Positive Culture Rate in Revision Shoulder Arthroplasty

Abstract

We recognized a trend of positive cultures taken from presumably uninfected shoulders during revision arthroplasty. Owing to the indolent nature of common shoulder pathogens such as Propionibacterium acnes, these cultures often become positive several days, even weeks, after surgery. Having concern regarding the potential importance of these positive cultures, we reviewed our revision arthroplasty population to determine the rate of positive intraoperative cultures in patients presumed to be aseptic, to characterize the isolated organisms, and to determine the subsequent development of infection. We retrospectively reviewed 27 patients (28 revisions) presumed to be uninfected between April 2005 and October 2007. Intraoperative cultures were positive in eight (29%) of the 28 revisions. Propionibacterium acnes was isolated in six. Methicillin-resistant Staphylococcus aureus was isolated in one patient and coagulase-negative Staphylococcus aureus was isolated in one patient. One-year followup was available on 24 of the 28 revisions. Two of the eight culturepositive revisions had a subsequent infection develop. Cultures taken at revision surgery for failed shoulder arthroplasty are often positive, and our findings document the importance of these positive cultures. Our data confirm previous reports isolating Propionibacterium acnes as a primary pathogen in revision shoulder arthroplasty.

Propionobacter acnes Infection as an Occult Cause of Postoperative Shoulder Pain: A Case Series

“…The nonspecific clinical findings and P. acnes' indolent nature have posed challenges to others in diagnosing a P. acnes infection after shoulder surgery [22]. Only one patient (10%) in our patient population had wound drainage and fever.…”

“…This nonspore-forming microaerophilic bacillus has a low level of virulence but has been established as a pathogen in endocarditis [30,42], meningitis [5,43], arthritis [23], osteomyelitis [1,31] and spondylitis [10,13]. It has been described as the infectious etiology in 16% of prosthetic shoulder infections [38] and in 21% of revision shoulder arthroplasties [22]. In another series, P. acnes was the major etiology of postoperative septic arthritis, comprising 56% of shoulder infections [26].…”

“…Patients present without the typical signs of infection such as fever or local inflammatory reaction and invariably have normal leukocyte counts (WBCs) [22].…”

Prosthesis Failure Within 2 Years of Implantation Is Highly Predictive of Infection

“…The role of P acnes in shoulder prostheses is well known [12,20]. However, the relevance of isolated positive cultures of P acnes in presumably cases of aseptic loosening and its potential clinical relevance in the pathogenesis of PJI need to be determined.…”

Two-stage Reimplantation for Treating Prosthetic Shoulder Infections

“…In many patients, the diagnosis is delayed because of the indolent nature of common shoulder pathogens, such as Propionibacterium acnes [5,8]. Early diagnosis and effective treatment can prevent chronic infections and serious damage to bone and soft tissue.…”