Shin splints (shin splint syndrome), preferably called medial tibial stress syndrome, is characterized by insidious onset activity-related leg pain caused by overuse and resultant musculotendinous and periosteal inflammation. It is the most common cause of chronic leg pain in runners but it has also been reported in basketball, tennis, and volleyball.
The underlying pathology is believed to be tibial periostitis secondary to chronic excessive stress at the bone–muscle junction. Repeated forceful dorsiflexion of the foot, repeated impact loading during foot strike, and excessive high-velocity foot pronation can lead to microtears at the soft tissue attachments, especially soleus muscle, to the periosteum of tibia.1–3 This results in a musculotendinous inflammatory reaction. Poor shock absorption from shoes, hard running surface, rapid increase in the intensity of training, muscular weakness, and imbalances in strength of leg muscles, poor conditioning, and overweight are contributing factors.
Athletes present with leg pain following a recent increase in running volume and intensity. Initially, the pain is felt during running and often relieved with continued running. With progressive severity, pain tends to recur at the end of the run and then felt throughout running with impairment of running. Pain and tenderness are localized along the middle third of the posteromedial border of the tibia (Figure 29-1). There may be relative weakness of the tibialis posterior and flexor hallucis longus muscles compared to the uninjured leg.
The differential diagnoses of exercise-related leg pain should include stress fracture of the tibia, exertional compartment syndrome, and other conditions (Tables 29-1 and 29-2).1–3 Differentiating features of chronic leg pain are summarized in Table 29-3. An algorithm characterizing the clinical features of common conditions causing lower leg pain based on history and examination is presented in Figure 29-2.1
Relatively More Common |
Medial tibial stress syndrome |
Chronic exertional compartment syndrome |
Stress fractures of tibia or fibula |
Achilles tendonitis |
Muscle strains |
Relatively Less Common |
Metabolic bone disease |
Referred pain from spine, hip, or knee |
Rare |
Popliteal artery entrapment syndrome |
Peripheral entrapment neuropathies (see Table 29-2) |
Bone and muscle neoplasms |
Osteomyelitis |
Nerve | Site of Characteristic Pain | Site of Tingling Sensation on Tinel Test |
|---|---|---|
Common peroneal nerve | Lateral leg and foot | From fibular neck with distal radiation |
Superficial peroneal nerve | Lateral calf and dorsum of the foot | Few centimeters proximal to lateral malleolus |
Saphenous nerve | Above the medial malleolus | From above medial malleolus with distal radiation to medial aspect of the foot |
Site | Pain | Effect of Exercise | Associated Features | Tenderness | Investigations |
|---|---|---|---|---|---|
Bone stress reaction or stress fracture | Localized, acute or sharp Subcutaneous medial tibial surface or fibula | Constant or increasing Worse with impact | Exacerbated by vibration (tuning fork) and ultrasound | Subcutaneous medial tibial surface or fibula | X-ray may be negative Use magnified views Look for callous or periosteal reaction MRI can stage severity and define prognosis but is nonspecific |
Medial tibial periostitis | Diffuse pain on posterior medial border of tibia; variable intensity | Decreases as athlete warms up and stretches | Worse in the morning and after exercise. Pes planus | Posterior medial edge of tibia at muscular insertions | X-rays negative. Bone scan shows diffuse uptake. MRI shows diffuse edema and periosteal thickening. |
Chronic exertional compartment syndrome | No pain at rest; ache, tightness, gradually building with exertion | Specific onset variable between athletes, usually 10–15 min into exercise Decreases with rest | Occasional muscle weakness or dysfunction with exercise. Paresthesia of nerve in affected compartment is possible | None at rest Antero and lateral more common with exertion Occasionally related to palpable muscle herniation (superficial peroneal nerve) | X-rays negative Bone scans negative Exertional compartment pressure testing is diagnostic Exertional MRI assessment may also be diagnostic |
Popliteal artery entrapment | Pain in calf with exertion not anterolateral ‘Atypical compartment syndrome’ | Worse with exertion, especially active ankle plantarflexion | Pulses may be diminished with palpation or Doppler ultrasound with active plantarflexion | Rarely in proximal calf | X-rays negative MRI may reveal hypertrophic or abnormal insertion of medial gastrocnemius MRA (arteriography) with provocative maneuvers is diagnostic |
