Efficacy and Adverse Effect of Continuous Femoral Nerve Block and Intrathecal Morphine with Patient-Controlled Epidural Analgesia Post-total Knee Arthroplasty: A Randomised Controlled Trial

Abstract

Achieving adequate analgesia after total knee arthroplasty (TKA) can be a challenging task. This study investigates the efficacy and adverse effects of continuous femoral nerve block using a patient-controlled analgesia machine (FNB-PCA) in comparison to intrathecal morphine (ITM) with patient-controlled epidural analgesia (PCEA) using bupivacaine in patients undergoing unilateral TKA under spinal anesthesia. Forty patients with ASA I-II scheduled for unilateral TKA were randomized into two groups. Group ITBM+Ep received 250 mcg of intrathecal morphine and 15 mg of hyperbaric bupivacaine, and group ITB-FNB received FNB with 30 ml of 0.375% Bupivacaine with 5 mcg/ml of epinephrine with 15 mg bupivacaine administered intrathecally. Post-operative analgesia for group ITBM+Ep was maintained by PCEA with bupivacaine, while group ITB-FNB used PCA. Visual analogue scales (VAS) on rest and movement, hemodynamics, and side effects were recorded post-operatively. A decrease in VAS at rest between group ITBM+Ep and ITB-FNB from the 24th - 48th hour was statistically significant (P<0.05). VAS on movement showed no statistical difference between both groups from the 1st until the 6th hour (P >0.05), but VAS was significantly different starting the 12th hour (P <0.05). Group FNB was associated with less hypotension, nausea, vomiting, and pruritus (P <0.05). This study concludes that ITB-FNB-PCA provides superior analgesia on rest and movement with a significant reduction in side effects in comparison to ITBM+Ep with PCEA for patients who underwent TKA. Further trials comparing different anesthetic techniques with larger sample sizes are necessary to establish “gold standard” management after TKA. 194/K-LKJ/ETIK/VI/2022