One stage femoral lengthening.

Femoral lengthening can be obtained by a technique using a Z osteotomy and a distraction device separate from the operative field. The expected gain in length is 3-3.5 cm in children, 4-4.5 cm in adults. Sustained flexion of the knee during the procedure prevents vascular and nervous complications. One peroneal nerve and 2 femoral nerve palsies were nevertheless observed in 180 cases of the whole series. These were caused by a failure to comply with technical details. Bony union occurs promptly in young children. Pseudarthrosis occurred 11 times in patients more than 16-years-old, and once in an 8-year-old child. Avascular necrosis of the bone fragments after total separation of the soft tissue from the femoral shaft explains the frequency of non-union after the age of skeletal maturity. Faster and sound union in adolescents and adults is obtainable by the use of decortication to exposure the femur and strong internal fixation. The best indication for this method is a moderate discrepancy allowing a safe and complete equalization of limb length.