Defective Running Shoes as a Contributing Factor in Plantar Fasciitis in a Triathlete

Transcription

1 Journal of Orthopaedic & Sports Physical Therapy 2000;30(1):21-31 Defective Running Shoes as a Contributing Factor in Plantar Fasciitis in a Triathlete Bruce R. Wilk, P7; OCS1 Karen 1. Fisher, MS, PTZ William Gutierrez, MS, PT; OCS, ATC3 Study Design: Case study of a patient who developed plantar fasciitis after completing a triathlon. Objectives: To describe the factors contributing to the injury, describe the rehabilitation process, including the analysis of defective athletic shoe construction, and report the clinical outcome. Background: Plantar fasciitis has been found to be a common overuse injury in runners. Studies that describe causative factors of this syndrome have not documented the possible influence of faulty athletic shoe construction on the symptoms of plantar fasciitis. Methods and Measures: The patient was a 40-year-old male triathlete who was followed up for an initial evaluation and at weekly intervals up to discharge 4 weeks after injury and at 1 month following discharge. Perceived heel pain, ankle strength, and range of motion were the primary outcome measures. Shoe construction was evaluated to assess the integrity of shoe manufacture and wear of materials by visual inspection of how shoe parts were glued together, if shoe parts were assembled with proper relationship to each other, if the shoe sole was level when resting on a level surface, and if the sole allowed unstable motion. Results The patient appeared to have a classic case of plantar fasciitis with a primary symptom of heel pain at the calcaneal origin of the plantar fascia. On initial evaluation, right heel pain was a 9 of 10, plantar flexion strength was a 3t15, and ankle dorsiflexion motion was 10". One month after discharge, perceived heel pain was 0, plantar flexion strength was 515, and dorsiflexion motion was 15" and equal to the uninvolved extremity. The right running shoe construction deficit was a heel counter that was glued into the shoe at an inward leaning angle, resulting in a greater medial tilt of the heel counter compared with the left shoe. The patient was taught how to examine the integrity of shoe manufacture and purchased a new pair of sound running shoes. Conclusions: A running shoe manufacturing defect was found that possibly contributed to the development of plantar fasciitis. Assessing athletic shoe construction may prevent lower extremity overuse injuries. ) Orthop Sports Phys Ther 2000;30: Key Words: defective athletic footwear, plantar ligament inflammatory syndrome, running I Orthopedic Rehabilitation Specialists, Miami, Fla. Orthopedic Rehabilitation Specialists, Miami, Fla. Orthopedic Rehabilitation Specialists, Miami, Fla. Send correspondence to Bruce R. Wilk, Orthopedic Rehabilitation Specialists, 8720 N Kendall Drive, #206, Miami, FL info@defectiveshoe.com P hysical therapists frequently treat patients with injuries sustained from running. Often these pathologic conditions stem from poor skeletal alignment in the pelvis and lower extremity. According to Grosslo and othe~-s,~.~j~j~j"~~ musculoskeletal pathologic conditions may be exacerbated by pelvic and lower limb malalignments or biomechanical imbalances caused by training techniques, footwear, running style, environmental terrain, and sport-specific athletic conditioning. Physical therapists routinely inspect shoes and wear patterns in patients who develop pelvic and lower limb musculoskeletal pathologic conditions. In our clinic, examination of athletic shoe construction (in patients with common lower extremity overuse injuries) has revealed manufacturing defects in shoes that were used at the time of injury. Although the cause of an overuse injury is multifactorial, a review of the literature did not reveal any studies of defective athletic shoe construction as a contributing source of common lower extremity overuse injuries. This case report is based on the clinical observation of a patient who developed plantar fasciitis while wearing a pair of running

2 TABLE 1. The patient's training schedule 8 weeks before the race. Saturday Weeks to Monday Tuesday Wednesday Thursday Friday swim, dbike, kmlmn, km Sunday race day swim, m run, km run, km bike, km swim, m or swim, mlrun, km bikelmn, km Rest Rest ' Rest 40 Rest Race day shoes that were found to have a manufacturing defect. The study identifies the musculoskeletal pathologic structure and looks at the possible factors that contributed to this injury. The patient's specific treatment plan is described, and the patient's response to the treatment is delineated. Suggestions are made for patient education in proper shoe selection and foot support. Clinical guidelines were created and are presented to teach patients how to assess the quality of athletic shoe construction. METHODS AND MEASURES Subject A 40-year-old male triathlete with a diagnosis of plantar fasciitis was referred to physical therapy by his family physician. The patient complained of the onset