How Effective Is Antibiotic-Loaded Bone Cement, Really?

How effective is antibiotic-loaded bone cement in preventing infection in total knee arthroplasty (TKA) patients? A group of researchers from Kaiser Permanente in San Diego, California, decided to try to answer that question and their study, “Commercially Prepared Antibiotic-Loaded Bone Cement and Infection Risk Following Cemented Primary Total Knee Arthroplasty,” which appears in the November 18, 2020 edition of The Journal of Bone and Joint Surgery.

Certainly, with the rising focus on the risk of surgery-derived infection, this is a particularly timely study which was prompted by, as co-author Robert Namba M.D. observed, “An increase in the utilization of antibiotic-loaded bone cement (ABC) in our organization.”

The team dug into the Kaiser Permanente Total Joint Replacement Registry, where they evaluated 87,018 primary cemented TKAs done from 2008 to 2016. The investigators looked at time to infection as the primary outcome (90-day deep infection or septic revision); time to aseptic revision and to revision for aseptic loosening were the secondary outcomes.

They set out to establish the effectiveness of commercially available antibiotic-loaded bone cement in reducing the risk of infection following TKA, not only overall, but in three subgroups of patients with an elevated risk of infection—diabetes, those with a body mass index ‡35 kg/m2, and those with an American Society of Anesthesiologists classification ‡3. The authors also evaluated the relationship between antibiotic-loaded bone cement and the risks of aseptic revision and revision for aseptic loosening.

“Regular cement was found to be noninferior to antibiotic bone cement with respect to risk infection and cost across all TKA patients,” wrote the authors. “However, a lower risk of infection was observed with ABC among TKA patients with diabetes. There was no evidence of a difference in risk of revision for ABC compared with regular cement.”

“We had previously looked into the efficacy of antibioltic bone cement with negative findings,” Dr. Namba told OTW. “In this analysis the observation that antibiotic bone cement was associated with a decreased risk of TKA infection was a little surprising. For the majority of patients undergoing TKA the extra cost of antibiotic bone cement is not warranted.”

Musing about future research, he noted, “The trend for higher use of antibiotic bone cement will make studies like ours more challenging in the future since there will be smaller sample sizes of regular cement cohorts.”