Effect of Pericapsular Nerve Group Block on Prehabilitation in Femoral Neck Fractures: A Randomized, Double-Blind, Placebo-Controlled Trial

BACKGROUND: Prehabilitation during unavoidable surgical delay after an acute femoral neck fracture may mitigate rapid functional decline but is often limited by movement-evoked pain. The pericapsular nerve group (PENG) block is a motor-sparing regional anesthetic technique that may facilitate active mobilization. We hypothesized that the PENG block would improve completion of a structured prehabilitation session. METHODS: In this single-center, randomized, double-blind, placebo-controlled trial, adults with Garden III to IV femoral neck fractures awaiting hip arthroplasty received ultrasound-guided PENG block with 20 mL 0.375% ropivacaine or saline before initial prehabilitation. The primary outcome was completion of all five predefined mobilization steps. Secondary outcomes included pain during prehabilitation, rescue analgesia within 24 hours, postoperative Cumulated Ambulation Score (postoperative days 1-3), Barthel Index at discharge, length of stay, discharge disposition, and adverse events. Analyses followed the intention-to-treat principle. RESULTS: We randomized 100 patients (50 PENG; 50 placebo). Completion of the full prehabilitation session did not differ between groups (22 of 50 [44%] vs 24 of 50 [48%], P =.841). Maximum movement pain was lower with PENG block (median [interquartile range], 7 [5-8.75] vs 8 [7-10], P =.022), and fewer patients required rescue analgesia (2 of 50 [4%] vs 10 of 50 [20%], P=.028). We did not observe between-group differences in postoperative outcomes. No block-related or prehabilitation-related adverse events occurred. CONCLUSIONS: PENG block administered before the initial prehabilitation was associated with reduced movement-related pain and rescue analgesic use but did not improve the initial prehabilitation completion or postoperative functional recovery. More effective multimodal analgesic strategies may be required to enable active prehabilitation.