MicrotraulDa Injuries and Rehabilitation of the Foot and Ankle Marie A. Johanson, MS, PT Private Practice, Physical Therapy Associates of Metro Atlanta, Jonesboro, Georgia

Aerobic exercise has grown in popularity as participants pursue goals of cardiovascular fitness, calorie consumption, and stress reduction. The increase in popularity of running has brought a host of injuries to the clinics of health professionals that differ fi'om the macro traumatic injuries associated with team sports. I An estimated 30 to 50% of all sports i~uries are due to microtrauma. 2 Microtrauma injuries at the fi)ot and ankle commonly occur in the running population. In a study of 4,358 runners and joggers, 45.8% were found to have suffered at least one jogging injury. g Seventy percent of this group suffered from microtrauma injuries, and foot and ankle joint injuries constituted 28.5% of all injuries. A study of 171 injuries in 121 runners found fully one-half of the injuries were at the foot. 4 James et al 5 reported 31 % of 232 diagnoses in 180 runners were microtrauma injuries of the foot and ankle. Microtrauma injuries of foot and ankle joint, however, are not confined to runners. Even among long distance bicyclists, a study determined that 7% of microtrauma injuries occurred at the fbot and ankle. 6 When treating microtrauma injuries of the foot and ankle joint, it is important to consider all etiologic factors to ensure the patient the most rapid progress possible and to prevent recurrence. This article reviews common microtrauma injuries of the f(Jot and ankle joint, extrinsic and intrinsic factors associated with each microtrauma injury, and presents case studies to illustrate the basic principles for evaluation and treatment of microtrauma il~juries.

COMMON MICROTRAUMA INJURIES AT THE FOOT AND ANKLE Structures commonly involved in micro trauma injuries include bursae, the musculotendinous unit, articular cartilage, and bone. Among the most common microtrauma injuries at the foot and ankle joint are Achilles' tendinitis, plantar fasciitis, shin splints, stress fractures, and metatarsalgia.

Achilles' Tendinitis Tendons are comprised of collagen and elastin. Staggered fibrils of collagen and elastin are organized into fibers, which form larger bundles of fascicles. 7 Tendons join muscle to bone and are subjected to tensile stresses. The blood supply to tendons is usually sparse, 8 rendering tendons vulnerable to injury and compromising their healing potential. Injuries to tendons can occur when tension is applied suddenly, tension is applied obliquely, the tendon is under tension before additionalloading occurs, the muscle attached to the tendon has a high motorneuron to muscle fiber innervation ratio, external stretch is applied to the muscle group, or the tendon is weak in relation to the muscle. 9 The Achilles' tendon is the conjoint tendon of the gastrocnemius and soleus muscles. Achilles' tendinitis occurs when repeated loading of the musculotendinous unit results in fatigue of the gastrocnemius-soleus muscles followed by shortening ofthe muscles. Shortening ofthe muscles, in turn, leads to an increase in passive loading of the tendon with activities that require dorsiflexion.]() Achilles' tendinitis may also occur when repetitive active loading of the musculotendinous unit leads to failure of collagen fibers. 10 A portion of the

J Back Musculoskel Rehabil

1992; 2(4):26-37

Copyright © 1992 by Andover Medical.

