Comparison of Adductor Canal Block and Femoral Nerve Block for Early Ambulation After Primary Total Knee Arthroplasty: A Randomized Controlled Trial.

ABSTRACT

PURPOSE: The purpose of this study was to assess the efficacy of adductor canal block (ACB) as compared to femoral nerve block (FNB) in ambulation distance, opioid consumption, and physical therapy participation on postoperative days (PODs) 1 and 2 after total knee arthroplasty (TKA). We hypothesized ACB would have increased the ambulation distance and decreased the opioid consumption in comparison to FNB. METHODS: All elective TKAs at a single institution, age 18 and older, without existing neurologic or anatomic deficit in the operative limb, were considered. Participants were randomized 11 to receive either an ACB (AC group) or a FNB (FN group), in addition to standard care. Visual analog pain scores (VAS) and oral morphine equivalents (OMEs) were recorded preoperatively, in post-anesthesia care unit (PACU), and on PODs 1 and 2. Postoperative ambulation distance was recorded on PODs 1 and 2. Patient satisfaction with analgesia and physical therapist-rated participation in therapy sessions was obtained as well.  Results: From 2014 to 2015, 84 participants were recruited 41 in FN, and 43 in AC. On POD 1, mean ambulation distances in AC and FN were 70.2 and 48.5 ft, respectively (p = 0.045). On POD 2, mean ambulation distances in AC and FN were 129.0 and 106.4 ft, respectively (p = 0.225). VAS, OME, satisfaction, and physical therapy participation were not significantly different. CONCLUSIONS: Ambulation after TKA is superior with ACB on the first POD, but there is no difference in VAS scores, OME, patient satisfaction, or ambulation on POD 2.