Shin Splints and Forefoot Contact Running: A Case Report

Transcription

1 Shin Splints and Forefoot Contact Running: A Case Report Michael 1. Cibulka, MHS, PT, OCS' David R. Sinacore, PhD, PTZ Michael 1. Mueller, PhD, PT3 Copyright All rights reserved. S hin splints are commonly described as pain in the anterior aspect of the leg which develops during or after prolonged weight bearing (5). Most often, there is pain and tenderness to palpation of the involved region resulting from an overuse type of injury. The specific tissues involved in the etiology of shin splints are unknown (7). Currently, shin splints are believed to have no single cause; rather, a variety of factors may contribute to their development. Factors that may contribute to shin splints include the running surface, level of the athlete's conditioning, change in activity level, footwear, musculoskeletal deformities, or running style (1,2,4-6, lo). Forefoot contact running is a particular running style that may be an important contributing factor in the development of shin splints in some patients. In forefoot contact running, initial ground contact is made by the forefoot instead of the heel (1). Several authors have reported a relationship between the lack of heel contact and shin splints (4,6). Kantor observed that many runners with a history of shin splints never make initial heel contact when running (6). Cans reported that ballet dancers with shin splints had decreased heel contact during jumping compared with ballet dancers without shin splints (4). Therefore, a forefoot contact running style may Many athletes develop shin splints after athletic activity. The purpose of this case report is to describe the treatment of a patient with posteromedial tibial pain (shin splints) who habitually ran with a forefoot contact running style. The 20-year-old male patient, who played volleyball and basketball about 7 hours a week, complained of pain in the middle one-third of the posterornedial tibia after an acute but prolonged episode of running. Routine observational analysis and in-shoe pressure analysis of the patient's running style showed that he habitually ran on his toes with an absence of heelstrike (forefoot contact running). After instructing the patient on heel-toe running, he no longer complained of posteromedial tibial bone pain. Several possible reasons are proposed for the reduction of leg pain following cessation of forefoot contact running. This case report proposes forefoot contact running as a possible contributor to posteromedial shin splints and that a change in running style may be the optimal treatment for some patients. Key Words: shin splints, overuse injury, running ' President and Physical Therapist, lefferson County Rehabilitation & Sports Clinic, 430 Truman Blvd., Crystal City, MO 'Assistant Professor, Program in Physical Therapy, Washington University School of Medicine, St. Louis, MO 'Assistant Professor, Program in Physical Therapy, Washington University School ol Medicine, St. louis, MO be important in the development of shin splints. Few previous reports describe appropriate treatment for shin splints in a patient who is a forefoot contact runner. Therefore, the purpose of this case report is to describe the treatment of a patient with posteromedial tibial pain (shin splints) who habitually ran with a forefoot contact running style. Interview Data A 20-year-old male college student was referred to physical therapy with a diagnosis of shin splints. The athlete complained of posteromedial tibial bone pain 12 cm above the ankle joint. He described that 2 weeks prior to his initial physical therapy assessment, he noticed posteromedial leg pain after playing approximately 1 hour of volleyball and running half a mile in a gymnasium. No previous history of leg pain was given. Walking did not affect his pain; however, running longer than 5 minutes aggravated his leg pain. He reported that he usually played volleyball five times a week (for about 1 hour) and played basketball once or twice a week (usually for 1 hour) on a hardwood floor. After running, he complained of left leg pain for approximately 1 hour after stopping activity. He reported that jumping during volleyball never aggravated his leg pain. Rest and ice were reported to help relieve the pain. The patient also complained of minor muscle soreness in the proximal calf muscle, 5

2 Copyright All rights reserved. cm distal to the popliteal crease. The calf soreness only developed after running. Physical Examination Data On his first visit (day l), the patient perceived his left leg pain as intense after running, as indicated by rating the pain as a seven on a 10-cm long visual analog scale. The left end of the scale was marked by a zero (indicating no pain), while the right end of the line was marked with the number 10 (indicating the worst possible pain). A slight depression could be felt with light palpation 12 cm proximal to the ankle joint on the posteromedial aspect of the tibia bone. Moderate fingertip palpation over the depressed area of the tibia reproduced the location of his leg pain. Upon firm pressure to the proximal calf muscles, reflex plantar flexion was noted to be intact, although he reported severe muscle soreness when deep pressure