Evaluating Analgesic Efficacy of Single Femoral Nerve Block versus Combined Femoral-Sciatic Nerve Block Post Total Knee Arthroplasty

BACKGROUND: With increasing knee replacement surgeries, there has been a constant search for effective pain control modality. AIMS: We compared the analgesic effect of femoral nerve block (FNB) alone with combined femoral and sciatic nerve block (SNB) for postoperative pain management after total knee arthroplasty (TKA). SETTING AND DESIGN: This was a prospective observational study. METHODS: A total of 150 adult patients of American Society of Anesthesiologists physical status class I and II scheduled for elective TKA under spinal anesthesia with 3.4-mL bupivacaine 0.5% and 20-μg fentanyl were randomly allocated to two groups. Group F patients received a single shot FNB with 20 ml 0.375% ropivacaine and Group FS patients received combined FNB with 20 mL of 0.375% ropivacaine and SNB with 40 ml of 0.375% ropivacaine at the end of surgery. The primary outcome was the change in Numeric Rating Scale (NRS) scores between Groups F and FS at 6, 12, 18, 24, and 48 h later. The secondary outcome was total doses of opioid required in both groups. RESULTS: The demographic data were comparable in both groups. The NRS scores were higher and statistically significant in Group F than that in Group FS at all five measured time points (P < 0.00001), and the total pain score with a mean of 15.43 in Group F and a mean of 9.61 in Group FS was statistically significant. Significantly more opioid consumption was seen postoperatively in Group F as compared to Group FS at 12, 18, 24, and 48 h as depicted by P < 0.00001. CONCLUSIONS: We conclude that the FNB, when combined with SNB, shows superior results than femoral block alone. SNB reduced pain scores and opiate consumption postoperatively up to 48 h.