Towards a Novel, Implantable Limb Lengthening Device1

Abstract

Several surgical techniques and devices have been developed to help patients born with limb deformities, limb length inequalities, and extreme short stature. People with such ailments often experience pain, dysfunction, and joint degeneration. The primary method of treating such deformities is an osteotomy followed by callus distraction [1]. Commonplace lengthening devices are external fixators and intramedullary devices, but each has its drawbacks. Traditional external fixators, such as the Ilizarov device and Taylor spatial frame, are cumbersome, painful, and produce large residual scars [2]. Due to pin tract infection rates of 10–20%, lengthening with these methods requires careful surveillance [3]. Intramedullary lengthening devices can cause severe complications such as intramedullary infection [4]. Surgeons have recently experienced success with a motorized, intramedullary nail (Fitbone), but pediatric use of this device can be limited due to interference with open growth plates [5]. The investigators have designed an extramedullary device that retains the attractive qualities of an intramedullary nail, without the risk of deep infection or damage to growth plates. Additionally, the device can be equipped with a six-axis force-torque sensor capable of measuring forces and moments in real time.