Is Adductor Canal Block Better Than Femoral Nerve Block in Primary Total Knee Arthroplasty? A GRADE Analysis of the Evidence Through a Systematic Review and Meta-Analysis.

BACKGROUND: Total knee arthroplasty (TKA) is associated with intense postoperative pain with a need for early ambulation to gain function and prevent postoperative complications. Compared with femoral nerve block (FNB), adductor canal block (ACB) can relieve postoperative pain and preserve quadriceps muscle strength. This meta-analysis was conducted to investigate which analgesic method provides better pain relief and functional recovery after TKA.

METHOD: We conducted a meta-analysis to identify relevant randomized controlled trials involving ACB and FNB after TKA in electronic databases, including Web of Science, Embase, PubMed, and the Cochrane Library, up to November 2016. Finally, 9 randomized controlled trials involving 609 patients (668 knees) were included in our study. Review Manager Software and Grading of Recommendations Assessment, Development, and Evaluation profiler were used to perform the meta-analysis.

RESULTS: Compared with FNB, ACB resulted in better quadriceps muscle strength and mobilization ability. There were no significant differences in the visual analog scale at rest, visual analog scale with mobilization, rescue opioid consumption, patient satisfaction, and length of hospital stay.

CONCLUSION: Compared with FNB, ACB shows similar pain control after TKA. However, ACB can better preserve quadriceps muscle strength and improve mobilization ability. In conclusion, ACB showed better functional recovery after TKA without compromising pain control. Therefore, ACB is recommended as an alternative analgesic method for early ambulation after TKA.