of podiatric injuries in US Marine recruits Podiatr Med Surg 6:629-637, 1989. undergoing basic training. J Am Podiatr Med Assoc 82:269-271, 1992. 47. Giladi M, Ahronson Z, Stein M, Danon YL, Milgrom C: Unusual distribution and onset 81. Macera CA, Pate RR, Powell KE, Jackson KL, Kendrick JS, Craven TE: Predicting lower- of stress fractures in soldiers. Clin Orthop 192:142-146, 1985. extremity injuries among habitual runners. Arch Intern Med 149:2565-2568, 1989. 48. Giladi M, Milgrom C, Danon Y, Aharonson Z: The correlation between cumulative 82. Macintyre J, Joy E: Foot and ankle injuries in dance. Clin Sports Med 19:351-368, march training and stress fractures in soldiers. Mil Med 150:600-601, 1985. 2000. 49. Gilbert RS, Johnson HA: Stress fractures in military recruits-a review of twelve years’ 83. Mann RA: Intermediate to long term follow-up of medial approach dorsal experience. Mil Med 131:716-721, 1966. cheilectomy for hallux rigidus. Foot Ankle Int 21:156, 2000. 50. Gottlieb G, White JR: Responses of recreational runners to their injuries. 84. Marr SJ, Quine S: Shoe concerns and foot problems of wearers of safety footwear. Phys Sportsmed 8:145-149, 1980. Occup Med Lond 43:73-77, 1993. 51. Gould N, Schneider W, Ashikaga T: Epidemiological survey of foot problems in the 85. Marti B, Vader JP, Minder CE, Abelin T: On the epidemiology of running injuries. continental United States: 1978-1979. Foot Ankle 1:8-10, 1980. The 1984 Bern Grand-Prix study. Am J Sports Med 16:285-294, 1988. 52. Greaney RB, Gerber FH, Laughlin RL, et al: Distribution and natural history of stress 86. McLennan JG, Ungersma J: Mountaineering accidents in the Sierra Nevada. fractures in U.S. Marine recruits. Radiology 146:339-346, 1983. Am J Sports Med 11:160-163, 1983. 53. Gross P, Martin B: Risk of degenerative ankle joint disease in volleyball players: study 87. Milgrom C, Burr DB, Boyd RD, Robin GC, Higgins WL, Radin EL: The effect of a of former elite athletes. Int J Sports Med 20:58-63, 1999. viscoelastic orthotic on the incidence of tibial stress fractures in an animal model. 54. Harrington KD: Degenerative arthritis of the ankle secondary to long-standing lateral Foot Ankle 10:276-279, 1990. ligament instability. J Bone Joint Surg Am 61:354-361, 1979. 88. Milgrom C, Finestone A, Zin D, Mandel D, Novack V: Cold weather training: a risk fac- 55. Hartsell HD, Spaulding SJ: Eccentric/concentric ratios at selected velocities for the tor for Achilles paratendinitis among recruits. Foot Ankle Int 24:398-401, 2003. invertor and evertor muscles of the chronically unstable ankle. Br J Sports Med 89. Milgrom C, Giladi M, Kashtan H, et al: A prospective study of the effect of a 33:255-258, 1999. shock-absorbing orthotic device on the incidence of stress fractures in military 56. Henry JH, Lareau B, Neigut D: The injury rate in professional basketball. Am J Sports recruits. Foot Ankle 6:101-104, 1985. Med 10:16-18, 1982. 90. Milgrom C, Giladi M, Stein M, et al: Stress fractures in military recruits. A prospective study showing an unusually high incidence. J Bone Joint Surg Br 67:732-735, 1985. 91. Moretz A III, Rashkin A, Grana WA: Oklahoma high school football injury study: a preliminary report. J Okla State Med Assoc 71:85-88, 1978. 92. Morgan WP, Costill DL: Selected psychological characteristics and health behaviors of aging marathon runners: a longitudinal study. Int J Sports Med 17:305-312, 1996. 93. Müller FO, Blyth CA: A survey of 1981 college lacrosse injuries. Phys Sports Med 10:87-93, 1982.
Chapter 8a ● References 339 94. Mundermann A, Nigg BM, Humble RN, Stefanyshyn DJ: Foot orthotics affect lower 119. Schwellnus MP, Jordaan G, Noakes TD: Prevention of common overuse injuries extremity kinematics and kinetics during running. Clin Biomech 18:254-262, 2003. by the use of shock absorbing insoles. A prospective study. Am J Sports Med 18:636-641, 1990. 95. Nielsen AB, Yde J: Epidemiology and traumatology of injuries in soccer. Am J Sports Med 17:803-807, 1989. 120. Sim FH, Simonet WT, Melton L J III, Lehn TA: Ice hockey injuries. Am J Sports Med 15:30-40, 1987. 96. Nigg BM, Bahlsen AH, Denoth J, Lüthi SM, Stacoff A: Factors influencing kinetic and kinematic variables in running. In BM Nigg, ed: Biomechanics of running shoes. 121. Simkin A, Leichter I, Giladi M, Stein M, Milgrom C: Combined effect of foot arch Champaign, IL, 1986, Human Kinetics, pp. 139-159. structure and an orthotic device on stress fractures. Foot Ankle 10:25-29, 1989. 97. Nigg BM, Stergiou P, Cole G, Stefanyshyn D, Mundermann A, Humble N: Effect 122. Skovron ML, Levy IM, Agel J: Living with artificial grass: a knowledge update. Part 2. of shoe inserts on kinematics, center of pressure, and leg joint moments during Epidemiology. Am J Sports Med 18:510-513, 1990. running. Med Sci Sports Exerc 35:314-319, 2003. 123. Smith AD, Micheli LJ: Injuries in competitive figure skaters. Phys Sportsmed 98. Oleske DM, Hahn JJ, Leibold M: Work-related injuries to the foot. Data from an 10:36-47, 1982. occupational injury/illness surveillance system. J Occup Med 34:650-655, 1992. 124. Soderstrom CA, Doxanas MT: Racquetball. A game with preventable injuries. 99. Olmsted LC, Vela LI, Denegar CR, Hertel J: Prophylactic ankle taping and bracing: a Am J Sports Med 10:180-183, 1982. numbers-needed-to-treat and cost-benefit analysis. J Athl Train 39:95-100, 2004. 125. Solgard L, Nielsen AB, Moller-Madsen B, Jacobsen BW, Yde J, Jensen J: Volleyball 100. O’Sullivan J, Wakai A, O’Sullivan R, Luke C, Cusack S: Ladder fall injuries: patterns injuries presenting in casualty: a prospective study. Br J Sports Med 29:200-204, and cost of morbidity. Injury 35:429-431, 2004. 1995. 101. Park RD, Castaldi CR: Injuries in junior ice hockey. Phys Sports Med 8:81-90, 1980. 126. Stacoff A, Kalin X, Stussi E: The effects of shoes on the torsion and rearfoot motion 102. Peterson TR: The cross-body block, the major cause of knee injuries. JAMA in running. Med Sci Sports Exerc 23:482-490, 1991. 211:449-452, 1970. 127. Sutherland GW: Fire on ice. Am J Sports Med 4:264-269, 1976. 103. Pino EC, Colville MR: Snowboard injuries. Am J Sports Med 17:778-781, 1989. 128. Taylor MS: Cold weather injuries during peacetime military training. Mil Med 104. Prebble TB, Chyou PH, Wittman L, McCormick J, Collins K, Zoch T: Basketball injuries 157:602-604, 1992. in a rural area. WMJ 98:22-24, 1999. 129. Temple C: Sports injuries. Hazards of jogging and marathon running. Br J Hosp Med 105. Reynolds KL, White JS, Knapik JJ, Witt CE, Amoroso PJ: Injuries and risk factors in a 29:237-239, 1983. 100-mile (161-km) infantry road march. Prev Med 28:167-173, 1999. 130. Tol JL, Slim E, van Soest AJ, van Dijk CN: The relationship of the kicking action in 106. Rheinstein DJ, Morehouse CA, Niebel BW: Effects on traction of outsole composition soccer and anterior ankle impingement syndrome. A biomechanical analysis. and hardnesses of basketball shoes and three types of playing surfaces. Med Sci Am J Sports Med 30:45-50, 2002. Sports 10:282-288, 1978. 131. Tomczak RL, Wilshire WM, Lane JW, et al: Injury patterns in rock climbers. 107. Rice SG: Epidemiology and mechanisms of sports injuries. In CC Teitz, ed: Scientific J Osteopath Sports Med 3:11-16, 1989. foundations of sports medicine. St. Louis, 1989, Mosby-Year Book, pp. 3-23. 132. Torg JS, Quedenfeld TC, Landau S: The shoe-surface interface and its relationship to 108. 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Rodeo SA, O’Brien S, Warren RF, Barnes R, Wickiewicz TL, Dillingham MF: Turf-toe: fracture—treatment outcome of 20 cases after 3.5 years. Am J Sports an analysis of metatarsophalangeal joint sprains in professional football players. Med 6:871-880, 2005. Am J Sports Med 18:280-285, 1990. 136. Walter SD, Hart LE, McIntosh JM, Sutton JR: The Ontario cohort study of running- 112. Rovere GD, Webb LX, Gristina AG, Vogel JM: Musculoskeletal injuries in theatrical related injuries. Arch Intern Med 149:2561-2564, 1989. dance students. Am J Sports Med 11:195-198, 1983. 137. Washington EL: Musculoskeletal injuries in theatrical dancers: site frequency, and 113. Rowe ML: Varsity football. Knee and ankle injury. N Y State J Med 69:3000-3003, severity. Am J Sports Med 6:75-98, 1978. 1969. 138. Watson TS, Anderson RB, Davis WH: Periarticular injuries to the hallux metatar- 114. Ruckert KF, Brinkmann ER: Fatigue fractures of the calcaneus in soldiers of the sophalangeal joint in athletes. 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CHAPTER 8b OSTEOLOGY Anatomy and Talus Biomechanics of the Ankle and Foot The talus consists of a body (corpus tali), a neck (collum tali), a head (caput tali), two processes (posterior and lateral talus Victor Valderrabano and Beat Hintermann processes), and a trochlea tali. The trochlea tali is wider anteriorly than posteriorly, which stabilizes the bony ankle mortise in FUNCTIONAL FOOT AND ANKLE ANATOMY dorsiflexion. The talus further shows a conic shape with radius smaller on the medial side than the lateral side, allowing the A part of the lower extremity, the foot (pes), consists of 28 bones movement transfer from the foot to the lower leg and vice versa. (Fig. 8b.1): 7 tarsal bones (talus, calcaneus, navicular, cuboid, In a cadaver study of 100 specimens, Inman29 determined that the medial, intermediate, and lateral cuneiforms), 5 metatarsal bones, medial angle of orientation of the talus (medial facet) measured 14 phalanges (two phalanges of the great toe, the other toes each 83.9 degrees with a range of 70 to 90 degrees. The lateral angle three phalanges), and 2 sesamoid bones at the first metatar- of orientation (lateral facet) formed a lateral angle averaging 89.2 sophalangeal joint. The skeletal framework of the foot is divided degrees with a range of 80 to 95 degrees. From this data, Inman into the tarsus (seven irregular bones), which is often subdivided determined that the talus is not a cylinder but rather a section of into midfoot (navicular, cuboid, and the three cuneiforms) and a frustum of a cone, the apex of which is directed medially. hindfoot (calcaneus and talus). A total of 13 tendons crosses the ankle joint (extrinsic muscles) and inserts at a bone of the foot. Unique for the talus is its being covered by cartilage on two Many more intrinsic muscles originate and insert within the foot thirds of its surface and its having no muscular attachments. The itself. Over 100 ligaments are described in the foot and ankle, inferior surface of the talus rests on the sustentaculum tali of the where they act as static stabilizers of the complex interplay of calcaneus, whereas anteriorly the bone articulates with the navic- all the foot and ankle joints. ular. The talus articulates with the tibia and fibula in the ankle mortise (talocrural joint) and with the calcaneus (subtalar joint) and navicular (talonavicular joint) distally. The blood supply of the talus is performed by the posterior tibial artery (branch to the tarsal canal, branches to the deep fibers of the deltoid ligament), the anterior tibial artery/dorsalis pedis artery (branches to the neck, branch to the sinus tarsi), and the posterior peroneal artery. Calcaneus Phalanges The largest bone of the foot, the calcaneus (heel bone) projects posterior to the ankle joint to provide leverage for the triceps Cuneiform I II III Metatarsals I–V surae muscle group and origin for the plantar fascia. The lower Medial IV Cuboid surface of the posterior end of the bone (tuber calcanei) has V rounded medial and lateral processes that provide contact surfaces Intermediate during locomotion. Anteriorly the calcaneus articulates with Lateral the cuboid, and superiorly and medially the sustentaculum tali supports the talus at the subtalar (talocalcaneal) joint. Navicular Navicular Talus Calcaneus The navicular lies anterior to the talus on the medial side of the foot. It articulates proximally to the talus with an oval-concave articular surface, distally with the three cuneiform bones, and laterally with the cuboid. The navicular tuberosity serves plantar-medially as insertion structure for the posterior tibial tendon. Figure 8b.1 Bones of the foot. The foot consists of 7 tarsal bones Cuneiform bones (medial, intermediate, (talus, calcaneus, navicular, cuboid, medial, intermediate, and lateral and lateral) cuneiforms), 5 metatarsal bones, 14 phalanges (two phalanges of the great toe, the other toes each three phalanges), and 2 sesamoid Lying in a series across the anterior surface of the navicular, bones beneath the first metatarsophalangeal joint. the cuneiform bones articulate with the cuboid and the first three
342 Chapter 8b ● Anatomy and biomechanics of the ankle and foot metatarsal bones. The medial cuneiform serves on its dorsal Subtalar joint aspect as insertion structure for the tibial anterior tendon. The subtalar or talocalcaneal joint consists of the bony articula- Cuboid tion of the talus and calcaneus building the posterior, medial, and anterior joint facets. The posterior facet is larger than the The cuboid articulates posterior with the calcaneus, anteriorly anterior and middle facets, is convex in shape, and articulates with two lateral metatarsal bones, and medially with the lateral with the talar body. Situated on the sustentaculum tali, the cuneiform. On the medial side the cuboid shows a groove for middle facet is slightly concave. The anterior facet is concave the peroneus longus tendon. and normally located just lateral to the middle facet. The middle and anterior facets articulate with the talar head. Between the Metatarsals posterior facet and the anterior and middle facets lies the tarsal canal, which opens broadly laterally and forms the sinus tarsi. The metatarsals are long bones that each have a base, body, and head giving rise to five rays that culminate in a toe. The five The subtalar joint is stabilized by four ligaments, both intrinsic metatarsal are numbered from medial to lateral I-V. The first and extrinsic.71 The intrinsic ligaments are the interosseus talo- metatarsal has a distal plantar cristae that articulates with the calcaneal ligament, which fills the tarsal canal, and the cervical two sesamoids: the fibular/lateral and the tibial/medial sesamoid. ligament (bifurcated ligament), which fills the sinus tarsi. Both the interosseus talocalcaneal ligament and cervical ligament can Phalanges be injured in lateral ankle sprains or aggravated by conditions such as inflammatory arthritis, leading to subtalar instability.42 The toes consist of short phalangeal bones: proximal, middle, The extrinsic ligaments of the subtalar joint are the calcaneo- and distal in the four lateral toes and proximal and distal in the fibular ligament, the lateral talocalcaneal ligament (beneath hallux. the calcaneofibular ligament), the tibiocalcaneal ligament (super- ficial deltoid), the medial talocalcaneal ligament (medial talus ARTHROLOGY tubercle-sustentaculum tali), and the posterior talocalcaneal ligament (lateral talus tubercle-posterior calcaneus). Ankle joint Transversal tarsal and tarsometatarsal joints The ankle or talocrural joint consists of the bony articulation of the distal tibia (tibial plafond), the medial malleolus and lateral Chopart’s joint is the transversal tarsal joint built proximally by malleolus (fibula), and the dome of the talus. The ankle joint the talus and calcaneus and distally by the navicular and cuboid. is stabilized by several ligaments: the deltoid ligament (medial Important ligaments within and around this joint are the plantar collateral ligament; complex arrangement of several ligaments calcaneonavicular ligament (spring ligament; coxa pedis), the in a deep and superficial layer6), the lateral collateral ligament calcaneonaviculocuboid ligament (bifurcated ligament), the dor- complex (anterior talofibular ligament, calcaneofibular ligament, sal talonavicular ligament, and the dorsal and plantar calca- and posterior talofibular ligament), the anterior and posterior neocuboid ligaments. inferior tibiofibular ligament, the transverse tibiofibular ligament, and the interosseus ligament. Lisfranc’s joint is the tarsometatarsal joint between proxi- mally the cuneiforms and cuboid and distally the basis of the Close11 found the deltoid ligament to be a strong restraint five metatarsals.59 The tarsometatarsal joints are stabilized by limiting talar abduction. With all lateral structures removed, dorsal, plantar, and interosseus ligaments. The Lisfranc ligament the intact deltoid ligament allowed only 2 mm of separation is a strong plantar ligament that connects the medial cuneiform between the talus and medial malleolus. When the deep deltoid to the base of the second and longest metatarsal bone. In about ligament was released, the talus could be separated from the 20% of patients, two separate bands of the Lisfranc ligament medial malleolus by a distance of 3.7 mm. The tibiocalcaneal (dorsal and plantar) are present. Between the bases of the first ligament (the strongest superficial ligament) specifically limits and second metatarsals there are no ligaments, creating a relative talar abduction, whereas the deep portions resist more external weakness between the first and the other metatarsals. rotation as well.16,61,62 Another important midfoot and arch stabilizer is the plantar In dorsiflexion, the posterior talofibular ligament is maximally aponeurosis (also called plantar fascia). A strong fibrous stressed and the calcaneofibular ligament is taut, whereas the tissue, the plantar aponeurosis has three components: central, anterior talofibular ligament is loose. In plantar flexion, however, medial, and lateral. The plantar aponeurosis arises from the os the anterior talofibular ligament is taut, and the calcaneofibular calcis and inserts into the metatarsals and the plantar aspects of and posterior talofibular ligaments become loose.13,63,70 Some the toes, making possible the windlass mechanism described by variation of this tension pattern is allowed by the different Hicks.23 patterns of divergence between the anterior talofibular and calca- neofibular ligaments. Metatarsophalangeal joints The metatarsophalangeal joint of the hallux is different from those of the other toes by the sesamoid mechanism. Here the
