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

Introduction 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. Materials and Methods 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. Results 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). Conclusion 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. Clinical Trial Registration Number 194/K-LKJ/ETIK/VI/2022