Complications of Femoral Nerve Block for Total Knee Arthroplasty

TLDR

Preemptive and multimodal pain control protocols have been introduced to enhance rehabilitation after total knee arthroplasty (TKA). We determined the complication rate associated with preoperative femoral nerve block (FNB) for TKA. Among 1018 TKA operations, 709 preoperative FNBs were delivered by single‑injection into the femoral nerve sheath with nerve‑stimulation confirmation, and weight‑bearing as tolerated was begun on postoperative day 1 using a walker or crutches. The study found a 1.6 % fall rate (including 0.4 % reoperations), 5 cases of postoperative femoral neuritis, and one new atrial fibrillation episode, indicating that preoperative FNB is not harmless and warrants modified postoperative protocols to mitigate early quadriceps weakness. See Guidelines for Authors for a complete description of levels of evidence.

Abstract

Preemptive and multimodal pain control protocols have been introduced to enhance rehabilitation after total knee arthroplasty (TKA). We determined the complication rate associated with preoperative femoral nerve block (FNB) for TKA. Among 1018 TKA operations, we performed 709 FNBs using a single-injection technique into the femoral nerve sheath and confirming position with nerve stimulation before induction. After TKA, weightbearing as tolerated was initiated using a walker or crutches on postoperative Day 1. Twelve patients (1.6%) treated with FNB sustained falls, three (0.4%) of whom underwent reoperations. Five patients had postoperative femoral neuritis, which may have been secondary to the block. One patient had new onset of atrial fibrillation after FNB, and the TKA was postponed. Femoral nerve block before TKA is not a harmless intervention. We recommend postoperative protocols be modified for patients who have FNB to account for decreased quadriceps function in the early postoperative period, which can lead to falls.Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.