Background: An effective pain management strategy with minimal muscle weakness is crucial for the prompt start of physical therapy and early hospital discharge. The fascia iliaca compartment block (FICB) is commonly recommended due to its ability to provide substantial pain relief with a minimal risk of causing motor weakness. Alternatively, the pericapsular nerve group (PENG) block combined with the lateral femoral cutaneous nerve (LFCN) block has been suggested as a potentially more effective option. This combination is believed to offer superior pain control with a significantly reduced risk of motor block compared to FICB. Our objective was to compare these two methods to determine which one results in the lowest numeric rating scale (NRS) score for pain.

Methods: We conducted a retrospective analysis of patients who underwent elective total hip arthroplasty. The primary outcome measured was the numeric rating scale (NRS) score for pain at 6, 12, and 24 hours postoperatively. Secondary outcomes included the total amount of opioids consumed, the time until the first PRN (as needed) opioid dose, and the time until the first postoperative ambulation.

Results: 52 patients were recruited, (13 PENG plus LFCN, 39 FICB). PENG plus LCFN resulted in a lower NRS at all three‑time points (mean difference and 95%CI at 6 h 0.378 [‑0.483; 1.240], at 12 h 0.336 [‑0.378; 1.050], and at 24 h 0.464 [0.013; 0.914] P = 0.02). Moreover, less PRN opioids were requested in the PENG plus LCFN vs. FICB group (0 [0;7.5] vs 60 [15;80] milligrams of morphine equivalents, P = 0.001). No delay in the first ambulation or initiation of physical rehabilitation was reported in either group.

Conclusions: The PENG plus LFCN block appears to provide better pain control and reduce the need for PRN opioids. Neither block interfered with physical therapy or ambulation. These findings should be validated through a larger prospective and randomized study.

References:

Memtsoudis SG et al. Anaesthetic care of patients undergoing primary hip and knee arthroplasty: Consensus recommendations from the International Consensus on Anaesthesia‑Related Outcomes after Surgery group (ICAROS) based on a systematic review and meta‑analysis. Br J Anaesth 2019;123:269‑87

Zhang X‑Y et al.The efficacy of fascia iliaca compartment block for pain control after total hip arthroplasty: A meta‑analysis. J Orthop Surg Res 2019;14:33

Pascarella G et al. et al. Impact of the pericapsular nerve group (PENG) block on postoperative analgesia and functional recovery following total hip arthroplasty: A randomised, observer‑masked, controlled trial. Anaesthesia 2021;76:1492‑8