OrthoBuzz occasionally receives posts from guest bloggers. This guest post comes from Grigory Gershkovich, MD.
Shoulder arthroplasty continues to grow in popularity, and as the number of shoulder arthroplasties rises, so will the number of revisions. Infection is one major reason for shoulder arthroplasty failure, and Propionibacterium has been increasingly recognized as a major culprit.
However, Propionibacterium infection is difficult to diagnose. Despite improved detection techniques, diagnosis at the time of revision remains elusive because obvious signs of acute infection are often absent. The need to perform explantation in the setting of clinically apparent periprosthetic infection is obvious, but the appropriateness of single-stage revision with antibiotic treatment in shoulders with only apparent mechanical failures remains questionable.
Hsu et al. attempted to address this question in a study published in the December 21, 2016 issue of JBJS. The group retrospectively reviewed the outcomes of 55 shoulders that underwent revision arthroplasty due to continued pain, stiffness, or component loosening without obvious clinical infection. Mean follow up was 48 months. At least five cultures were obtained intraoperatively during each revision, and each case was treated with antibiotics as if were truly infected until the final culture results were received after three weeks. Shoulders were revised to either hemi-arthroplasty, total shoulder arthroplasty, or reverse total shoulder arthroplasty.
Hsu et al. analyzed outcomes according to two groups: the positive cohort (n=27), where shoulders had ≥ 2 cultures positive for Propionibacterium, and the control cohort (n=28), where shoulders had either 0 or 1 positive culture. The two groups were compared by before- and after-revision performance on the simple shoulder test (SST) and pain outcome scores.
Both groups improved postoperatively based on these patient-reported outcome measures, and no significant difference was found between the two groups. Three patients in each group required a return to the OR. Gastrointestinal side effects were the most commonly reported complication from prolonged antibiotic administration.
This study design was limited by its retrospective nature and the lack of a two-stage revision treatment comparison group. Furthermore, this study included only patients with no signs of clinical infection, and the findings may not be applicable to patients with perioperative signs of infection. The study also incorporated three revision surgery implant options, which could have influenced postoperative SST and pain scores. Larger, multicenter controlled trials will be needed to produce a more definitive answer to this complicated question.
Still, there are clear benefits of single-stage revision over two-stage revision, especially with regard to operative time, anesthesia risks, and patient recovery. Given the wide antibiotic sensitivity profile of Propionibacterium and these initial results from Hsu et al., single-stage revision with appropriate antibiotic therapy may be suitable for patients undergoing revision shoulder arthroplasty in the setting of suspected Propionibacterium infection.
Grigory Gershkovich, MD is chief resident at Albert Einstein Medical Center in Philadelphia. He will complete a hand fellowship at the University of Chicago in 2017-2018.