of heel pain in his right foot after completing a half-ironman triathlon, which consists of a 2-km swim, a 90-km bike ride, and a 21-km run. The patient was an experienced triathlete, and he described a well-rounded training program. His regimen included a daily flexibility routine and a biweekly strength training routine. Biking and running workouts were performed over bridges to simulate hill training, because the patient lived in a flat environment and the race course was hilly. Interview Data The patient was familiar with the race course, because he had trained and competed on it previously. Table 1 shows the patient's training schedule 8 weeks before the race. The patient used the same brand and model of running shoes for more than 2 years, with replacement of worn shoes every km. The patient felt the weather conditions during the race were favorable, since it had been cool and overcast, even though it rained for a short period at the beginning of the run. Several hours after the race, the patient noticed a gradual onset of right inferomedial heel pain, which presented as a dull, constant ache. The day after the race, the patient noticed sharper pain in the same location on the right foot, especially when taking the first several steps in the morning. These symptoms were severe enough to cause the patient to limp while walking and made it impossible to run. There was no history of heel pain. Rest from weight-bearing activities and icing helped to alleviate the pain. The patient also noted that initially he had minor muscle soreness in the right proximal calf. Physical Examination Two days after the race, the patient was seen for an initial physical therapy evaluation. One clinician completed the patient examination. The right lower extremity plantar fascia and soft tissues were examined with palm and fingertip palpation. Varying pres sures from light touch to deep pressure were used to determine the irritability of the plantar fascia and associated tissues and the patient's perceived pain. With the toes maintained in passive extension, firm palpation pressure was exerted on the medial border of the plantar fascia along the longitudinal arch. This palpation procedure was repeated with the patient actively dorsiflexing the right ankle and extending the great toe. The patient's lower extremity alignment was evaluated by measuring the subtalar joint angle in standing, using a goniometer. The therapist measured the angle created by a line bisecting the posterior aspect of the distal third of the lower leg and a line bisecting the posterior aspect of the rear foot."' There were 5" of calcaneal eversion bilaterally. Further musculoskeletal evaluation of the right lower extremity included gait analysis, manual muscle testing, and flexibility testing of the gastrocnemius muscle. The patient's gait was visually examined, with the patient walking at a moderate pace within his pain tolerance. Gait deviations were compared with the conventional components of a normal gait cycle. Manual muscle testing was completed using the traditional manual muscle testing positions and scale, according to Daniels and Worthingham's manual mus cle testing text.i4 Gastrocnemius muscle flexibility testing was completed by measuring the angle of ankle dorsiflexion with a goniometer, while passively J Orthop Sports Phys Ther.Volnme SO-Nrimber 1.January 200

3 FIGURE 1. Sections and components of a running shoe. dorsiflexing the non-weight-bearing ankle from a subtalar neutral position with the knee in 0" extension. The end feel of the dorsiflexion range of motion was noted. An x-ray report revealed no evidence of anatomic abnormalities, stress fractures, bony tumors, osteophytes, or degenerative joint disease. Shoe evaluation involved visual inspection of shoe parts as shown in Figure 1.1"JR.21 The shoe was assessed for the integrity of construction and the wear of the shoe materials. The patient's heel pain and deficits were found exclusively on the right lower extremity. The patient appeared to have a classic case of plantar fasciitis, with a primary symptom of heel pain at the calcaneal origin of the plantar fascia. Outcome Measures The patient perceived his right heel pain as intense by rating the pain as a 9 on a subjective 0 to 10 visual analog scale (where 0 indicates the absence of pain and 10 indicates the maximum pain). Moderate pressure fingertip palpation over the right inferomedial calcaneus elicited a verbal pain response and limb withdrawal due to pain. With the toes maintained in extension passively, firm pressure to the medial border of the plantar fascia elicited the previous pain response. In bare feet, the patient's standing posture revealed ankle pronation on both lower extremities. Using a goniometer, 5" of calcaneal eversion were measured during static single-limb support on each lower extremity. Musculoskeletal evaluation of the right lower extremity revealed the following. First, the patient displayed an antalgic gait pattern, where the transfer of body weight was executed with a