Diagnosis andManagement of Periprosthetic Shoulder Infections

The unique bacterial flora of the shoulder present diagnostic and treatment challenges that are distinct from those seen with failed hip and knee arthroplasties. The presentation, diagnosis, and management of suppurative periprosthetic joint infections of the shoulder are similar to those of the hip and the knee. Failed arthroplasties with positive cultures (FAPCs) are poorly performing shoulder reconstructions associated with low-virulence microorganisms that do not evoke a suppurative inflammatory response. Propionibacterium acnes is the predominant bacterium isolated from these cases. With improved surgeon awareness and the addition of longer tissue-culture incubation times, detection of FAPCs has become more common. However, management is hampered by the lack of reliable, timely tests that can determine the presence of less virulent organisms in the preoperative or intraoperative settings. The implications of positive culture results in FAPCs are unclear. Key test characteristics such as the false-positive rate and the prevalence of positive cultures in well-performing shoulders are unknown as there is no useful confirmatory test to validate the culture data and no reliable way to detect the presence of less virulent micro-organisms without reoperation. Soft-tissue and osseous deficits are frequently encountered when revising previously infected shoulders. The rat