Susan Bettcher, MD and Chad Asplund, MD The Ohio State University. exertional compartment syndrome. To minimize confusion, the terms exerciseinduced

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1 PHYSICIAN PERSPECTIVE Tracy Ray, MD, AMSSM Member, Report Editor Exertional Leg Pain Susan Bettcher, MD and Chad Asplund, MD The Ohio State University EXERCISE-INDUCED leg pain is a common condition in athletes, which accounts for 10% to 15% of all running injuries and up to 60% of leg pain s. 1 Many terms for the description of exercise-induced leg pain have been used in the literature, including shin splints, medial tibial stress, recurrent exercise-induced ischemia, and chronic Key Points Exercise-induced leg pain is common in athletes. A thorough history is essential in developing a diagnosis since athletes will frequently have minimal symptoms or clinical signs at the time of presentation. Choice of diagnostic studies should be guided by the clinical picture. Medial tibial stress and tibial stress fracture are the most common causes of exertional leg pain, but the differential should be broadened to include anatomic and neurovascular conditions if treatments for common conditions fail. exertional. To minimize confusion, the terms exerciseinduced or exertional leg pain should be used to describe symptoms until a clear diagnosis has been established. The causes of exertional leg pain in the athlete are numerous, with the common causes listed in Table 1. The purpose of this report is to provide a practical approach to the assessment of exertional leg pain. History and Physical Exam Patients presenting with exertional leg pain will rarely provide all the information necessary to arrive at a proper diagnosis; therefore, the clinician should use careful guidance and focused questions. Upon clinical presentation, an athlete will frequently have minimal symptoms or clinical signs. Key questions about the history of the condition may help the provider better characterize the quality and location of the pain, the timing and events surrounding pain onset, and contributing factors (Table 2). Also, there are some historical clues that may guide the examiner Table 1 Common Causes of Exertional Leg Pain Medial tibial stress (Shin splints) Tibial stress fracture Exertional Dynamic popliteal artery entrapment Dynamic nerve entrapment (peroneal nerve) Table 2 History Taking Questions for Exertional Leg Pain Onset of pain acute versus chronic Location of pain site and extent (isolated versus diffuse) Characteristics of pain quality (achy, sharp, burning) and timing (exertional, rest, nighttime) Exacerbating and remitting factors Mechanism of injury (if known) Contributing factors Change in training pattern or equipment, hormonal imbalance, etc Human Kinetics Att 13(6), pp november 2008 Athletic Therapy Today

2 Pain Occurrence Table 3 Historical Clues Only with exertion At rest and with exertion After a certain intensity of exercise After a certain distance of exercise Along with numbness and tingling of extremity Possible Diagnosis Medial tibial stress, exertional, nerve entrapment Stress fracture Exertional Arterial entrapment, exertional Nerve entrapment to focus on particular areas and maneuvers during the physical examination (Table 3). The physical examination begins with observation as the patient walks into the athletic training room or clinic. Is there a limp? Is the patient using crutches or wearing a brace? Are shoes particularly worn-out? Next, a complete inspection and range of motion testing of both lower extremities including the ankle, knee, hip, and lumbar spine is performed to assess for focal areas of deformity, swelling, or redness. There are some physical examination findings that may help guide your differential diagnosis (Table 4). Abnormal findings by inspection should be carefully palpated and examined. Palpation along the anteromedial and anterolateral border of the patient s tibia and fibula can identify diffuse or focal pain. Medial tibial stress (MTSS), or periostitis, typically involves a diffuse tenderness to palpation along the tibial border. In contrast, the tenderness associated with stress fractures is usually focal, with the point of maximal tenderness covered by a single finger; however, multiple sites of stress fracture are possible in the same limb. Each of the four s (anterior, lateral, deep posterior, and superficial posterior; Figure 1) should be palpated for tenderness and tension. Significant tightness, especially after exercise, should raise concern for exertional (ECS). Distal neurologic and vascular examinations, performed both statically and dynamically, may help discover contributing or associated causes of leg pain. Exam Findings Table 4 Exam Clues Diffuse tenderness along tibial border Focal tenderness of tibia Tense s following exercise Decreased distal pulses with plantar flexion Neurological deficits following exercise Possible Diagnosis Medial tibial stress Stress fracture Additional Tests Exertional Arterial entrapment Nerve entrapment or ECS Narrowing the specific diagnosis of exertional leg pain in athletes may require more specialized physical examination techniques. Having the athletes recreate their pain with sport-specific exercise is the simplest and least expensive method to aid diagnosis. The tuning fork test or the hop test may be suggestive of a tibial stress fracture. Sliding a vibrating tuning fork along the skin should severely exacerbate pain in a focused area at the site of a stress fracture. Athletes with stress fractures will also be unable or unwilling to hop on the affected limb. Sport-specific exercise that produces pain or tightness that was absent at rest is consistent with ECS. Additional diagnostic studies should be guided by the clinical diagnosis as needed. Anteroposterior, lateral, and oblique plain radiographs of the lower extremity are usually the initial step to rule out underlying bony pathology. Osteomyelitis, bone tumors, periosteal reaction, and stress fractures may be seen; however, with stress fractures, plain radiographs may not be positive until a few weeks after the initial presentation. If stress fractures, MTSS, or bone tumors are the primary focus of the working diagnosis, a triple-phase bone scan may be indicated. If the clinical suspicion is high for ECS, pressure should be measured before and after exercise to confirm the diagnosis. Magnetic resonance imaging (MRI) can provide high-resolution views and in-depth information regarding musculotendinous injuries and stress fractures; however, its routine use is debatable because of its cost. Athletic Therapy Today november