nearly flat foot, resulting in a shortened stance of the right lower extremity due to decreased heel strike and push-off phases. Second, manual muscle testing produced heel pain and showed impaired gastrocnemius and FIGURE 2. In this posterior view, gray arrows (A and B) point to the mild inward lean of the training (T) shoe heel counters. The upper, outside borden of the heel counters show an inward bending of the lateral portion of the heel counter due to the stress from the repetitive pronation force during running. soleus strength; the patient was able to complete 5 repetitions of full-range heel raises, representing strength in the 3+/5 range on the standard manual muscle testing scale.14 Third, a limitation in the passive (non-weight-bearing) dorsiflexion of the ankle from a subtalar neutral position (with 0" knee extension) revealed a decreased flexibility of the gastrocnemius muscle; right ankle dorsiflexion measured 10" compared with 15" on the left ankle; there was a firm end feel to the motion, and the patient reported feeling a pulling sensation in the right calf. The stabilizing components of the patient's training and racing shoes included a visible rear foot grid system with heel counter reinforcement and a compression-molded midsole of ethylene-vinyl acetate foam and dualdensity polyurethane. Both pairs of shoes showed posterolateral heel wear. Each of the training shoes showed a mild inward lean of the heel counter (Figure 2). According to the patient, the training shoes had approximately 480 km of wear, and the racing shoes had approximately 48 km of wear. Examination of the racing shoes revealed the right shoe heel counter had a visibly larger inward tilt compared with the left racing shoe (Figure 3) and the training shoes (Figure 2). The right racing shoe heel counter was glued into the shoe at an angle that we thought could have caused excessive inward rolling of the right foot. Treatment The goals of treatment for plantar fasciitis were to decrease inflammation; increase flexibility and strength; improve functional agility, running skills, and conditioning; return gradually to a training schedule; and educate the patient about the components of sound athletic shoe construction. J Orthop Sports Phys Ther.Volume 30. Number 1.January 2000

4 FIGURE 3. A, In this posterior view, a clear arrow points to the left racing (R) shoe heel counter. B, A black arrow points to the visible inward deformity of the right racing (R) shoe heel counter. The outside borders of the heel counters show that the shoe in A has heel counter that is glued in at a perpendicular angle, whereas the shoe in B has a heel counter that is glued in at a slightly medial angle. Treatment to decrease inflammation included soft tissue mobilization and deep friction massage of the plantar fascia in a stretched position (ie, ankle dorsiflexion). The patient rolled his foot with a firm pressure on a 3/4indiameter wooden dowel rod for 5 minutes daily. The patient also received 8 ultrasound treatments to the right plantar fascia at an intensity of 1.0 W/cm2, continuous wave frequency of 1.0 MHz, for 5 minutes. A cold pack was applied daily to the bottom of the right foot for 20 minutes. The patient performed 20 minutes of stretching exercises daily for the right lower extremity as part of his home exercise program. Physical therapy sessions included passive and active assistive stretches that emphasized increasing the flexibility of the plantar fascia and the posterior lower extremity musculature (ie, piriformis, hamstring, iliotibial band, gastrocnemius and soleus, and both the intrinsic and extrinsic toe flexor musculature). The patient performed calf stretches leaning toward a wall in a weight-bearing position by moving the tibia anteriorly over the foot, with the knee flexed and with the knee extended. The patient also stretched off the edge of a step by keeping the toes pointing slightly inward with the forefoot weight-bearing on the step. The patient then dropped the heel downward slowly, while preventing the foot from pronating. A progressive rehabilitation protocol was implemented (Table 2). Strengthening exercises were performed on alternate days in series of 3 sets to temp* rary muscle fatigue (ie, loss of form or ability to push the resistance through the full range of motion or substitution of a stronger muscle group for a weaker muscle group). The patient continued a swimming program and biking outside his treatment sessions. As soon as the patient was pain-free during activity in the morning, he began the walking program described in week 1 of the rehabilitation prot* col (Table 2). Balance, conditioning, and agility skills were also addressed in a home program that was consistent with the progression of the treatment plan. The patient was educated about the components of sound athletic shoe construction. The following guidelines were developed to teach the patient how to look for sound shoe construction: The shoe should be glued together securely. Test this by holding the shoe and trying