Ultrasound-guided single-injection femoral nerve block provides effective analgesia after total knee arthroplasty up to 48 hours

Abstract

Objectives: The purpose of this study is to evaluate the effects of ultrasound (US) guided single-injection femoral nerve block (FNB) spinal anesthesia on pain control, morphine consumption, adverse effects, and patient satisfaction during the postoperative 48-hour period in patients undergoing total knee arthroplasty (TKA). Methods: One hundred four ASA physical status I-III patients undergoing single TKA for degenerative joint disease were enrolled in this clinical study. Patients were randomly distributed into two groups: US-guided single-injection FNB with 40 ml of 0.5% bupivacaine and 1:200,000 epinephrine was administered to Group F (n=51) patients. Preservative-free saline was injected in Group P (n=53) patients using the same method as Group F. Pain scores, morphine consumption, incidences of adverse events, and patient satisfaction were assessed over the course of 48 hours. Results: Group F used significantly less morphine compared with Group P (18.7 mg vs. 39.6 mg) during the first 48 hours after surgery (p<0.001). When compared with group P, the VRS scores both at rest and during movement were significantly lower in Group F at 4, 8, 12, 24, and 48 hours after TKA (for all comparisons p<0.001). In addition, patient satisfaction was better in Group F than Group P. Conclusion: This study suggests that a US-guided single-injection femoral nerve block following TKA improves patient satisfaction and reduces consumption of morphine during the first 48 hours.