Chapter 8b ● Biomechanics of the foot and ankle 343 sesamoids articulate on their dorsal surfaces with the medial Measurement of foot and ankle movement and lateral facets on the plantar aspect of the first metatarsal head. An intersesamoidal ridge (crista) separates these facets. The ankle joint complex allows for relative movement between The two sesamoids, lateral and medial, are incorporated into the foot and the leg. The following paragraphs concern possibil- the two tendons of the flexor hallucis brevis. The first ities to assess this movement, specifically addressing the clinical metatarsophalangeal joint is further stabilized on the plantar and functional assessment and the three-dimensional assessment. medial and lateral side by the fan-shaped collateral ligaments and sesamoidal ligaments. The hood ligaments of the extensor Clinical and functional assessment expansion and the capsule form the stabilizing structures dorsally. Rotational movement between two segments occurs around a momentary axis of rotation determined primarily by the shape, FOOT ARCHES the ligamentous structures, and the muscle-tendon units of the joint. Rotations describing the functional movement of two Morphologically, the foot may be described as having three adjacent segments are those occurring around functional axes. arches. Longitudinally, the arch of the foot is higher on the medial The ankle joint complex is a peculiar joint in the sense that than on its lateral side. The former involves the calcaneus, talus, during locomotion one can estimate the location of two of the navicular, cuneiforms, and three medial digits; the latter, although three bones that make up the joint, the tibia, and the calcaneus. also arising from the calcaneus, proceeds through the cuboid It is practically impossible, however, to estimate the location and two lateral digits. In the midfoot region, the arch in the of the talus during locomotion. Additionally, it is extremely dif- transverse plane is observed passing through the talus and navic- ficult to determine the ankle joint axes87 around which the actual ular on the medial side to the calcaneus and cuboid on the lat- rotational movements occur. Consequently, it is difficult to eral side. This arch gradually flattens anteriorly so that the heads describe the movement of the ankle joint complex by using of the metatarsal bones are all in the same plane. The arches are functional axes. Movement of the foot, however, can be deter- dynamically maintained by the following: mined much more easily in a clinical environment by defining ● The keystone effect of the talus, cuboid, and middle cuneiform foot axes such as the anteroposterior, the mediolateral, and the inferosuperior axes. within the medial, lateral, and transverse arches, respectively. The articular surfaces of these bones form a wedge that drops Movement of the foot can be defined with respect to the into place between adjacent bones. direction of locomotion,58 the position of the foot with respect ● The bowstring effect of the plantar ligaments. The plantar to a laboratory coordinate system, or the position of the foot calcaneonavicular (spring) ligament maintains the medial with respect to the leg. Specific descriptions of foot movement arch, whereas the short and long plantar ligaments maintain may be advantageous for specific questions. Foot movement with the lateral arch. respect to the direction of movement of the center of mass may ● The intrinsic and extrinsic muscles of the foot, which assist in be appropriate for energy considerations. Foot movement rela- maintaining the arches. tive to the leg may be appropriate for local loading aspects.83-85 In any case, it is crucial to define the system of reference clearly, Morphologically, it is convenient to describe the foot in because the results depend on it. terms of three discrete arches; however, when forces distributed throughout the foot are considered, there is a complex interplay Three-dimensional assessment of stresses that acts among all the components of a single dynamic structure. Clinically-morphologically and based on The rapid development of technology has provided gait analysis plantar pressure assessment, the human arch can generally be systems offering the possibility for three-dimensional movement described as normal, high (pes cavus), or flat (pes planus) analysis.58 This development is not without concerns, two of (Fig. 8b.2). which, the use of two-dimensional analysis and the sequence of angle determination, are discussed shortly. BIOMECHANICS OF THE FOOT AND ANKLE For many questions, a two-dimensional approach is appro- The foot is a specialized organ with the following contrasting priate, and errors resulting from these restrictions are minimal. It characteristics (Fig. 8b.3): is therefore appropriate to first check whether three-dimensional ● Support of body mass; analysis is really necessary and what errors occur by changing to ● Static and dynamic balance; two-dimensional analysis. ● Facilitation of locomotion. A three-dimensional rotational movement subdivided into These characteristics are achieved by large muscles located its three rotational components provides different results in the shank, smaller intrinsic muscles of the foot, bony levers, depending on the sequence of the rotations chosen.1 One can and various degrees of joint mobility within the foot and ankle. easily verify this by moving the arm from an “initial position” Adequate muscular development and joint function are essential where the arms are alongside the body with the palms facing for normal gait and foot mechanics. its sides to a “final position” where the arm points horizontally at a 45-degree angle from the sagittal plane and the palms face the sides. The angular components used are extension, abduc- tion, and axial rotation. One may reach the final position by first moving the arm upward and second by abducting it 45 degrees. This would correspond to an FL-abduction-axial rotation sequence with the values 90-45-0 degrees. One may reach the
344 Chapter 8b ● Anatomy and biomechanics of the ankle and foot AB CD Figure 8b.2 The dynamic pedobarography (A) allows an objective and accurate assessment of the plantar pressure distribution (system used here: Emed, Novel, Munich, Germany). Variables such as contact area, peak forces, and center of pressure (COP) can be evaluated graphically and numerically. (B) The feet of a subject with normal arch; (C) the feet of a subject with a high arch (cavus foot); (D) the feet of a subject with a flatfoot deformity. same final position, however, first by axially rotating the arm includes 45 degrees of abduction and no axial rotation, whereas 45 degrees and second by extending the arm 90 degrees. This the second movement sequence includes no abduction but corresponds to an axial rotation-FL-abduction sequence with 45 degrees of axial rotation. It is therefore important to under- the values 45-90-0 degrees. Both movement sequences include stand for which movement analyses the sequence of the angular 90 degrees of extension. The first movement sequence, however, components is crucial.
Chapter 8b ● Ankle joint complex motion 345 Many authors have argued about the appropriateness of some Van den Bogert et al87 showed a subject-specific three- of the sequences.1,17 However, logical arguments described earlier54 dimensional model of the ankle joint complex for calculation that have used anatomic definitions of flexion-extension, abduc- of the ankle and subtalar joint axis. The talocrural and subtalar tion-adduction, and axial rotation indicate that the appropriate joints were modeled as a three-segment system connected by two sequence in agreement with the definition of these movements ideal hinge joints. A mathematical formulation was developed to for all human joints is as follows: express the three-dimensional translation and rotation between the foot and shank segments. Their results showed that the In general For the ankle joint complex lateral side of the talocrural axis was directed slightly posterior Flexion-extension Plantar flexion-dorsiflexion (6.8 ± 8.1 degrees) and inclined down by 7.0 ± 5.4 degrees. Abduction-adduction Abduction-adduction Further, they showed that the inclination of the subtalar joint Axial rotation Inversion-eversion axis from the horizontal plane was 37.4 ± 2.7 degrees and the medial deviation was 18.0 ± 16.2 degrees. ANKLE JOINT COMPLEX MOTION Leardini et al31 developed a mathematical model to explain Anatomic and biomechanical studies indicate that the ankle the multiaxial motion of the ankle in the sagittal plane. These moves not as a pure hinge mechanism2,22,26,39 but rather in the authors described a four-bar linkage model showing the sagittal, coronal, and transverse planes.39,41 talus/calcaneus and tibia/fibula rotating about one another on inextensible line segments that represent the calcaneofibular Rotational axis and movement and tibiocalcaneal ligaments without resistance. Motion between transfer of the ankle joint the polycentric polyradial trochlea consisted of a combination of “rolling” and “sliding” motions. In this model, rotation is An early anatomic study pointed out that the wedge of the dictated by the most anterior fibers of the anterior talofibular and talus and the differing medial and lateral talar dome radii of calcaneofibular ligaments. Leardini30 later observed that these curvature implied that tibiotalar congruency could not be specific fiber bundles were isometric through the range of sagittal maintained through sagittal motion unless the talus exhibited motion of the ankle. The instant center of rotation translates from coupled axial rotation.2 The joint axis tends to incline down a posteroinferior to a superoanterior position, a finding consistent laterally when projected onto a frontal plane and posterolaterally with several studies suggesting that the ankle is incongruent and when projected onto a horizontal plane.3,29,39 Because of this rotates about a transient center.68,69,73 The complex and dynamic oblique orientation, dorsiflexion of the ankle results in eversion nature of the ankle’s axis of rotation may be one reason for poor of the foot, whereas plantar flexion results in inversion. When results in total ankle replacement surgery and has important the foot is fixed on the ground, dorsiflexion causes internal rota- implications for the design of total ankle prostheses. tion of the leg, and plantar flexion causes external rotation.2,7,24,38, 67,73,84,93 This has been substantiated in kinematic tests of loaded Ankle range of motion cadaver ankle specimens.47,84 Overall values found in the literature for normal range of motion Having studied sagittal plane motion relative to the tibiotalar in the ankle range from 23 to 56 degrees of plantar flexion joint surface, Sammarco67 explained that the motion between and from 13 to 33 degrees of dorsiflexion22,34,35,38,50,64,66,78,84,92,93 the tibia and talus takes place about multiple instant centers of (Fig. 8b.3C and 8b.3D). Ten to 15 degrees of plantar flexion rotation. Ankles taken from plantar flexion to dorsiflexion showed and 10 degrees of dorsiflexion are used during walking.66 About a tendency toward distraction early in motion, followed by a 14 degrees in range of motion are used in the stance phase of sliding movement through the midportion that ends in compres- gait, whereas 37 degrees are needed for ascending and 56 degrees sion at the end of dorsiflexion. This process was reversed when for descending stairs.78 In the diseased ankle, dorsiflexion is the joint was moved in the opposite direction. Locations and typically decreased and limits daily activities, especially in the patterns of instant centers varied among different individuals, presence of pain. Ten to 15 degrees of dorsiflexion are all that direction of motion, weight-bearing states, and pathologic states. are needed for daily activities in patients who do not rely on An unstable ankle demonstrated normal gliding during weight their ability to ascend and descend stairs.39 The goal in total bearing, but non-weight-bearing motion was grossly abnormal. ankle replacement should therefore be to provide a minimum of 10 degrees of dorsiflexion and 20 degrees of plantar flexion for Using stereophotogrammetry, Lundberg et al39 performed a an appropriate push-off. three-dimensional evaluation of the joint axis in eight healthy ankles. They explained that talar rotation occurs about a dynamic Several factors influence sagittal plane motion of the axis during sagittal plane movement of the ankle, which in each ankle. Healthy older individuals demonstrate decreased plantar subject lay close to the midpoint of a line between the tips of the flexion.36,50,66 Sagittal motion (primarily dorsiflexion) has been malleoli. Plantar flexion axes were more horizontal and inclined found to increase significantly by assessing subjects while bearing down and medially compared with those of dorsiflexion. Most weight as compared with passive measuring.35,64 interestingly, no frontal plane movement occurred between the talus and the tibia during inversion/eversion of the loaded foot Rotation of the ankle in the transverse plane is usually within a physiologic range of motion. reported relative to instability,43,79 but transverse plane motion is coupled with that in the sagittal plane.11,37,39,46,66 Transverse plane motion is noted also during normal gait.11,37,38,73 Lundberg et al39
346 Chapter 8b ● Anatomy and biomechanics of the ankle and foot AB CD Figure 8b.3 The function of the foot and ankle. The foot and ankle function mainly as a locomotion organ, allowing the plantigrade ambulation and providing support of body mass and static and dynamic balance. Anterior view of the weight-bearing static position of both feet (A), lateral view (B); plantar flexion of the ankle joint complex during heel rise test (C), dorsiflexion of the ankle joint complex during heel standing test (D). observed 8.9 degrees of external rotation of the talus as the ankle plantar flexion. In unloaded specimens, some coupling between moved from neutral position to 30 degrees of dorsiflexion, the ankle and subtalar joints was observed also with sagittal plane whereas a small amount of internal rotation occurred with motion.73 With dorsiflexion, there was internal rotation at the plantar flexion from neutral to 10 degrees followed by external subtalar joint and external rotation at the ankle joint. The idea rotation at terminal plantar flexion.38 Michelson and Helgemo46 that this coupling is caused by tensioning of the deltoid ligament reported that dorsiflexion resulted in an average of 7.2 ± 3.8 degrees is supported by the findings of McCullough and Burge,43 of external rotation of the foot relative to the leg with ankle who described greater external rotation of the talus after deltoid dorsiflexion and 1.9 ± 4.12 degrees of internal rotation with ligament sectioning.