was applied. Passive range of motion measurements were performed with a standard 15.2-cm (6-inch) goniometer with the patient prone with his feet extending over the edge of the treatment table. Left ankle plantar flexion measured 55 ", while right ankle plantar flexion measured 53 ". Passive ankle dorsiflexion with the knee extended measured 1 5 " on the left and 1 5 " on the right. Passive ankle dorsiflexion with the knee flexed measured 18" on the left and 17" on the right. A nonweight-bearing examination of the rearfoot and rearfoot-toforefoot alignment was also performed with the patient prone on a treatment table. The patient's neutral position of the subtalar joint was determined by palpating for talar congruency with the foot dorsiflexed and slightly abducted (3). Next, maximal passive inversion and eversion were measured with a standard cm (6-inch) goniometer. Maximal passive left inversion and eversion measured 26 and lo0, respectively. Maximal passive right inversion and eversion measured 25 and lo0, respectively. The measurements demonstrated a slight bilateral rearfoot varus deformity (2"), which confirmed the patient's neutral rearfoot position by palpating for talar congruency. Passive left and right dorsiflexion, plantar flexion, inversion, and eversion were all painless when pressure was applied at the end of movement. Examination of the forefoot to rearfoot relationship was performed with the subtalar joint maintained in its neutral position (ie., 2" of varus) Factors that may contribute to shin splints include the running surface, level of the athlete's conditioning, change in activity level, footwear, musculoskeletal deformities, or running style. and the midtarsal joint maximallv pronated. The bisection of the calcaneus was compared with the plane of the plantar surface of the second through the fifth rays. Visual examination revealed a slight forefoot valgus (2") on both the left and right sides. All rays demonstrated a normal range of motion in both plantar flexion and dorsiflexion for both feet. Visual inspection of the feet also showed a bilateral forefoot adductus deformity. Manual muscle tests showed normal muscle grades in the left and right ankle joint evertor, invertor, dorsiflexor, and plantar flexor muscles. Resisted left ankle plantar flexion, however, created pain in the proximal calf muscle. Squeezing the left proximal calf also produced muscle soreness. Anterior/posterior and lateral radiographs of the tibia bone taken by the referring physician were negative for evidence of stress fracture. A bone scan was not performed. Observation of the patient's gait pattern from the side did not reveal any significant deviations from the normal walking pattern. Running style also was observed from the lateral side, and it was noticed that the patient ran with a forefoot contact gait. His subtalar joint appeared to remain in supination throughout the stance phase of running. To confirm the suspicions of forefoot contact running, the F-scan (Tekscan, Boston, MA) was used while the patient ran on a treadmill with the grade set at zero. The patient was instructed to select the running speed that felt similar to when he experienced his leg pain. The F- scan is a pressure-sensing system that incorporates 960 pressure-sensing cells beneath the entire plantar surface of the foot. Sampling rate was set at 100 Hz. The insole, containing the pressure sensors, was trimmed according to the patient's shoe size and then inserted inside the left shoe. The F-scan was calibrated with the patient in the unilateral stance position according to the manufacturer's instruction. Figure la depicts the three-dimensional composite peak plantar pressure distribution, Figure I b depicts the path of the center of pressure, and Figure lc shows a graph of the total normal force exerted on the foot throughout one stance phase of the left foot as the patient ran at 5.2 mph (8.3 km/hr). As depicted in Figure I b, the center of pressure path begins and ends in the forefoot. Cavanagh and Lafortune have previously described this type of pattern as char- JOSPT * Volume 20 * Number 2 * August 1994

3 Copyright All rights reserved. FIGURE 1. An F-scan of the left foot during the stance phase of the forefoot contact running style. The patient was running at 5.2 mph (8.3 krnlh) in running shoes. A) The composite peak vertical pressures on the plantar surface of the foot showing larger vertical pressures in the forefoot. 8) The vertical pressures on the plantar surface of the foot demonstrating the path of center of pressure beginning and ending in the forefoot. C) A graph of the peak vertical pressure-time curve during the stance phase of the running cycle. Key is shaded in kilopasca1 (kpa); I kpa = Ib/inch2. (See fullcolor illustration on journal cover). acteristic of forefoot (midfoot) contact runners (I). The three-dimensional composite peak pressures during the stance phase of running (Figure la) indicated that this patient took virtually no pressure in the rearfoot. The absence of significant plantar pressure throughout the stance phase of the running cycle and the center of pressure pattern confirms the observation that the patient ran with a forefoot contact running style. Assessment Since the patient's