Limb lengthening over an intramedullary nail. An animal study and clinical report.

With the goal of reducing the duration of external fixation in limb lengthening, the authors investigated the feasibility of limb lengthening over an intramedullary nail that could be statically locked when the desired length was achieved, permitting early removal of the external fixation device. In a preliminary study, 8 minigoats underwent 2.0-cm lengthening of the tibia by means of a uniplanar external fixator. Half of the goats had a reamed nail placed in the tibia at the initial surgery. By 10 weeks after lengthening, there no difference in radiographic, histologic, or biomechanical evidence of bone regeneration was found between the tibiae that were nailed and those that were not. In a following clinical series, 15 patients underwent tibial or femoral lengthening by means of a circular frame fixator with a reamed intramedullary nail in place. The postoperative course was uneventful except for 1 infection. The distraction gaps became ossified from 6 months to 1 year, and only 2 patients needed additional bone graftings. The joint function of the lengthened limb at last followup was good. Gradual limb lengthening with a reamed intramedullary nail in place is safe and effective and allows for early removal of the external fixation device.