What is the characteristic sign of Legg-Calve-Perthes disease?

• A. Osteoarthritis
• B. Avascular necrosis of the hip
• C. Fracture of the femoral neck
• D. Dislocation of the hip

Answer: (B)

Legg-Calve-Perthes disease is primarily characterized by avascular necrosis of the femoral head in children, which occurs due to a temporary loss of blood supply. This condition leads to degeneration of the femoral head, followed by revascularization and reorganizational phases that may result in deformity. Clinically, this presents as hip pain, limping, and decreased range of motion, particularly in children aged 4 to 10 years.

The hallmark of this condition is that it specifically impacts the blood supply to the hip joint, which can lead to significant structural changes and dysfunction if left untreated. Recognizing this feature is crucial for diagnosis and management. Other options, such as osteoarthritis or hip dislocations, do not specifically resonate with the unique pathology of Legg-Calve-Perthes disease, making avascular necrosis the clear and appropriate characteristic sign.