Microtrauma Injuries and Rehabilitation of the Foot and Ankle

Achilles' tendon, 2 to 6 cm from its insertion on the calcaneus, is particularly susceptible to chronic tendinitis because the reduced vascularity of this region reduces healing capability. Progression of tendinitis to complete spontaneous rupture is also most common in this region of reduced vascularity. II Achilles' tendinitis is common in runners and athletes who participate in sports that include running, such as basketball or tennis. Clinical symptoms consist of a gradual onset of pain and swelling in the Achilles' tendon 2 to 3 cm proximal to the insertion of the tendon. 12 Some patients have pain and stiffness when rising in the morning or pain at the start of activity that improves as the activity progresses. Others have pain that increases with activity and improves with rest. IO ,13 Clinical signs of Achilles' tendinitis are elicitation of pain with palpation just proximal to the insertion of the Achilles' tendon. 12 Swelling or thickening and crepitus may also be detected with palpation. 12 ,13 Pain can also be reproduced with a hop or skip on the involved extremity and with passive dorsiflexion of the involved ankle joint. 12 Extrinsic factors are commonly associated with the onset of Achilles' tendinitis. 10,12,13 Clement et al 12 reported 75% of runners with Achilles' tendinitis had committed one or more training errors. These training errors included a sudden increase in mileage, excessive hill running, and improper shoes. Problems identified in footwear included insufficient heel counter stability, excessive rigidity of the sole in the metatarsophalangeal region, and inadequate heel lifts. Intrinsic factors are also commonly identified in patient populations diagnosed with Achilles' tendinitis. IO ,12,13 Clement et al 12 reported 56% of 109 runners diagnosed with Achilles' tendinitis exhibited excessive pronation, and 38% had either decreased strength or decreased flexibility of the gastrocnemius-soleus muscles. Femoral anteversion is also an intrinsic factor in Achilles' tendinitis, presumably due to the compensatory torsional changes in the lower extremities that result in excessive subtabular joint (STJ) pronation. 10 Finally, a flexion contracture of the knee joint may contribute to the onset of Achilles' tendinitis due to a compensatory increase in ankle joint dorsiflexion.

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Plantar Fasciitis Plantar fasciitis occurs when microtears at the insertion of the plantar fascia result in a chronic inflammatory response that leads to fibrosis and degeneration. lo ,14 The plantar fascia originates on the medial tubercle of the calcaneus, and consists oflateral, central, and medial portions. 8 The plantar fascia courses anteriorly, and the central portion divides into five bands. Each band bifurcates at the level of the metatarsophalangeal joints and attaches to each side of the proximal phalanx. 8 During extension of the metatarsophalangeal joints, the plantar fascia provides a "windlass effect," shortening and increasing the height of the arch. 15 Hicks l5 reported the plantar aponeurosis bears 60% of the stress to the arch during weight bearing and the windlass mechanism is able to sustain 1.7-3.4 times the body weight before rupture. Plantar fasciitis is the most common cause of heel pain in runners. 16 Calcaneal bone spurs in conjunction with plantar fasciitis may occur, especially in overweight individuals, but are not thought to be the direct cause of pain. 17 Clinical symptoms consist of gradual onset of sharp pain in the plantar aspect of the heel that is worst when rising after a rest period. 14 The pain may be felt at the beginning of exercise and improve after the warm-up period, or the pain may be worst after exercise. 10,14 Clinical signs include pain with palpation of insertion of the plantar fascia on the medial tubercle of the calcaneus, over the medial aspect of the calcaneus, or both.IO,18 Passive dorsiHexion of the metatarsophalangeal joints may elicit pain due to the stretch of the plantar fascia. 19 Extrinsic factors that predispose to plantar fasciitis are sudden increases in activity, increases in hill running, running on transverse grades or in the same direction on a track, and change of footwear. 14,20 Intrinsic factors associated with plantar fasciitis include both abnormal pronation and abnormal supination during running. IS Lutter 21 reported that 13% of injured runners with pronated feet and 26% of injured runners with cavus feet were diagnosed with plantar fasciitis. Excessive pronation of the subtalar joint (STJ) results in excessive or prolonged calcaneal