Chapter 8b ● Internal forces and contact area 347 Described as varus or valgus rotation, coronal motion may loaded conditions is provided by the articular surfaces. This also be described as inversion or eversion. Michelson et al45 has important implications in the design of total ankle prosthe- observed that plantar flexion of the ankle was associated with ses and may explain poor results with prosthetic designs that internal rotation and inversion. They attributed coronal plane expose the ankle ligaments to eversion and inversion forces motion to the position of the deltoid ligament, showing that after while the ankle is loaded.84 During most activities, the soft progressive medial ankle destabilization, talar external rotation tissues are the major torsional and anteroposterior stabilizers and inversion increased. of the ankle,8,9 whereas its articulating surface geometry is the major inversion/eversion stabilizer, with collateral ligaments Restraints of ankle motion playing a secondary role.43,79 The stability and integrity of the ankle joint depends on articular INTERNAL FORCES AND CONTACT AREA geometry and ligamentous attachments. Ankle ligaments have a passive tracking and stability effect on the joint. On the medial External forces acting on the human foot, geometric alignment side, the strong deep deltoid ligament is a secondary restraint of the foot and the leg, muscle forces, and segmental inertia against lateral and anterior talar excursion,6,19,63 whereas on the forces are responsible for the internal forces acting in joints lateral side, the relatively weak anterior talofibular ligament is and on ligaments and tendons. Mathematical models are used the only restraint against anterior talar excursion.32,48,63 The ante- to estimate the magnitude of forces in internal structures such as rior talofibular ligament is that which is most susceptible to joints, tendons, and ligaments. These estimations use several injury and subsequent insufficiency,4 often leading to antero- (sometimes different) assumptions that are still being discussed lateral dislocation of the talus out of the mortise and posterior in the literature.21 However, the order of magnitude of the dislocation of the fibula, respectively. In such a case, reconstruc- estimated forces is assumed to be correct. tion of the anterior talofibular ligament (or “ligament balancing”) may be advised when unconstrained prostheses are used for total Typically, the geometry of the acting forces (the distance ankle replacement. from the line of action of an acting force to a joint of interest) is the most important factor that determines the internal forces. Several studies27,74 reported the effects of the lateral liga- Technically, the internal forces in the anatomical structures of ments on axial rotation of the loaded ankle. Hintermann et al27 the human foot can be either measured directly in vitro or cal- observed that the rotation of the tibia occurring after sectioning culated from in vivo pressure distribution of the foot sole; of the anterior talofibular ligament was more profound from in most cases the pedobarography technique using pressure neutral to plantar flexion than that observed in 10 to 20 degrees distribution sensors is applied (Fig. 8b.2)12,87 The results of of dorsiflexion. When the deltoid ligament was sectioned, no pressure distribution measurements have been used as localized tibial rotation was observed. This finding is consistent with those input into the different foot structures to provide a possible of Michelson et al,44 whose report suggested a motion-coupling means of quantifying internal forces in joints, ligaments, and role for the deltoid ligament in addition to stabilization. tendons of the foot, an estimation that cannot be performed using the ground reaction force as input. During walking, rotation occurs about a vertical axis.11,33 Rotatory stability is provided by tension in the collateral liga- In the ankle joint, a vertical load of 5.2 times body weight ments, by compression of the medial and lateral talar facets has been found during gait.78 In diseased ankles, the joint load against their corresponding malleoli, and by the shape of the decreased to approximately three times body weight, and the same articular surfaces.19,43,74,79 Because of the truncated conical shape values have been noted in replaced ankles.78 Anteroposterior of the talus with its medially directed apex, the three separated and lateral shear forces during gait have been estimated to reach lateral ligaments control the greater movement on the lateral levels of two and three times body weight, respectively. With an side, whereas the deltoid ligament controls the lesser movement interface area of 7 cm2, the average compressive load per unit on the medial side. This has important implications for ligament area at the interface during gait would be approximately 3.5 MPa balancing in total ankle replacement, because nonanatomic in a person of 700 N body weight. prosthetic design and/or inappropriate implantation may pro- voke medial ligament stress with consequent pain, posterome- The complex geometry of the mortise and trochlea of the dial ossification, and loss of range of motion82 or lateral ligament talus influences load characteristics.5,7,39,41,80 Reports of whole insufficiency with consequent lateral ankle instability, respectively. ankle contact area vary from 1.5 to 9.4 cm2 depending on load and ankle position.90 The tibiotalar area, however, accounts for Stability in the loaded ankle depends on articular shape.19,43,74,79 only approximately 7 cm.2,78 Controversies exist about changes Stormont et al79 performed serial sectioning of the ankle liga- in the contact area as a function of flexion position5,7,41 that ments and subjected the ankle to physiologic torque and loads. may be attributed to differences in load, position, and measure- The articular surface accounted for 30% of ankle stability in ment technique.32 Calhoun et al7 found that contact surface area rotation and 100% of ankle stability in inversion and eversion. increased from plantar flexion to dorsiflexion and that force In a similar study, McCullough and Burge43 found that with per unit area decreased proportionately. They observed also increased loading of the ankle, increased rotatory forces are that the medial and lateral facets had greatest contact with the necessary to cause displacement. The congruity of the articular malleoli in dorsiflexion. In another study, using a dynamic surface of the ankle joint thus creates an inherently stable artic- model, progressive lateral loading with concomitant medial ulation with loading, and no ligamentous restraints exist in unloading was observed during dorsiflexion and associated inversion and eversion. The sole restraint of the joint under external rotation.46
348 Chapter 8b ● Anatomy and biomechanics of the ankle and foot Ground reaction and gravitational, ligament, and muscle forces produce a mixture of three-dimensional compressive, shear, and torsional loads in the ankle joint. Therefore, one may easily assume that force may not necessarily be directly perpendicular to the bone-implant interface but more angular. This introduces shear forces in addition to those of direct compression. GROUND REACTION FORCES AND PRESSURE DISTRIBUTION Whenever the foot is in contact with the ground, forces act from Figure 8b.4 Picture of a normal shoe (Küzli AG, Schuhfabrik, the ground onto the foot and vice versa. These ground reaction forces are resultant forces that correspond to the movement of Windisch, Switzerland). the center of mass and gravity. Typically subdivided into impact and active forces, ground reaction forces are determined by for movement involving landing on the forefoot as is typical in movement of the various segments involved in the locomotion volleyball or basketball.75,77 It is believed, however, that excessive process. Among the axes of the xyz coordinate system, they can cushioning found in modern shoewear prevents appropriate be divided into the vertical, anteroposterior, and mediolateral sensory feedback and results in a “pseudo-neurotropic” effect in force. Different for various activities, ground reaction forces running.65 can easily exceed body weight several times.56 In normal walk- ing the vertical ground reactive force shows a typical two-peak The sensibility potential of the foot sole is the main reason active force pattern in a level around the body weight,58 the first that professional gymnasts and some dancers perform with no peak associated with deceleration and the second with accelera- shoes or minimally shod feet. Stacoff and Lüthi76 reported that tion. In running at a speed of 4 m/s, the vertical component of shoewear has been recorded as a source of injury since the early the ground reaction force typically shows a single peak that Greeks. Having been the norm in ancient times, barefoot running increases into about two to three times body weight.56,58 As inte- received international attention with Zola Budd’s 3000-m gral quantities, the ground reaction forces are limited in pro- Olympics participation in 1984 (www.runningbarefoot.org). viding information on local phenomena, especially those During barefoot running, the least amount of pronation and specific to the foot. Pressure distribution measurement over therefore injuries occur.75 Lysholm and Wiklander40 showed in the whole contact area of the foot sole provides more accurate 60 runners with 55 injuries within 1 year that shoe and surface information. problems were the primary sources of injury. Ground reaction forces and plantar pressure distribution can Considering that impact forces are the critical variable in the typically be measured either by the Kistler force plate technique pathophysiology of sports-related pain and injury,51 however, (piezoelectric elements, as in the case of the classic motion cushioning and shock absorption in sport shoes protect athletes analysis) or by computerized pedobarography systems (Fig. 8b.2). and military recruits from overload injuries.15,49,72 By influencing In the pedobarography (plates or insoles equipment, static or impact loads, shoe material properties affect exposure to injury, as dynamic measurement) many hundreds of small force plates in cases of intraarticular cartilage damage and osteoarthritis.60,88,89 or sensors measure the force of the plantar aspect of the foot perpendicular to the surface.56,57,82,86 Compared with the Kistler Excessive ankle joint eversion has been typically associated plate technique, pedobarography pressure distribution sensors with the development of overuse injuries in locomotion.10,18,91 are better suited to provide more local information. Pressure Subjects with injuries typically have foot eversion movement distribution sensors are used in the form of insoles to assess that is about 2 to 4 degrees greater than that of those with no foot-specific problems within the shoe, as in diabetic patients,20 injuries. Further, it has been suggested that a combination of or in the form of plates to assess postoperative outcome after excessive ankle joint eversion and substantial movement transfer orthopedic treatment, as in fracture reduction,81 total ankle of foot eversion into internal tibial rotation is a good predictor of replacement,28,82 tendon rupture repair,86 or fusion.14 the development of overuse injuries, especially in the knee.25,26 SHOE CONSIDERATIONS It has been proposed that movement transfer between foot eversion and tibial rotation is small for subjects with low arches The shoe’s main function is to protect the foot sole from the and high for those with high arches.53 Consequently, subjects hazards of the environment and furthermore to facilitate running, with high arches and excessive ankle joint eversion are more to stabilize and treat foot deformities, and to serve as symbol susceptible to overuse injuries. in the society and fashion world (Fig. 8b.4). Without shoes, the foot has a natural ability to allow for torsional motion between Ankle joint eversion is substantially influenced by shoes. the hind- and forefoot. Shoes often have torsional stiffness Differences in ankle joint eversion for a subject using different that decreases this physiologic movement. Studies have sug- running shoes are considerable. It is easily possible that the gested that low torsional stiffness is advantageous, especially
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Pawelka S, Kopf A, Zwick E, Bhm T, Kranzl A: Comparison of two insole materials changes after fusion and total replacement of the ankle: part 2: movement transfer. using subjective parameters and pedobarography (pedar-system). Clin Biomech Foot Ankle Int 24:888-896, 2003. 12:S6-S7, 1997. 85. Valderrabano V, Hintermann B, Nigg BM, Stefanyshyn D, Stergiou P: Kinematic changes after fusion and total replacement of the ankle: part 3: talar movement. 58. Perry J: Gait analysis—normal and pathological function. Thorofare, NJ, 1992, Foot Ankle Int 24:897-900, 2003. SLACK Incorporated. 86. Valderrabano V, Hintermann B, Wischer T, Fuhr P, Dick W: Recovery of the posterior tibial muscle after late reconstruction following tendon rupture. Foot Ankle Int 25:85-95, 2004. 59. Potter HG, Deland JT, Gusmer PB, Carson E, Warren RF: Magnetic resonance imaging 87. van den Bogert AJ, Smith GD, Nigg BM: In vivo determination of the anatomical axes of the Lisfranc ligament of the foot. Foot Ankle Int 19:438-446, 1998. of the ankle joint complex: an optimization approach. J Biomech 27:1477-1488, 1994. 88. Voloshin AS: Shock absorption during running and walking. J Am Podiatr Med Assoc 60. Radin EL, Orr RB, Kelman JL, Paul IL, Rose RM: Effect of prolonged walking on 78:295-299, 1988. concrete on the knees of sheep. J Biomech 15:487-492, 1982. 89. Voloshin AS, Wosk J, Brull M: Force wave transmission through the human locomotor system. J Biomech Eng 103:48-50, 1981. 61. Rasmussen O, Kroman-Andersen C, Boe S: Deltoid ligament: functional analysis of 90. Ward KA, Soames RW: Contact patterns at the tarsal joints. Clin Biomech the medial collateral ligamentous apparatus of the ankle joint. Acta Orthop Scand 12:496-501, 1997. 54:36-44, 1983. 91. Warren BL: Plantar fasciitis in runners: treatment and prevention. Sports Med 110:338-345, 1990. 62. Rasmussen O, Tovberg-Jensen I: Mobility of the ankle joint: recording of rotatory 92. Weseley MS, Koval R, Kleiger B: Roentgen measurement of ankle flexion-extension movements in the talocrural joint in vitro with and without the lateral collateral motion. Clin Orthop 65:167-174, 1969. ligaments of the ankle. Acta Orthop Scand 53:155-160, 1982. 93. Wright DG, Desai SM, Henderson WH: Action of the subtalar and ankle-joint complex during the stance phase of walking. J Bone Joint Surg 46A:361-382, 1964. 63. Renstrom P, Wertz M, Incavo S, et al: Strain in the lateral ligaments of the ankle. Foot Ankle 9:59-63, 1988. 64. Roaas A, Andersson GB: Normal range of motion of the hip, knee and ankle joints in male subjects, 30-40 years of age. Acta Orthop Scand 53:205-208, 1982. 65. Robbins S, Waked E: Humans amplify impact to compensate instability caused by shoe sole materials. Arch Phys Med Rehabil 78:463-467, 1997. 66. Sammarco GJ, Burstein AH, Frankel VH: Biomechanics of the ankle: a kinematic study. Orthop Clin North Am 4:75-96, 1973. 67. 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8cC H A P T E R related to trade, transportation, and utilities demonstrate the highest number of foot and toe injuries, comprising 35% of Foot and Ankle Disorders all foot and toe injuries recorded. Construction constitutes the in the Workplace second most represented occupational category, recording nearly 16% of foot or toe injuries. Sprains and strains were the most Ross Taylor and G. James Sammarco common type of injury of the ankle, constituting almost 70% of all ankle injuries. On the other hand, fractures are the most Workplace injuries of the foot and ankle represent a unique common nature of injury recorded in the foot or toes, compris- set of challenges within occupational medicine. The average ing 26% of such injuries. The most typical event leading to injury adult takes approximately 7500 steps per foot in the course of was falling to a lower level for ankle injuries (20%) versus contact an average day. The foot may be subject to forces in excess of with objects for foot injuries (86%). A contributing source of twice body weight during routine activities. The workplace is injury is noted to be floors, walkways, or ground surfaces most even more demanding with requirements for ambulation on commonly for both foot (20%) and ankle (40%) injuries but uneven surfaces, balancing on scaffolds, ladder climbing, and was more commonly found to be parts and materials (23%) for carrying heavy loads commonplace. Although the foot and toe injuries. The median number of days of work missed per ankle are supremely adapted to perform these functions, injuries injury of the foot was seven days and for toe injuries, six days. may make these routine occupational activities impossible. Furthermore, underlying systemic conditions such as vascular APPROACH TO THE PATIENT WITH disease, diabetes, obesity, and tobacco abuse frequently compli- WORK-RELATED FOOT AND ANKLE INJURY cate the lower extremity injury or disease process and compound diagnostic and treatment dilemmas. The first and perhaps most important step in returning the injured worker to their preinjury status when possible is prompt Successful treatment begins with timely and accurate diag- and accurate diagnosis. This is all too evident in cases in which nosis. This requires not only skilled history taking but also a the initial diagnosis is incomplete or inaccurate, leading to the solid fund of anatomic knowledge. An understanding of the initiation of incorrect or inadequate treatment. Subsequently, multitude of pathologic entities that affect the foot and ankle is physical therapy may be initiated when immobilization is more a prerequisite. The occupational medicine practitioner must rely appropriate or vice versa. The result of failure at the diagnosis on this understanding to not only arrive at a working diagnosis level is not only a disgruntled worker but also increased expenses but to determine the contribution of nonoccupational factors in related to multiple referrals and time away from work. Accurate the worker’s disease process. Once diagnosis has been established, diagnosis begins with a thoughtful history. expeditious treatment is of paramount importance. Whenever possible, the worker should be returned to modified duty during Often, the history is straightforward and that of traumatic the rehabilitation process to minimize the psychosocial impact injury. For instance, a fall from a height with sudden onset of of occupational impairment. heel or leg pain may suggest a calcaneus or distal tibia fracture. Ankle sprain or fracture often occurs when the ankle is forcibly It is hoped that the reader may take away from this chapter rolled in inversion. Twisting of the ankle in external rotation an understanding of the broad spectrum of injuries to the foot suggests high ankle sprain or ankle fracture. Midfoot fracture- and ankle incurred in the workplace setting. All too often a dislocation may occur with a crushing mechanism to the foot, swollen and painful foot with negative radiographs is dismissed such as when heavy machinery rolls onto the foot or a large object as a “sprain.” Only when the patient fails to improve in a reason- is dropped directly onto the foot. Metatarsal or toe fractures can able period of time are additional possibilities considered. This result when such a force is applied across the unprotected forefoot. leads to an untold waste of human resources and is often avoid- Hyperdorsiflexion of the toes may result in injury to the plantar able were the treating practitioners more thorough in their plate or cartilage of the hallux metatarsophalangeal (MTP) joint. approach to injuries of the foot and ankle. This chapter is intended to serve as a foundation of knowledge regarding workplace Certainly, traumatic injury simplifies history taking. When injuries to the foot and ankle upon which successful diagnosis, the worker gives a history of onset of pain during routine activi- treatment, and return to work can be efficiently executed. ties, the differential diagnosis expands dramatically and the line between work-related injury and a degenerative or inflammatory EPIDEMIOLOGY disorder is less than distinct. More controversial is the role of repetitive overuse in the work-related injury. Diseases such as The Bureau of Labor Statistics data indicate a total of 1.3 million plantar fasciitis, hallux valgus, tarsal tunnel syndrome, interdigi- injuries and illnesses required recuperation away from work tal neuroma, lesser toe deformities, adult acquired flatfoot, beyond the day of injury in private industry in 2003.25 Conditions and osteoarthritis may present in the workplace. Guyton et al9 of the foot or ankle constituted approximately 125,000 of these applied Koch’s postulates to examine the possible relationship injuries or approximately 9.5%. Those involved in occupations between cumulative industrial trauma and causation of these seven disorders but found no association. Nonetheless, these are important disease entities that may be perceived as initiated by work-related activities. In the interest of confining the scope of this chapter to injuries of less controversial etiology, these processes are excluded from this chapter.
