Use and Clinical Relevancy of Pericapsular Nerve Block (PENG) in Total Hip Arthroplasty - A Systematic Review and Meta-analysis.

BACKGROUND: Ultrasound-guided pericapsular nerve group (PENG) block is an emerging regional anesthesia technique that may provide analgesia for patients undergoing total hip arthroplasties (THA). There are clinical studies comparing this fascial plane block to other established methods, however, evidence on the actual efficacy of this block for THA continues to evolve.

OBJECTIVE: Available clinical studies conducted over the past 4 years, were reviewed to evaluate the analgesic efficacy and effectiveness of PENG block in patients undergoing THAs.

METHODS: A meta-analysis of randomized controlled trials (RCTs) in patients undergoing THA, where PENG block was compared to no block, placebo/sham block (injection with saline), or other analgesic techniques including suprainguinal fascia iliaca block (FIB), or periarticular infiltration (PAI) was performed. Our primary outcome was opioid consumption during the first 24 hours. Secondary outcomes were postoperative rest and dynamic pain scores at 6-12, 24 and 48 hours, block performance time, sensory motor assessment, quadriceps weakness, incidence of postoperative falls, first analgesic request, block and opioid related complications, surgical complications, patient satisfaction scores, post anesthesia care unit length of stay, hospital length of stay, and functional and quality of life outcomes.

RESULTS: We included 12 RCTs with a total of 705 patients. Data showed that PENG block decreased 24-hour oral morphine milligram equivalent consumption by a mean difference (MD) of 3.75 mg (95%CI: -5.96,-1.54; P=0.0009). No statistically significant differences in rest or dynamic pain were found, except for a modest MD reduction in dynamic pain score of 0.55 points (95% CI: -0.98, -0.12; P=0.01), measured 24 hours after surgery in favor of PENG block.

CONCLUSIONS: Our systematic review and meta-analysis suggest that PENG block provides better analgesia, measured as MME use, in the first 24 hours after THA, with no real impact on postoperative VAS scores. Despite statistical significance, the high heterogeneity across RCTs implies that PENG's benefits may not surpass the minimal clinically important difference threshold for us to recommend PENG as best practice in THA.