Postoperative pain relief and functional outcome following total knee arthroplasty - a prospective comparative audit of three analgesic regimes.

Pain control plays a key role in joint-replacement -surgery. As a surgeon the challenge is to reduce pain to an acceptable level in the post-operative period. The aim of the study was to assess the efficacy of bolus -local anaesthesia, infusion in to the surgical site and nerve blocks with femoral nerve catheter and its functional outcome. A prospective audit of 114 patients undergoing total knee arthroplasty were carried out.The patients were divided in to three groups : Group 1 (n = 27) received a bolus injection of 20 ml 0.25% levobupivacaine + 10 ml 0.25%bupivacaine + adrenaline + 30 ml saline. Group 2 (n = 39) received a bolus injection as on group 1 with 240 ml 0.25% bupivacaine infusion and 5 ml/hour using a Pain Buster pump. Group 3 (n = 48) received 30 ml 0.125% levobupivacaine to femoral (3-in-1) block with 30 ml 0.25% levobupivacaine to -sciatic nerve and introduction of a femoral nerve catheter. All patients were prescribed paracetamol 1 g QDS, Oxycontin 20 mg BD and Ibuprofen post -operatively. Pain was assessed with a Visual Analog Scale (VAS). The incidence of PONV was measured by PONY intensity score. The mean post-op VAS score for Group 3 was 4. The demand of oxynorm and NSAID were minimal in Group 3. The mean in patient stay for Group 3 was 3.1 days. The PONV intensity score was > 50 for 9 (36%) in Group 1, 15 (40%) in Group 2 and 9 (20%) in Group 3. There was loss of 20-30 degrees of flexion movements in Group 3 in the first 4 to 6 days post-op. Our study demonstrated that Regime 3 with the use of nerve blocks and femoral nerve catheter has given the maximum pain relief and good functional outcome following total knee replacement.