Effectiveness of Intraosseous Morphine for Pain Control in Total Knee Arthroplasty

BACKGROUND: Effective pain management following total knee arthroplasty (TKA) is crucial to optimizing patient outcomes and experiences. Multimodal pain management protocols vary between institutions, with some recently proposing the addition of an intraosseous (IO) injection of morphine intraoperatively. The purpose of this study was to investigate whether the addition of an intraoperative, IO injection of morphine during elective primary TKA would lead to improved pain control and decreased narcotic consumption during the postoperative period. METHODS: In this double-blinded, randomized controlled trial, 100 patients undergoing elective primary TKA were prospectively enrolled. All patients received spinal anesthesia and intravenous sedation combined with an intraoperative, surgeon-administered adductor canal block. The experimental group received an intraoperative, IO injection containing 10 mg of morphine and 500 mg of vancomycin in 110 mL of normal saline solution. The control group received the same injection but without morphine. All patients received 6 daily text-message surveys (3 in the morning and 3 in the evening) for 14 days postoperatively to collect pain scores, morphine milligram equivalent (MME) consumption, and nausea and vomiting events. Data on demographics, operative factors, post-anesthesia care unit (PACU) pain scores, PACU MME consumption, and patient-reported outcomes were also collected. Linear mixed-effects (LME) models were utilized. RESULTS: A total of 88 patients (52.3% [n = 46] female; mean age, 69.1 ± 9.0 years [range, 46 to 89 years]; 89.8% [n = 79] White) were included in the analysis. The LME model demonstrated no differences between the groups with respect to daily pain scores at any time point within 14 days postoperatively (p = 0.969). There were no differences between the groups with respect to daily MME consumption at any time point within 14 days postoperatively (p = 0.377). There were also no differences in total MME consumption or weekly MME consumption postoperatively (p ≥ 0.878). CONCLUSIONS: IO morphine did not significantly improve postoperative pain control or decrease narcotic consumption up to 2 weeks postoperatively among patients undergoing elective primary TKA. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.