Prosthetic joint infections in the elderly.

PURPOSE: The aim of this study was to review risk factors, presenting symptoms and signs, organisms causing infection, treatment modalities, and outcomes in elderly patients with infection of prosthetic joints. PATIENTS AND METHODS: Patients over 60 years of age treated at the University of Michigan Hospital or Ann Arbor Veterans Administration Medical Center from 1977 to 1987 who had a diagnosis of prosthetic joint infection were reviewed. Early infections were defined as those occurring within 12 months of insertion of the prosthesis; late infections were those occurring more than 12 months after insertion.
RESULTS: Fifty-one episodes of infection in 38 elderly patients were reviewed. There were 20 infections in prosthetic hips and 31 infections in prosthetic knees. Twenty-seven infections occurred early and 24 occurred late. Coagulase-negative staphylococci, Staphylococcus aureus, and Group D enterococci were the organisms most commonly isolated (33%, 27%, and 24% of episodes, respectively). Pseudomonas aeruginosa and other gram-negative bacilli were the causative organisms in approximately a third of the infections, and anaerobic organisms were noted in almost one fourth of episodes. In 33 episodes, the infected device was eventually completely removed, but infection resolved in only 20 of these 33 episodes (61%). In 18 episodes treated without removal of the device, none resolved. Outcome was poor; only five patients could walk without assistance, six patients developed contiguous osteomyelitis, two required amputation, and three died.
CONCLUSIONS: Infection of prosthetic joints in elderly patients is a serious disease with poor functional outcome. The device has to be removed in order to clear the infection, and even then the infection is often difficult to eradicate.