A Fully Implantable Motorized Intramedullary Nail for Limb Lengthening and Bone Transport

TLDR

The study introduces a fully implantable motorized intramedullary nail with a programmable sliding mechanism designed to perform limb lengthening and bone transport while minimizing infection, discomfort, and scarring compared to external fixators. Twelve patients underwent surgical implantation of the device—eleven with unilateral femur shortening of 3–7.5 cm and one with a 12‑cm defect after tumor resection. All femur‑shortening cases achieved complete leg‑length correction, the bone‑defect case showed successful segment transport, and no infections or axial deformities occurred, though two early lengthening procedures required motor replacement and delayed bone formation was noted post‑chemotherapy.

Abstract

This article describes an intramedullary nail that contains a fully implantable motorized programmable sliding mechanism for limb lengthening and bone transport that reduces the risk of infection, discomfort, and scarring usually associated with the external fixators used for the same purpose. Twelve patients were treated surgically with the new system. Eleven patients had unilateral femur shortening between 3 and 7.5 cm, and one patient had a 12-cm defect after tumor resection. In all patients with femur shortening the leg length discrepancy was corrected completely. In the case of bone defect the segment transport worked well without any problems. There was no infection and no axial deformity. Immediately after chemotherapy, delayed bone formation was seen. In two early cases of limb lengthening a technical problem led to replacement of the motor.