strength, range of motion, and alignment were essentially within normal limits and equal bilaterally, we believed his FIGURE 2. An F-scan of the left foot during the stance phase of the heel contact running style. The same patient was again running at 5.2 mph (8.3 km/ h) in running shoes. A) The composite peak vertical pressures on the plantar surface of the foot showing larger vertical pressures in the heel and more distribution of pressure throughout the forefoot. B) The vertical pressures on the plantar surface of the foot demonstrating the path of center of pressure extending throughout the entire foot. C) A graph of the peak vertical pressure-time curve during the stance phase of the running cycle. Key is shaded in kilopascal (kpa); 1 kpa = Ib/inch2. (See fullcolor illustration on journal cover). forefoot contact running style was the primary factor contributing to his leg pain. Therefore, treatment focused on modifying his running style. Plan of Treatment The first goal was to change his running style by converting forefoot contact running to heel-toe running style. This was accomplished by instructing the patient, coach, and family in heel-toe running. The patient was thoroughly counseled that running was allowed only if his leg was painless. Secondly, in order to determine if the patient learned heel-toe running. his plantar pressures were again examined with the F-scan on a treadmill immediately after instructions were given. The F- scan demonstrated initial heel contact as indicated by significantly larger heel pressures (Figure 2a), an extended path of center pressure throughout the entire foot (Figure 2b), and the bimodal normal force curve of the foot while running (Figure 2c). Finally, his shoes were assessed for evidence of excessive forefoot wear. In addition, his coach was urged to observe him frequently during practice for forefoot contact running. The patient and the coach confirmed the patient had made a change in his running pattern. The patient made no other changes in his activity level or his shoes. Within the first 3 days of changing his running style, the patient noticed a reduction in posteromedial leg pain (311 0 on the pain scale). However, during the first 3 weeks, he still complained of occasional pain, especially with prolonged weight-bearing activities. After 2 1 days of changing his running style to heel contact running, he was pain free (0110 on the pain scale). Running during basketball and volleyball was pain free. Eight weeks later, he continued to report that he still was completely pain free with running. Upon physical examination, no tenderness existed with palpation over the posteromedial tibia or gastrocnemius muscle. Discussion This case report demonstrates the possible relationship between habitual forefoot contact running and posteromedial shin splints. Posteromedial leg pain from shin splints is a poorly understood problem. Forefoot contact running may contribute to injury for several reasons. Subotnick reported that forefoot contact running generates significantly higher ground reaction forces during stance than heel contact running (1 0). Cavanagh and Lafortune reported no differences in vertical

4 Copyright All rights reserved. ground force reactions, but the mean peak-to-peak amplitudes of the mediolateral ground force reactions were three times greater in a group of midfoot contact runners compared with a group of heel contact runners (1). The normal ground force reactions derived from the F- scan system recorded from this single subject indicate higher forces in forefoot contact running (Figure 1 c) compared with heel contact running (Figure 2c). In addition, the stance time was less in the forefoot contact style compared with the heel contact running style (Figures lc and 2c). Therefore, to accomplish running at the same speed with a heel contact pattern instead of a forefoot contact pattern, this subject appeared to increase his entire stance time which, in turn, decreased his peak normal force. This speculation is supported by the work of Cavanagh and Lafortune, who found a correlation between peak vertical force and contact time during running. Decreasing the peak normal force during running may have been a contributing factor to this patient's improved clinical outcome. Another reason that forefoot contact running may contribute to injury is that less subtalar joint pronation occurs during the stance phase in forefoot contact running compared with heel contact running (10). Subtalar joint pronation is an important mechanism for attenuating the ground force reactions (1 0). Although subtalar joint excursion or velocities during the different running styles were not measured, the patient appeared to show more subtalar joint excursion during heel contact running than the forefoot contact running style. Another reason that forefoot contact running may contribute to overuse injuries is that the plantar flexor muscles remain in a continuous contraction throughout the stance phase (8). It is easy to speculate that during prolonged periods of forefoot contact running, the larger posterior muscles may be overused and may contribute to periosteal pain or shin splints. The posterior tibialis is a potential site of injury, since it functions as a plantar