Preoperative Ropivacaine with or without Tramadol for Femoral Nerve Block in Total Knee Arthroplasty

Purpose To compare the analgesic effect of preoperative ropivacaine with or without tramadol for femoral nerve block in total knee arthroplasty (TKA). Methods 14 men and 46 women aged 59 to 80 years who were American Society of Anesthesiologists (ASA) grade I or II and were scheduled for TKA were randomised to receive preoperative femoral nerve block with 20 ml of 0.375% ropivacaine plus tramadol 0 mg (n=15), 50 mg (n=15), or 100 mg (n=15), or no preoperative femoral nerve block (control) [n=15]. Femoral nerve block was performed by a single anaesthesiologist before the standardised combined spinal epidural anaesthesia. Postoperatively, patient-controlled analgesia was given. The visual analogue score (VAS) for pain at rest and on movement was recorded at 8, 12, 24, 48, and 72 hours. Passive knee range of motion (ROM) was measured at 24, 48, and 72 hours. Results The 4 groups were comparable in terms of age, gender, weight, ASA grade, and operating time. Compared with patients who received no femoral nerve block or ropivacaine alone, those who received femoral nerve block with 20 ml of 0.375% ropivacaine plus tramadol 50 mg or 100 mg recorded a lower VAS for pain at rest and on movement at 8 to 72 hours, longer sensory and motor block time, and lower demand, delivery, and total amount of patient-controlled analgesia. The passive knee ROM at 24 to 72 hours was greater in patients with femoral nerve block than in those without. Conclusion Preoperative femoral nerve block with 20 ml of 0.375% ropivacaine and 100 mg tramadol resulted in the best analgesic effect.