Published 3/11/2025
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Keightley Amen, BA, ELS
A recent study found detectable levels of bacterial contamination in 50 percent of 16 anterior cruciate ligament (ACL) reconstruction surgeries, and the most common step of the procedure for contamination was just prior to ACL graft passage. The findings, which will be presented at the AAOS 2025 Annual Meeting, highlight the prevalence of bacterial contamination despite orthopaedic surgeons’ best attempts at maintaining a sterile surgical field.
“While the overall postoperative infection risk or risk of developing postoperative septic arthritis is low following ACL reconstruction, the morbidity of a postoperative infection is significant. More specifically, recent literature has also described subclinical bacterial colonization of grafts, the development of biofilms, and the impact of bacteria on the mechanical properties of the graft. These factors have been implicated as possible contributors to graft failure,” presenting author Parker A. Cavendish, MD, orthopaedic resident at the Ohio State University College of Medicine, told AAOS Now Daily Edition.
Therefore, it is important that orthopaedic surgery teams fully understand potential sources of contamination and the times when it is more likely to occur. The current study assessed surgical gloves for the presence of bacterial contamination during 16 ACL reconstructions (eight bone–
patellar tendon–bone autografts and eight hamstring autografts). Glove sample collection occurred at four timepoints during surgery:
- after patient draping
- after graft harvest
- after graft preparation
- prior to graft passage
At each of those timepoints, the primary member of the surgical team performing each task pressed their gloved fingers onto a sterile Tryptic Soy Agar (TSA) plate. Then they removed the outer gloves and replaced them with fresh sterile gloves. The researchers incubated the TSA plates for 48 hours, then checked for bacterial growth. The researchers also analyzed tissue trimmings from the autografts before they were soaked with antibiotics. Each case had a negative control plate, which was set out, handled, and transported along with the experimental plates.
Eight of the 16 cases (50 percent) produced at least one sample with bacterial growth, and 9 percent of all plates collected were positive for bacterial growth. One plate of the 16 (6 percent) collected after graft harvest had one colony-forming unit (CFU), and one plate of the 16 (6 percent) collected after graft preparation had one CFU. Contamination occurred most frequently prior to graft passage: Seven of those 48 plates (15 percent) demonstrated growth (five had one CFU, one had three CFUs, and one had four CFUs). Three of the 16 tissue samples (19 percent) were positive for bacterial growth. None of the control plates had bacterial growth. Although the authors did not find statistically significant differences between time points or graft types, the findings indicate overall presence of detectable bacteria during ACL reconstruction surgeries. Notably, no patients experienced overt septic arthritis after surgery.
“Despite our best efforts to maintain sterility, we were able to identify some level of bacterial contamination in 50 percent of cases, with the most common time point being just prior to graft passage,” Dr. Cavendish said. The research group is planning sequencing studies to further understand contamination risks and to elucidate potential strategies for prevention.
“Complete sterility may not be practically feasible considering factors that cannot be completely controlled in the OR,” Dr. Cavendish said. “However, there are timepoints during this procedure to be mindful of the risk of contamination, and appropriate precautions should be taken, as subclinical graft contamination can still have a detrimental impact on reconstruction outcomes.”
Based on the findings of this study, the authors recommend possible steps to help minimize risk of graft contamination, including soaking or wrapping the graft in antibiotic solution and changing gloves frequently when handling the graft, especially prior to graft passage.
Paper 257 will be presented during VIPER: Sports Medicine IV, 3:30 p.m. on Tuesday in Ballroom 20B.
Dr. Cavendish’s coauthors of “Are We Really Sterile? Bacterial Contamination Rates during Anterior Cruciate Ligament Reconstruction: A Laboratory Analysis of Surgical Gloves” are Christopher C. Kaeding, MD, FAAOS; David C. Flanigan, MD, FAAOS; Eric Milliron, MD; Kathryn E. Greskovich, BS; Paul Stoodley, PhD; Robert A. Magnussen, MD, FAAOS; and Tyler Barker, PhD.
Keightley Amen, BA, ELS, is a freelance writer for AAOS Now.