Effectiveness of continuous adductor canal block versus continuous femoral nerve block in patients with total knee arthroplasty A PRISMA guided systematic review and meta-analysis

Background: This study aimed to evaluate the effectiveness of continuous adductor canal block (CACB) versus continuous femoral nerve block (CFNB) in postoperative analgesia and early rehabilitation of patients with total knee arthroplasty (TKA). Methods: The Cochrane Library, PubMed, and EMbase were systematically searched to retrieve literature comparing efficacy of CACB versus CFNB on pain relief and functional recovery in knee replacement patients until December 2018, without language limitation. Meta-analysis was performed using RevMan 5.3 software. Results: A total of 7 clinical randomized controlled trials and 4 retrospective studies were included, involving 484 cases in the CACB group and 491 in the CFNB group. The results of the meta-analysis showed that the visual analogue scores (VAS) at rest were similar between the CACB group and the CFNB group at 8hours (standard mean difference(SMD)=-0.26, 95% confidence interval(CI): -0.62, 0.11), 12hours (SMD=-0.02, 95%CI: -0.50, 0.47), 24hours (SMD= 0.05, 95%CI: -0.22, 0.33), and 48hours (SMD=-0.10, 95%CI: - 0.29, 0.09) after TKA (P>.05 for all). The muscle strength of patients in the CACB group postoperation was significantly improved than those of the CFNB group (SMD= 0.81; 95% CI: 0.35, 1.26; P=.0005). There were no significant differences in the amount of opioids consumption and the incidence of postoperative fall between CACB and CFNB (P>.05). Conclusion: The analgesic effects of CACB versus CFNB are equivalent after TKA. CACB has less effect on the quadriceps muscle strength, which is beneficial to the early postoperative activities and functional rehabilitation.