Postoperative epidural analgesia compared with intraoperative periarticular injection for pain control following total knee arthroplasty under spinal anesthesia: a randomized controlled trial.

BACKGROUND: Although epidural analgesia has been used for postoperative pain control after total knee arthroplasty, its usefulness is being reevaluated because of possible adverse effects. Recent studies have proven the efficacy of periarticular analgesic injection and its low prevalence of adverse effects. The present study compares the clinical efficacies of epidural analgesia and periarticular injection after total knee arthroplasty.

METHODS: This is a prospective, single-center, randomized controlled trial involving patients scheduled for unilateral total knee arthroplasty. One hundred and eleven patients were randomly assigned to periarticular injection or epidural analgesia groups. All patients were managed with spinal anesthesia. The surgical technique and postoperative medication protocol were identical in both groups. The primary outcome was postoperative pain at rest, quantified as the area under the curve of the scores on a visual analog pain scale to seventy-two hours postoperatively. The Student t test and chi-square test were used to compare the data between groups.

RESULTS: In the intention-to-treat analysis, the periarticular injection group had a significantly lower area under the curve for pain score at rest (788.0 versus 1065.9; p = 0.0059). In the periarticular injection group, the mean knee flexion angle was small but significantly better at postoperative day 1 (64.2° versus 54.6°; p = 0.0072) and postoperative day 2 (70.3° versus 64.6°; p = 0.021) than in the epidural analgesia group. The incidence of nausea at postoperative day 1 was significantly lower in the periarticular injection group (4.0% versus 44.3%; p < 0.0001). Transient peroneal nerve palsy was frequently seen in the periarticular injection group (12.0% versus 1.6%; p = 0.026).

CONCLUSIONS: Compared with epidural analgesia, periarticular injection offers better postoperative pain relief, earlier recovery of knee flexion angle, and lower incidence of nausea. Care should be taken to avoid transient peroneal nerve palsy when using periarticular injection.

LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.