Rotary malunion of the proximal femur following femoral osteotomy.

Malunion of the proximal femur developed in a three-year-old girl with congenital dislocation of the hip following osteotomy and the use of inadequate internal fixation. The deformity was diagnosed by computerized tomographic scanning. The proximal femur had rotated 90 degrees around its long axis before uniting with the femoral shaft. The deformity required three-dimensional correction with adequate internal fixation.