This meta-analysis aimed to determine whether peripheral nerve blocks (PNB) reduce postoperative delirium (POD) in elderly patients undergoing hip surgery. This study was registered in the International Prospective Register of Systematic Reviews (PROSPERO; CRD42022328320). The PubMed, EMBASE, Web of Science, and Cochrane Library databases were searched for randomized controlled trials (RCTs) on 26 April 2022. A total of 19 RCTs with 1977 participants were included. Perioperative PNB lowered the POD incidence on the third postoperative day (OR: 0.59, 95% CI [0.40 to 0.87], p = 0.007, I2 = 35%), in patients without underlying cognitive impairment (OR: 0.47, 95% CI [0.30 to 0.74], p = 0.001, I2 = 30%), and when a fascia iliaca compartment block (OR: 0.58, 95% CI [0.37 to 0.91], p = 0.02, I2 = 0%) or a femoral nerve block (OR: 0.33, 95% CI [0.11 to 0.99], p = 0.05, I2 = 66%) were performed. The pain score was also reduced (SMD: -0.83, 95% CI [-1.36 to -0.30], p = 0.002, I2 = 95%) after PNB. Perioperative PNB can lower the POD incidence and pain scores up to the third postoperative day. However, considering the wide variety of PNBs performed, more trials are needed to identify the effects of each PNB on POD.
Keywords: elderly; hip surgery; meta-analysis; peripheral nerve blocks; postoperative delirium.