3 Compartments of the Leg Tibia Anterior Deep posterior Lateral Fibula Figure 1 Compartments of the leg. Superficial posterior Medial Tibial Stress Syndrome (Shin Splints) The true incidence of MTSS is unknown, but it is the most common cause of exertional leg pain in athletes, especially in those participating in repetitive activities, such as running and jumping. MTSS accounts for 5-15% of injuries in runners and military recruits. 2 MTSS is an overuse injury characterized by dull aching to intense pain, which occurs with exercise and usually remits with rest. The etiology is believed to be a stress reaction at the tibial attachment of the soleus and deep crural fascia resulting in a periostitis or traction fasciitis. 3 Intrinsic risk factors include pes cavus, excessive foot pronation, and increased hind foot varus; however, extrinisic factors (i.e., training errors) contribute to the majority of cases. 2,3 On examination, there is diffuse tenderness along the border of the tibia in the absence of neurovascular abnormalities. Plain radiographs are usually normal, although rare cases show evidence of periosteal reaction. 3 Triple-phase bone scan will show a classic diffuse longitudinal uptake along the tibial periosteum on the delayed images only. 4 MRI has also shown some clinical utility in diagnosing and distinguishing MTSS from stress fractures. 5 The mainstay of treatment is relative rest and correction of intrinsic and extrinsic risk factors. 4 For severe or recalcitrant cases, posterior fasciotomy to relieve traction from the deep crural fascia has reported success rates of 69% to 90% november 2008 Athletic Therapy Today

4 Tibial Stress Fracture Stress fractures result when bone fails to adapt adequately to the repetitive stress of exercise. Risk factors include previous stress fracture, low bone mineral density, menstrual irregularity, poor nutritional status, and biomechanical factors such as pes cavus. 4 Onset of pain is insidious and tibial tenderness is usually in a focal region. In the majority of patients, radiographs are initially negative with only half of stress fractures eventually demonstrating radiographic abnormalities. Triple-phase bone scan will show focal uptake in all three phases, and MRI is highly sensitive and specific for stress fractures. 4 Treatment for medial tibia stress fractures may require a short period of immobilization in a walking boot, with gradual return to play, generally in 6 to 8 weeks. Anterior cortex tibial stress fractures are prone to nonunion and often require prolonged rest and immobilization for up to 6 months, use of a bone stimulator, and surgical intervention for refractory cases. 4 In patients who fail treatment for these more common diagnoses, other causes must be considered to include anatomic and neurovascular etiologies such as exertional, popliteal artery entrapment, or nerve entrapments. Exertional Compartment Syndrome Exertional (ECS) is a condition associated with development of pressure in the fascial s of the lower extremities, which leads to recurrent episodes of leg discomfort. 4 In an athletic population, increased pressure is the result of increased oxygen demand and the subsequent inflow of blood to supply the exercising muscle. There are four major s in the lower leg (Figure 1), each containing muscles and neurovascular structures that are bound by fascia and bone. 4,7 The anterior is most commonly involved (45%), followed by deep posterior (40%), lateral (10%), and superficial posterior (5%) s. 4 After a predictable intensity or duration of a specific exercise, symptoms gradually progress until pain, cramps, muscle tightness, distal paresthesias, or altered muscle function require the athlete to stop. After a predictable rest period, usually minutes to hours, symptoms resolve. The symptoms may occur in one leg; however, 85% to 95% of the time, bilateral symptoms occur. 8 Physical examination at rest is usually benign but may reveal a fascial defect and/or muscle hernia. Examination immediately following exertion usually reveals a tense, firm that is tender to deep palpation and passive stretch. 7 Neurological examination may exhibit findings specific to the affected, such as foot drop and paresthesia over the dorsum of the foot with anterior involvement; however, this is a late finding and is an indication for urgent surgical consultation. 4,7 Diagnosis relies on confirmation of elevated pressure coinciding with reproduction of the patient s symptoms. 9 Treatment is largely considered to be surgical fasciotomy of the involved s. When surgery is performed, release of the anterior is generally more successful than release of the other s, with 87% improvement in symptoms reported at two years. 10 Popliteal Artery Entrapment Popliteal Artery Entrapment is uncommon but should be included in the differential diagnosis of young adults presenting with ischemic lower-extremity symptoms. Compression may occur at the origin of the medial head of the gastrocnemius or plantaris or as a result of an aberrant course of the vessel. 11 Compression of the popliteal vein also occurs in 10% to 15% of patients with popliteal artery entrapment and may be responsible for the initial presentation of leg pain, edema, and even deep vein thrombosis. 12 Diagnosis begins with a complete history, physical examination (specifically, dynamic examination of the distal pulses with the foot in a normal position and then with the foot plantar flexed), and a high index of suspicion. Dynamic MRI combined with MR angiography has recently been advocated as the most effective way to view these lesions. 13 Treatment is usually surgical and depends on the patient s underlying condition. Removal of the offending compressive structure with reconstruction of the artery has been advocated in the medical literature. 14 Nerve Entrapments Although relatively rare, nerve entrapments may be a cause of persistent exertional leg pain. The common peroneal nerve may be compressed where it passes around the fibular neck and the superficial peroneal Athletic Therapy Today november