to pull the upper part of the shoe away from the midsole and the midsole from the outsole (Figure 4). The upper part of the shoe should be glued straight into the sole. Test this by using a goniometer to measure a 90" angle. Place the vertical arm (of the goniometer) along the center of the posterior heel counter and the horizontal arm parallel to the surface on which the shoe is resting (Figure 5A). As you view the shoe from the back on a level surface, the whole upper part of the shoe should appear even. Figure 5B shows the upper shoe leaning to the right. The sole of the shoe should be level to the surface on which the shoe is resting. Test this by measuring the medial and lateral vertical distance of the posterior sole on the heel of each shoe. With a tape measure or a ruler, measure the distance from the top edge of the posterior sole to the surface on which the shoe is resting (Figure 6A and B). Compare these measurements within each shoe. The shoes should not roll excessively inward or outward when resting on a level surface. Test this by applying a downward medial and then a downward lateral force to both the right and left shoe to see if they rock inward or outward (Figure 7A and B). Air pockets and gel pockets must be inflated evenly. Test this by pushing a thumb into the air and gel pockets to check for firmness of inflation (Figure 8). Also, push with a medially directed downward force from the top of the shoe upper over the heel counter. Repeat this test with a laterally directed downward force (Figure 9A and B). Look for a loss of height in the pocket. The patient was seen for treatment 2 times a week for 4 weeks. Heel pain during standing and walking and morning foot pain were monitored to determine progression of activity and treatment. By the end of the first week of treatment, the patient's subjective pain level was 6 of 10 to deep palpation of the calcaneal attachment and medial border of the plantar fascia. The patient no longer had J Orthop Sports Phys Ther.Volume SO. Number 1.January 2000

5 TABLE 2. Rehabilitation protocol for patient with plantar fasciitis. Week 1 r Ankle and foot strengthening exercises in non-weight-bearing positions with light elastic bands r Marble pick ups and towel pushing and pulling for intrinsic foot muscle strengthening r Double-limb heel raises on ankle board Single-limb balance exercises on 3-in foam r Lower-body ergometer 30 minutes at 70-8O0/0 maximum heart rate at a pedaling cadence of revolutions per minute Functional agility activities of forward and backward and lateral walking drills Home exercise program of walking for 1 hour 4 times per week Week 2 r Single-limb heel raises from a flat surface Heel raises from the edge of a step beginning with both limbs and progressing to single limb r Continue single-limb balance exercises on 3-in foam Lower-body ergometer 30 minutes as in previous week Functional agility activities as in week 1 with resistive tubing Home exercise program of walking for 20 minutes, jogging 2 minutes, and walking 3 minutes for a 20-minute period, ending with walking for 20 minutes, for a total time of 1 hour 4 times per week Week 3 Right lower extremity weight-bearing exercises using elastic tubing resistance around the left ankle to resist hip flexion, extension, abduction, and adduction patterns to stress the muscles of the right foot and calf Single-limb balance exercises emphasizing posture assumed during running Lower-body ergometer 30 minutes as in week 1 Functional agility activities of forward and backward and lateral jogging drills r Home exercise program of 20 minutes walking and 20 minutes jogging, ending with 20 minutes walking, for a total time of 1 hour 4 times per week Week 4 Lower-body weight-bearing exercises on pulley system with an adjustable weight stack Lower-body ergometer 30 minutes as in week 1 Running drills (drills performed at a slow jogging pace for 46 m) a. High kicks-exaggerate kicking behind by kicking the heel of each foot back and upward tapping the buttock with each step taken to work on increasing stride length and enhancing the follow through of each leg b. High knee turnovers-exaggerate lifting each knee upward in a marching fashion without extending the knee or throwing the foot forward to work on keeping knees high during running to prevent a shuffling pattern c. Hands on head emphasizing a neutral posture-run with hands placed on the top of the head to exaggerate an upright posture to work on preventing a forward lean and forward posture, emphasizing forward progression from the pelvis d. Exaggerated trunk twisting and correction--begin with exaggerated (contralateral) trunk rotation with the forward progression of each leg and slowly correct to smooth, efficient control of trunk motion to work on conserving energy by not allowing unnecessary trunk motion to occur e. Exaggerated arm swings and correction--begin with exaggerated (contralateral) arm swinging with each step taken and slowly correct to smooth, efficient arm swing being sure not to allow arms to cross