Malaligned and Short Femur Associated with Vascular Deficit: Two-Stage Realignment and Lengthening with Custom-Made Magnetic-Driven Intramedullary Nail

Abstract

A teenage boy presented with a post-traumatic leg length discrepancy (LLD) of 7 cm with bifocal femoral deformity, impairment of soft tissue and a long, segmental defect of the superficial femoral artery. Limb lengthening and deformity correction was performed in a two-staged project. After partial consolidation of a bifocal osteotomy and realigment with a customized, straight tibial nail, lengthening was then performed with a custom-made, magnetic-driven lengthening nail (MDLN/Phenix^©) in the second step.

In the latter part of the distraction period, a vascular impairment occurred. It could be solved uneventfully by controlled, minor backtracking of the MDLN and subsequent reduction of the distraction rate. This caused a low distraction index of 0.68 mm/day. Nevertheless, bone formation was excellent with early weight-bearing (weight-bearing index: 16.2 days/cm).

The main issues for the successful treatment of this case of LLD and bifocal deformity with soft tissue and vascular impairment were meticulous analysis and planning (End point first planning method – EPF), a staged procedure to reduce risks, and a custom-made MDLN with the option of non-invasive controlled shortening.