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BACK AND MUSCULOSKELETAL REHABILITATION / FALL 1992

eversion, which results in increased stretching of the plantar fascia. Pronation of the SlJ at push-off further strains the insertion of the plantar fascia due to the windlass effect. Limited STJ pronation occurs in cavus feet. Since S1] pronation from foot-strike to midstance assists with dissipation of ground reaction forces, limited pronation during this phase of gait may result in increased transmission of forces to the plantar fascia. 22 In a study of weight-bearing patterns of patients with plantar fasciitis, longer heel contact times and shorter forefoot contact times were noted, indicating that the patients attempted to decrease stress on the plantar fascia by minimizing the windlass effect. 19 Leg-length discrepancies (LLD) also occur more frequently in athletes with plantar fasciitis than in uninjured athletes, presumably due to compensatory abnormal pronation or supination. One study showed 53% of runners with plantar fasciitis had at least a 0.64 em LLD compared with 21 % of a control group. 23 Recently, Kibler et al 14 conducted a study of 43 athletes with plantar fasciitis and found 95% had strength deficits of the plantarflexors when isokinetically tested. The gastrocnemius-soleus muscles produce the greatest torque during active inversion of the foot 24 and strength deficits of these muscles may result in instability of the foot from foot-flat to midstance when eccentric control of dorsiflexion is needed. At push-off, weak plantarflexor muscles decrease propulsive strength and may increase tensile loading on their tendinous and ligamentous attachments. 19 Kibler et al 14 also found 86% of the athletes exhibited restricted passive ankle joint dorsiflexion. Excessive STJ pronation is a common compensatory mechanism when ankle joint dorsiflexion is limited.

Shin Splints Shin splints may be diagnosed in any exerciserelated pain in the leg, excluding stress fractures or ischemic disorders. 25 Based on the location of pain, shin splints are divided into two types: anteromedial and posteromedial. Conditions that are most often cited as the cause of anteromedial shin splints are strains of the tibialis anterior, ex-

tensor hallucis longus, and extensor digitorum longus muscles; tearing of the interosseous membrane between the tibia and fibula; periostitis at the proximal attachments of the pretibial muscles; or tendinitis of the pretibial muscles. 26.27 Conditions comprising posteromedial shin splints include strains or tendinitis of the tibialis posterior, flexor hallucis longus, and flexor digitorum longus musculotendinous units, or periostitis of the proximal attachments of these three muscles or the soleus muscle. 26-28 Shin splints are most common in runners but also occur in athletes involved in running and jumping sports such as basketball, tennis, and football. 26 Generally, the patient will initially report a dull aching pain in the anterolateral or posteromedial leg following activity, though as the condition worsens, pain may also be present during running, ambulation, or even at rest. 26 Tenderness is generally palpable over the pretibial muscles or their periosteal attachments, or posteromedially over one or more of the plantarflexor muscles, or at the periosteal attachment of the posterior tibialis or soleus muscles on the tibia. 26 Tenderness over the anterolateral distal twothirds of the tibia is thought to indicate tendinitis or periostitis of the anterior tibialis, extensor digitorum longus, or extensor hallucis longus muscles. 29 Tenderness over the posteromedial distal one-third of the tibia is thought to represent a periostitis of the soleus muscle. Cadaver studies demonstrated that the origin of the soleus muscle extends to about 4 inches above the medial malleolus, and its investing fascia extends from the distal origin to just below the medial malleolus. 28 Tenderness at the posteromedial proximal onethird of the tibia is thought to represent tendinitis or periostitis of the tibialis posterior, flexor hallucis longus, or flexor digitorum longus muscles. 3o Rising on the to~s may be painful. 28 Resisted inversion, toe extension or flexion, or isolated great toe extension or flexion may also provoke pain due to inflammation of the pretibial or posterior muscle group or inflammation at their sites of attachment. 30 Radiographs are generally negative, but in rare instances, may show an area of cortical hypertrophy.28 Radionuclide bone scans have demonstrated increased uptake along the

