Addition of femoral nerve block to epidural infusion for pain control post total knee arthroplasty: Does it make a difference? 

Melvin KANDASAMY, Muhammad MAAYA, Raha ABDUL RAHMAN, Nadia MD NOR, Nurlia YAHYA

Department of Anaesthesiology and Intensive Care, Faculty of Medicine, Universiti Kebangsaan Malaysia Medical Centre, Malaysia

Introduction: Effective post-operative analgesia is a major factor in functional outcome after total knee arthroplasty (TKA). To reduce post-operative pain and expedite recovery, peripheral nerve blocks, such as the femoral nerve block (FNB) have been used as an adjunct to the analgesic regime. We assessed whether the addition of a FNB to continuous epidural analgesia (CEA) would improve pain control after TKA. Materials and Methods: A prospective, randomised, controlled study was conducted on 58 patients undergoing TKA and randomised into two groups. The CEA+FNB Group received a single-shot FNB of 30 ml 0.5% bupivacaine using a nerve stimulator technique. The CEA Group acted as a control group and did not receive FNB. Patients in both groups then received combined spinal-epidural anaesthesia for the surgery. Post-operative epidural infusion with 0.1% bupivacaine and 2 µg/ml of fentanyl, at 6 ml/hr was continued up to 48 hours post-operatively. Visual analogue scale (VAS) scores, motor blockade, requirement of rescue analgesia and patient satisfaction were recorded. Results: VAS scores were not significantly different between the CEA+FNB and CEA groups during rest (3 vs. 2) and flexion (5 vs. 6) on postoperative day-1 and during rest (1 vs. 2) and flexion (4 vs. 4) on postoperative day-2. There was no significant difference in rescue analgesia required, the volume of epidural infusion, motor blockade or patient satisfaction between both groups. Conclusion: We concluded that the addition of FNB to epidural infusion did not improve analgesia after TKA.

Keywords: Epidural analgesia, femoral nerve block, regional anaesthesia, total knee arthroplasty

Correspondence author: Melvin KANDASAMY, Department of Anaesthesiology and Intensive Care, Faculty of Medicine, Universiti Kebangsaan Malaysia Medical Centre, Jalan Yaacob Latif, Bandar Tun Razak, Cheras, 56000, Kuala Lumpur, Malaysia. E mail: melvinkandasamy@gmail.com

Brunei Int Med J. 2012; 8 (6): 334-341