Chapter 38: Leg pain

INTRODUCTION

The leg, defined as the anatomic region below the knee but above the ankle, is a common site of complaints among athletes, particularly distance runners. The term ‘shin splints’ is commonly used by runners as a non-specific reference to leg pain. The same term is also often used by health professionals to describe pain along the medial tibial border or to describe shin pain in general. Neither use of the term is pathologically precise. There are multiple causes with defined pathophysiology that should lead the clinician to a more specific diagnosis of leg pain in athletes. A more accurate and specific diagnosis allows for targeted treatment. Therefore, the term ‘shin splints’ should be abandoned in favour of a more specific, anatomic and diagnostic terminology.

This chapter focuses on four major pathologies that cause leg pain:

• medial tibial stress fracture

• anterior tibial cortical stress fracture

• medial tibial stress syndrome

• chronic exertional compartment syndromes.

CLINICAL APPROACH

Leg pain in athletes generally involves one or more of several pathological, anatomically specific processes.

1. Bone stress. A continuum of increased bone damage exists from bone strain to stress reaction and stress fracture.

2. Vascular insufficiency. This includes reduction in arterial inflow such as popliteal artery entrapment or vascular outflow due to venous insufficiency, thrombotic disease or vascular collapse due to elevated intracompartmental pressures.

3. Inflammation. This develops at the muscle insertions or along the tendons. Periosteal changes at the tibialis posterior and soleus, and fascia to the medial border of the tibia may be due to traction or a variation of the stress injury to bone.

4. Elevated intracompartmental pressure. The lower leg has a number of muscle compartments, each enveloped by a thick inelastic fascia. The muscle compartments of the lower leg are shown in Figure 38.1. As a result of overuse or inflammation, these muscle compartments may become swollen and painful, particularly if there is excessive fibrosis of the fascia.

5. Nerve entrapment.

The clarification between these processes and the narrowing of the differential diagnosis begins with the history, narrowed by clinical examination findings, and confirmed with specific targeted imaging or clinical tests (Table 38.1). It is important to remember that two or three of these conditions may exist simultaneously. For instance, it is not uncommon to have a stress fracture develop in a patient with chronic periostitis. Periostitis or stress fracture may lead to intracompartmental swelling ...