Muscle–tendon injuries Strains Tendinopathy | Pain at pathological site with resisted stretch | Pre-exercise stretching usually helps | Good response to NSAIDs and ice | Pain can be at muscle belly, muscle–tendon junction, tendon, or tendon insertion | Rarely required X-rays usually negative MRI gives best view of soft tissue pathology |
X-ray of the leg (tibia, fibula) in AP and lateral view is indicated in the evaluation of activity-related leg pain. In medial tibial stress syndrome, x-rays are usually normal. In some cases a thick tibial cortex and subperiosteal lucency on the anterior or medial aspect of the tibia may be seen. Characteristic longitudinal uptake pattern along the tibia is characteristically seen on a bone scan. MRI scan is highly specific and sensitive in the diagnosis of medial tibial stress syndrome as well as stress fracture. It is also useful to evaluate soft tissue pathology in the leg. A diagnostic studies algorithm in presented in Figure 29-3.1
A period of relative rest from running (and jumping activity) is essential and the most effective treatment for medial tibial stress syndrome. During the period of healing and recovery, alternative activities such as swimming, water running, biking, and exercising on the elliptical machine are recommended. Modification of current level and type of activity is needed. Local application of ice is recommended. Shoes with good shock-absorbing capacity should be worn while excessive pronation should be corrected by using orthosis; a softer training surface is preferred. The athlete should follow a regular program of stretching and strengthening of leg muscles, especially the Achilles, tibialis anterior, and posterior tibialis muscles.
Preventive measures include a regimen of gradually increasing the level of activity, on-going stretching and strengthening exercises, and maintaining good running shoes. It may take from 6 to 8 weeks before returning to pre-injury level of activity. The most common cause of recurrence is too early return to running and is seen within the first 1 to 3 weeks of resumption of running. Athletes who fail conservative treatment should be referred to orthopedics for evaluation and consideration for surgical treatment.
Chronic exertional compartment syndromes of leg can affect one or more compartments of the leg (Figure 29-4) and are usually seen in long-distance runners.1–3 Pain in the leg characteristically occurs at a certain point in running and is relieved with cessation of running. There may or may not be neurovascular symptoms and signs.
Vascular perfusion of the muscle is dependent on the normal arterial–venous pressure gradient and is most efficient when the muscle is in the relaxed state. Muscle contractions result in increase in the intramuscular pressure, which is normally accommodated by an increase in the muscle volume. If the fascia that the muscle is contained in is unyielding, the intramuscular pressure will rise to a level that impairs the arterial-venous gradient and muscle perfusion. This will affect the muscle, vascular, and nerve function in that compartment. The pain in the compartment syndrome is believed to be caused by ischemia.
Initially the runner feels aching or burning pain in the leg during running without any neurovascular symptoms or signs. The pain is characteristically predictable and tends to occur at a certain point in time during running and with certain intensity, with resolution after complete cessation of running for a certain period of time. It may take from several minutes to hours for the pain to resolve. The symptoms and signs vary depending upon the particular compartment affected (Table 29-4).3 In most cases, by the time the diagnosis of exertional compartment syndrome is made the symptoms have been present for almost 1 to 2 years. The anterior and lateral compartments are the most commonly affected accounting for 80% of all cases. The examination at rest during the time the athlete is pain-free is normal. When the athlete is having pain, there may be tenderness over the affected compartment. Once the diagnosis of leg compartment syndrome is entertained based on clinical evaluation, the athlete should be referred to orthopedic surgeon or other specialist with expertise in the condition for definitive diagnostic testing.
