Chapter 29. Overuse Injuries of the Leg, Ankle, and Foot

Definition and Epidemiology

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.

Pathogenesis

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.

Clinical Presentation

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.

Differential Diagnosis

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