midline to work on efficiency of arm use for enhancing forward progression f. Bounding-leap with large strides exaggerating the push-off of each foot to work on the power of pushing off with each lower extremity Home exercise program of 10 minutes walking and 40 minutes jogging, ending with 10 minutes walking, for a total time of 1 hour 4 times per week FIGURE 4. The upper shoe is separating from the midsole when testing is performed to pull these 2 parts of the shoe apart. The outsole stays intact with the midsole. morning pain with initial weight-bearing and no complaints of calf tightness. After learning how to evaluate shoe construction, the patient purchased a new pair of the same model of running shoes he had worn for the half-ironman race. He brought the shoes to a treatment session, and there appeared to be no visible manufacturing defects. He started to use the new running shoes and was able to walk for 1 hour with a normal gait pattern. He could perform 10 single-limb heel raises before showing signs of fatigue. After week 2 of rehabilitation, the patient's pain level dropped to a 4 during deep palpation and was 1-2 at the end of a busy day. His muscle strength was in the good manual muscle testing range. He was tolerating 20 minutes of combined jogging and walking, with 40 minutes of walking. By week 3 of rehabilitation, the patient had a 1-2 pain level to palpation and no pain with active or passive dorsiflexion or at rest. The flexibility of J Orthop Sports Phys Ther *Volume SO. Number 1 January 2000

6 FIGURE 5. A, Dotted lines show a 90" angle, measured with a goniometer, formed by the vertical center of the posterior left shoe heel counter and a horizontal line that is parallel to the resting surface. B, Vertical and horizontal dotted lines show the outward lean of the heel counter of the right shoe because it is glued into the midsole with a lateral angle. the right gastrocnemius muscle was equal to the left, and he could perform 16 heel raises before showing signs of fatigue. He was able to tolerate 20 minutes of jogging in his 60-minute walking program. At the end of the fourth week, the patient was ready for discharge from physical therapy. He reported a 0-1 pain level to deep palpation of the plantar fascia and no pain at rest. He was able to run 40 minutes without pain or gait deviation. The plantar flexor strength of the right lower extremity was 4+/5 (ie, good plus), and the flexibility was within normal limits. At a 1-month follow-up visit, the patient was asymptomatic and progressing his running program in intensity and time. The patient displayed equal flexibility of the right lower extremity to the left lower extremity of 15" ankle dorsiflexion, with 0" knee FIGURE 7. A, A downward, medially directed force does not rock the left shoe inward. B, A downward, medially directed force does rock the right shoe inward. joint extension. He had no complaint of heel pain with active or passive dorsiflexion and was able to complete 20 heel raises through full range of motion against gravity, representing gastrocnemius strength within normal limits. The patient was able to walk and run with a pain-free, normal gait pattern. DISCUSSION Pronation occurs at the subtalar joint during the stance phase of the gait cycle. Midtarsal joint (ie, talonavicular and calcaneal cuboid) motion results and the medial arch flattens. The talus adducts, plantar flexes, and moves anteriorly with respect to the calcaneus. The calcaneus everts, and forefoot valgus occurs. In the lower leg, the tibia internally rotates and migrates anteriorly to maintain ankle joint congruency. Pronation provides for shock absorption and adaptation to th; terrain under the foot.-when this motion is excessive, a torsional force is created and FIGURE 6. A, The lateral (a) and medial (b) vertical heights of the posterior sole are equal on the left shoe, demonstrating that the left shoe sole is level. B, The medial (c) vertical height of the posterior sole of the right shoe is larger than the lateral (d) vertical height, demonstrating that the right shoe sole is not level. FIGURE 8. A force is directed into the inside air and gel pockets, with the thumb, to check for firmness and symmetry of inflation. J Orthop Sports Phys Ther-Volume SO Number 1.January 2000

