Prevalence and Impact of Positive Intraoperative Cultures in Partial Hip or Knee Revision

Background Our aim was to investigate the impact of unexpected positive cultures on the outcome of partial prosthetic revisions. Methods Data regarding patients who underwent a partial hip or knee revision from 2003 and 2012 with the preoperative diagnosis of aseptic loosening was retrospectively reviewed. The protocol of revision included at least 3 intra-operative cultures. Failure was defined as the need for re-revision due to aseptic or septic loosening at 5 years. Results A total of 99 hip and 46 knee partial revisions were included. All cases had at least 5 years follow-up. Ninety-seven cases (66.9%) had all cultures negative, 35 (24.1%) a single positive culture and 13 (9.0%) ≥2 positive cultures for the same microorganism. The median time from primary arthroplasty to partial revision was significantly shorter for patients with ≥2 positive cultures (26 months) than in those with all cultures negative (48 months) or with a single positive culture (51 months). Partial revisions performed within the first 5 years of implantation had a higher 5-year re-revision rate. The presence of a single positive culture during the partial exchange was not associated with a higher re-revision rate (2 out of 35, 5.7%) than in those with negative cultures (3 out of 97, 3.1%). On the contrary, re-revision rate was significantly higher in cases with ≥2 positive cultures (3 out of 13, 23.1%) than in those with negative cultures (p=0.02). Conclusion Partial revisions performed within the first 5 years from implantation and ≥2 intraoperative positive cultures were associated with a higher re-revision risk at 5 years.