Lengthening over nails (LoN): Femur and tibia

Classical limb lengthening with an external fixator requires a lengthy external fixation time until the regenerate bone is fully consolidated. Patients are generally unhappy if they have to wear an external fixator on their leg for many months. One advantage of LON is that the patient only needs to wear the external fixator during the lengthening phase, not the consolidation phase. When compared to classical lengthening with an external fixator alone, LON cuts the fixator time in half or even less than half. Other advantages include decreased axial deviation during lengthening and decreased risk of regenerate bone fracture after external fixator removal. Internal lengthening telescopic nails (Fit Bone, ISKD, Guichet, and PRECICE) are available, and they avoid the need for external fixation. However, they are expensive and not readily available worldwide. Lengthening over nails (LON) is an alternative technique that combines a simple, inexpensive trauma intramedullary nail with a monolateral or circular external fixator. Depending on the specific medical system, cost savings of LON over internal lengthening telescopic nails can be considerable, making this a particularly attractive technique for the developing world. The downsides of LON are that it is technically challenging and has a risk of deep infection if contaminated pin sites are in communication with the internal rod. This chapter presents a detailed description of the surgical technique for LON in the femur and tibia, including tips on how to avoid pitfalls.