7 FIGURE 9. A, A downward force on the lateral aspect of the left shoe (depicted by black arrows) demonstrates compression but no loss of height in the outside air pocket. 0, A downward force on the medial asped of the right shoe (depicted by black arrows) causes the inside air pocket to lose height and collapse. stretches the plantar fascia, leading to inflammation and pain.5,7.1p.ij Plantar fasciitis is characterized by inflammation or degeneration of the plantar fascia, particularly at the calcaneal atta~hrnent.~~ Excessive pronation of the subtalar joint beyond the normal range of approximately 9.4" is the primary cause of plantar fasciitis.ll Anatomic causes of abnormal pronation include ah normalities secondary to neuromuscular disease, congenital pes planus, and acquired deformities. Excessive pronation can be acquired from limited flexibility of the gastrocnemius and soleus muscle groups, resulting in a shortened Achilles tend~n.~.'~ We feel that this case study reveals that a defectively manufactured running shoe may have promoted the development of plantar fasciitis in the presence of other contributing factors. There are ample studies that record potential sources that might cause plantar fasciitis.~.4.fi-n.12~1j~ifi~17 In this case, the patient had a predisposition to pronate, which he compensated for by wearing a running shoe designed to enhance foot stability. The running mileage on the racing shoes was low and fell within the km of wear guideline used for replacing wornaut shoes.y Although the patient's training program seemed well rounded, the demands of a hilly race course and the accumulation of long distance workouts must be considered as potential causes of this overuse injury. Also, the influence of demands on the gastrocnemius and soleus muscles are complicated in a sporting event that involves 3 different activities (ie, swimming, biking, and running). There is the potential for the calf muscles to tighten during the swim and bike ride to produce increased pronation during the run.' The defective running shoe may have facilitated the patient's pronation because the heel counter was canted inward. If the rainy weather conditions caused the shoe to stretch and become more unstable, the pronation deviation may have worsened. Therefore, the defective shoe may have added to the combination of factors that could cause plantar fasciitis because it might not have properly stabilized the right foot. Because today's running shoes tend to be somewhat customized, it is beneficial for patients to know their foot type and running style to purchase shoes designed to support their needs. Various sources have documented the appropriate running shoe design and selection related to lower extremity anatomy and biomechanics lH.2123 We felt it was important for patients to know how to avoid buying defective athletic shoes. The guidelines developed to teach the patient in this case study how to look for sound shoe construction were made available to our patients and local athletic community. CONCLUSION This case study describes a patient with heel pain and plantar fasciitis after completing a triathlon. We feel this case identifies faulty running shoe construction as a factor that contributed to the development of plantar fasciitis. Lower extremity overuse running injuries usually arise from multiple sources. The type of running shoe worn by an athlete can be an important factor in the prevention and treatment of overuse inj~ries.~-~~j"'~ Shoes that are appropriate and compensate for a biomechanical deviation may not prevent injury if they are manufactured with a defect. An increased awareness of the need to assess athletic shoe construction may potentially prevent an athlete from using a defective shoe that might contribute to ankle injury. ACKNOWLEDGMENTS We thank Willesley Chin for his assistance with our literature search and Ann Carre for the original drawings she created. REFERENCES 1. Arnheim DD. Modern Principles of Athletic Training. St Louis, Mo: Times MirrorIMosby College Publishing; Cipriani DJ, Swartz JD, Hodgson CM. Triathlon and the multisport athlete. ) Orthop Sports Phys Ther ;27: Clarke TE, Frederick EC, Hamill CL. The effects of shoe design parameters on rearfoot control in running. MedSci Sports Exerc. 1983;15: Clement DB, Taunton JE, Smart GW, McNicol KL. A survey of overuse running injuries. Physician Sportsmed. 1981;9(5): Donatelli R. The Biomechanics of the Foot and Ankle. Philadelphia, Pa: FA Davis Co; J Orthop Sports Phys Ther.Volome 30.Number 1.Janualy 2000

8 6. Eggold IF. Orthotics in the prevention of runners' overuse injuries. Physician Sportsmed ;9(3): Engsberg JR, Andrews JG. Kinematic analysis of the tabcalcaneal/talocrural joint during running support. Med Sci Sports Exerc. 1987;19: Evans P. Clinical biomechanics of the subtalar joint. Physiotherapy ;76: Frey C. Helping the athletic woman find a shoe that fits. 1 Musculoskel Med. 1998;15(3): Gross MT. Lower quarter screening for skeletal malalignment-suggestions for orthotics and shoewear. ) Orthop Sports Phys Ther ;2 1 : Hall SJ, Messier SP. Biomechanics of fitness exercises. In: Duntine JL, King AC, Painter PL, Roitman JL, Zwiren LD, eds. American College of Sports Medicine's Resource Manual for Guidelines for Exercise Testing and Prescription. 2nd ed. Indianapolis, Ind: American College of Sports Medicine, Lea & Febiger; 1993: Heil B. Lower limb biomechanics related to running injuries. Physiotherapy. 1992;78: Heil B. Running shoe design and selection related to lower limb biomechanics. Physiotherapy ;78: Hislop HJ, Montgomery J, Connelly B (contributor). Dan- iels and Worthingham's Muscle Testing: Techniques of Manual Examination. 