Legg–Calvé–Perthes Disease
A 4-year-old boy was brought to the orthopedic clinic with a 2-day history of pain in the right hip and limping. There had been no preceding trauma or fever. Physical examination showed no limitation in hip range of motion on either side. There was an antalgic gait favoring the right side but no discrepancy in leg length and no soft-tissue changes or neurologic abnormalities. A radiograph of the pelvis showed a focal area of collapse in the right femoral head. A diagnosis of Legg–Calvé–Perthes disease was made. Legg–Calvé–Perthes disease is an idiopathic avascular necrosis of the femoral head in preadolescent children. It manifests as acute- or insidious-onset hip pain or limping, and the differential diagnosis includes infection, trauma, and synovitis. Early in the course of the disease, plain radiographs may appear normal. Treatment with short-term bracing was initiated to maintain hip abduction within a range of approximately 30 degrees to contain the femoral head within the acetabulum. The patient was also advised to avoid high-impact physical activity and was reassured with regard to an expected favorable prognosis. At the 2-month follow-up visit, the patient’s pain and limping had resolved.