flexor of the talocrural joint and a supinator at the subtalar joint (9). Its origin at the posteromedial tibia is the same anatomical location as this patient's reported pain. Perhaps overuse of the posterior tibialis muscle during forefoot contact running contributed to his pain. Further studies are needed to clarify the role that continuous activity of the posterior compartment leg muscles has on the development of tibial pain or shin splints. The coincidental devel- This case report suggests that some forefoot contact runners may require change in running style rather than a change in footwear. opment of calf soreness and shin splints gives some support to the concept that excessive calf muscle contraction may be important in the development of posteromedial leg pain. Perhaps the continuous dorsiflexor and plantar flexor muscle contractions during forefoot contact running induced posteromedial leg pain as well as gastrocnemius muscle strain. Further investigation is necessary to determine the many factors that may contribute to posteromedial leg pain as well as the relationship between shin splints and the potential for tibial stress fracture. Although problems such as the running surface, level of athletic conditioning, change in activity level, footwear, and musculoskeletal de- formities may contribute to shin splints in some patients, none of these problems seemed to be the primary factor with this patient. The patient continued in all previous activities, wore the same footwear, and had no significant musculoskeletal deformities. The only change that occurred prior to the improvement was a change in his running style. Therefore, we believe the forefoot contact running style was the predominant factor contributing to his pain. Some previous reports suggest using orthotics to limit subtalar joint pronation in the treatment of shin splints and anterior tibia bone stress fracture (2.5). Orthotics may help heel-toe runners who pronate excessively; however, forefoot contact runners remain in a supinated position throughout the stance phase of the running cycle (1 0). Therefore, we decided not to use orthotics to treat posteromedial leg pain in this patient. Cavanagh and Lafortune report that the shoe is the major means of attenuating the impact that the body experiences during running (1). They suggest that runners with midfoot vs. rearfoot contact may require different types of footwear. This case report suggests that some forefoot contact runners may require a change in running style rather than a change in footwear. Clearly, more research is needed to determine the optimal treatment approach for each individual patient. One limitation of this case report is that we only performed the F-scan on the involved side; therefore, we don't know if this patient was a bilateral or a unilateral forefoot contact runner. Also, our patient played volleyball, which involves running and jumping. Gans showed that ballet dancers who jump and land on their forefoot often develop shin splints (4). However, the F-scan was only used to measure normal forces while running on the treadmill and not while jumping. Future studies using JOSPT Volume 20 Number 2 August 1994

5 Copyright All rights reserved. the F-scan while jumping would be interesting. Although this case report suggests that forefoot contact running and posteromedial leg pain may be related, a causal effect and the efficacy of this treatment approach cannot be demonstrated with a case report. Further research using a randomized clinical trial is needed to evaluate cause and effect. Conclusion Posteromedial leg pain developed in a runner who ran exclusively with forefoot contact running. We believe instructions on heel-toe running were important in eliminating the leg pain. The importance of evaluating running style in patients with shin splints is emphasized. JOSPT REFERENCES Cavanagh PR, Lafortune MA: Ground reaction forces in distance running. 1 Biomech 13: , 1980 Clancy WC: Runner's injuries, evaluation and treatment of specific injuries. Am I Sports Med 8: , 1980 Diamond le, Mueller MI, Delitto A, Sinacore DR: Reliability of a diabetic foot evaluation. Phys Ther 69: , 1989 Cans A: The relationship of heel contact in ascent and descent from jumps to the incidence of shin splints in ballet dancers. Phys Ther 65: , 1985 Greenfield 6: Evaluation of overuse syndromes. In: Donatelli R, Wolf 5, The Biomechanics of the Foot and Ankle, pp Philadelphia: F.A. Davis Company, 1990 Kantor LA: Survey of the etiology of shins splints. Master's thesis, Springfield College, Springfield, MA, 1948 McPoil TC, McBarvey TC: The foot in athletics. In: Hunt CC, Physical Therapy of the Foot and Ankle, Clinics in Physical Therapy (Vol IS), pp New York: Churchill livingstone, 1988 Rettig AC, Shelbourne KD, McCarroll /R, Bisesi M, Watts I: The natural history and treatment of delayed union stress fractures of the anterior cortex of the tibia. Am I Sports Med 16: , 1988 Root ML, Orien WP, Weed lh: Normal and Abnormal Function of the Foot, Clinical Biomechanics (Vol 2), pp s Angeles: Clinical Biomechanics Corporation, 1977 Subotnick SI: Forces acting on the lower extremity. In: Subotnick 51 (ed), Sports Medicine of the Lower Extremity, pp New York: Churchill Livingstone, 1989