A Comparison of the Efficacy and Complications Between Intraosseous and Periarticular Multimodal Analgesic Cocktail Injections After Primary Total Knee Arthroplasty: A Randomized Controlled Trial.

BACKGROUND: Early postoperative pain control after total knee arthroplasty (TKA) plays a crucial role in patient satisfaction following surgery. Despite current multimodal pain management strategies, postoperative pain remains a concern for patients and can hinder the decision to undergo TKA. With the advent of intraosseous (IO) analgesic injections, the efficacy of IO multimodal analgesic cocktail administration compared to standard periarticular (PA) injections remains controversial.

METHODS: A prospective randomized controlled trial was conducted comparing 45 patients who received an IO multimodal cocktail injection (five mg of morphine, 30 mg of ketorolac, 20 mL of 0.5% bupivacaine, and 0.6 mL of 1:1,000 epinephrine) with 45 patients who received a standard PA cocktail injection. A total of 43 patients in each group completed the study. Postoperative visual analog scale for pain at rest and during motion, morphine consumption, functional outcomes, and postoperative complications were recorded.

RESULTS: In the IO group, visual analog scale for pain was significantly lower both at rest and during motion at four, six, and 12 hours, as well as two weeks postoperatively. The Timed Up and Go test was faster in the IO group at 48 hours, but not at two weeks. However, morphine consumption, time to start walking, time to discharge, postoperative range of motion, and complications showed no differences up to two weeks.

CONCLUSIONS: Intraosseous multimodal cocktail injection resulted in better pain control compared to PA injection during the early postoperative period, as well as improved function in the Timed Up and Go test at 48 hours after TKA, without increasing postoperative complications.

LEVEL OF EVIDENCE: Therapeutic Level I.