352 Chapter 8c ● Foot and ankle disorders in the workplace Examination of the foot and ankle begins with observation external fixation and delayed open reduction and internal of the patient in the standing position whenever possible. fixation (ORIF). Complications after treatment are common and Overall alignment of the foot and ankle should be noted as well include full thickness skin loss, infection, and posttraumatic as any asymmetry between sides. Swelling, edema, and ecchy- arthritis. McFerran et al13 reported a major complication rate of mosis should be noted at this time, as well as any lacerations 42% after operative treatment of severe tibial pilon fractures. or obvious abrasions. The position of the foot or ankle may Long-term impairment is common and is usually due to pain provide insight into the potential for injury to various structures. and stiffness secondary to posttraumatic arthritis. For instance, accentuation of the longitudinal arch of the foot (cavus foot) predisposes the worker to injuries over the lateral Ankle fractures Ankle fractures are typically the result of side of the foot and ankle such as ankle sprain, peroneal tendon sudden twisting, inversion, or eversion of the ankle. Immediate tear, or fracture of the base of the fifth metatarsal. A flattened onset of pain and swelling usually ensues. Depending on the sever- arch may suggest medial ankle sprain or injury to the posterior ity of the injury, weight bearing may be impossible. Examination tibial tendon. Inspection of gait is fundamental as well, primarily reveals swelling, tenderness, and ecchymosis about the ankle. to note the presence or absence of shortening of stance (antalgia) These injuries vary considerably with respect to severity, treat- on the affected side. Careful range-of-motion assessment of the ment, convalescence, and potential for long-term impairment. ankle, hindfoot, midfoot, and forefoot joints should be performed with special attention to any limitations of motion that may call Isolated fractures of the distal fibula are the most common attention to injury of each respective joint or associated muscle ankle fractures. Unless open or widely displaced, these relatively group. Localization of pathology is facilitated through palpation low-energy injuries are amenable to closed treatment. Closed of the easily appreciated bony and tendonous structures of the treatment requires four to six weeks of non–weight bearing in foot and ankle. Thorough neurovascular examination is essential. a short leg cast followed by an additional four to six weeks of weight bearing in a removable cast. Once weight bearing is begun, The practitioner must resist the temptation to rely solely physical therapy is initiated, focusing on strengthening, range of on history and physical examination even when the diagnosis motion, and edema reduction. Work-specific therapy may begin seems obvious. Quality weight-bearing radiographs in the in a soft or lace-up ankle brace once resisted ankle eversion anteroposterior (AP), lateral, and mortise planes are standard for strength cannot be overcome by the examiners hand (Fig. 8c.1). evaluation of the ankle. Radiographic examination of the foot should consist of AP, lateral, and oblique projections. When thorough history, examination, and standard radiographs fail to yield a diagnosis, specialized radiographic views may be helpful. Stress views, magnetic resonance imaging (MRI), computed tomography (CT), and radionuclide studies are all powerful tools when applied in the appropriate setting. OVERVIEW OF WORKPLACE INJURIES Ankle Five percent of all work-related injuries requiring time away from work in 2003 involved in the ankle.25 This section presents an overview of workplace ankle injuries divided into two major subsections, the first devoted to fractures and the second to sprains. Of course, injuries to the ankle are seldom this black and white. Included in the section on ankle fractures is a section on tibial pilon fractures. Although not ankle fractures per se, tibial pilon fractures involve and profoundly affect the ankle and are therefore included. The section on ankle sprain includes a dis- cussion of fractures and other pathology that may present simi- lar to ankle sprains, so that the reader may keep these injuries in mind when evaluating a seemingly straightforward ankle sprain. Fractures about the ankle Figure 8c.1 Examination of ankle evertor strength. The patient is asked to evert the ankle against resistance. Tibial pilon fractures Fractures involving the distal weight- bearing articular portion of the tibia are termed tibial pilon fractures. These fractures represent high-energy injuries and occur most commonly after a fall or motor vehicle crash. Not only are these fractures frequently comminuted, but they represent severe soft tissue injury to the ankle as well. These injuries are seldom amenable to closed treatment and often require immediate
Chapter 8c ● Overview of workplace injuries 353 At this point, part-time light duty work may begin. Return to unable to return to physically demanding occupations especially unrestricted duty may take three to four months after injury. after ankle fusion. Maximum medical improvement is typically reached within six months of injury. Ankle sprain Isolated fractures of the medial malleolus are less common. Acute inversion injury of the ankle may occur with minimal Unlike isolated fractures of the lateral malleolus, these injuries energy such as when handling heavy objects on an uneven sur- are typically displaced and relatively unstable. When combined face such as a ramp or when stepping on an unexpected object with a fracture of the proximal fibula, this injury represents a on the floor. Higher energy ankle sprains may occur when the highly unstable injury pattern with rupture of the syndesmotic worker unloads from a higher level such as a truck cab or bed membrane (Massoneuve fracture). Nonetheless, if nondisplaced onto an uneven or unstable surface. Regardless of the mecha- and stable, they may be treated closed using a similar protocol nism, disruption of one or more of the lateral ankle ligaments as outlined for isolated fractures of the lateral malleolus. More occurs, resulting in pain and often impressive swelling over the commonly, these injuries require ORIF. After ORIF, a six to anterolateral aspect of the ankle. Weight bearing is often but not twelve week period of short leg casting with non–weight-bearing always limited secondary to pain. restriction is instituted until healing has occurred as determined by lack of tenderness and bridging bone on radiographs. A six Grading of ankle sprain is clinical with an anatomic basis. week course of protected weight bearing is combined with The clinical hallmark of grade I ankle sprain is isolated tender- physical therapy focusing on strengthening, range of motion, ness over the anterolateral aspect of the ankle. Range of motion and edema reduction. Work-specific therapy may begin in a of the ankle and hindfoot is usually limited by pain and swelling. soft or lace-up ankle brace once resisted ankle eversion strength The patient is typically able to bear weight, although with dis- cannot be overcome by the examiners’ hand. At this point, part- comfort. This injury represents a partial tear of the anterior time light duty work may begin. Return to unrestricted duty may talofibular ligament. Grade II ankle sprain is suggested by pain take six months or more after injury. Maximum medical prohibitive of weight bearing after the acute inversion injury. improvement may not be achieved for nine to twelve months Tenderness is still localized to the anterolateral ankle. Complete after injury. disruption of the anterior talofibular ligament is likely to have occurred at this stage. Finally, disruption of both the ante- Often, medial and lateral malleolar fractures occur in combi- rior talofibular ligament and calcaneofibular ligament occurs in nation, creating an unstable bimalleolar ankle fracture. Fracture grade III sprain. Examination reveals tenderness both laterally of the posterior articular surface of the distal tibia in association and medially along the deltoid ligament and is often accom- with lateral, medial, or bimalleolar fracture is not uncommon panied by massive swelling. Radiographs of both the ankle and as well. Bimalleolar and trimalleolar ankle fractures are almost foot should be obtained to rule out fracture. always unstable and may even be open. Immediate closed reduction is performed under conscious sedation followed by Treatment is the same initially for all grades of sprain. emergent ORIF for open fractures or ORIF within the first few Immobilization, either in an ankle stirrup splint or a removable days of injury for closed fractures. Syndesmotic fixation may fracture boot, is combined with ice, compression, and elevation. be required if the distal fibula fracture occurs more than 3.5 cm This is conveniently summarized in the pneumonic RICE: rest, above the level of the ankle joint. The temptation to rely on ice, compression, and elevation. Although pain is often prohibi- internal fixation alone for fracture stability is dangerous. Short tive of weight bearing, ambulation may be encouraged in a leg casting and non–weight-bearing restriction for eight to twelve removable fracture boot with the aid of crutches. Physical ther- weeks is required while the fractures heal. Syndesmotic screws apy should be initiated as soon as possible. Initial modalities are removed before the institution of weight bearing at approx- should be aimed at edema reduction including elevation, inflat- imately eight weeks after surgery. Although the rehabilitation able foot pump, and active range of motion in a whirlpool. phase is similar to that after ORIF of isolated malleolar fractures, Within one week of injury, strengthening exercises of the per- prolonged pain and stiffness is common. Engelberg et al8 noted oneal muscles and proprioceptive training are initiated. Once the residual physical effects, including pain and stiffness, for up to patient demonstrates return of peroneal function such that ankle 20 months after injury. eversion strength cannot be overcome by the examiner’s hand, they are graduated to a lace-up ankle brace with Velcro inversion- Unfortunately, posttraumatic arthritis occurs in as many resistant straps such as an ASO brace (Medical Specialties, Inc., as 14% of ankle fractures, often beginning within two years of Charlotte, NC, USA). Discontinuation of immobilization and the injury.12 Persistent symptoms of pain, stiffness, and swelling physical therapy before this endpoint is reached predisposes the beyond the typical course should prompt suspicion that post- patient to risk of recurrent sprain and chronic ankle instability. traumatic arthritis is imminent. Examination usually demonstrates persistent ankle swelling, tenderness, and decreased range of Anticipated return to work depends on the grade of injury. motion. Weight-bearing radiographs may show joint space Generally, patients with all grades of ankle sprain may be returned narrowing, osteophyte formation, and subchondral collapse. to work at the sedentary level within one to two weeks of injury. Bracing in an ankle foot orthosis, oral antiinflammatory medica- Advancement to full duty should be withheld until peroneal tions, and a single intraarticular corticosteroid injection may be muscle strength, swelling, and range of motion are within 90% beneficial. Ultimately, surgical intervention may be required. of the opposite side. This may take as little as four weeks for Although ankle arthroscopy has a limited role, it may be helpful grade I sprains and as long as eight weeks for grade III sprains. in osteophyte excision. Ankle arthrodesis is often required. Workers who do progress to posttraumatic arthritis may be Persistently painful ankle sprain Unfortunately, as many as 20% to 40% of patients who sustain a grade III ankle sprain
354 Chapter 8c ● Foot and ankle disorders in the workplace Figure 8c.2 Lateral radiograph of the ankle showing abnormal anterior translation of talus with anteriorly applied stress. experience continued pain and stiffness beyond eight weeks postin- jury. Although this is most often due to inadequate rehabilitation, other etiologies must be considered, including ankle instability, tears or tendonitis of the peroneal tendons, impingement lesions, osteochondral lesions of the talus, and occult fractures. Ankle instability Instability of the ankle is not uncommon after Figure 8c.3 Anteroposterior radiograph of the ankle showing ankle sprain. Ankle instability may be functional or mechanical; abnormal varus angulation of the talus with medialward stress. in both types the patient may complain of sudden giving way of the ankle as it rolls into inversion on uneven or unstable A tear of one or more of the peroneal tendons should be surfaces. Mechanical instability, unlike functional instability, suspected if lateral ankle pain persists beyond the expected course may be readily demonstrated by examination by a positive ante- of improvement for ankle sprains. Typically, these patients rior drawer test and confirmed by positive stress radiographs demonstrate a varus heel and high arch. Tenderness is often greatest (Figs. 8c.2 and 8c.3). Regardless of the type of ankle instability, along the course of these tendons, particularly posterior to the the response is usually favorable to aggressive physical therapy tip of the distal fibula when the peroneus brevis is involved and in emphasizing peroneal muscle strengthening and proprioceptive the soft spot just proximal to the base of the fifth metatarsal training. If symptoms and findings persist, surgical reconstruc- about the plantar lateral midfoot when the peroneus longus is tion of the lateral ankle ligaments may be indicated. Return involved.18 MRI examination usually confirms the diagnosis. to full duty at the heavy demand capacity may require 12 to These patients often have residual instability of the ankle and 16 weeks, until which the worker may benefit from continued deserve an additional six week course of physical therapy devoted proprioceptive training and peroneal strengthening. to strengthening of the peroneus brevis and longus tendons. Surgical repair is indicated if conservative treatment fails. Tear of peroneus longus or brevis tendon The peroneus longus Simultaneous surgical treatment of ankle instability may be nec- and brevis tendons are important dynamic stabilizers of the essary if stress radiographs are positive. The return to work pro- ankle. Originating from the fibula and interosseous membrane, tocol is similar to that after lateral ankle ligament reconstruction. the peroneus longus and brevis muscles give rise to their respective tendons above the ankle joint. Sitting anterior to the longus at Subluxation or dislocation of the peroneal tendons may be the level of the ankle joint, the peroneus brevis is cup shaped in diagnosed acutely. The examiner has the patient dorsiflex the cross-section and cradles the peroneus longus tendon posteriorly ankle against resistance and a palpable pop may be elicited over as they are redirected anteriorly around the tip of the distal the peroneal tendons (Fig. 8c.4). Overt dislocation may be seen fibula. Both tendons are held firmly in a groove in the posterior as an abnormal prominence of these tendons coursing over rather fibula distally by the superior and inferior peroneal retinaculum. than behind the lateral malleolus (Fig. 8c.5). A six week course At this level the peroneal tendons are susceptible to either tear- of casting the ankle in the inverted position with a felt pad ing or subluxation out of the fibular groove with failure of the posterior to the lateral malleolus is often successful if the con- peroneal retinaculum. The exact incidence of peroneal tendon dition is discovered and treated early. Delayed presentation tears or subluxation with ankle sprain is speculative.20 Most tears are longitudinal and probably heal with treatment of the sprain.
Chapter 8c ● Overview of workplace injuries 355 Figure 8c.4 The examiner has the patient dorsiflex the ankle against Figure 8c.5 Overt dislocation may be seen as an abnormal resistance and a palpable pop may be elicited over the peroneal prominence of the peroneal tendons coursing over rather than behind tendons (arrow). the lateral malleolus (arrow). of this problem often requires surgical reconstruction of the ankle sprains.1 That said, not all osteochondral lesions of the peroneal retinaculum and deepening of the peroneal groove. talus are due to trauma. Canale and Kelly3 noted that only 67% of medial talar dome lesions are associated with injury. Impingement lesion Persistent anterolateral ankle pain in the Tenderness is usually nonspecific but may be greatest over the absence of specific findings on examination and MRI should dome of the talus when the ankle is hyperplantarflexed. These prompt suspicion of an anterolateral ankle impingement lesion. lesions may be staged by radiographic appearance using the Due to single or repeated ankle sprains, hypertrophy of the anterior Berndt and Harty classification (Table 8c.1).1 Stage I or II lesions tibiofibular or talofibular ligament may occur, resulting in a painful usually respond to an initial period of non–weight bearing with pinching sensation over the front of the ankle with dorsiflexion cast immobilization, followed by progressive weight bearing and as this tissue subluxes into and out of the ankle joint. Diagnosis mobilization to full weight bearing within 12 to 16 weeks. Failure may be confirmed if pain resolves with sterile saline injection of nonsurgical treatment or advanced stage III or IV lesions may into the ankle joint. This syndrome commonly resolves with rest require surgical management. as edema around the ankle subsides. Nonetheless, persistence of this problem may result in the need for arthroscopic debridement. Occult fracture Fractures of the anterior process of the calca- neus and injuries to the posterior process of the talus may be Osteochondral lesion of the talus Injury to the cartilage and overlooked on initial examination and radiographs after inver- subchondral bone of the talus occurs in as many as 6.7% of sion injury to the ankle. Fracture of the anterior process of Table 8c.1 Berndt and Harty classification of osteochondral lesions of the talus, radiographic appearance, and recommended treatment options Berndt and Harty stage Radiographic appearance Treatment options I Subchondral bone compression Non–weight bearing in short leg cast for 6 weeks Surgery reserved for persistent symptoms II Partially detached osteochondral fragment Non–weight bearing in short leg cast for 6 weeks Surgery reserved for persistent symptoms III Completely detached nondisplaced osteochondral Surgical treatment: either excision, drilling, and curettage or internal fragment fixation Osteochondral autografting IV Displaced osteochondral fragment (loose body) Surgical treatment: either excision, drilling, and curettage or internal fixation Osteochondral autografting
356 Chapter 8c ● Foot and ankle disorders in the workplace Figure 8c.6 Lateral radiograph showing anterior process of the the calcaneus may be detected with plain radiographs (Fig. 8c.6) calcaneus fracture. or CT (Fig. 8c.7). If detected acutely, anterior process of the calcaneus fractures are best treated non–weight bearing in a removable cast, with institution of range-of-motion and strength- ening exercises beginning 5 to 7 days after injury. ORIF may be required for large displaced fractures propagating through the calcaneocuboid or subtalar joints. Delayed presentation is common and is best treated with excision of the fragment with or without subtalar or talonavicular arthrodesis. These fractures may require 2 to 3 months for healing, at which point physical therapy may begin. Paulos et al15 noted that 17 of 20 posterior processes of the talus fractures (Shepherd’s fractures) after inversion injuries were missed. Confusion arises from the frequent presence of an accessory ossicle originating from the posterior process of the talus (os trigonum). Fracture may occur either through the syn- chondrosis between the os trigonum and posterior talus or through the posterior process itself. Examination reveals pos- terior ankle pain on forced plantarflexion of the ankle. CT, technetium bone scan, or MRI are helpful when confusion regarding diagnosis exists. Acute injuries are treated in a short leg walking cast for 4 to 6 weeks until fracture union occurs or symptoms resolve. If pain persists or if these injuries are discov- ered late, excision after diagnostic injection is recommended. FOOT Almost 5% of all work-related injuries requiring time away from work in 2003 involved in the foot or toes.25 Like the section on ankle injuries, this section is divided into sections on fractures and on sprains and dislocations. Three sections are also included relating to nerve injuries, chronic regional pain syndrome, and crush injuries. The reader must keep in mind that although these topics are all individualized to facilitate discussion, they seldom occur in isolation. For instance, sprains or dislocation of the tarsometatarsal (TMT) joints are usually accompanied by frac- tures of one or more metatarsal or tarsal bones, and these injuries must be considered together. Nerve injuries are discussed individually but commonly coexist with significant disruptions to the major bony or ligamentous structures of the foot. This section clarifies these relationships whenever possible. Fractures of the foot This section provides an overview of work-related fractures of the foot, including fractures of the calcaneus, talus, midtarsal bones of the midfoot, metatarsals, sesamoids, and the phalanges of the toes. Figure 8c.7 Computed tomography confirming anterior process of the Calcaneus fracture In 1916, Cotton4 commented, “the man calcaneus fracture. who breaks his heelbone is done.” Fortunately, advances in operative technique and improved understanding of operative indications have since improved this outlook. Nonetheless, these remain one of the most challenging injuries to treat in the workers’ compensation population. Calcaneus fractures are almost always the result of a high- energy crushing mechanism such as a fall from a height or motor vehicle crash. Ipsilateral fractures of the medial malleolus, tibial plateau, or lumbar spine are commonplace. These patients must
Chapter 8c ● Overview of workplace injuries 357 X-RAY Figure 8c.8 Radiograph showing the tuber angle of Böhler (From Figure 8c.9 Schematic drawings showing the technique for making Brodén’s views. With the patient supine, the x-ray cassette is placed Borrelli J Jr, Torzilli PA, Grigene R, Helfet DL: Effect of impact load on under the leg and the ankle. The foot is in neutral flexion, with the leg internally rotated 30 to 40 degrees. (From Burdeaux BD Jr: Reduction articular cartilage: development of an intraarticular fracture model. of calcaneal fractures by the McReynolds medial approach technique and its experimental basis. Clin Orthop (177):87-103, 1983.) J Orthop Trauma 11(5):319-326, 1997, and from Sanders R: J Bone Figure 8c.10 The x-ray beam is centered over the lateral malleolus Joint Surg Am 82(2):225-250, 2000.) and four radiographs are made, with the tube angled 40, 30, 20, and 10 degrees toward the head of the patient. (From Sanders R: J Bone be approached as any potential multisystem trauma using standard Joint Surg Am 82(2):225-250, 2000.) trauma protocols; injuries to the head, chest, abdomen, spine, and pelvis take obvious precedence. Once more significant injuries have been ruled out, evalua- tion of the potential calcaneus fracture is performed. The patient usually complains of heel pain. Shortening and widening of the hindfoot may be seen. Tenderness, swelling, and ecchymosis are typical. Standard radiographic assessment of the ankle and foot should be performed. Lateral radiograph of the heel is use- ful to quantify the degree of calcaneal shortening by meas- urement of Böhler’s angle (Fig. 8c.8). Produced by the acute intersection of a line drawn parallel to the posterior tuberosity and another connecting the highest point on the anterior process to that of the posterior facet, a Böhler angle normally measures 20 to 40 degrees. Intraarticular step-off of the posterior facet may be visualized using Brodén’s view (Figs. 8c.9 and 8c.10). Axial projection is helpful to demonstrate widening and the degree of varus malalignment of the posterior tuberosity. Although radi- ographs are essential, the CT has become a vital assessment tool in evaluation of the calcaneus fracture. Semicoronal cuts through the posterior facet of the subtalar joint are obtained to ascertain the number of intraarticular fracture lines, the degree of intraar- ticular step-off, and the magnitude of varus malalignment. Immediate treatment is aimed at reducing the impact of soft tissue injury. Ideally, a Jone’s cotton compressive dressing and a posterior splint are applied. Admission to the hospital is recommended for ice, elevation, and observation for compart- ment syndrome. Compartment syndrome of the foot should always be suspected prompting low threshold for manometry and subsequent fasciotomies. Over the ensuing days, massive soft tissue swelling often develops with subsequent fracture blisters. Sterile decompression of nonhemorrhagic fracture blis- ters followed by application of nonadherent dressing should be
358 Chapter 8c ● Foot and ankle disorders in the workplace Figure 8c.11 Classification of intraarticular calcaneal fractures according to Sanders et al: type I, nondisplaced fractures; type II, displaced fractures; and type III, comminuted fractures. (From Sanders R: J Orthop Trauma 6:254, 1992, and From Sanders R: J Bone Joint Surg Am 82(2):225-250, 2000.) performed within the first week of injury. Definitive treatment Each type is further divided into subtypes based on the depends on the integrity of the overlying soft tissues, presence of location of the fracture lines. Classification of calcaneus fractures comorbid conditions, and classification of the fracture. has become a vital tool in determining both the treatment and prognosis of these injuries. Numerous classification systems for calcaneus fractures exist. Sanders et al23 devised a useful classification based on CT Closed treatment is indicated for Sanders type I fractures or (Fig. 8c.11). This system is based on the number and position of when poor quality soft tissues prevent safe surgical incisions. displaced intraarticular fracture lines propagating into the widest Tobacco dependence, diabetes, and vascular disease may dictate segment of the posterior facet of the subtalar joint as seen on closed treatment as well due to inordinately high potential for coronal CTs wound complications postoperatively.21 Early mobilization is ● Type I fractures are defined by the absence of displacement preferable to prolonged immobilization. The patient is placed in a removable CAM walker boot and begins range-of-motion regardless of the number of fracture lines. exercises of the ankle and foot within two weeks of the injury. ● Type II represent displaced fractures defined by a single Partial weight bearing may commence within six weeks of injury. The patient may be advanced to weight bear as tolerated, and intraarticular fracture line. within 12 weeks the boot may be discontinued altogether. ● Type III fractures are displaced fractures defined by two The worker may then resume regular shoe wear, although a larger size may initially be required to accommodate heel widening. intraarticular fracture lines. ● Type IV represent displaced fractures defined by three or more intraarticular fracture lines.
