Hip and knee pain in a child

Case presentation

A 9-year-old girl presented with a three-month history of pain in the hip and knee associated with a limp. Examination revealed restricted movement of the hip, particularly internal rotation and adduction in flexion. The Trendelenburg sign was positive.

Initial x-rays were normal, apart from a slight increase in medial joint space (Figure 1). Three months later, x-rays revealed Perthes’ disease – that is, flattening and sclerosis of the femoral head.

A femoral osteotomy was performed to bring the femoral head under the acetabulum to protect the epiphysis while healing occurred (Figure 2). At skeletal maturity, the patient has a near-normal hip, with signs of old Perthes’ disease visible on x-ray (Figure 3).