Although both local infiltration analgesia (LIA) and continuous femoral nerve block (FNB) are common analgesic modalities for pain relief after total knee arthroplasty (TKA), we are aware of no parallel-group, randomized controlled trial that has solely compared the efficacy of LIA and continuous FNB.
We conducted a prospective, 2-arm, parallel-group, randomized controlled trial involving patients scheduled for TKA. A total of 45 patients were randomly assigned to either the LIA or the continuous FNB group. Except for the analgesic modality, perioperative managements were identical in both groups. The primary outcome was postoperative pain score at rest 1 day after surgery, measured using a 100-mm visual analog scale.
Patients in the LIA group had a significantly lower visual analog scale score at rest 1 day after surgery than those in the continuous FNB group (34 ± 10 vs 42 ± 13 mm; P = .028). The opioid consumption during the initial 24 hours was significantly lower in the LIA group (12 ± 4 vs 16 ± 7 mg; P = .031). There were no differences in the rate of complications between the groups.
LIA was associated with better pain relief with a comparable complications rate for patients undergoing TKA than FNB. We recommend LIA for pain relief after TKA.