Comparison of periarticular multidrug injection versus epidural catheter in 55 patients undergoing total hip arthroplasty: A prospective randomized controlled trial.

Introduction: Epidural catheter (EC) and periarticular multidrug injection (PMDI) are widely performed for reducing total hip arthroplasty (THA) postoperative pain. However, the more effective analgesic technique between the two is unclear. Thus, we aimed to answer the following questions: (1) does PMDI contribute to less postoperative pain than EC? (2) is there any difference in side-effect occurrence between the methods? (3) does PMDI provide better functional recovery than EC? (4) is there any difference in inflammatory parameters between the methods?

Hypothesis: PMDI would reduce postoperative pain and side effects, provide better functional recovery, and contribute to lower inflammation compared with EC.

Materials And Methods: This single-center, randomized controlled trial was conducted from 2017 to 2019 and enrolled 55 patients randomly allocated into two groups (28 patients: PMDI, 27 patients: EC). The primary outcome was evaluated using the pain visual analogue scale (VAS). The secondary outcomes were narcotic consumption, side effects, hip range of motion (ROM), ratio of patients performing the straight leg raise (SLR) on postoperative day (POD) 1, the day the patient started using a walker and cane, and inflammatory parameters (white blood cell [WBC], and C-reactive protein [CRP]). Paired t-tests and Fisher's exact test were used for comparisons.

Results: There were no significant differences in the pain VAS scores between groups. The EC group experienced significantly more side effects than the PMDI group (p<0.01). ROM of the PMDI group on POD 3 was significantly better than the EC group (p<0.05). Furthermore, more patients in the PMDI group could perform SLR than those in the EC group on POD 1 (p=0.01). On POD 1, the WBC count was significantly higher (p<0.01) in the PMDI group, whereas CRP levels were significantly lower in the PMDI group (p<0.05) and remained lower than the EC group on POD 3 (p<0.01).

Discussion: The patients in the PMDI and EC groups had comparable postoperative pain. Those in the PMDI group had lower side effects. Functional recovery was comparable between the patients in the PMDI and EC groups. Compared to the EC group, the PMDI group had higher WBC count and lower CRP levels.

Level Of Evidence: I; Prospective randomized controlled trial.