Ultrasound guided obturator versus sciatic nerve block in addition to continuous femoral nerve block for analgesia after total knee arthroplasty.

Both obturator and sciatic nerve block in combination with femoral nerve block (FNB) have been suggested to be useful in relieving pain after total knee arthroplasty (TKA), compared with FNB alone. We compared their efficacy in this retrospective study. For six consecutive months, patients undergoing unilateral TKA under general anesthesia with continuous FNB plus obturator nerve block (n = 8) or continuous FNB plus sciatic nerve block (n = 8) were investigated. Knee pain was assessed using visual analogue scale (VAS) on the day of surgery and on postoperative days one to three. In addition, we also investigated intraoperative and postoperative morphine consumption. VAS scores and total morphine consumption were not different between the two groups, although patients in the FNB plus sciatic nerve block group were administered less morphine during surgery. Sciatic nerve block with continuous FNB may be superior to obturator nerve block with continuous FNB for analgesia during surgery for TKA.