Severe Perthes' disease or late avascular necrosis after successful closed reduction of developmental dysplasia of the hip.

A 5-month-old boy was treated with an adductor tenotomy, closed reduction, and a hip spica cast 2 months after failure of the Pavlik harness for developmental dysplasia of the hip. Satisfactory development of the hip was achieved at the age of 3 years. However, Perthes' disease with Catterall's type IV developed in the same hip at the age of 3 years and 7 months. A proximal femoral varus derotational osteotomy combined with greater trochanter epiphysiodesis was performed at 6 years and 1 month. The Stullberg classification at follow-up, at 10 years of age, was type II.