Chapter 8c ● Overview of workplace injuries 359 A full-length custom-molded or over-the-counter heel insert may brake pedal foot is forced dorsally with the direct impact of a provide additional comfort. A return to unrestricted duty may motor vehicle crash. The anterior aspect of the distal tibia acts take up to six months. as a wedge, splitting the talus at the neck. Fractures of the talar body occur from axial loading such as those seen in falls from Surgical treatment is indicated for all open fractures. Sanders a height. Lateral process fractures are avulsion injuries of the type II, III, and IV fractures generally benefit from surgical origin of the lateral talofibular ligament and generally occur treatment; however, surgery is best deferred for 7 to 14 days with inversion injury. Posterior process fractures result from until swelling has improved as indicated by circumferential skin hyperplantarflexion and impingement between the posterior wrinkling. Surgery through skin blisters should be avoided. aspect of the tibia and the calcaneus. Although ORIF is preferable whenever possible, primary subta- lar arthrodesis may be indicated when two or more displaced The injured worker with a talus fracture complains of pain intraarticular fracture lines extend into the subtalar joint, as in about the ankle joint. Swelling, tenderness, and ecchymosis are Sanders type IV fractures. Coughlin,5 Sanders,22 and others usually present. Forced plantar flexion of the ankle reproduces recommended a lower threshold for primary arthrodesis in work- pain when posterior process fractures are present. High-energy related calcaneus fractures. Coughlin5 demonstrated that return talar neck or body fractures may present with skin tenting or even to work was delayed from an average of 6 months to 18 months, extrusion of the talar body. Open injuries are commonplace. and treatment cost nearly doubled when ORIF failed and Coexisting injuries are common and must be ruled out using delayed subtalar arthrodesis was required. standard trauma protocols. Unfortunately, 10% to 20% of patients who undergo ORIF Radiographic examination consists of AP, mortise, and lateral of calcaneus fractures sustain postoperative complications such views of the ankle. Lateral, AP, and oblique views of the foot as delayed wound healing, infection, or sural neuritis.24 Wound must be obtained. A talar neck view is helpful and is obtained by complications may be twice as likely in tobacco users, and elevating the lateral border of the foot 15 degrees off the plantar smoking cessation should be included in the treatment plan. placed x-ray cassette and canting the x-ray gantry 15 degrees away As with all periarticular lower extremity fractures, posttraumatic from the ankle toward the forefoot (Fig. 8c.12). CT has become arthritis is common. Coughlin5 reported that 7 of 16 intraar- the standard for evaluating talus fractures and may reveal frac- ticular calcaneus fractures that underwent initial ORIF later tures or comminution not appreciated on standard radiographs. required subtalar arthrodesis. Anterior impingement of the ankle; peroneal tendon subluxation, dislocation, or tendonitis; Nondisplaced fractures of the neck or body of the talus may and chronic heel pain are all potential long-term sequelae of be treated closed. As soon as swelling permits, a short leg cast calcaneus fractures. is applied. Non–weight-bearing restriction is enforced for six to eight weeks until healing occurs. Displaced talar neck or body After surgical treatment, the limb is immobilized in a fracture fractures may be accompanied by dislocation of the ankle or brace or short leg cast. Strict elevation is maintained for the subtalar joint and should undergo urgent reduction followed by initial four weeks after surgery to minimize edema and poten- tial wound complications. After four weeks, physical therapy is Figure 8c.12 Radiographic positioning for the oblique view of the begun at a frequency of three visits weekly. Range-of-motion, talar neck, as described by Canale and Kelly.3 (From Fortin PT, Balazsy JE: edema control, and strengthening exercises are performed. Partial Talus fractures: evaluation and treatment. J Am Acad Orthop Surg weight bearing begins six weeks after surgery, and full weight bear- 9(2):114-127, 2001.) ing is usually delayed until 12 weeks after surgery. Immobilization and non–weight-bearing restriction is extended to at least eight weeks postoperatively after primary arthrodesis. Most patients may return to part-time sedentary work while maintaining strict elevation of the foot between four and six weeks after surgery. Progression to part-time light duty with hourly elevation breaks lasting 15 minutes may begin 12 weeks after surgery. Progress is usually gradual, and it may take four to six months before a full eight hour light duty shift is tolera- ble. A return to full duty may take a year or more. Chronic swelling and pain may limit tolerance to standing and walking. Uneven surfaces such as those encountered in the roofing and construction trades may be intolerable. Pain and stiffness may preclude occupations requiring ladder climbing and balancing on scaffolding. Unfortunately, workers within these professions are disproportionately represented among those who sustain calcaneus fractures. Work hardening and functional capacity evaluation are helpful to establish long-term work restrictions. Talus fractures Fractures of the talus are divided into those of the neck, body, and posterior or lateral processes. Fractures of the neck of the talus are typically caused by dorsiflexion of the ankle beyond the physiologic range of motion, such as when the
360 Chapter 8c ● Foot and ankle disorders in the workplace ORIF as soon as soft tissues permit. Open injuries require emer- crush injuries with coexisting skin compromise, nerve injury, or gent irrigation, debridement, and stabilization. Immobilization compartment syndrome. Once the soft tissues are stabilized, in a short leg cast may be required for up to four months. After four treatment of these injuries should focus on maintaining column months, the weight-bearing status is advanced to allow weight geometry and articular congruity. Posttraumatic arthritis is bearing as tolerated in a fracture boot. After cast removal, range- common after these fractures, and highly comminuted fractures of-motion and strengthening exercises as well as edema reduction may require primary intertarsal arthrodesis. Return to work varies techniques are performed three times weekly in physical therapy. widely depending on the severity of the injury. Isolated nondis- placed fractures treated closed may be returned to sedentary Fractures of the posterior process are often difficult to distin- duty almost immediately. A patient with injuries requiring ORIF guish from injury to the os trigonum. Fortunately, treatment is or primary arthrodesis may expect a delay in returning to full similar. If symptoms persist beyond a six week course of casting, unrestricted duty of three to six months. excision of the symptomatic os trigonum or posterior process fragment after positive diagnostic injection is recommended. Metatarsal fractures Metatarsal fractures may occur through Nondisplaced fractures of the lateral process are under-diagnosed. either or both the base or shaft of the metatarsals. When one If discovered, late excision may be required; otherwise they may or more metatarsal base fractures are accompanied by midfoot be treated with a six week course of short leg casting with a tenderness, the diagnosis of TMT fracture dislocation must non–weight-bearing restriction. Large displaced fragments may be entertained. TMT fracture dislocations are unstable injuries require ORIF, whereas comminuted fractures may benefit from that often require operative stabilization; these are covered in excision. the section pertaining to these injuries. Long-term complications of talus fractures are common and On the contrary, isolated metatarsal fractures generally respond include posttraumatic arthritis and avascular necrosis. Elgafy well to conservative treatment. The injured limb is initially et al7 reported high rates of posttraumatic arthritis of the subta- elevated in a soft compressive dressing to control swelling. This lar joint (53%) and ankle joints (25%) after fracture of the talus is then changed to a hard-soled shoe or removable fracture boot in a series of 60 talus fractures. Failure of conservative treatment for four to six weeks. Weight bearing to pain tolerance is per- may necessitate subtalar or ankle arthrodesis. Reported rates mitted during this time. Sedentary work may be permitted of avascular necrosis vary but may approach 100% of severely until radiographic healing has occurred. Once healing is evident displaced fractures. Subchondral lucency of the dome of the radiographically, the patient may begin part-time light duty. talus on AP radiographs of the ankle occurring between six and During this time, physical therapy is performed, aimed at edema ten weeks after fracture (Hawkins sign) is considered diagnostic reduction and strengthening. Residual forefoot pain is best of viability of the talar dome.10 Limitation of weight bearing treated with a semirigid custom foot orthotic. A return to heavy using a patellar tendon bearing ankle foot orthosis may be duty is usually possible within 8 to 12 weeks of injury. required for up to a year while the talus revascularizes. Certain metatarsal fractures require special attention. Displaced Workers with conservatively treated fractures of the talus may fractures of the first metatarsal require anatomic reduction. return to sedentary duty within two to three weeks of injury. If anatomic reduction cannot be maintained, then operative After surgical management, the requirement for strict elevation stabilization may be required. Fractures of the proximal fifth precludes return to sedentary work until four weeks postop- metatarsal metadiaphyseal junction (Jones fracture) are important eratively. Once full weight bearing is achieved, part-time light to recognize because these have a significant rate of nonunion duty with frequent rest breaks may be initiated. Patients with (Figs. 8c.13 and 8c.14). These injuries are best treated with conservatively treated talus fractures may be returned to full duty non–weight-bearing cast immobilization for 6 to 8 weeks. The three to four months after injury, whereas those with displaced rate of successful union with this treatment has been reported to fractures treated surgically may require 6 to 12 months depend- be between 72% and 93%.17 ing on the presence of avascular necrosis (AVN) or osteoarthritis. Work hardening, functional capacity evaluation, and even occu- Sesamoid fractures Fracture of the medial or lateral sesamoid pational change may be required. bones of the foot may occur either acutely or in response to stress. Acute injuries are usually the result of sudden hyperdor- Tarsal bones of the midfoot fractures The midtarsal bones siflexion injury to the hallux MTP joint. This may result in are important in maintaining the geometry of the foot. They transverse fracture more commonly of the medial sesamoid may be thought of as constructing two columns, medial and (Fig. 8c.15). Stress injuries are most common in athletes and lateral. The medial column consists of the navicular proximally dancers and usually demonstrate a stellate fracture pattern. Point and the three cuneiforms distally. The cuboid constitutes the tenderness is usually found directly beneath the involved sesamoid. lateral column. The analogy to columns is important, because Radiographic studies should include basic AP, lateral, and oblique fractures of tarsal bones within either column tend to result in projections of the foot. Specialized axial and oblique sesamoid loss of pedal length either medially or laterally with profound views may also be helpful (Figs. 8c.16 and 8c.17). Radiographic effects on the shape and function of the foot. Crush fractures studies may be somewhat confusing due to the high incidence of of the cuboid may result in lateral column shortening, midfoot bipartite sesamoids (5-30%). MRI or technetium-labeled red abduction, and pes planus. Pes cavus may occur with shortening blood cell radionuclide study may be useful when radiographs of the medial column, usually secondary to navicular fractures. are nondiagnostic. Furthermore, fractures of the midfoot bones are usually intraar- ticular, and these injuries may result in posttraumatic arthritis. Acute fractures deserve a six week course of non–weight- Often, midtarsal fractures are but one component of high-energy bearing restriction in a short leg cast. The worker may then
Chapter 8c ● Overview of workplace injuries 361 Figure 8c.13 Anteroposterior radiograph of a typical acute Jones Figure 8c.16 Sesamoid oblique view showing fracture of the medial fracture (arrow). The fracture line is intraarticular and involves the sesamoid. fourth-fifth intermetatarsal articular facet. (From Rosenberg GA, Sferra JJ: J Am Acad Orthop Surg 8(5):332-338, 2000.) return to part-time light duty in a semirigid foot orthosis with relief under the affected sesamoid and a metatarsal bar. Although unrestricted duty may generally be resumed within three months, kneeling may prove especially difficult as it requires maximum dorsiflexion of the hallux MTP joint. Work hardening and physical therapy should focus specifically on the restoration of painless dorsiflexion of the great toe. Phalangeal fractures Fractures of the toe phalanges are the most common osseous injury to the foot in the general popula- tion.6 Phalangeal fractures are best treated with closed reduction Figure 8c.14 Lateral radiograph of a typical acute Jones fracture (arrow). The fracture line is intraarticular and involves the fourth-fifth intermetatarsal articular facet. (From Rosenberg GA, Sferra JJ: J Am Acad Orthop Surg 8(5):332-338, 2000.) Figure 8c.15 Intraoperative photo showing medial sesamoid fracture. Figure 8c.17 Sesamoid axial view showing lateral (A) and medial (B) sesamoids.