Microtrauma

I~juries

posterior medial border of the tibia in patients with posteromedial shin splints.2H Extrinsic factors associated with shin splints are walking, running, or jumping on hard surfaces, lack of cushion in the athletic shoe, excessive distance or speed of running in an untrained individual, and hiking or marching over uneven terrain. 26,:\0,:1 I Intrinsic factors that predispose an individual to anterolateral shin splints are weakness of the pretibial muscles (the pretibial muscles fatigue as they work to decelerate plantarflexion and pronation of the foot from foot-strike to midstance) and excessive pronation. 26 ,30,31 The most common intrinsic factors associated with posteromedial shin splints are excessive or abnormal pronation and restricted ankle joint dorsiflexion. 23 ,27,28,30 Studies have specifically assessed biomechanical differences between healthy athletes and athletes diagnosed with shin splints, and these studies show statistically significant increases in the calf-to-calcaneal angle in standing and during running (Fig. 1).27,30 An increase in subtalar joint pronation during gait increases strain on the distal aspect of the origin of the soleus muscle and its investing fascia on the medial tibia because the calcaneus excessively everts during the stance phase of gait. The posterior tibialis, flexor hallucis longus, and flexor digitorum longus muscles may also fatigue as they overwork to eccentrically control pronation from foot-strike to midstance. 31

Stress Fractures Stress fractures may develop as a result of repetitive mechanical stress. 32 Bone often cannot adapt to the repeated submaximal loading imparted from the musculotendinous tissues at the onset of physical activity. A study of 142 stress fractures resulting from exercise activities showed over 50% occurred in the tibia. 32 Most ofthe stress fractures of the tibia were located posteromedially in the proximal and distal one-third of the tibia. Infrequently, stress fractures were diagnosed anteriorly in the middle one-third of the tibia. :12,33 Conversely, a study of military recruits showed that 88% of stress fractures in the tibia occurred along the medial cortex of the middle one-third of the

and Rehabilitation of the Foot and Ankle

29

Figure 1. Calf~to-calcaneal angle. One arm of the goniometer is aligned with the midline of the calf and the other with the midline of the calcaneus.

tibia. 34 Other common sites of stress fi'actures in Orava et aI's study32 were the metatarsals (18%) and the fibula (14%). Most stress fractures of the metatarsals occurred in the shaft or neck of the second and third metatarsals, though some were located in the fourth and fifth metatarsals. Most fibular stress fractures occur just proximal to the tibio-fibular syndesmosis, 4 to 7 cm superior to the tip of the lateral malleolus. :12 Running causes most stress fractures, though jumping can also produce stress fractures. According to Orava et aI's work,32 joggers usually develop stress fractures two to four months after onset of their training program. Patients with stress fractures report dull pain that begins following activity, then progresses to pain during activity, and finally occurs during walking. :12,:1:1 A callus may be palpated, as may be local edema and tenderness over the site of the stress fracture. :~2,:n Radiological evidence of stress fracture will not appear for two to six weeks after

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BACK AND MUSCULOSKELETAL REHABILITATION / FALL 1992

the onset of symptoms, so repeated radiograms are usually necessary to differentially diagnose a stress fracture from tendinitis or periostitis. Evaluation of intramuscular pressure in the anterior or posterior compartments of the leg can be used to differentially diagnose compartment syndromes from stress fractures or shin splints. 35 Additionally, chronic compartment syndromes are not associated with the onset of physical activity, pain behavior is that of intermittent claudication, and pain is more diffuse and is provoked with palpation over the entire compartment. 33 Tomography and bone scanning are more useful for early diagnosis of stress fractures than radiograms. 18 ,32,34,36 Extrinsic factors that may result in stress fractures of the leg and foot are running on hard surfaces, improper running shoes, or sudden increases in jogging or running distance. 26,32 Intrinsic factors to consider when evaluating stress fractures include malalignment of the lower extremity, particularly excessive pronation. A less common, often overlooked stress fracture occurs in the navicular bone. The central portion of the navicular bone may be vulnerable to stress fracture due to its relative avascularity.18 Symptoms are insidious onset of diffuse pain over the dorsal aspect of the medial midfoot or the medial aspect of the longitudinal arch. 18,36 Generally, tenderness to palpation is localized over the navicular bone or longitudinal arch. 18 Intrinsic factors that may predispose a physically active individual to stress fractures of the navicular bone are a short first metatarsal, metatarsus adductus, limited ankle joint dorsiflexion, limited subtalar joint mobility, or excessive pronation. 18,36

