Six months after in situ pinning of a stable slipped capital femoral epiphysis, a 13-year-old boy reports worsening hip pain and stiffness. Radiographs show uniform narrowing of the hip joint space to less than 3 mm with periarticular osteopenia, but the physis has consolidated. What is the diagnosis?

• A Chondrolysis ✓
• B Recurrent slip
• C Avascular necrosis of the epiphysis
• D Septic arthritis

Explanation

Chondrolysis is defined as progressive loss of more than half the articular cartilage width, classically a joint space below 3 mm on the affected side, causing pain, stiffness, and restricted motion after SCFE, whether treated or untreated. Avascular necrosis affects the epiphysis itself and shows collapse or sclerosis rather than diffuse cartilage loss. Recurrent slip is unlikely after physeal closure, and septic arthritis would show systemic features.

Reference: Tachdjian's Pediatric Orthopaedics, 5th ed.

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