Effect of 0.1% Ropivacaine with Dexmedetomidine Compared to 0.125% Bupivacaine with Dexmedetomidine in Ultrasound‑Guided Femoral Nerve Block for Postoperative Analgesia after Total Knee Arthroplasty – A Comparative Observational Study

Background and Aim: Total knee arthroplasty (TKA) is a common procedure for severe knee joint conditions, requiring effective postoperative pain management to improve outcomes and minimize side effects. This study aims to compare the analgesic efficacy and safety of 0.1% ropivacaine versus 0.125% bupivacaine, each combined with dexmedetomidine, for femoral nerve block in TKA. Methods: This comparative observational study was conducted at KMC Hospitals, Mangalore, from September 2022 to January 2024. Seventy-two patients undergoing spinal anesthesia for unilateral TKA were included, with 36 in each group. Group R received 0.1% ropivacaine with 0.75 μg/kg dexmedetomidine and Group B received 0.125% bupivacaine with 0.75 μg/kg dexmedetomidine. Pain was assessed using the Visual Analog Scale (VAS) at various time points postoperatively. Other outcomes included SPO2 levels, blood pressure, nausea, vomiting, and time to rescue analgesia. Results: Both groups showed comparable pain relief, with no significant differences in VAS scores at rest or during motion at 24 h postoperation. SPO2 levels were similar across groups, with a significant difference only at 10 min postoperation. Blood pressure measurements showed no significant differences. Nausea and vomiting rates were high but similar between groups. The time to first rescue analgesia was slightly longer for the bupivacaine group (318 min vs. 305 min). Conclusion: Both 0.1% ropivacaine and 0.125% bupivacaine, each with dexmedetomidine, provide effective analgesia for TKA with minimal impact on vital signs. Bupivacaine showed a trend toward lower blood pressure, which may benefit cardiovascular patients. Further research with larger cohorts and extended monitoring is recommended.