Metatarsalgia Metatarsalgia, like shin splints, is a catchall term used to describe the symptom of pain in the forefoot. Scranton 37 studied 98 patients with metatarsalgia and recommended use of the diagnosis of primary metatarsalgia to describe pain in one or more metatarsophalangeal joints as a result of abnormal weight distribution across the metatarsal heads and toes during gait. Patients with primary metatarsalgia report a gradual onset of pain in the forefoot that increases with ambulation and

decreases with rest. Systemic diseases, such as rheumatoid arthritis, gout, or Charcot-Marie Tooth disease, that may result in pain in the forefoot are excluded from a diagnosis of primary metatarsalgia. 37 Plantar keratoses are often present under the metatarsal head subjected to abnormally high weight bearing. Force plate analysis demonstrates abnormal pressure distribution across the metatarsal heads. 37 Extrinsic factors in primary metatarsalgia may be forefoot striker patterns in inexperienced runners. Primary metatarsalgia is more common in women due to ambulation in high heel shoes, which shifts weight bearing anteriorly onto the metatarsal heads. Intrinsic factors relevant to onset of primary metatarsalgia are hallux valgus deformities, hammer-toe deformities, significant length discrepancies between the metatarsals, and an equinus gait due to restricted ankle joint dorsiflexion or gastrocnemius-soleus tightness. 37 Restricted ankle joint dorsiflexion or tight gastrocnemiussoleus muscles result in early heel-rise and increased weight bearing on the forefoot. Additional primary problems that create pain in the forefoot need to be considered, such as tarsal tunnel syndrome or Morton's neuroma. Morton's neuroma is differentiated from metatarsalgia by a history of sudden acute episodes of radiating pain and paraesthesias into the toes, increased pain with lateral compression of the forefoot, and palpation of the affected web space. 38

CASE STUDIES The following case studies illustrate the problemsolving approach to the evaluation and treatment of microtrauma injuries of foot and ankle joint. The elements of problem-solving for clinical decision-making in each case study include: identification of the patient's problem, characteristics of the problem (symptoms), factors affecting the problem (evaluative findings, extrinsic factors, intrinsic factors), determination of a method to resolve the problem, treatment program, evaluation of effectiveness of the treatment program, and modification of the treatment program.

Microtrauma Injuries and Rehabilitation of the Foot and Ankle

Case Study I

31

Identifying characteristics of the problem. I. The pain is intermittent; it appears during both jogging and basketball play, but is worse with running. 2. I"ain resolves with cessation of the activities in about 3-4 hours. 3. Mild discomfort is felt during the first several steps in the morning.

Identifying factors affecting the problem. Evaluation. Palpation elicited tenderness over the medial tubercle of the calcaneus. Pain was provoked with passive extension ofthe right first metatarsophalangeal joint and with rising on the toes. Range of motion of the subtalar joint was normal. Forefoot varus measured 4 degrees on the right and 5 degrees on the left. Ankle joint dorsiflexion, measured with the STJ in neutral and the knee extended, was 3 degrees on the right and 7 degrees on the left. Ankle joint dorsiflexion measured with the knees flexed was 10 degrees bilaterally. In standing, the right iliac crest, posterior superior iliac spine (PSIS), and anterior superior iliac spine (ASIS) were all higher on the right (Fig. 2). In supine, the right medial malleolus was longer than the left, measuring 10 mm longer from the ASIS to the midpoint of the medial malleolus. The standing calf-to-calcaneal angle measured 10 degrees on the right and 5 degrees on the left (Fig. 1).

A

B

Identifying the patient's problem. The patient is a 28-year-old male who states he developed pain in the plantar aspect of the right heel that gradually increased over a two-month period. His activities include participation on a recreational basketball team and jogging 3-6 miles four or five times weekly for the past five years. His goal is participation in a 10 km race in six months.

Figure 2. Palpation of bony landmarks to assess relative heights of the pelvis. (A) Relative heights of the iliac crest. (B) Relative heights of the PSIS.

