Relieving pain after arthroscopic knee surgery: Ultrasound-guided femoral nerve block or adductor canal block?

Objective: To compare the analgesic effects of femoral nerve block (FNB) and adductor canal block (ACB) after arthroscopic knee surgery. Methods: This was a prospective randomised clinical trial that enrolled 92 patients undergoing arthroscopic knee surgery. Ultrasound-guided FNB or ACB was performed immediately after surgery for pain relief. Visual analogue scale (VAS) scores and modified sedation-agitation scale (SAS) were recorded and analysed immediately following block and at 3, 6, 12 and 24 hours. The satisfaction level was also evaluated using a Likert-based patient questionnaire. Results: VAS scores decreased to 4.1±0.8 from 5.6±1.2 immediately after any nerve block, and within 3 hours, they continued to decrease to 2.0±0.6 in the FNB group and 3.4±1.0 in the ACB group (P=0.014). More patients in the FNB group were satisfied with the quality of the pain control compared to the ACB group. Additionally, patients in the ACB group required more supplemental analgesia compared to the FNB group. Conclusion: This study demonstrated that patients with FNB had denser analgesia after arthroscopic knee surgery and had less analgesic requirement compared with ACB. Greater satisfaction scores also reflected superior analgesia in patients receiving FNB.