Local infiltration vs epidural analgesia for postoperative pain control after total knee or hip arthroplasty A meta-analysis of randomized controlled trials

Background: Inconsistent results have been obtained regarding postoperative pain control using local infiltration and epidural analgesia for patients after total knee or hip arthroplasty (TKA and THA). We therefore conducted a meta-analysis of randomized controlled trials (RCTs) to assess the efficacy and safety of local infiltration vs epidural analgesia for TKA and THA. Methods: Electronic searches were conducted on PubMed, EmBase, and the Cochrane library to identify eligible RCTs conducted up to February 2020. Weighted mean difference (WMD) and relative risk with 95% confidence interval (95%CI) were applied to calculate pooled effect estimates between local infiltration and epidural analgesia using the random-effects model. Results: Seven RCTs including a total of 412 TKA patients, and three RCTs including a total of 200 THA patients were selected for this meta-analysis. We noted that local infiltration was associated with lower visual analog scale (VAS) scores at rest after 48 hours (WMD: -1.31; 95%CI: -2.44 to -0.18; P = .024) and 72 hours (WMD: -0.95; 95%CI: -1.39 to -0.52; P < .001) for patients with TKA, while local infiltration significantly reduced VAS scores at rest after 12 hours for patients with THA (WMD: -1.00; 95%CI: -1.49 to -0.51; P < .001). Moreover, local infiltration was associated with lower VAS scores during movement after 48 hours in TKA patients (WMD: -1.08; 95%CI: -1.86 to -0.29; P = .007), while there were higher VAS scores during movement after 24 hours for patients with THA (WMD: 1.06; 95%CI: 0.67 to 1.45; P < .001). Furthermore, we noted that local infiltration was associated with higher flexion angles compared with epidural analgesia after 24 hours (WMD: 7.11; 95%CI: 2.30-11.93; P = .004), 48 hours (WMD: 6.69; 95%CI: 3.78 to 9.59; P < .001), and 72 hours (WMD: 5.19; 95%CI: 0.95-9.44; P = .016). There were no significant differences between local infiltration and epidural analgesia for the length of hospital stay, nausea, or wound infection. Conclusions: Local infiltration is superior to epidural analgesia for postoperative pain control after TKA, whereas for THA patients inconsistent results were obtained at various times.