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BACK AND MUSCULOSKELETAL REHABILITArION / FALL 1992

Determining a method to resolve the problem. Assessment oj the problem: Plantar fasciitis in a subacute phase. The patient is predisposed to this injury due to a leg-length discrepancy, however, the injury was precipitated by running on crowned roads and initiation of hill running. Tightness of the gastrocnemius muscle increased the need for compensatory pronation on the longlimb side, especially when running uphill. Program of treatment 1. Iontophoresis was applied at 5.0 rna for 20 minutes using dexamethasone and 4% xy-

c Figure 2. (continued)

(C) Relative heights of the

ASIS.

Extrinsic factors contributing to the problem. I . The patient moved to a new location three months ago. At this time, he began jogging on his neighborhood streets, rather than driving to the dirt trail where he had been training. He runs against traffic for safety purposes. This meant that his right lower extremity was always on the uphill side ofthe transverse grade of the road, resulting in functional pronation and increasing stress to the plantar fascia. 2. The patient had begun increased hill training in preparation for a race on a hilly course. Intrinsic factors contributing to the problem. I . Leg-length discrepancy: longer on the right. 2. Tightness of the gastrocnemius: worse on the right.

locaine every other day for three treatments. Glass et al 39 demonstrated this dosage increased local tissue concentration of these agents greater than did systemic administration ofthe same medications in monkeys. Clinical research also indicates iontophoresis is effective in the treatment of tendinitis, both for subjective pain levels and range of motion and function. 4o 2. The patient was given a 5 mm heel lift in the left shoe to reduce the need for compensatory pronation on the right. Leg-length discrepancies of approximately 4 cm or more that are associated with microtrauma injuries may benefit from a hecllift. 41 The initial hecllift should attempt to correct no more than one-half of the measured leg-length discrepancy.42 3. The patient was advised to return to level running for two weeks and then gradually return to roads and hills. He was instructed to alternate running with or against traffic whenever possible to distribute the unequal pronatory and supinatory stresses of running on a transverse grade more equally. The goal is to prevent an environmentally induced exaggeration of the leg-length discrepancy, and to temporarily avoid hill running that is associated with increased stress to the plantar fascia. 20 4 . The patient was instructed to ice the plantar aspect of the heel after running for 15-20 minutes. Ice is used following activity to reduce tissue inflammation. Ice acts as a vasoconstrictor and slows cell metabolism, thereby preventing or reducing swelling that results from inflammation. 43

Microtrauma Injuries and Rehabilitation of the Foot and Ankle

5. The patient was instructed to stretch the gastrocnemius muscle for ten repetitions of 10 seconds ten times per day. He was instructed to stretch with the STJ in a neutral or supinated position, rather than in a pronated position (Fig. 3). The change in stretching methods isolates talocru ral joint dorsiflexion rather than a combination of talocrural dorsiflexion, STJ pronation, and midtarsal joint pronation. Increased extensibility ofthe gastrocnemius muscle is hypothesized to decrease symptoms and prevent recurrence of plantar fasciitis. 14

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a subjective improvement scale of 0 to 10). Ankle joint dorsiflexion with the knee extended improved to 8 degrees on the right and 12 degrees on the left. Passive first right MTP extension was painfree. Mild tenderness was palpable over the medial tubercle of the calcaneus. Reassessment: The present program of a heel lift and gastrocnemius stretching is effective. No modifications were deemed necessary. The patient was instructed to return to the clinic if the symptoms did not fully resolve within another month.

Case Study II Evaluating effectiveness of the method of resolution. After five treatment sessions, the patient was interviewed on the telephone two weeks after the final clinic treatment and was seen one month later in the clinic. Subjective symptoms had decreased 90% fi"om the initial evaluation (based on

Identifying the patient's problem. The patient is a 23-year-old woman who reported bilateral calf pain, worse on the left side. She recently joined her church soccer team and is practicing with the team one or two times weekly. She is an administrative assistant by occupation. Her usual

B

Figure 3. (A) Incorrect method of stretching the gastrocnemius muscle. The patient is stretching into subtalar and midtarsal pronation, as well as ankle dorsiflexion. (B) Correct method of stretching the gastrocnemius. The patient is maintaining the subtalar joint in a neutral to inverted position.

