[Epidural analgesia versus femoral or femoral-sciatic nerve block after total knee replacement: comparison of efficacy and safety].

OBJECTIVE: Pain after total knee replacement surgery is intense. The aim of this study was to compare 3 techniques for providing postoperative analgesia (epidural analgesia, femoral nerve block, and a combined femoral-sciatic nerve block) in total knee arthroplasty.

MATERIAL AND METHODS: Observational study of 1550 elective primary unilateral total knee replacement operations. The safety and efficacy of the following 3 techniques were compared: epidural analgesia, femoral nerve block, and femoral-sciatic nerve block. Demographic, anesthetic, and surgical data were recorded. Study variables included pain intensity on a visual analog scale every 4 hours, need for rescue analgesia (morphine), complications and adverse events within 5 postoperative days.

RESULTS: No significant differences were found in demographic, anesthetic, or surgical variables. In the first 24 hours after surgery, pain intensity was significantly less for patients who received a femoral-sciatic nerve block. The mean levels of morphine consumption in the first 96 hours after surgery were similar in the femoral-sciatic nerve block group (3.18 mg) and the epidural analgesia group (3.19 mg); morphine consumption in the femoral block group was significantly higher (4.51 mg). Epidural analgesia was associated with the highest rate of complications (17%).

CONCLUSIONS: A sciatic nerve block combined with a femoral nerve block attenuates pain more effectively and is associated with less postoperative morphine consumption in comparison with a femoral nerve block alone. Peripheral nerve block techniques have fewer adverse side effects than epidural analgesia.