Identification and Analysis of The Microbiome in Patients Undergoing Removal of Hardware

Category: Basic Sciences/Biologics; Ankle Introduction/Purpose: Next-generation DNA sequencing (NGS) technologies have increased the sensitivity of bacterial cultures and helped to better understand the normal flora of different joints. Researchers have utilized NGS to identify organisms associated with reoperations in shoulder surgery, but there is very little data on the field of foot and ankle. This study uses NGS to determine whether there is a unique microbiome that exists on orthopaedic hardware in the foot and ankle. Methods: A prospective study recruited 34 patients undergoing hardware removal surgery from the foot or ankle during 2020- 2023 with one of two fellowship-trained foot and ankle surgeons at an academic medical center. Patients were excluded based on the diagnosis or suspicion of infection prior to surgery. Explanted hardware was sent for analysis at a CLIA-licensed molecular diagnostic laboratory. Demographics, medical comorbidities, surgical indication, postoperative complications, readmission, and reoperation rates were collected from patient records. The majority of patients underwent surgery for diagnosis with painful orthopaedic hardware (70.6%). The cohort was majority female (67.6%) and average age was 53.15 (range 18-78) years. Results: Of the 34 samples sent for NGS, 5 (14.7%) indicated 9 bacteria were present (positive), while the remaining 29 (85.3%) had no bacteria present (negative). The most common organisms were of the genus Staphylococcus, representing 4 bacteria (44.4%), and Corynebacterium, representing 2 bacteria (22.2%). C. acnes was only present in one sample. There was no relationship between bacterial presence and patients undergoing hardware removal for diagnosis of painful orthopaedic hardware. No demographics nor postoperative outcomes were statistically associated with the presence of bacteria on removed hardware samples. The overall rate of complication, reoperation, and readmission were 8.8%, 2.9%, and 2.9%, respectively. Conclusion: This study found that there is no common microbial community present in patients undergoing hardware removal surgery. The most commonly present bacteria were of the genus Staphylococcus, bacteria overall were isolated in 14.7% of specimens. C acnes appeared to be uncommon. Further research should be done with a larger sample to support these findings.