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BACK AND MUSCULOSKELETAL REHABILIlf\TION / FALL 1992

exercise routine is swimming at a moderate intensity level for 20 minutes at a YMCA, three times weekly. Her goal is to continue participation on the soccer team without pain as well as painfree daily activities. Identifying characteristics of the problem. 1. An aching pain begins about 30 minutes after beginning soccer practice and continues throughout practice. 2. In the evening, after practice, she experiences aching in the posteromedial calves and stooping is painful. Identifying factors affecting the problem. Evaluation. Tenderness was palpable over the distal one-third of the medial aspect of the tibia and was much worse on the left. Jumping reproduced the pain and was worst during the landing phase. Resisted contractions of the ankle invertors and plantarflexors provoked the pain. The patient's forefoot position measured 12 degrees of varus on the left and 9 degrees of varus on the right. Left ankle in SIJ neutral was 5 degrees when the knee joint was positioned in extension, and 8 degrees when the knee joint was flexed. Right ankle dorsiflexion measured 10 degrees and 15 degrees, respectively. In standing, excessive calcaneal valgus, "squinting patellae," and excessive external tibial torsion were noted. The patient was observed during ambulation, and excessive pronation bilaterally was noted. Extrinsic factors contributing to the problem. 1. Sudden onset of a sport that requires running and some jumping, without adequate preparation. Intrinsic factors contributing to the problem. 1. Tightness of the left gastrocnemius-soleus muscle group. 2. Isokinetic strength testing at 60 degrees per second showed a 30% deficit in peak torqueto-body weight ratio as compared to the right side plantarflexors, while average power per repetition showed a 45% deficit on the left. The peak torque-to-body weight ratio of the right

3. 4.

5.

6. 7.

plantarflexors was 22%, which is slightly below the expected strength for a woman her age. 44 Q-angle of 25 degrees on the left and 20 degrees on the right. Possible femoral anteversion, suggested by 60 degrees of hip internal rotation measured prone, on the left, and 50 degrees on the right (Fig. 5 of article in this issue titled "Contributing Factors in Microtrauma Injuries of the Lower Extremity"). Forefoot varus deformities (Fig. 2 of article in this issue titled "Contributing Factors in Microtrauma Injuries of the Lower Extremity). Excessive pronation during gait. Excessive external tibial torsion, measuring 30 degrees on the left and 27 degrees on the right.

Determining a method to resolve the problem. Assessment of the problem: Posteromedial shin splints involving the soleus muscle due to "miserable malalignment" with femoral anteversion, external tibial torsion, and excessive pronation at the subtalar joint. The patient's previous exercise activity of swimming utilized gastrocnemius-soleus contractions of long duration/low intensity, primarily in the plantarflexed position. The soleus muscle was unable to tolerate a sudden demand for more forceful contractions during bursts of running and jumping and sudden stops that require strong eccentric contractions of the gastrocnemius-soleus muscles during deceleration. Excessive subtalar motion subjected the distal attachment of the soleus to additional strain due to increased calcaneal eversion. 28 Program of treatment. 1. Phonophoresis using 10% hydrocortisone ointment for six minutes at 1.0 VWcm 2 over six visits. Phonophoresis introduces hydrocortisone into tissue, thereby decreasing inflammation, providing pain alleviation, and increasing range of motion for a variety of inflammatory problems. 45 A 10% solution has been reported more effective than a 1% solution. 45 2. Application of moist heat before activity and ice after activity. Heat before activity increases circulation within the muscle, improving efficiency of

Microtrauma Injuries and Rehabilitation of the Foot and Ankle

subsequent muscle contractions. Ice reduces a potential inflammatory response to activity.43 3. Fabrication of foot orthoses with 5 mm varus posting in the forefoot on the left and 4 mm on the right, and reari()ot varus posting of 4 mm bilaterally (Fig. 4). Orthoses with varus posting have been found to decrease STJ pronation in the frontal plane. 46 - 48 Compensatory subtalar pronation that results from femoral anteversion and forefoot varus deformities subjects the distal aspect of the origin of the soleus to additional strain. 28 Reducing the need for compensatory pronation with varus wedging reduces the strain on the soleus.