5 nerve, a branch of the common peroneal nerve, is most commonly compressed as it exits the deep fascia at the distal third of the leg. This can lead to exercise-induced leg pain, post-exercise weakness, and paresthesias accompanied by a positive percussion sign at the site of entrapment. Patients may have activity-related pain and neurologic symptoms in the lower leg or the dorsum of the foot and ankle. Weakness is not expected because the innervation of the peroneals is proximal to the site of compression. Physical examination should include a detailed neurovascular examination. Additional tests include palpation at the site where the nerves travel (at the level of the fibular neck and where the superficial branch exits the deep fascia, approximately 11 cm above the tip of the lateral malleolus) while the patient actively dorsiflexes and inverts against resistance. Electrodiagnostic studies, before and after exercise, are helpful in determining the exact location of the lesion. Treatment includes activity modification with surgical release for resistant cases. Conclusion Exercise-induced leg pain is common in an active population. The importance of a detailed history and physical examination cannot be overemphasized. It is a challenging problem to treat, but satisfactory results will be obtained with an accurate, timely diagnosis and a multidisciplinary approach to treatment. References 1. Bates P. Shin splints: a literature review. Br J Sports Med. 1985;19(3): Thacker SB, Gilchrist J, Stroup DF, Kimsey CD. The prevention of shin splints in sports: a systematic review of literature. Med Sci Sports Exerc. 2002;34: Kortebein PM, Kaufman KR, Basford JR, Stuart MJ. Medial tibial stress. Med Sci Sports Exerc. 2000;32(Suppl):S27-S Wilder RP, Sethi S. Overuse injuries: tendinopathies, stress fractures,, and shin splints. Clin Sports Med. 2004;23: Aoki Y, Yasuda K, Tohyama H, et al. Magnetic resonance imaging in stress fractures and shin splints. Clin Orthop Relat Res. 2004;4: Yates B, Allen MJ, Barnes MR. Outcome of surgical treatment of medial tibial stress. J Bone Joint Surg Am. 2003;85A: Blackman PG. A review of chronic exertional in the lower leg. Med Sci Sports Exerc. 2000;32(Suppl):S4-S Touliopolous S, Hershman EB. Lower leg pain: diagnosis and treatment of s and other pain s of the leg. Sports Med. 1999;27(3): Pedowitz RA, Hargens AR, Mubarak SJ, Gershuni DH. Modified criteria for the objective diagnosis of chronic of the leg. Am J Sports Med. 1990;18: Verleisdonk EJ, Schmitz RF, van der Werken C: Long-term results of fasciotomy of the anterior in patients with exerciseinduced pain in the lower leg. Int J Sports Med. 2004;25: Taunton JE, Maxwell TM. Intermittent claudication in an athlete popliteal artery entrapment: a case report. Can J Appl Sport Sci. 1982;7(3): Gerkin TM, Beebe HG, Williams DM, et al. Popliteal vein entrapment presenting as deep venous thrombosis and chronic venous insufficiency. J Vasc Surg. 1993;18(5): Atilla S, Akpek ET, Yucel C, et al. MR imaging and MR angiography in popliteal artery entrapment. Eur Radiol. 1998;8(6): Stager A, Clement D. Popliteal artery entrapment. Sports Med. 1999;28(1): Susan Bettcher is a family medicine chief resident at the University of Michigan Medical Center and will be entering The Ohio State University Primary Care Sports Medicine Fellowship. She enjoys a variety of sports and outdoor activities with an interest in distance running. Chad Asplund is a staff family physician at Eisenhower Army Medical Center and coordinates the sports medicine curriculum for the residency program and is an avid multisport athlete with an interest in endurance medicine. The American Medical Society for Sports Medicine (AMSSM) is an organization founded in 1991 whose sports-medicine physician members are trained to provide cutting edge care in all aspects of sports medicine, from evaluation of orthopedic and medical problems to nutritional and psychosocial issues. AMSSM members treat all ages and athletic abilities grade school to senior citizen, recreational to professional. Learn more at 24 november 2008 Athletic Therapy Today