Compartment | Lateral | Anterior | Superficial Posterior | Deep Posterior |
|---|---|---|---|---|
Site of pain | Middle one-third of anterolateral leg | Anterior leg | Posterior middle third of leg | Distal one-third of posteromedial leg |
Pain elicited by passive | Inversion and plantar flexion of ankle | Flexion of great toes. Inversion and plantar flexion of the ankle | Dorsiflexion of the ankle | Extension of the toes and dorsiflexion of ankle |
Muscles affected | Peroneus longus and brevis | Tibialis anterior, extensor hallucis longus and extensor digitorum longus | Gastrocnemius and soleus | Flexor hallucis longus, flexor digitorum, and tibialis posterior |
Motor weakness elicited with resisted | Eversion of the ankle | Extension of toes and dorsiflexion of ankle | Plantar flexion of ankle | Flexion of the toes and inversion of the ankle |
Nerve affected | Superficial peroneal | Deep peroneal | Sural | Tibial |
Site of paresthesia and cutaneous sensory loss | Web space between great and second toe | Dorsum of the foot | Lateral aspect of the foot | Plantar aspect of toes and foot |
Arterial pulse that may be diminished | Dorsalis pedis | Posterior tibial |
The diagnosis of the compartment syndrome is made by the measurement of intracompartmental pressure with the use of specific instrument. The diagnostic criteria are listed in Table 29-5.
Time of Pressure Measurement | Pressure Diagnostic of Compartment Syndrome |
|---|---|
Resting or pre-exercise | Equal to or more than 15 mm Hg |
1 minute postexercise | Equal to or more than 30 mm Hg |
5 minute postexercise | Equal to or more than 20 mm Hg |
Running should be stopped. Leg massage, stretching, and use of NSAIDs may help relieve pain and discomfort. If the runner gives up running he or she may fully recover and remain asymptomatic without surgical intervention. However, most athletes will be reluctant to give up sports or running and the definitive treatment is fasciotomy and these athletes are referred to orthopedics (Box 29-1). Generally, failure to improve pain after 3 months of nonoperative measures, fasciotomy is considered. Fasciotomy has been reported to relieve the pain in 90% of cases. Following fasciotomy, the athlete goes through rehabilitation over a period of 10 to 12 weeks. Regular running can be resumed gradually after the athlete is pain-free at rest and on initial trials at running, has no leg tenderness, and has gained previous level of leg muscle strength and flexibility. Most athletes can expect to return to unrestricted sport participation by 8 to 12 weeks following fasciotomy.
Chronic exertional compartment syndromes of the leg |
Popliteal artery entrapment syndrome |
High-risk stress fractures of the tibia |
High-risk stress fractures of the foot |
Chronic symptomatic posterior tibial tendon dysfunction |
Symptomatic tarsal coalition |
Hallux valgus |
Flat feet or pes planus is characterized by loss of the medial arches of the feet. Pes planus is common in children up to the age of 6 years.4–6 Flexible pes planus occurs in up to 15% of the overall population, and most of those affected have no symptoms. In a young athlete who competes in running or field sports, pes planus and overpronation of the foot may predispose him or her to knee, leg, or ankle pain, but less commonly than previously thought. Many great athletes have flexible flat feet, almost always bilateral.
Pes planus in most children is of flexible type. Because asymptomatic flat feet are common before age 6 years, a diagnosis of flexible flat feet is generally not made until after 6 years of age. The medial arch is lost while weight bearing and there is associated hyperpronation of the feet. Flexible flat feet in older children and adolescents are often associated with generalized ligamentous laxity and are an autosomal dominant condition. In flexible flatfoot the subtalar joint motion is preserved whereas rigid flat feet are characterized by loss of subtalar motion.4–6 Causes of rigid flat feet include tarsal coalition, neuromuscular disease, tight Achilles, and familial trait.6,7
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