Comparison of Early-Stage and Late-Stage Periarticular Injection for Pain Relief After Total Hip Arthroplasty: A Double-Blind Randomized Controlled Trial.

Abstract

No randomized controlled trial has investigated a more optimal timing of periarticular injection for pain relief after total hip arthroplasty. The study included 140 patients, and these patients were randomly allocated to the early-stage (periarticular injection was performed just before arthrotomy, and placebo was injected after implantation) or late-stage (placebo was injected just before arthrotomy, and periarticular injection was performed after implantation) injection groups. Other perioperative interventions were similar in all participants. The prespecified primary outcome was postoperative pain score at the recovery room. The visual analog scale score at the recovery room of the early-stage injection group was significantly lower than that of the late-stage injection group (30 ± 28 vs 46 ± 30 mm; 95% CI, -25 to -5 mm; P = .0022), and this difference reaches a minimal clinically important difference level of 10 mm. No differences were observed with regard to complication rate. Early-stage periarticular injection during total hip arthroplasty provided better postoperative pain relief than late-stage periarticular injection without elevating complication rate. Level I, randomized controlled trial.