6th ed. Philadelphia, Pa: WB Saunden Co; Hunt GC, ed. Physical Therapy of the Foot and Ankle. New York, NY: Churchill Livingstone Inc; James SL, Bates BT, Osternig LR. lnjuries to runners. Am 1 Sports Med. 1978;6: Martin DR. How to steer patients toward the right sport shoe. Physician Sportsmed ;25(9): McPoil TG. Footwear. Phys Ther. 1988;68: Novacheck TF. The biomechanics of running and sprinting. In: Guten GN, ed. Running Injuries. Philadelphia, Pa: WB Saunders Co; 1997: Perry J. Gait Analysis: Normal and Pathological. Thorofare, NJ: Slack Inc; 1992: Pink MM, Jobe FW. The footkhoe interface. In: Guten GN, ed. Running Injuries. Philadelphia, Pa: WB Saunders Co; 1997: Roy S. How I manage plantar fasciitis. Physician Sportsmed. 1983;11: Stacoff A, Denoth J, Kaelin X, Stuessi E. Running injuries and shoe construction: some possible relationships. Int J Sport Biomech. 1988;4: J Orthop Sports Phys Ther.Volume SO. Number 1.January 2000

9 Invited Commentary Wilk, Fisher, and Gutierrez performed a careful biomechanical and clinical analysis of a single subject who presented with heel pain and a deficit in plantar flexor strength following competition in a triathlon (2 krn swim, 90 km bicycling, 21 km run). The patient, an experienced triathlete, was diagnosed with a classic case of plantar fasciitis. The patient received treatment twice a week and was discharged from care after 4 weeks. At a one month follow-up visit, the patient appeared asymptomatic and had resumed normal training. The authors evaluated the patient's training and racing shoes and found that the heel counter of the right racing shoe (the side where the plantar fasciitis occurred) was glued into the shoe at an angle, which may have caused excessive inward rolling of the right foot. The authors concluded that this deficit in shoe construction might have caused the plantar fasciitis. The interesting aspect of this case study is that the authors propose faulty shoe construction (rather than faulty shoe design) as a possible contributing factor for the observed injury because the deficit in shoe construction only appeared on the right shoe. The plantar fasciitis also occurred on the right side. The authors are very careful to point out that plantar fasciitis is likely caused by several factors and that the observed faulty shoe construction is just one of many possible factors. In fact, they are even more cautious (and rightly so) to emphasize that the faulty shoe may have contributed to the development of plantar fasciitis, they never state that it actually did. There are many limitations associated with this study. It is a case study with a single observation and one cannot make a causal relationship between the injury and the faulty shoe construction. Not even the authors' statement that "the defective running shoe may have facilitated the patient's pronation because the heel counter was canted inward" was directly observed. One could fault the authors because it would have been possible to measure the patient's inward roll with the "faulty" shoe and a "proper" shoe once he had recovered from the injury and directly assess the statement they make. I fault the authors somewhat for the way they interpreted and discussed other published data. In contrast to the very cautious interpretation of their own result, they appeared to accept other published results quite readily. For example, the statements that stretching the plantar fascia leads to inflammation and pain and that excessive pronation beyond 9.4" is the primary cause of plantar fasciitis (taken from the literature) are statements that should be debated rather than accepted as facts. Another limitation of a case study is that control cases cannot be studied. For example, it is quite possible that the subject might have developed plantar fasciitis with a perfectly constructed running shoe. In addition, the recovery of the subject may have progressed equally well with a very different treatment. It is possible that one month of rest (instead of treatment) might have had the same treatment effect. All of these issues, however, are speculation in their case study. Summarizing, the authors build an interesting case for faulty running shoe construction as a factor that may have contributed to the development of plantar fasciitis. Although the "scientific" evidence is thin because it is based on a single observation with no direct measures linking injury and fault in shoe, the "clinical" interpretation is appealing and warrants further consideration. I hope that this study makes people think about the relationship between injuries and sport shoe construction. Hopefully, a welldesigned, scientific study may shed additional light onto this interesting proposal made by Wilk, Fisher, and Gutierrez. Dr W. Herzog Professor, Faculty of Kinesiology University of Calgary 2500 University Drive NW Calgary, Alberta T2N 1N4 CANADA J Orthop Sports Phys Ther-Volume 3O.Number 1 *January 2000

