In 2021, a pivotal Houston Methodist study published in The Bone and Joint Journal found that patients undergoing knee replacement surgery who received vancomycin injections directly in the bone were dramatically less likely to experience a postoperative infection than those who received it in the vein.

At the American Academy of Orthopedic Surgeons (AAOS) annual meeting in March 2023, the study's senior author, Dr. Stephen Incavo, will present new evidence that intraosseous (IO) administration of vancomycin in total hip replacements produces similarly game-changing results.

"We are thrilled with these results and encourage orthopedic surgeons to review our findings and learn more about the benefits of the IO administration technique in both knee and hip arthroplasty procedures," says Dr. Incavo, a Houston Methodist orthopedic surgeon.

The original Bone and Joint Journal study, co-authored with Houston Methodist orthopedic surgeons Drs. Terry Clyburn and Kwan Park, received The Knee Society's Ranawat Award for 2021.

On Friday, March 10, at 8 a.m., the researchers' follow-up paper "Intraosseous Vancomycin Can Safely Be Used in Total Hip Arthroplasty with Low Systemic Vancomycin Levels and Local Tissue Concentrations of Vancomycin Exceeding Intravenous Levels" will be highlighted at AAOS as part of the Adult Reconstructive Hip program in Room 4103. This paper has been awarded the prestigious Aufranc award from the Hip Society.

The case for vancomycin

The 2021 study found more than six times as many periprosthetic joint infections (PJI) in total knee arthroplasty patients who received the antibiotic by intravenous administration than those who received it by intraosseous administration. 

Incidence of PJI at a minimum 90-day follow-up was 1.4% in the IV group, compared to 0.22% in the IO group, a statistically significant difference. Slightly more than half of the 1,060 patients reviewed in the study were treated by IV.

Eight patients in the IV arm developed an infection, compared to one in the IO arm.

Both groups of patients received the antibiotic in combination with a first-generation cephalosporin to prophylactically guard against PJI, which occurs in up to 2% of all total knee arthroplasties nationwide.

"Infection in knee replacement surgery is a devastating complication," Dr. Incavo says. "It involves multiple surgeries and hospitalizations. It's life-changing because it takes at least six to 12 months to get over it and sometimes even results in above-the-knee amputation."

In conjunction with stringent infection control procedures and education efforts preceding, during and after surgery, the prophylactic use of vancomycin has been adopted by some orthopedic surgeons to address the "not insignificant portion of bacteria which are not sensitive to a cephalosporin but are sensitive to vancomycin," according to Dr. Incavo.

Challenges to IV delivery

Intravenous administration of the antibiotic comes with several important disadvantages.

When used in total knee arthroplasty, the drug must be administered very slowly, starting two hours prior to surgery and finishing one hour prior to surgery. The timetable can present logistical challenges for OR scheduling and pre-op/peri-op communication and handoffs.

"Studies show that most centers don't administer the medication according to these strict guidelines," says Dr. Incavo. "They also show that it's not effective when it is not administered according to these strict guidelines. So you can wind up in a situation of wondering why you're doing it at all."

Prior to this report, no studies have demonstrated that the drug significantly lowered PJI rates, presumably due to timing and dosing issues limiting its impact. Faced with such lackluster evidence, many orthopedic surgeons have decided the possible side effects of the antibiotic aren't worth the risk. Those include kidney damage, hearing loss and Red Man Syndrome, an adverse effect characterized by rash, flushing or blood pressure drop.

Intraosseous delivery changes the calculus

The IO delivery technique avoids most of these systemic side effect risks because the medication goes directly into the bone of the limb being operated upon, not into the patient's bloodstream. It gives extremely high levels of antibiotic protection at the site of the surgery with very low systemic levels.

"IO delivery results in five to 10 times more local tissue concentration than IV delivery," Dr. Incavo says. "You get much more of the medicine exactly where you want it and have almost undetectable levels in the blood."

The procedure requires the placement of a tourniquet, which Dr. Incavo notes is common practice in most total knee arthroplasty cases already. The dose is injected into the proximal tibia after tourniquet inflation but prior to skin incision.

"It's very easy and straightforward for any orthopedic surgeon to perform, that's the beauty of it," Dr. Incavo says. "As long as the tourniquet is left on for at least 30 minutes while the operation is performed, there's no issue with the antibiotic being released into the patient's system."

The IO delivery mechanism also bypasses the timing and logistical challenges that IV administration presents, as the IO infusion typically takes less than five minutes and is delivered by the operating team at the time of the surgery.

"The takeaway is that IO is safe, easy and shows remarkable promise in terms of reducing the number of devastating infections among knee replacement surgery recipients," reiterates Dr. Incavo. "Currently, only a small number of orthopedic surgeons are doing it, but we think and hope that will change once our report is published. This is an important new tool for our toolkit and it really changes the way we look at vancomycin risk vs. reward."