35

4. Instruction in a progressive resistive exercise

(PRE) program for the gastrocnemius-soleus muscles. Exercise began with elastic resistance to ankle joint inversion and plantarflexion and progressed to bilateral and then unilateral heel raises on a step as symptoms decreased . The patient began with three sets of ten repetitions with 60 second rest periods between sets. She progressed to ten sets of ten repetitions before increasing the resistance. 5. The patient was instructed in stretching of the gastrocnemius and soleus muscles. Increased extensibility of the gastrocnemius-soleus muscle group results in increased dorsiflexion range of motion at the ankle joint, and the need for compensatory STJ pronation is reduced . Evaluating effectiveness of the method of resolution. Reassessment in four weeks: The patient reported a 50% reduction in symptoms in the left calf and complete resolution of symptoms in the right cal£ She still experienced pain after soccer practice, but no longer during practice. Tenderness remained over the distal one-third of the left medial tibia. Repeat isokinetic testing of the ankle musculature revealed improvement to a 25% deficit of the left plantarflexors in average power per repetition, while peak torque was within normal limits. Ankle dorsiflexion had improved, with the left now measuring 8 degrees with the knee extended and 10 degrees with the knee Hexed, and 10 degrees and 15 degrees, respectively, on the right.

Figure 4. place.

Forefoot and rearfoot varus posts in

Modifying management. I. The patient was started on gradual plyometric exercises using a sled in the supine position (Fig. 5). She began with minimal resistance and three time bouts of 30 seconds each, with 90 second rest periods between bouts. Time bouts were gradually increased to ten bouts. At that point, resistance was increased with addition of more surgical tubing, and time bouts were reduced to three bouts. The cycle was repeated . The plyometric program adapts the gastrocnemius-soleus muscles and Achilles tendon by simulating a jumping maneuver in a gravityeliminated position. Jumping requires a quick,

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BACK AND MUSCULOSKELETAL REHABILITATION / FALL 1992

Figure 5. Plyometric sled. Controlled, gravity-eliminated jumping exercises can be used to train for sports activities.

powerful, eccentric contraction of the plantarflexors, followed by a concentric contraction. 49 2. Forefoot varus post on the left was increased to 7 mm. The patient was tolerating the orthoses well, and posting on the left side was increased to further support the forefoot varus deformity and reduce compensatory STJ pronation.

CONCLUSION An overview of common microtrauma injuries at the foot and ankle identified common symptoms, intrinsic factors, and extrinsic factors associated with each microtrauma injury. Case studies demonstrated the need to evaluate symptoms, identifY intrinsic factors, and identify extrinsic factors to effectively treat microtrauma injuries.

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7. Herring SA, Nilson KL. Introduction to Overuse Injuries. Clin Sports Med 1987; 6:225-239. 8. Pick TP, Howden R (eds). Gray's anatomy. New York: Bounty Books, 1977. 9. Barfred T : Experimental rupture ofAchilles tendon. Comparison of various types of experimental ruptures in rats. Acta Orthop Scand 1971 ; 42:528-543. 10. Clancy we. Tendinitis and plantar fasciitis in runners. In: D'Ambrosia R, Drez D, eds. Prevention and treatment of running injuries. Thorofare, N.J.: Charles B. Slack, 1982: pp. 77-87. II. Ralston EL, Schmidt ER. Repair of the ruptured Achilles tendon. J Trauma 1971 ; 11: 15-21. 12. Clement DB, Taunton JE, Smart ew. Achilles

Microtrauma Injuries and Rehabilitation of the Foot and Ankle

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