Purpose: Surgical site infection remains a common concern in orthopaedic surgery. A multitude of factors contribute to colonization of the operative site, not all of which are controllable. This study investigates the time-dependent contamination of sterile C-arm covers as a potentially modifiable risk factor during routine fracture surgery.

Method: A consecutive fracture case study was performed from the two senior authors’ orthopaedic practices. Cultures were obtained from the top and side of the image intensifier cover after initial draping and every 20 minutes until the end of the operation. Survival time analysis was performed to evaluate the median time to first contamination.

Results: Twenty-five cases were enrolled with a mean operative time of 91.8 ± 42.9 minutes and an average people/hour/case of 9.6 ± 1.5. Time to contamination is correlated with person hours per case at 0.52 (p=0.07). The median survival time was 20 minutes (95% CI =12 to 68 minutes). There was 17% contamination upon initial draping, 50% at 20 minute, 57% at 40 minutes, 73% at 60 minutes and 80% by 80 minutes. Of the 30 cases, only 5 did not become contaminated during the surgery. The bacteria detected were Staphylococcus (59%), Corynebacterium (31%), Micrococcus (7%), and other (3%). There were no post-operative wound infections that required medical treatment.

Conclusion: A rapid and significant rate of contamination for C-arm drapes during orthopaedic fracture surgery was recorded. Based on these findings, the surgeon should not touch the C-arm cover to manipulate the machine. If contact with the C-arm cover is necessary, then a change of gloves is warranted to minimize contamination risk.