Effect of Single-injection Femoral Nerve Block Using Real-time Ultrasound on the Postoperative Pain after Bilateral Total Knee Arthroplasty: 0.25% vs 0.5% Levobupivacaine

ABSTRACT

BACKGROUND: The purpose of this study was to compare the analgesic effect of 0.25% and 0.5% levobupivacaine for real time ultrasound guided single-injection femoral nerve block for the patients who are undergoing bilateral total knee arthroplasty (TKA). METHODS: Femoral nerve block was done to all patients with 20 ml of 0.9% normal saline on one leg and 20 ml of 0.25% levobupivacaine on the other leg for group I (n = 16) and 0.5% levobupivacaine for group II (n = 15) with 1 200,000 epinephrine and using real-time ultrasound and a nerve stimulator. The data concerning the verbal numerical rating scale (VNRS) for each leg, the consumption of the intravenous patient-controlled analgesia (IV PCA) and the demands for the additional analgesics was collected at 0, 1, 6, 12, 24 and 48 hours after the operation. RESULTS: The legs on which femoral nerve block was done with levobupivacaine showed a lower VNRS score than the legs with normal saline in either group I or group II. The VNRS scores between the two legs, the consumption of the IV PCA and the demand for additional analgesics showed no significant differences between the groups. CONCLUSIONS: Our results demonstrate that single-injection femoral nerve block using real-time ultrasound with either 0.25% levobupivacaine or 0.5% levobupivacaine 20 ml provides a good effect for the postoperative pain control after TKA.