Effect of continuous adductor canal or femoral nerve block on pain relief and early rehabilitation following total knee arthroplasty

Abstract

Objective To compare the analgesic effect of continuous adductor canal block(ACB) and continuous femoral nerve block(FNB) after total knee arthroplasty(TKA). Methods Sixty patients scheduled for unilateral TKA were randomly assigned into two groups, receiving continuous ACB(group A) or continuous FNB(group F). Intravenous anesthesia was applied throughout the operation. The adductor canal and the femoral nerve were catheterized for block under the guidance of sonography before induction of general anesthesia. Patient-controlled analgesia was provided immediately after surgery with 0.2% ropivacaine through the perineural catheter. The pain severity at rest and upon movement (passive knee flexion of 45 degrees) with a 0-10 numeric rating scale (NRS), the Lovett score of muscle strength of the quadriceps femoris, and the modified Bromage score of the motor block of the affected extremity were assessed 4, 8, 12, 24, 48 h after surgery. The maximal range of active/passive motion of the knee joint was recorded 1, 2, 3, 14 d after surgery. The number of effective patient-controlled bolus of ropivacaine and the number of need for opioid rescue within 48 h after surgery, the first time of out-of-bed activity, the time of active knee flexion reaching 90 degrees, and the hospital for special surgery(HSS) score of knee function 14 d after surgery were also recorded. Results There was no difference between group A and group F in terms of the NRS scores at rest and upon movement, the number of effective patient-controlled bolus of ropivacaine and the number of need for opioid rescue (P>0.05). Patients in group A had a higher Lovett score of muscle strength of the quadriceps femoris and a lower modified Bromage score of the motor block than those in group F within 12 h after surgery (P 0.05). Conclusions An equal postoperative analgesic efficacy was observed in patients receiving continuous ACB and continuous FNB. Furthermore, continuous ACB did not provide a superior effect on early rehabilitation than continuous FNB. Key words: Adductor canal block; Femoral nerve block; Total knee arthroplasty; Postoperative analgesia; Rehabilitation