Femoral lengthening over an intramedullary nail. A matched-case comparison with Ilizarov femoral lengthening.

Twenty-nine patients (thirty-two femora) had femoral lengthening over an intramedullary nail, with the nail and the external fixator applied concomitantly at the time of the femoral osteotomy. After gradual distraction at a rate of one millimeter per day, the nail was locked and the fixator was removed. The mean age was twenty-six years (range, ten to fifty-three years), and the mean amount of lengthening was 5.8 centimeters (range, two to thirteen centimeters). For comparison, thirty-one patients (thirty-two limbs) who had had standard Ilizarov femoral lengthening were matched with the group that had had lengthening over an intramedullary nail; the matching was performed on the basis of the amount of lengthening, the age of the patient, the etiology of the indication for lengthening, and the level of difficulty of the procedure. Lengthening over an intramedullary nail reduced the average duration of external fixation by almost one-half. The radiographic consolidation index (the number of months needed for radiographic consolidation for each centimeter of lengthening) for the limbs that had had lengthening over an intramedullary nail was reduced significantly (p < 0.001) compared with that for the matched-case group. The range of motion of the knee returned to normal a mean of 2.2 times faster in the group that had had lengthening over an intramedullary nail. There were six refractures of the distraction bone in the matched-case group. In the group that had had lengthening over an intramedullary nail, one nail and one proximal locking screw failed. The over-all rate of complications was 1.4 per cent in the group that had had lengthening over an intramedullary nail compared with 1.9 per cent in the matched-case group. With the numbers of patients available for study, we could not detect a significant difference between the groups with respect to the operative time (p = 0.124); however, the cost of treatment and the estimated blood loss were higher in the group that had had lengthening over an intramedullary nail. On the basis of clinical and radiographic criteria, there were twenty-three excellent, seven good, and two fair results in the group that had had lengthening over an intramedullary nail compared with twenty-six excellent, four good, and two fair results in the matched-case group (p = 0.37). The advantages of lengthening over an intramedullary nail include a decrease in the duration of external fixation, protection against refracture, and earlier rehabilitation.