Nerve transfers for femoral nerve palsy: an updated approach and surgical technique

OBJECTIVE Femoral nerve palsy results in significant impairment of lower extremity function due to the loss of quadriceps muscle function. The authors have previously described their techniques utilizing the anterior obturator and sartorius nerves for transfer in cases of femoral nerve palsy presenting within 1 year of injury. In the current study, the authors discuss their updated techniques, results, and approach to partial and complete femoral nerve palsies using femoral nerve decompression and nerve transfers. METHODS They conducted a retrospective review of patients with femoral nerve palsies treated with their technique at the Washington University School of Medicine in 2008-2019. Primary outcomes were active knee extension Medical Research Council (MRC) grades and visual analog scale (VAS) pain scores. RESULTS Fourteen patients with femoral nerve palsy were treated with femoral nerve decompression and nerve transfer: 4 with end-to-end (ETE) nerve transfers, 6 with supercharged end-to-side (SETS) transfers, and 4 with ETE and SETS transfers, using the anterior branch of the obturator nerve, the sartorius branches, or a combination of both. The median preoperative knee extension MRC grade was 2 (range 0-3). The average preoperative VAS pain score was 5.2 (range 1-9). Postoperatively, all patients attained an MRC grade 4 or greater and subjectively noted improved strength and muscle bulk and more natural gait. The average postoperative pain score was 2.3 (range 0-6), a statistically significant improvement (p = 0.001). CONCLUSIONS Until recently, few treatments were available for high femoral nerve palsy. A treatment strategy involving femoral nerve decompression and nerve transfers allows for meaningful functional recovery and pain relief in cases of partial and total femoral nerve palsy. An algorithm for the management of partial and complete femoral nerve palsies and a detailed description of surgical techniques are presented.