Introduction. Historically, a majority of prosthetic joint infections (PJIs) grew Gram-positive bacteria. While previous studies stratified PJI risk with specific organisms by patient comorbidities, we compared infection rates and microbiologic characteristics of PJIs by hospital setting: a dedicated orthopaedic hospital versus a general hospital serving multiple surgical specialties. Methods. A retrospective review of prospectively collected data on 11,842 consecutive primary hip and knee arthroplasty patients was performed. Arthroplasty cases performed between April 2006 and August 2008 at the general university hospital serving multiple surgical specialties were compared to cases at a single orthopaedic specialty hospital from September 2008 to August 2016. Results. The general university hospital PJI incidence rate was 1.43%, with 5.3% of infections from Gram-negative species. In comparison, at the dedicated orthopaedic hospital, the overall PJI incidence rate was substantially reduced to 0.75% over the 8-year timeframe. Comparing the final two years of practice at the general university facility to the most recent two years at the dedicated orthopaedics hospital, the PJI incidence was significantly reduced (1.43% vs 0.61%). Though the overall number of infections was reduced, there was a significantly higher proportion of Gram-negative infections over the 8-year timeframe at 25.3%. Conclusion. In transitioning from a multispecialty university hospital to a dedicated orthopaedic hospital, the PJI incidence has been significantly reduced despite a greater Gram-negative proportion (25.3% versus 5.3%). These results suggest a change in the microbiologic profile of PJI when transitioning to a dedicated orthopaedic facility and that greater Gram-negative antibiotic coverage could be considered.

Background: Gross trunnion failure (GTF) after total hip arthroplasty is a rare complication and has only been reported in a few case series. Some of the associated risk factors have been described in the literature and include larger femoral heads, greater offset, and increased BMI. Despite this, the mechanism behind GTF is poorly understood and early diagnosis and treatment continues to be challenging. Case Presentation: We present the case of complete femoral head and trunnion dissociation in a 63 year-old female nine years after total hip arthroplasty. Unique to this case is the lack of classic patient and implant risk factors for GTF along with the acute onset nearly nine years after implantation. Discussion: This case presentation highlights the fact that the contributing factors and mechanism behind GTF continue to be poorly understood. There is a need for future research to help better understand this phenomenon and to help potentially identify those at risk for GTF.