Macroscopic contamination of orthopaedic instruments with particulates, including
cortical bone and polymethyl methacrylate (PMMA) bone cement, that have previously
undergone pre-operative sterilization is frequently encountered peri- or intraoperatively,
calling into question the sterility of such instruments.
To determine if macroscopic contaminants of orthopaedic surgical instrumentation maintain
a bacterial burden following sterile processing, and to determine the most commonly
contaminated instruments and the most common contaminants.
Macroscopic contaminants in orthopaedic instrument trays were collected prospectively
at a single tertiary referral centre over a 6-month period from August 2021 to May
2022. When identified, these specimens were swabbed and plated on sheep blood agar.
All specimens were incubated at 37 °C for 14 days, and inspected visually for colony
formation. When bacterial colony formation was identified, samples were sent for species
In total, 33 contaminants were tested, and only one contaminant was found to be growing
bacterial colonies (Corynebacterium sp.). The items most commonly found to have macroscopic contamination were surgical
trays (N=9) and cannulated drills (N=7). The identifiable contaminants were bone (N=10), PMMA bone cement (N=4) and hair (N=4). Eleven macroscopic contaminants were not identifiable.
This study found that 97% of macroscopic orthopaedic surgical instrument contaminants
that underwent sterile processing did not possess a bacterial burden. Contaminants
discovered during a procedure are likely to be sterile, and do not pose a substantially
increased risk of infection to a patient.