10 Author Response We appreciate the commentary by Dr Herzog. We are pleased to have the opportunity to address Dr Herzog's concerns. Our case study was observed in a private-practice setting where musculoskeletal injuries have been found in patients who wore athletic shoes at the time of injury-shoes which were found to have faulty construction after further inspection. While we were not able to cite these findings due to the observational nature of this trend, we believed that it was important to publish our case study. By doing so, we can increase physical therapists' awareness of the assessment of shoe design and construction. Since the patient had successfully worn other pairs of running shoes of the same brand and style during training and racing under similar conditions prior to the race that resulted in the plantar fasciitis, we felt that the design of the shoe controled the patient's pronation motion up to this point and time. We carefully pointed out that plantar fasciitis is likely caused by several factors, but up to now, faulty shoe construction has not been mentioned as a possible contributing factor. While Dr Herzog believes that there are many limitations associated with this study, we will address 3 that he mentioned. We agree that this is a case study with a single observation and one cannot make a causal relationship between injury and faulty shoe construction. The patient's pronation was observed at the time of the initial evaluation in the shoe where the heel counter was inwardly canted. Foresight, time constraints for the patient and clinicians, limited capability to capture and record the patient's gait pattern (ie, having video camera and treadmill available or photographer and camera available), and failure to realize at the time of follow-up that we would attempt to submit this paper for publication are several reasons why we did not observe the patient's pronation in the faulty shoe after recovery from plantar fasciitis. We agree that this would have provided a direct observation of how the patient's gait would have been affected by the inwardly canted heel counter when he no longer suffered from plantar fasciitis. We believe that an observation of the foot in the defective shoe would have shown the patient pronating due to the influence of the inwardly canted heel counter. This pronation was probably due to the mile- age and pattern of wear already established in the shoe from the time of (and preceding) the injury. To add credibility to the contribution of the defective shoe to injury, we could have asked the recovered patient to walk in a new pair of the same brand and model shoes with the same defective construction. Our literature search found many sources documenting the causes of plantar fasciitis and we used these to explain the nature and contributing factors to this problem. The purpose of our case study was to reveal another potential contributing source for the onset of plantar fasciitis, not to debate the established causes, although we appreciate Dr Herzog's viewpoint and agree that the debate would be stimulating. We agree that because control cases are not studied with a case report, it is quite possible that the subject might have developed plantar fasciitis with a perfectly constructed running shoe. We felt that it was important to reveal our findings as a possible complicating factor in this patient's development of plantar fasciitis. We also agree that the patient may have progressed equally well with different treatment or rest. The original version of our manuscript did not address the treatment since we did not deem the treatment as anything new or different from a "typical" treatment approach of plantar fasciitis. Our peer-reviewers, however, required us to include this information. Thus, the issues of treatment effectiveness in dealing with plantar fasciitis are speculation, but not the focus of the information that we were interested in presenting. The purpose of our case study was to reveal the onset of plantar fasciitis in an individual who was a triathlete with foot pronation. A faulty heel counter was found on the shoe that was worn on the foot that developed plantar fasciitis. Since we had observed shoe construction faults as a possible contributing factor in other patients' injuries, we felt that it was important to document this in the literature and increase the awareness of our colleagues to assess athletic shoe construction. We developed the guidelines to assess shoe construction (presented in the paper) based on the defects we have observed in our clinic. We wholeheartedly recognize that a welldesigned scientific study is needed to shed light onto our proposal regarding faulty athletic shoe construc- J Orthop Sports Phys Ther-Volume 3O.Number 1.January 2000

11 tion. Despite the limitations of our study, we feel this case provides a reason for practicing physical therapists to analyze athletic shoe construction when evaluating patients who have plantar fasciitis. A closer inspection of athletic shoes in this patient population may promote the inspection of athletic shoe construction in other patients where shoe examination is warranted. Bruce R. Wilk, OCS, PT J Orthop Sports Phys Ther-Volume 30-Number 1.January 2000