Pericapsular Nerve Group Block Plus Lateral Femoral Cutaneous Nerve Block vs. Fascia Iliaca Compartment Block in Hip Replacement Surgery

Background: Optimal pain control with limited muscle weakness after total hip arthroplasty (THA) is paramount for a swift initiation of physical therapy and ambulation, thus expediting hospital discharge. FICB (Fascia Iliaca Compartment Block) has been recommended because it offers pain control with a low risk of motor block. PENG (Pericapsular Nerve Group) block with LFCN (Lateral Femoral Cutaneous Nerve) has been proposed as an alternative that offers comparable pain control with a lower risk of motor block; however, evidence is limited. We aimed to investigate the degree of muscle weakness and pain control with PENG + LFCN. Methods: Patients undergoing elective THA from November 2022 to October 2023 have been retrospectively analyzed. The degree of quadriceps femoris muscle paresis was assessed with the MRC scale at 6 h postoperatively. Secondary outcomes: NRS score at 6, 12, and 24 h, total opioid consumption, and time to first rescue opioid. Results: In total, 80 patients were included in the study, 57 received PENG + LFCN, and the remaining 23 received FICB. PENG + LCFN resulted in a higher MRC at 6 h (4 [4; 5] vs. 3 [2; 4] p = 0.0001) and better pain control (mean difference [95% CI] at 6 h, 0.93 [0.14; 1.72], at 12 h, 0.47 [-0.49; 1.43], and at 24 h, 0.39 [0.25; 1.2], p = 0.0006). Less PRN opioids were requested in the PENG + LFCN vs. FICB groups (7.5 [0; 15] MME vs. 60 [40; 80], p = 0.001). Conclusions: PENG + LFCN was associated with less muscle weakness, better pain control, and less rescue opioids in patients undergoing elective THA. A larger prospective study is needed to confirm this finding.