Upper leg lengthening on an intramedullary nail: a preliminary report

Current methods of treatment for anisomelia are based on distraction osteogenesis. This involves creating callus during gradual distraction using an external fixator. The lengthening of long bones by Ilizarov's method requires keeping the external fixator in place for a long period of time, which increases the risk of complications, such as pin - track infection, stiffness of the joint, misalignment, and fracture of the regenerate. In order to shorten the period during which the external fixator must remain in place, we have introduced a method which enables the external fixator to be removed when the distraction phase is completed. During the period 1999-2001 we carried out femoral lengthening in 9 patients, using a combination of external fixation and intramedullary nail. After osteotomy of the femur and fixation by intramedullary nail, an external fixator was also applied, allowing for gradual distraction. After the requisite lengthening had been obtained by distraction at the rate of 1 mm per day, the nail was locked and the external fixator was removed. The operated patients ranged in age from 13 to 23; the average age at the moment of surgery was 16,2 years. The mean femoral anisomelia was 4,5 cm (range: 2,5-8,3). In seven cases the etiology of the anisomelia was congenital, in one case avascular necrosis of the femur, and in one case a history of femur fracture. The average duration of external fixation was 11 days for 1 cm of bone lengthening. All the lengthening femurs healed without bone union complications. In 8 cases we obtained complete isomelia, wile in 1 case there remained an inequality of 6 mm due to premature callus maturation and bone union. This is turn was caused by the patient's voluntary termination of distraction in conjunction with a two-week delay in the scheduled clinical follow-up. The removal of the external apparatus upon completion of distraction made it possible to institute early rehabilitation and enabled a quick restoration of physiological mobility in the knee joint. The chief advantages of limb lengthening using an intramedullary nail are the significant reduction in the duration of external fixation, protection of the bone regenerate against fracture, and a shorter period of time for rehabilitation. The disadvantages of this method include the extended surgical procedure and the risk of nail wedging in the intramedullary canal, which prevents lengthening.