362 Chapter 8c ● Foot and ankle disorders in the workplace under digital block anesthesia, followed by buddy taping to the adjacent medial toe. A hard-soled shoe is worn until cessa- tion of pain, tenderness, and swelling herald fracture healing, usually within four weeks. The worker is then returned to regular duty with preventative measures such as steel-toed shoes in place. Unstable closed reductions that manifest as obvious toe defor- mity require percutaneous pinning. These patients need to remain non–weight bearing on the affected extremity until the pin is removed, usually around six weeks after injury. Displaced intraar- ticular fractures of the hallucal proximal phalanx may benefit from ORIF with a return to light duty between six and ten weeks after injury. Persistent swelling or pain should always be taken seriously, because it may belie fracture nonunion. This may be addressed with operative fixation and grafting. Residual disability is uncommon. Sprains and dislocations Ligament injuries may occur about any joint in the foot, but most commonly occur about the TMT and the hallux MTP joints. Strong ligamentous attachments and highly congruent articulations, particularly about the TMT joint, may result in coexisting fractures when these joints are injured. TMT joint injuries The TMT joint, also known as Lisfranc’s Figure 8c.18 (A) Anteroposterior view of the bony and ligamentous joint, is the stable articulation between the five metatarsal bases anatomy of tarsometatarsal joint complex I through V = metatarsal and the midtarsal bones (medial, middle and lateral cuneiforms, bones. (From Myerson MS: Fractures of the midfoot and forefoot. In and the cuboid). The most important of these articulations is MS Myerson, ed: Foot and ankle disorders. Philadelphia, 2000, W.B. the second TMT joint. The second TMT joint is a stable mortise Saunders, pp. 1265-1296.) (B) Coronal section through the metatarsal created proximally by the geometry of the three cuneiform bases illustrating the Roman arch configuration. (From Lenczner EM, bones. These bones create a three-sided notch into which sits Waddell JP, Graham JD: Tarsal-metatarsal (Lisfranc) dislocation. the base of the second metatarsal (Fig. 8c.18). The second J Trauma 14(12):1012-1020, 1974, and from Thompson MC, metatarsal is the only metatarsal to articulate with three tarsal Mormino MA: Injury to the tarsometatarsal joint complex. J Am Acad bones and is anchored in its mortise by Lisfranc’s ligament. Orthop Surg 11(4):260-267, 2003.) Lisfranc’s ligament originates from the plantar aspect of the medial cuneiform and extends to the base of the second metatarsal. Radiographic findings are often subtle, consisting of widening Injury to this ligament has a destabilizing effect on the midfoot between the base of the second metatarsal and medial that may lead to deformity, dysfunction, and pain if not recog- cuneiform. Widening of more than 2 mm compared with the nized and treated. opposite side is considered diagnostic of unstable injury. A fleck of bone may be seen in this interval on radiographs representing Although motor vehicle crashes are the most common cause avulsion of the origin of Lisfranc’s ligament from the medial of injury to the TMT joint, these injuries are also frequently seen cuneiform. Disruption of normal continuity between the medial in the industrial setting. They may occur as a result of direct cortex of the second metatarsal base and middle cuneiform or trauma such as a crush as seen in a forklift injury or as the result between the medial base of the fourth metatarsal and cuboid are of a sudden twisting and axial loading of the plantar flexed foot. The Napoleonic era surgeon Lisfranc provided insight into the mechanism of injury by noting it to occur in cavalry with trau- matic dismount from the stirrup. The severity of these injuries varies considerably. Mild sprains are characterized by mild midfoot tenderness and swelling. Radiographic appearance is normal. Minor sprains may be treated with rest, ice, and elevation followed by immobilization in a removable fracture boot with early institution of weight bearing. Sedentary work restriction is placed for four to six weeks or until tenderness has resolved. Unfortunately, these injuries are often underestimated in terms of severity or missed outright. Moderate and severe sprains are usually characterized by pain prohibitive of weight bearing. Examination reveals marked swelling, tenderness, and ecchymosis about the midfoot. Ecchymosis localized to the plantar aspect of the midfoot beneath the first TMT joint may be seen (Fig. 8c.19).
Chapter 8c ● Overview of workplace injuries 363 removal, so that work hardening may begin shortly thereafter. A custom semirigid foot orthosis is often beneficial. Although light duty may begin five months after injury, it may be six to nine months before a return to regular duty may occur. Unfortunately, posttraumatic arthritis is common after unsta- ble injuries, particularly when these injuries are missed. Persistent midfoot pain, tenderness, and joint space narrowing are sugges- tive of posttraumatic arthritis. When rigid foot orthosis and oral and injected antiinflammatory medications fail, surgical arthrodesis of the midfoot may be required. Calder et al2 noted a poor outcome in 13 of 46 patients with unstable work-related TMT joint injuries. In this study, delay in diagnosis of more than six months and the presence of a workers’ compensation claim were associated with a poor outcome. Permanent change in occupation is often necessary, and a functional capacity eval- uation may be useful in establishing recommendations for future employment. Figure 8c.19 Ecchymosis localized to the plantar aspect of the MTP joint injuries Injuries to the MTP joint are most com- midfoot beneath the first tarsometatarsal (TMT) joint as seen with TMT mon about the great toe. Popularized in the sports medicine joint fracture dislocation. literature as “turf toe,” hallux MTP joint injuries are not uncom- mon in the industrial setting. Typically occurring with hyperdor- also diagnostic of unstable injury. Comparison views of the siflexion of the hallux MTP joint, these injuries may result in opposite foot are helpful. Clinical signs and symptoms, even in both compression injuries to the dorsal articular cartilage of the setting of negative comparison radiographs, warrant CT of the first metatarsal head in addition to tensile damage to the the midfoot. Even when plain radiographs are normal, fractures MTP joint capsule structures. Osteochondral defect of the first of one or more metatarsal bases or their corresponding tarsal metatarsal head; rupture of the plantar plate, collateral liga- bones may be seen on CT belying an unstable injury to the TMT ments, or flexor hallucis brevis tendon; and bony injury to the joint complex. Fracture dislocation of one or more metatarsal sesamoids are all within the spectrum of injury to the hallux bases, the cuneiform, or cuboid bones is not uncommon. Soft MTP joint. tissue injury may be marked, with skin tenting or even skin penetration occurring. Compartment syndrome must always be Mild injuries represent stretch injuries to the plantar joint suspected. Tense edema of the foot, paresthesias in the toes, and capsule. Tenderness is isolated to the plantar and occasionally midfoot pain with flexion-extension of the toes are all support- the dorsal aspects of the hallux MTP joint. Radiographs are ive of the diagnosis of compartment syndrome. Threshold typically negative. Acutely, rest, ice, and immobilization and should be low for manometric examination of the foot and antiinflammatory medications are helpful. Taping of the great subsequent fasciotomies, as the sequelae of missed compartment toe should be instituted to limit extension of the MTP joint. syndrome are unacceptable and may include disabling deformity Weight bearing is allowed in a wooden-soled shoe until tender- and neurologic injury. ness resolves. Treatment of an unstable TMT joint injury requires surgical Moderate to severe injuries represent complete disruption of stabilization. Minimally displaced injuries may be treated with the plantar plate of the hallux MTP joint. Fracture of either medial closed reduction and internal fixation, whereas more severe or lateral sesamoid or disassociation of the bipartite sesamoid and open injuries require ORIF. Transarticular fixation must be may be present. Osteochondral injury to the dorsal head of removed before weight bearing is resumed, usually between three the first metatarsal may coexist. Examination reveals tenderness, and four months after surgery. Nonetheless, range-of-motion swelling, and ecchymosis about the hallux MTP joint. Pain and strengthening exercises may be instituted before hardware occurs with any attempt at range of motion, and the hallux MTP joint may be unstable with dorsal translation. Radiographs are negative unless unreduced dislocation of the MTP joint, avul- sion fracture of the base of the proximal phalanx, or sesamoid fracture disassociation are present. Rest, ice, immobilization, and antiinflammatory medications are helpful in the acute stage. Irreducible dislocation may require open reduction. As with mild injuries, protected weight bearing in a wooden-soled shoe and taping are instituted. Even with mild injuries, return to unrestricted or heavy work may take as long as six months. Initially, sedentary work may be initiated in a wooden-soled shoe. Once swelling and ten- derness have resolved, the worker may return to light duty in a standard shoe containing a low-profile rigid foot orthosis with a Morton’s forefoot extension (Fig.18c.20). Return to unrestricted
364 Chapter 8c ● Foot and ankle disorders in the workplace Figure 8c.20 Low-profile rigid foot orthosis with a Morton’s forefoot Typical complaints that should alert the practitioner to under- extension (Springlite Inc., Salt Lake City, UT, USA). lying nerve injury include numbness, burning pain, or hyper- sensitivity in the distribution of one or more sensory nerves of duty is delayed until full painless motion of the hallux MTP the foot. Percussion along an injured nerve with the examiners joint has returned as compared with the opposite side. fingertip may reproduce descending paresthesias (Tinel’s sign). Thorough neurologic examination may uncover underlying Persistent pain after these injuries should not be dismissed. radiculopathy or peripheral neuropathy predisposing to nerve If symptoms continue beyond three months, MRI examination injury.19 Peripheral nerve blocks are helpful in both localizing is warranted to detect either a stress fracture of the sesamoid or pathology and determining potential response to treatment. an osteochondral injury to the first metatarsal head. Stiffness and Electrodiagnostic studies should also be performed early to doc- pain persisting six months beyond injury should prompt suspi- ument the location and degree of nerve injury and to uncover cion of posttraumatic arthritis. Posttraumatic arthritis of the contributing pathology such as radiculopathy or neuropathy. hallux MTP joint, or hallux rigidus, is treated with antiinflamma- tory medications and a rigid foot orthosis with a Morton’s fore- Treatment of peripheral nerve injuries in the acute setting foot extension. Refractory pain may require surgical treatment. involves direct surgical repair of transected essential motor nerves Dorsal cheilectomy is indicated if the joint space is largely pre- including the tibial and common peroneal nerves. Although pri- served; hallux MTP arthrodesis is reserved for end-stage arthritis. mary repair of sensory nerves such as the distal superficial and Return to heavy labor is a reasonable goal after surgical man- deep peroneal nerves and the sural and saphenous nerves is con- agement of hallux rigidus; however, a steel-toed shoe and a rigid troversial, clean lacerations may benefit from epineural suturing. orthotic with a Morton forefoot extension are advised. Return of sensory function from the site of repair is gradual and may be followed by descending percussion sensitivity that is Injuries to the lesser MTP joints should not be discounted. generally thought to proceed at 1 mm/day. Electrodiagnostic testing Hyperdorsiflexion injury may result in rupture of the plantar is indicated three months after repair to confirm recovery of nerve plate with delayed claw toe deformity. Dorsal dislocation may function. Stretch injuries such as those to the superficial peroneal require open reduction if unreducible. Acutely, immobilization nerve after inversion injury of the ankle are best managed in the in a Budin splint (Apex Foot Health Industries, Inc., Teaneck, NJ, acute stage by splinting the affected extremity in neutral align- USA) and buddy taping is helpful. The patient may be graduated ment to minimize further nerve tension. Crush injuries should to a full-length rigid insert with a metatarsal bar once swelling be monitored for compartment syndrome with a low threshold and tenderness have resolved. for compartment manometry and subsequent fasciotomies. All nerve injuries should also be treated with early initiation of nerve Nerve injuries stabilizing medications such as gabapentin, followed by physical therapy desensitization techniques such as contrast baths, tran- Peripheral nerve disorders are common sequelae of traumatic scutaneous nerve stimulation, and range-of-motion exercises.16 events in the lower extremity. Painful and hypersensitive areas of perineural scarring may occur either along a nerve (neuroma Many optimally treated patients with peripheral nerve injuries in continuity) or at a site of nerve transaction (stump neuroma). progress to chronic neuralgia. Pharmacologic therapy should be Adhesive neuralgia may affect a length of nerve in response to initiated and may include topical agents such as lidocaine patches either injury or surgery. Delayed diagnosis of compartment and capsaicin cream. Antiepileptic and antidepressant medica- syndrome may result in ischemic nerve damage. Given the lack tions such as Neurontin and amitriptyline should be initiated at of objective findings and the often disabling symptomatology initially low dosages and may be titrated to effectiveness. Physical associated with peripheral nerve lesions, these injuries represent therapy desensitization techniques, including contrast baths, formidable diagnostic and treatment challenges in any setting. transcutaneous nerve stimulation, and range-of-motion exercises, are helpful as well. Finally, surgical management may benefit patients with well- defined nerve lesions who have failed all other treatment. Neuroma resection with stump burial is most effective in patients who respond favorably to diagnostic injection with local anesthetic. Adhesive neuralgia may respond to neurolysis with or without a vein-wrapping procedure. Patients with peripheral nerve lesions who fail conventional pharmacologic, physical therapy, and surgical treatment may benefit from application of an implanted peripheral nerve stimulator. In summary, treatment of peripheral nerve injuries involves a multimodality approach incorporating pharmacologic agents, physical therapy desensitization, and surgery. Treatment of associated pathology such as ligamentous disruption, fracture, or compartment syndrome is a prerequisite for successful treatment of peripheral nerve injuries. Nonetheless, these injuries remain among the most challenging conditions to treat for the occupa- tional physician.
Chapter 8c ● Conclusion 365 Chronic regional pain syndrome RETURNING THE FOOT- AND ANKLE-INJURED WORKER TO WORK Chronic regional pain syndrome may occur in response to either noxious or nonnoxious stimuli to the extremity. Chronic Correct and timely diagnosis is the first step in treatment of regional pain syndrome is divided into types I and II. Type I the worker with foot or ankle injury. Incorrect diagnosis may develops after an initial event that may or may not have been lead to unnecessary tests, inappropriate treatment, prolonged traumatic. Type II generally develops after nerve injury. Both disability, and perceptions of malingering for secondary gain types I and II result in pain, allodynia (painful response to among the employer, insurance carriers, and physicians. It is nonpainful stimuli), and hyperalgesia often involving the entire hoped that the information within this chapter may guide the distal extremity. Autonomic dysfunction is common and may diagnostician in timely diagnosis. Nonetheless, even the most manifest as color or temperature changes and hyperhydrosis. The astute diagnostician may be confounded. Early referral to an involved extremity may appear cool and mottled or warm, orthopedic foot and ankle specialist may be beneficial when the erythematous, and swollen. Trophic changes may include a diagnosis is less than clear. smooth shiny appearance to the skin with thickened or thinned toenails. Radiographs may show nonspecific osteopenia. A three- Once the diagnosis is established and treatment plans are phase, technetium-labeled, red blood cell radionuclide study in place, it is important to discuss with the injured worker an may show nonspecific periarticular uptake on all phases. appropriate timetable for return to work. This includes a timetable for return to modified or part-time duty. The nurse case manager Early initiation of appropriate treatment is paramount to should establish whether modified duty is available. Obviously, successful management of this challenging disorder. Physical acutely after severe injury or surgical treatment, strict elevation therapy, medications, and regional anesthesia are all important requirements make return to even sedentary duty impractical. therapeutic tools. Lee and Kirchner11 outlined a stepwise and sensible physical therapy protocol. Initial therapy focuses on Once the patient can tolerate short periods with the injured mobilization and desensitization. Once the injured worker extremity in the dependent position, part-time sedentary duty becomes tolerant of limb manipulation, flexibility and edema should be instituted. This may be advanced to part-time light reduction techniques are used. Isotonic strengthening, stress load- duty with hourly elevation breaks once weight bearing is no longer ing, and aerobic conditioning are followed by vocational reha- contraindicated. As range of motion, strength, and endurance bilitation, work hardening, and functional capacity evaluation. improve through physical therapy, the work day may be elongated Adjunctive medications include antidepressants such as amitripty- until the appropriate shift length is tolerable. Functional capacity line and antiepileptics such as gabapentin. Regional anesthesia evaluation may be useful at this point to delineate deficiencies in techniques may be an effective compliment to physical therapy task-specific functions and guide subsequent work hardening. and medications. Lumbar sympathetic blocks or combined Work hardening may succeed in preparing the worker for his or somatic-sympathetic blocks may be helpful especially when her previous physical work capacity. If the worker fails to meet combined with physical therapy. these expectations, an additional functional capacity evaluation or even an independent medical evaluation may be useful. Crush injury Despite many advances in caring for foot and ankle injuries, Crush injuries of the foot represent a subgroup of high-energy return to work is not always possible at the injured worker’s foot trauma resulting in both bony and soft tissue injury with previous occupational level. It is perhaps paradoxical and cruel far-reaching treatment and rehabilitation implications. The pre- that those most likely to sustain lower extremity impairment are ponderance of these injuries in the industrial setting has been those whose occupations are most dependent on lower extrem- well documented.14 Crushing was responsible for 7.4% of all ity functions. For example, roofers and construction workers foot and toe injuries incurred in private industry in 2003.23 are among the trades most likely to sustain a fall from a height with a resulting lower extremity fracture. Many of these fractures Management of these injuries begins with standard trauma are periarticular and may result in arthritis and joint stiffness protocols. Once life-threatening injuries have been ruled out, sta- even when optimally treated. It is easy to see how arthritis and bilization and assessment of the injured extremity commences. joint stiffness may make balancing on uneven surfaces, climbing Neurovascular examination is followed by soft tissue evaluation. ladders, and negotiating scaffolding impossible. Even in the Compartment syndrome should be anticipated and early manom- event of a highly motivated patient and optimal treatment, the etry performed, followed by fasciotomies of the foot if compart- return to a previous occupational level is not always feasible. ment pressures are elevated. Treatment requires aggressive surgical Should return to the previous occupation be unlikely, this should decontamination, debridement of nonviable tissues, bony stabi- be established with the patient as soon as possible. lization, and early soft tissue coverage. Broad spectrum antibi- otic coverage is required for open injuries. CONCLUSION Unfortunately, long-term morbidity is common after crush In general, the treatment of foot and ankle disorders incurred injuries of the foot. Associated problems include deformity, in the workplace is even more challenging than in the population stiffness, chronic neuralgia, posttraumatic arthritis, and chronic at large. Workers frequently perform demanding tasks while regional pain syndrome. The series of Myerson et al14 noted that standing and walking on often dynamic and uneven terrain. only 46% of patients with crush injuries to the foot sustained a good outcome. Poor outcome was noted more commonly in those sustaining either chronic neuralgia or chronic regional pain syndrome.
