A comparison of ultrasound alone vs ultrasound with nerve stimulation guidance for continuous femoral nerve block in patients undergoing total knee arthroplasty

50 patients scheduled for total knee arthroplasty with a continuous femoral nerve block for postoperative analgesia were randomized to catheter placement with ultrasound plus nerve stimulation guidance, or simply ultrasound guidance alone. The purpose of this study was to compare analgesic efficacy between groups, including pain scores, analgesic requirement, and block failure rate. Patient satisfaction and time required for catheter placement were also compared. No significant differences were observed in any outcome, with the exception of catheter placement time which was significantly longer in the group managed with nerve stimulation.