Chondrolysis following surgical resection of an osteoid osteoma of the hip in an adolescent: a case report.

Juvenile chondrolysis of the hip is a rare condition characterised by the rapid loss of articular cartilage. Although several aetiologies have been proposed, chondrolysis following surgical resection of an osteoid osteoma in the hip has not been previously reported. This report aims to highlight the case of a 14-year-old boy with a 2-month history of persistent left hip pain, initially misdiagnosed as a stress fracture based on magnetic resonance imaging findings of bone marrow oedema in the femoral neck. Upon referral to our institutions, computed tomography imaging revealed a radiolucent nidus with central calcification, confirming the diagnosis of osteoid osteoma. En bloc resection of the lesion was performed via a medial approach, and histological examination confirmed the diagnosis. Although his hip pain initially resolved, it recurred 4 months postoperatively. Chondrolysis was diagnosed based on the recurrence of hip pain accompanied by restricted range of motion and joint space narrowing. A non-weight-bearing regimen with range-of-motion exercises was initiated. Over the following year, symptoms gradually improved, and joint space progressively widened. By the third postoperative year, the patient maintained near-normal hip function without pain. This case represents the first report of chondrolysis of the hip following open resection of an osteoid osteoma. Chondrolysis should be considered a potential complication after surgical treatment of osteoid osteoma of the hip. The underlying pathogenesis may involve a pro-inflammatory state triggered by surgical trauma and prostaglandin overproduction.