366 Chapter 8c ● Foot and ankle disorders in the workplace Their occupation may require prolonged standing and walking 4. Cotton FJ: Os calcis fracture. Ann Surg 64-80, 1916. while carrying heavy objects. Furthermore, resting the injured 5. Coughlin MJ: Calcaneal fractures in the industrial patient. Foot Ankle Int 21(11): extremity is often difficult even when not working due to the weight-bearing demands of everyday life. Because people’s liveli- 896-905, 2000. hoods are often at stake, timely and accurate diagnosis becomes 6. DeLee J: Surgery of the foot. In R Mann, ed: Fractures and dislocations of the foot. even more important. St. Louis, MO, 1980, C.V. Mosby, pp. 729-749. The successful diagnosis of the worker with a foot and ankle 7. Elgafy H, Ebraheim NA, Tile M, Stephen D, Kase J: Fractures of the talus: experience injury requires an understanding of the broad range of diagnos- tic possibilities in the foot and ankle. In addition to fractures, of two level 1 trauma centers. Foot Ankle Int 21(12):1023-1029, 2000. sprains, and dislocations, peripheral nerve and crush injuries 8. Engelberg R, Martin DP, Agel J, Obremsky W, Coronado G, Swiontkowski MF: are common about the foot and ankle in the industrial setting. A well-directed and comprehensive history and physical exami- Musculoskeletal function assessment instrument: criterion and construct validity. nation when combined with appropriate imaging studies usually J Orthop Res 14(2):182-192, 1996. yields a correct diagnosis. 9. Guyton GP, Mann RA, Kreiger LE, Mendel T, Kahan J: Cumulative industrial trauma as an etiology of seven common disorders in the foot and ankle: what is the evidence? Once a clear diagnosis has emerged, a stepwise treatment Foot Ankle Int 21(12):1047-1056, 2000. plan may be implemented. Consideration of underlying medical 10. Hawkins LG: Fractures of the neck of the talus. J Bone Joint Surg Am 52(5): conditions is an important consideration in devising a treatment 991-1002, 1970. strategy. The nurse case manager and physical therapist are inte- 11. Lee KJ, Kirchner JS: Complex regional pain syndrome and chronic pain management gral treatment team members in executing the plan of care. in the lower extremity. Foot Ankle Clin 7(2):409-419, 2002. Physical therapy, orthotics, functional capacity evaluations, and 12. Lindsjo U: Operative treatment of ankle fracture-dislocations: a follow-up study of work hardening are all useful treatment tools in rehabilitating the 306/321 consecutive cases. Clin Orthop 199:28-38, 1985. worker as a final phase of treatment. 13. McFerran MA, Smith SW, Boulas HJ, Schwartz HS: Complications encountered in the treatment of pilon fractures. J Orthop Trauma 6(2):195-200, 1992. Restoring an injured worker to the workplace is indeed a dif- 14. Myerson MS, McGarvey WC, Henderson MR, Hakim J: Morbidity after crush injuries to ficult and challenging endeavor. It is hoped this chapter may the foot. J Orthop Trauma 8(4):343-349, 1994. serve as a general guide to approaching the worker with a foot 15. Paulos LE, Johnson CL, Noyes FR: Posterior compartment fractures of the ankle: a and ankle ailment and thus positively impact the diagnosis, treat- commonly missed athletic injury. Am J Sports Med 11(6):439-443, 1983. ment, and rehabilitation of these patients. 16. Raikin SM: Nerve injuries to the foot and ankle in the industrial setting. Foot Ankle Clin 7(2):351-366, 2002. REFERENCES 17. Rosenberg GA, Sferra JJ: Treatment strategies for acute fractures and nonunions of the proximal fifth metatarsal. J Am Acad Orthop Surg 8(5):332-338, 2000. 1. Berndt AL, Harty M: Transchondral fractures (osteochondritis desiccans) of the talus. 18. Sammarco GJ: Peroneal tendon injuries. Orthop Clin North Am 25(1):135-145, J Bone Joint Surg 41A:988-1020, 1959. 1994. 19. Sammarco GJ, Chalk DE, Feibel JH: Tarsal tunnel syndrome and additional nerve 2. Calder JD, Whitehouse SL, Saxby TS: Results of isolated Lisfranc injuries and the lesions in the same limb. Foot Ankle 14(2):71-77, 1993. effect of compensation claims. J Bone Joint Surg Br 86(4):527-530, 2004. 20. Sammarco GJ, DiRaimondo CV: Chronic peroneus brevis tendon lesions. Foot Ankle 9(4):163-170, 1989. 3. Canale ST, Kelly FB Jr: Fractures of the neck of the talus: long-term evaluation of 21. Sanders R: Displaced intra-articular fractures of the calcaneus. J Bone Joint Surg Am seventy-one cases. J Bone Joint Surg Am 60(2):143-156, 1978. 82(2):225-250, 2000. 22. Sanders R: Intra-articular fractures of the calcaneus: present state of the art. J Orthop Trauma 6(2):252-265, 1992. 23. Sanders R, Fortin P, Dipasquale T, Walling A: Operative treatment in 120 displaced intraarticular calcaneal fractures: results using a prognostic computed tomography scan classification. Clin Orthop 290:87-95, 1993. 24. Sangeorzan BJ, Benirschke SK, Sanders R, Carr JB, Thordarson DB: The literature on calcaneal fractures is highly controversial. Foot Ankle Int 22(10):844-845, 2001. 25. U.S. Bureau of Labor Statistics: Lost work time injuries and illnesses: characteristics and resulting days away from work. http://www.bls.gov/iif/home
CHAPTER 8d progression to inversion. The lateral joint capsule tears first, followed by rupture of the ATFL, which causes hemarthrosis and Treatment and subsequently subcutaneous ecchymosis. With further inversion, Indications for Surgical the CFL ruptures, and the posterior talofibular and deltoid liga- Treatment of Foot and ments sustain varying degrees of injury. In acute ankle sprains, Ankle Injuries the ATFL tears alone in 60% of cases, the ATFL tears in combi- nation with the CFL in 20%, the posterior talofibular ligament Per A. F. H. Renström, Ulf Eklund, and Tönu Saartok tears in 10%, and the deltoid ligament tears in 3%. Injuries to the foot and ankle are common at work and during Treatment of severe grade III lateral ankle ligament tears has recreation. The foot is an anatomic masterpiece involving generated much controversy, but a critical review of the literature 28 bones, 19 muscles and tendons, and 115 ligaments. Many of shows that functional treatment provides the quickest recovery these structures may be injured in one way or another, and it is to full range of motion (ROM) and return to work and physical important to secure a correct diagnosis if treatment is to be activity without major residual problems.5 Functional treatment successful. This chapter includes a description of the different should include a short period of protection by tape, bandage, or injuries that can occur in the foot and ankle with a focus on brace along with early weight bearing. In most acute cases, this is describing how these can be diagnosed and treated and when sur- recommended as the treatment of choice. ROM exercises and gery is indicated. Included is an evaluation of when it is possible neuromuscular training should begin early. If residual problems to return to work after surgery in each case. persist after functional treatment, delayed surgical reconstruction or repair can be performed even years after the injury, with Because the foot and ankle are pathways for the impact of body results comparable with those after primary repair. weight and gravity, problems in these body parts are common, especially in active people. In industrial life, not only are people Some authors have recommended early surgical repair of acute walking a great deal on hard surfaces, but they are also climbing, severe ankle sprains in young athletes. Indications for acute repair jumping, and so forth, thereby increasing the risk of foot and ankle for athletes listed by Leach and Schepsis7 are (1) a history of injuries. Many of these injuries such as fractures and ligament and momentary talocrural dislocation with complete ligamentous tendon ruptures are acute, and their treatment is seldom controver- disruption, (2) a clinical anterior drawer sign, (3) 10-degree or more sial. Probably most injuries, however, are overuse injuries that con- tilt on the affected side with stress inversion testing, (4) clinical or stitute a great clinical, diagnostic, and therapeutic problem. In these radiographic suspicion of tears in both the ATFL and CFL, and cases treatment and indications for surgery are often controversial, (5) osteochondral fracture. Most techniques described for acute many times because the exact diagnosis is not clear. In this chapter repair of ankle ligament injuries are similar. However, 10-20% of we try to shed some light on these injuries, suggest indications for patients treated functionally develop residual problems. If a patient surgery, and estimate the postoperative time to return to work. has continuous pain and swelling 3 to 4 months after an ankle lig- ament sprain, attention should be refocused to possible intraar- ANKLE SPRAINS ticular (such as cartilage) lesions or other differential diagnoses. It is very important to be aware of the many differential diagnos- In spite of the high frequency of ankle injuries, clinical diagnostic tic possibilities. techniques and methods of treatment vary greatly, perhaps because the biomechanics of the ankle joint, its ligaments, and Chronic ankle instability their clinical evaluation are not fully known. The anterior talofibular ligament (ATFL), the calcaneofibular ligament (CFL), Chronic ankle instability may be either mechanical or functional. and the posterior talofibular ligament function as a unit. These Characterized by ankle mobility beyond the physiologic ROM, may alternatively resist a specific motion, so the primary stabiliz- mechanical instability is measurable by the anterior drawer and ing ligament depends on foot position. As the foot plantar talar tilt tests, respectively. Mechanical instability is considered flexes, for example, strain in the ATFL increases, whereas that in to be present if anterior translation is more than 10 mm (or more the CFL decreases. Although the ATFL is the weakest ligament, than 3 mm greater than that of the uninjured ankle) or when it is clinically the most significant, involved as it is in 85% of talar tilt is more than 9 degrees (or 3 degrees greater than the common inversion ankle sprains and in 20% of those in combi- uninjured ankle). Functional instability is a subjective feeling nation with the CFL. Clinical ligamentous damage is primarily a that the ankle is giving way during physical activity or walking function of tensile loading and is only secondarily affected by on uneven ground. Chronic ankle instability, regardless of type, twisting or sheer forces. that presents with pain, recurrent giving way, and/or positive stress testing is an indication for operative treatment. The most common mechanism of injury to the lateral ligaments of the ankle is plantar flexion and thereafter gradually increasing Surgical treatment The combination of mechanical and functional instability is the most frequently reported indication for delayed surgery. More than 50 procedures and modifications thereof have been described for treating chronic ankle instability. These can be loosely grouped
368 Chapter 8d ● Treatment and indications for surgical treatment of foot and ankle injuries as nonanatomic reconstructions or anatomic repairs. The reported The patient usually has a history of a sprained ankle. Sometimes success rates for nearly all these procedures are more than 80%. a “pop” can be heard. With a recent injury, moderate or severe lingering swelling of the joint can be seen. Tenderness is typically Nonanatomic reconstructions use another structure or mate- located just distal to the anterior tibiofibular syndesmosis or rial to substitute for the injured ligaments in the aim to stabilize behind the medial malleolus, depending on the location of the the joint. Structures commonly used for grafting are the fascia lesion. After an inversion injury, the symptoms of a concomitant lata or the peroneus brevis tendon. Numerous modifications of anterolateral osteochondral lesion may be “masked” in the signs these classic procedures have been described. of the ligament tear. Anatomic reconstruction is based on the 1966 Broström When an osteochondral lesion is suspected, a careful plain report3 that direct suturing and repair of chronic ankle ligament radiographic examination is needed with anteroposterior, lateral, injuries was possible and also successful promptly or many years and oblique views of the ankle. Mortise views in plantar flexion after the initial injury, even if the ends of the ligament could be should disclose a posteromedial lesion, and the corresponding detected at surgery. Others reported that the elongated ligaments view in dorsiflexion reveals an anterolateral lesion. If the patient had healed encased in fibrous scar tissue. Several authors reported is treated for a ligament injury alone (usually immediate functional successful imbrication, or shortening, and reimplantation of the rehabilitation), the symptoms persist, such as pain just distal to ligaments to bone to achieve good results. The Peterson proce- the anterior syndesmosis, recurrent swelling, or even catching or dure, for example, includes shortening of the ligament, repair locking. A renewed plain radiograph investigation usually con- through bony tunnels, and imbrication with local tissue.9 This tinues to be negative, calling for a bone scan of the ankle, which anatomic technique repairs both the ATFL and the CFL, whereas is very sensitive although not specific. If the bone scan is “hot” most nonanatomic reconstructions, except for the Elmslie proce- over the talus, further evaluation by plain tomography, com- dure and the Chrisman-Snook modification, repair only the ATFL. puted tomography (CT), magnetic resonance imaging (MRI), or Repair of the CFL appears to be important, because insufficiency possibly diagnostic arthroscopy accurately determines the exact of this ligament may be a factor in the development of subtalar location and extent of the lesion. instability. Appropriate staging and early treatment of osteochondral Anatomic repair of both the ATFL and CFL through bony tun- lesions of the talus provide the best results. Healing depends on nels produces good long-term results and is recommended as the capillary overgrowth of the injury site from the body of the talus. initial and standard procedure in most cases. If anatomic repair Immobilization of the area seems to be necessary to prevent the fails, a tenodesis procedure such as the Chrisman-Snook recon- frictional effects of an uneven joint surface and potential progress struction is a good alternative. Nonanatomic reconstructions are of the lesion into more advanced stages, leading to nonunion. indicated in patients with moderate arthritis or generally lax joints. Lesions in stages I-III without established nonunion signs such as marked sclerosis, gross uneven joint surfaces, or osteoarthrosis After surgery and mostly depending on the pain, it is possible are treated with a non–weight-bearing lower leg cast for to return to a desk job within 1 to 2 weeks, wearing an ankle 6 weeks, followed by a weight-bearing cast until radiographic orthosis for about 6 weeks. However, the patient will depend on evidence shows healing. An intraarticular injection of 10 ml lido- crutches during this period. Return to walking and more active caine can be effective in stage I lesions. Delayed nonoperative work is possible after the healing and rehabilitation period, which treatment of stage III lesions often fails. These lesions, as well as most commonly lasts 3 to 4 months after surgery. stage IV lesions, are often treated early surgically to prevent further deterioration of the joint. An experienced arthroscopic surgeon CHRONIC ANKLE PAIN reaches many of these lesions arthroscopically (removal of the detached lesion and debridement of the lesion bed), but open Persistent ankle pain has been attributed to many causes, including approaches are occasionally needed. Reattachment of the osteo- incomplete functional rehabilitation. It has also been attributed to chondral lesion might be considered in the acute phase. Proper chondral or osteochondral lesions of the talus, occult fractures, intraarticular access occasionally requires osteotomy of the medial and impingement syndromes. or lateral malleolus. If an osteotomy is performed, it is essential that subsequent internal fixation is rigid to allow the important Osteochondral lesions of the talus early motion in rehabilitation. Postoperative weight bearing is delayed 2 to 6 weeks (a full 6 weeks if osteotomy of the medial Osteochondral fracture, talar dome fracture, transchondral fracture, malleolus was performed). and osteochondritis dissecans are currently believed to be similar lesions. The etiology is traumatic, either as a single event or as The prognosis after early nonoperative treatment in stages I-III multiple microtraumatic insults. Osteochondral lesions are arthro- is good in 75% of cases. The results of surgery are mixed, with scopically staged in four levels. Stage I is a compression injury reports that it yields a 40% to 80% rate of good results in late causing microscopic damage to an area of subchondral bone. stage III and in stage IV lesions. Advanced lesions, where treat- Plain radiographs are negative. In stage II, a partially detached ment has been delayed more than 1 year, historically have had a osteochondral fragment is detectable on careful examination of poor outcome.8 More recent treatment options such as osteo- an adequate series of plain radiographs. In stage III, the osteo- chondral grafting or autologous chondrocyte transplantation, chondral fragment is completely detached but remains in anatomic however, seem to yield promising results. position, and in stage IV, the detached fragment is displaced else- where in the joint. Return to work that involves walking is possible within 2 to 3 months of nonsurgical treatment and 1-4 months after surgery, depending on the extent of the lesion and the method used.
