Bilateral slipping of the upper femoral epiphysis in a 15-year-old boy with renal osteodystrophy caused by a right polycystic, and left dysplastic Kidney, is reported. Biplane intertrochanteric osteotomy (Southwick) was carried out to both hips. The left hip developed non-union and was successfully treated with a bone graft. JOA (Japanese Orthopedic Association) hip score improved from 55 to 98 after surgery. Slipping of the upper femoral epiphysis associated with renal osteodystrophy has rarely been an indication for osteotomy because of the high surgical risk. However, Southwick' osteotomy can be done with less risk with the progress in management of renal dysfunction. We conclude that even in children with slipping of the upper femoral epiphysis accompanied by renal osteodystrophy, adequate reduction of the deformity can be achieved by osteotomy leading to improvement in the activity of the patient.
