Sufentanil Improves the Analgesia Effect of Continuous Femoral Nerve Block After Total Knee Arthroplasty

Purpose: We examined whether the addition of sufentanil to local anesthetics improves the quality of continuous femoral nerve block in patients undergoing total knee arthroplasty (TKA).Patients and Methods: With institutional ethical approval and having obtained written informed consent from each, 35 patients scheduled for elective bilateral TKA with ASA I or II physical status were studied. Bilateral femoral perineural catheters were preoperatively inserted. Both-sided catheters were randomly assigned to receive perineural ropivacaine of 0.2% plus 0.5 mu g/mL sufentanil deemed as RS group or 0.2% ropivacaine alone deemed as R group at the end of surgery. Visual analogue pain scores (VAS) during activity and at rest of each lower limb were recorded at 6,12,18,24,30,36,42 and 48h after surgery. During the first 48 postoperative hours, the number and reason of patients sleep interruption at night, the number of painful compressions, patient satisfaction and morphine requirements were recorded for each lower limb of patients.Results: Pain scores of RS group on movement were significantly lower than R group, but no difference was noted at rest. When compared to R group, RS group had a lower incidence of sleep interruption at night, fewer painful compressions, higher satisfaction scores and less morphine requirement.Conclusion: The addition of sufentanil to ropivacaine improved analgesia quality of continuous femoral nerve block after arthroplasty.