Chapter 8d ● Chronic ankle pain 369 Loose bodies in the ankle Osteophytes at the anterior rim of the tibia, often called “soccer player’s ankle,” is a condition with decreased dorsiflexion Typically seen on plain radiographs, loose bodies in the ankle are and pain over the anterior part of the ankle joint. Dorsiflexion is often related to intermittent pain, swelling, and clicking. They blocked because of the formation of osteophytes on the distal emanate either from a stage IV transchondral fracture of the anterior rim of the tibia and sometimes on the corresponding talus, from osteophytes on the anterior distal rim of the tibia or area of the dorsum of the talar neck. The osteophytes probably the dorsal neck of the talus, or, if multiple, from “synovial osteo- result from repetitive traction microtrauma to the ankle joint chondromatosis.” Posteriorly located loose bodies must be dif- capsule with subsequent bleeding and ultimately reactive osteo- ferentiated from an extraarticular os trigonum. Chip fractures phyte formation. The history, clinical examination, and plain radi- may appear as loose bodies as well. Pure chondral loose bodies ographs reveal the condition. Apart from soccer, the condition is from lesions in the tibial plafond, in the talar dome, or from seen also in sports such as American football and orienteering synovial chondromatosis cause the same symptoms. If plain radi- but only rarely in recreational athletes. The incidence in workers ographs are negative, however, more advanced measures such as is unknown, but in occupations requiring repetitive traction of MRI or arthroscopy are needed. Arthroscopic removal of loose the anterior capsule of the ankle, this condition may appear. bodies by a skilled arthroscopic ankle surgeon is the treatment of Although ankle dorsiflexion is not always fully restored, removal choice. Return to walking work is possible after 2-6 weeks. of the osteophytes openly or arthroscopically, followed by rapid rehabilitation consistently yields good or excellent results. Impingement syndromes After an impingement syndrome due to anterior osteophytes, Impingement synovitis of the lateral ankle after an inversion return to work should be possible within 1 to 3 months, depend- injury is not uncommon. Symptoms can fully mimic those of an ing on the type of job. The results and the prognosis after surgical anterolateral talar osteochondral lesion. Radiographic evaluation treatment are usually good. such as contrast-enhanced MRI used for detecting osteochondral pathology should reveal soft tissue abnormalities also. In the Sinus tarsi syndrome absence of concomitant chronic ligamentous instability, treat- ment of impingement synovitis involves the surgical removal of Patients with a history of multiple lateral ankle sprains occasion- impinging tissue by way of the arthroscope. When lateral liga- ally have residual pain and tenderness to palpation 2 cm anterior mentous insufficiency is present also, open removal of impinging and distal to the tip of the lateral malleolus. This area, the sinus chronic synovitis tissue together with an appropriate stabilizing tarsi, is a funnel-shaped cavity bordered by the talar neck superi- procedure is recommended. Provided that no chondral lesions orly, the anterolateral calcaneus inferiorly and posteriorly, and are present, postoperative results are generally excellent. the interosseous talocalcaneal ligament anteriorly. Recurrent subtalar sprains may cause microruptures in this broad flat liga- Residual symptoms after ankle inversion sprains are quite ment, leading to a chronic inflammatory reaction. The diagnosis common and are most often due to both mechanical and func- is determined from the patient’s history and localized tenderness tional instability of the joint. Occasionally, however, anterolat- slightly but significantly distal to the ATFL. Usually, subtalar eral ankle pain and a feeling of giving way persist in spite of motion is impaired and may present with dull pain. Typically, normal stability and well-performed functional rehabilitation. ankle joint stability is not affected. Radiographs are negative, so Examination reveals tenderness just anterior to the lateral malle- the easiest way to diagnosis is a local anesthetic block into the olus, especially in dorsiflexion. Additionally, at times a snapping sinus tarsi, which gives immediate pain relief. phenomenon from this region can be elicited when the foot is tested for inversion stability. In these instances, a meniscoid lesion Initial treatment consists of rest and nonsteroidal antiinflam- of the ankle should be suspected. In such cases, both radiographs matory drugs (NSAIDs). Steroid injection into the sinus tarsi has and bone scintigraphy are normal, thereby excluding osteochon- proven helpful.6 In the rehabilitation phase, peroneal remobiliza- dral lesions. A possible etiology is local fibrosis that has developed tion is emphasized because a sinus tarsi syndrome may be related after posttraumatic impingement synovitis after the inversion to functional instability of the ankle joint. In the rare cases where injury. Possibly torn strands or distal parts of the ATFL are caught symptoms persist, surgical “decompression,” that is, excision in the talofibular joint, with subsequent synovitis and ultimately of the sinus tarsi contents (ligaments, fat), has been successful. fibrosis developing. An intraarticular injection of 10 ml lidocaine Return to work may vary but is often possible 1 to 2 months may limit the pain. Together with a limited dorsiflexion, this test after surgery. with local anesthesia secures the diagnosis. Arthrosis of the ankle On surgical exploration, which is readily done arthroscopi- cally, the lesion has a hyalinized meniscoid appearance. In most Compared with that of the hip and knee, the incidence of ankle patients, simple excision of the lesion and surrounding reactive arthrosis is low. It is most commonly seen after a fracture around synovitis leads to full recovery. the ankle, especially when fracture healing was allowed in a nonanatomic position. This leads to incongruency of the ankle After an impingement syndrome that involves impingement mortise and often to rapid development of arthrosis. Other predis- synovitis or a meniscoid lesion that has been treated surgically, posing factors include severe ligamentous laxity and stage III-IV return to work may vary but should be possible within 1 to osteochondral lesions of the tibial plafond or the talar dome. 3 months, depending on the type of job. The results and the prognosis after surgical treatment are usually good.
370 Chapter 8d ● Treatment and indications for surgical treatment of foot and ankle injuries As yet, no curative treatment has been found for articular sur- distinct tenderness. The healing potential of partial Achilles face injury and/or degeneration. Symptomatic treatment aiming tendon tears is poor, with more than 80% of patients having at unloading the surfaces and reducing the reactive inflammation residual problems after 5 years.1 is easy and often very helpful for pain control. Especially with 4. Retrocalcaneal bursitis, an inflammation of the bursa between catching and locking sensations from detached osteophytes or the calcaneus and the anterior aspect of the Achilles tendon, pieces of cartilage, arthroscopic or open debridement and loose is characterized by pain combined with tenderness and swelling body removal may occasionally be an option. In severe cases, anterior to the distal part of the heel cord. With time and more extensive treatment must be considered; ankle arthrodesis when left untreated, the anterior fibers of the tendon insertion is a reliable and well-proven way to relieve pain. Empirically, the are severed, necessitating more extensive treatment and pro- functional disability of the arthrodesis often is well compensated longed recovery period. in young patients. In selective cases where the ankle mobility and soft tissue quality are preserved, total ankle replacement is a recent Except in cases of partial tears, treatment of Achilles tendon treatment alternative. Return to work is often possible 1-2 months overuse injuries is primarily conservative, the cornerstones being after arthroscopic procedures but may take 3-6 months after correction of malalignment, ice, and, most often, medication for arthrodesis or total ankle replacement. pain control, ankle ROM exercises, and both stretching and strengthening of the plantar flexors and dorsiflexors of the ankle. TENDON INJURIES AROUND THE ANKLE For tendinosis types of lesions, daily eccentric strength training of the gastrocsoleus complex has proven successful in about 7 of Traditionally, the term tendinitis has been used to describe most 10 patients and is now considered to be the initial treatment and tendon overuse injuries. The tendon itself, however, consists of rehabilitation for most cases of tendinopathy. A 1-cm heel wedge dense connective tissue with little inherent vascularity and is not can be useful also in reducing symptoms during daily activities predisposed to inflammatory change. Instead, the term tendinosis like walking. We strongly advise against the use of local cortico- is used to define structural, most often degenerative, tendon steroid injections in the treatment of heel cord injuries. changes. The surrounding tendon sheath, the peritenon, is usually highly vascularized and subject to inflammation or peritendinitis If conservative measures fail in spite of a 3- to 6-month period (paratenonitis) when overused. Tendon disease (excluding ruptures) of adequate rehabilitation, surgery is indicated. Preoperatively, can thus be described as tendinosis, peritendinitis (paratenonitis), radiographic investigation excludes calcifications, and MRI or or a combination. The symptom of pain from the tendon itself ultrasonography reveals the extent of structural changes within or paratenon is usually termed tendinopathy. and around the tendon. These images help the surgeon chose and plan the appropriate procedure. Recently, Doppler-ultrasound Achilles tendon overuse injuries investigations have been shown to reveal the presence of any patho- logic neovessel formations anterior to the tendon, which seem to be Achilles tendon overuse injuries are common. Predisposition to associated with the pain of Achilles tendinopathy. these injuries can result from a number of intrinsic and extrinsic factors: lower extremity malalignment such as hyperpronation, Experimentally, ultrasound-guided sclerosing injections of the increased femoral anteversion, or cavus foot and a tight Achilles neovessels anterior to the tendon have shown promising results tendon with poor flexibility. In recreational running athletes, poor in control of the pain. Surgery for chronic peritendinitis includes shoes, hilly tracks, and training errors (such as sudden changes removal of the thickened, scarred paratenon. A partial tear or in mileage or speed and improper warm-up and cool-down) are tendinosis involves an incision longitudinally in the tendon and related to heel cord overuse problems. The main symptom is careful removal of pathologic tissue, after which the tendon pain, typically located 2-6 cm above the Achilles tendon insertion should be closed carefully by adapting sutures side to side. In on the calcaneus. This region of the Achilles tendon complex retrocalcaneal bursitis, the bursa should be removed and an exci- is considered vulnerable and prone to overuse because of poor sion osteotomy of the superior corner of the calcaneal tuberosity vascularity. Physical examination should include an evaluation of should be carried out. Postoperative care usually involves immo- alignment and flexibility of the heel cord and inspection/palpation bilization for about 10 days followed by mobilization that allows of the cord, the insertion, and the retrocalcaneal area, respectively. plantar flexion of 0-20 degrees in a walking boot. With appropriate indications and carefully monitored postoperative rehabilitation Four major differential diagnoses must be considered: for 4-6 months, surgery yields good results in more than 80% 1. Peritendinitis is manifested as inflammation of the surrounding of patients. paratenon with crepitation occasionally present. After surgery, return to work depends on the diagnosis and 2. Tendinosis, or degenerative changes within the tendon itself, is the type of job. The patient can return to desk work within the first week but should keep the leg elevated. If the patient has characterized by gradual onset of pain and stiffness and localized mobile work that includes much walking, he or she can return to tenderness and swelling of the tendon complex. limited activities after 1 month using the walking boot. Return 3. Partial rupture typically causes a sudden onset of pain. to full activity is usually possible 3-4 months after surgery. After The condition is relatively rare and must be distinguished sclerosing injections, the amount of pain reduction controls the from the much more common total tendon rupture discussed return to work, which may vary significantly from 2-4 weeks to below. Clinical examination reveals localized swelling and months. Another diagnosis to consider, complete Achilles tendon rup- ture most commonly occurs in active people around 40 years
Chapter 8d ● Tendon injuries around the ankle 371 of age. As learned from sports activity, the most common injury Treatment of these injuries is normally surgical; however, a situation involves a sudden change of motion, including dorsal nonoperative approach using a below-knee cast may be war- ankle hyperextension. The typical history is a sensation of sudden ranted in the acute setting. For recurrently disabling dislocations pop and immediate but moderate local pain. Injured people often or subluxations, tendon stabilizing surgery that imbricates or believe that somebody has hit the ankle from behind. Failure or reconstructs the stabilizing retinacula is the only meaningful treat- impaired ability to plantar-flex the foot is typical as shown by ment. Deepening of the peroneal groove is sometimes indicated. squeezing the unweighted calf muscles (Thompson’s test). Before If the tendon has also a chronic pathologic condition, surgical significant local swelling sets in, there is a clearly palpable gap at incision and removal of the pathologic tissue can be valuable, rupture level, typically 2-6 cm above the distal insertion. although this procedure is not very common. Recommended treatment for active people is most commonly After surgery, return to a desk job wearing a cast or a walking surgical, allowing early tension to be put on the tendon for boot is possible within the first week. For people with more proper orientation of the healing collagen and better possibility demanding duties, however, the rehabilitation time is 6 weeks in to regain full strength. Early motion in the form of plantar a walking boot followed by 6 weeks of rehabilitation, making flexion from 0 to 20 degrees is permitted after 1 week, and the return to harder labor possible after 3-4 months. patient can walk with this ROM in a walking boot after 2-3 weeks. The boot is usually discarded after 6 weeks. An alternative option Flexor hallucis longus tendon for less active people, nonsurgical treatment involves at least overuse problems 6-8 weeks of immobilization and a longer rehabilitation. With nonsurgical therapy, the risk for rerupture is much higher, and Overuse problems in the flexor hallucis longus tendon complex early motion is not possible. are common in ballet dancers because of frequent and forceful plantar flexion of the ankle and great toe (plié and point work). After a complete Achilles tendon tear, return to a desk job Repetitive push-off maneuvers also transmit substantial forces depends on crutch walking but is possible within 3 to 5 days across the tendon and its sheath with possible irritation, swelling, regardless of treatment. If surgery has been performed, the and nodulus formation following. patient can often walk reasonably well within 1 month using a walking boot and can walk properly and resume full activity The result is pain and sometimes catching or even locking of 3-4 months after surgery. After nonsurgical therapy, return to the tendon, so-called functional hallux rigidus. Symptoms are demanding physical activity or work is usually not possible for most often located behind the medial malleolus where the tendon 4-9 months. passes through a narrow fibrous tunnel, thereby predisposing to impingement. Other tight areas for flexor hallucis longus tendon Peroneal tendon injuries passage are under the base of the first metatarsal and between the great toe sesamoids. The peroneus longus and brevis tendons run down the lateral aspect of the ankle and midfoot to their insertions on the plantar Therapy consists of active rest, ice, NSAIDs, and crutches side of the medial side of the midfoot (first metatarsal, medial in the acute phase. A longitudinal arch support with firm soles cuneiform, and navicular) and on the proximal end of the fifth is often helpful. Plié and point work in dancers, as well as metatarsal, respectively. The tendons pass behind the lateral malle- similar forced toe-off exercises in labor, must be avoided until olus beneath the two retinacula, which hold them in position. the patient is symptom free. If symptoms persist, especially if they are stenotic, surgery is indicated. At surgery, the fibrous Peroneal peritendinitis or tendinosis is typically elicited via tunnel is divided, and tenosynovectomy and tendon debride- stenosis under these retinacula. A longitudinal tear can occur as a ment are performed. When explored, local swelling of the result of either acute trauma or overuse. A common predisposing tendon proper often reveals a partial rupture, necessitating factor to the various forms of peroneal tendon disease is distortion scar tissue excision and tendon reconstruction. Postoperatively, of the local anatomy caused either by a fracture of the lateral malle- the ankle is immobilized up to 10 days followed by a rehabilita- olus or the calcaneus or by an ankle sprain. Pain, swelling, and joint tion program for at least 1-2 months. Whereas return to desk jobs sheath tenderness are located posterior and inferior to the lateral can occur within weeks, hard labor becomes possible after malleolus. Pain may be increased on weight bearing, but forced 2-4 months. plantar flexion and inversion as well as resisted eversion of the ankle are even more painful. Physical examination must include an Tibialis posterior tendon overuse problems evaluation of tendon stability as discussed below. Subtalar motion usually is decreased. Primarily nonsurgical, treatment includes Posterior tibial tendon injuries due to overuse are seen in young active rest, ice, NSAIDs, and crutches as acute measures. The addi- active persons such as runners. Hyperpronation is a strong pre- tion of casting or a walking boot can possibly be helpful in some disposing factor because mechanical demands on the tendon along patients. Surgery to correct the cause is only occasionally necessary. its course behind the medial malleolus to the insertion on the navicular bone are significantly increased. Repetitive microtrauma Recurrent subluxation or dislocation of the peroneal tendons leads to inflammation in the tendon sheath followed by partial is an important differential diagnosis. The initial mechanism for tears and scar formation in the tendon itself. Complete ruptures this injury involves significant internal rotation in combination are seen mostly in the elderly. Long-standing unidentified with inversion. There is sudden pain and a sensation of dislocation or subluxation over the lateral malleolar region.
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