Analgesic effect of lateral femoral cutaneous nerve block added to the pericapsular nerve group (PENG) block in primary total hip arthroplasty: a randomized clinical trial.

Abstract

Background: Adequate hip joint and surgical incision analgesia represent a challenge in the postoperative period of primary total hip arthroplasty (THA). This study aimed to evaluate whether the combination of the lateral femoral cutaneous nerve block (LFCN block) and the pericapsular nerve group block (PENG block) influences postoperative analgesia and rescue opioids, in primary THA surgeries.

Methods: A trial was proposed with 74 patients for THA surgeries under spinal anesthesia, where 37 received PENG block (GPENG) and the other 37, PENG block and LFCN block (GPENG+LFC). The primary outcome was the presence and intensity of pain at rest and on movement, using the Numeric Rating Scale. The secondary main outcome was the total consumption of opioids. The follow-up was 48 h.

Results: Significantly fewer patients reported pain in the GPENG+LFC compared to GPENG: at rest, at 4 h (17 [45.95%] vs. 28 [75.68%] respectively, P=0.088), 12 h (4 [10.81%] vs. 17 [45.95%] respectively, P=0.016), and 24 h (4 [10.81%] vs. 13 [35.14%] respectively, P=0.0252); on movement, at 4 h (17 [45.95%] vs. 30 [81.08%] respectively, P=0.0002), 12 h (4 [10.81%] vs. 19 [51.35%] respectively, P=0.0003), and 24 h (5 [13.51%] vs. 14 [37.84%] respectively, P=0.0166). Total opioid consumption was significantly lower in GPENG+LFC compared to GPENG up to 48 hours postoperatively (1200 mg of tramadol and 6 mg of nalbuphine vs. 2400 mg and 21 mg respectively, P=0.0188).

Conclusions: The combination of the LFCN block and the PENG block, compared to the sole PENG block, results in better analgesia at rest and on movement up to 24 h and a reduction in the total consumption of opioids up to 48 h after THA.