Separation of the proximal femoral epiphysis after derotation varus osteotomy of the femur

Proximal femoral varus and derotation osteotomy is a common procedure performed in the management of developmental dysplasia of the hip. This procedure imposes high shear stress on the femoral epiphysis, depending on the degree of varus obtained. We report two cases of proximal femoral epiphyseal slip after varus derotation osteotomy and discuss the management and outcome. Such epiphyseal slip may or may not be symptomatic, and a careful radiologic examination should be carried out in suspected cases. Management should be individualised. Surgical correction of varus may be required.