Morphine + Antibiotics: New Study Uncovers Interesting Benefits

Does delivering morphine directly into the bone along with antibiotics bring enhanced pain relief for patients undergoing total knee arthroplasty (TKA)?

That is what a team from Texas sought to determine via a double-blind, randomized controlled trial. Their work, “Intraosseous Morphine Decreases Postoperative Pain and Pain Medication Use in Total Knee Arthroplasty: A Double-Blind, Randomized Controlled Trial,” appears in the March 7, 2022, edition of the Journal of Arthroplasty.

Co-author Stephen Incavo, M.D. an orthopedic surgeon at Houston Methodist Hospital explained the hypothesis of the study to OTW, “Pain following knee replacement surgery remains a common reason for patient dissatisfaction and may prevent patients from seeking knee replacement surgery.”

For this study, total knee arthroplasty was performed on 48 patients undergoing primary TKA (split 50/50 between the treatment group and control group). Those in the treatment group received an intraosseous antibiotic injection with 10 mg of morphine, while individuals in the control group received an intraosseous injection of antibiotics.

The researchers tracked pain, nausea, and use of opioids up to 14 days following surgery. They also assessed morphine and interleukin-6 serum levels at the 10-hour postoperative in a subgroup of 20 patients.

The researchers determined that those individuals in the experimental group had lower Visual Analog Scale pain scores at 1, 2, 3, and 5 hours postoperatively, a trend that was maintained for postop days 1, 2, 8, and 9 (40% reduction; 49% reduction; 38% reduction; 33% reduction).

Overall, said the investigators, “The experimental group had lower opioid consumption than the control group for the first 48 hours and second week post-surgery. Knee Injury and Osteoarthritis Outcome Score for Joint Replacement scores for the experimental group showed significant improvement at 2 and 8 weeks post-surgery. Serum morphine levels in the experimental group were significantly less than the control group 10 hours after intraosseous injection.”

“Using pain medication, such as morphine, directly at the site of TKA surgery provides pain control with minimal systemic effects because the morphine generally remains in the knee joint,” Dr. Incavo told OTW. “We have found that intraosseous delivery of medication, such as antibiotics and pain relievers, can minimize infection and decrease pain associated with knee replacement surgery.”