Comparison of the Effect of Intra-Articular, Periarticular, and Combined Injection of Analgesic on Pain Following Total Knee Arthroplasty: A Double-Blinded Randomized Clinical Trial

Background:The aim of this study was to compare the efficacy of 3 methods of intraoperative analgesic cocktail injection during total knee arthroplasty (TKA)-intra-articular (IA), periarticular (PA), and combined intra-articular and periarticular (IA+PA)-on controlling early postoperative pain. Methods:This was a prospective double-blinded parallel randomized clinical trial. A total of 153 patients scheduled for TKA were allocated to IA, PA, or IA+PA (51 patients each) by block randomization. The primary outcome was morphine consumption. Secondary outcomes were visual analogue scale (VAS) pain, knee flexion, straight leg raising, Knee Society Score (KSS), and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Results:The morphine consumption was lowest in the PA group (median = 0, interquartile range [IQR] = 5) and highest in the IA group (median = 10, IQR = 5). The PA group had significantly lower VAS pain at rest than either IA (mean difference = -0.70; 95% confidence interval [CI] = -0.93 to -0.46; p < 0.001) or PA+IA (mean difference = -0.41; 95% CI = -0.65 to -0.18; p < 0.001). The PA group had also lower VAS pain during activity compared with IA (mean difference = -0.63; 95% CI = -0.85 to -0.40; p < 0.001) and IA+PA (mean difference = -0.38; 95% CI = -0.61 to -0.16; p < 0.001). The PA group had significantly greater active knee flexion compared with IA (mean difference = 9.68 degrees; 95% CI = 5.50 degrees to 13.86 degrees; p < 0.001) and IA+PA (mean difference = 5.13 degrees; 95% CI = 0.95 degrees to 9.31 degrees; p = 0.010). Passive knee flexion was greater for PA than IA (mean difference = 7.85 degrees; 95% CI = 4.25 degrees to 11.44 degrees; p < 0.001). Other outcome variables were not significantly different among the 3 groups. The only complications were wound drainage (1 each in the IA and IA+PA groups) and deep venous thrombosis (1 in the IA group). Conclusions:PA was associated with less early postoperative pain and greater active knee flexion compared with the other 2 analgesic methods. Level of Evidence:Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.