John P. Meehan

Periprosthetic supracondylar fractures of the femur after total knee arthroplasty represent a devastating complication for the patient and a technical challenge for the surgeon. Treatment is often complicated by advanced patient age, retained cement, and accompanying osteoporosis. We present the case of a 54-year-old woman with a comminuted fracture of the distal femur just above a total knee prosthesis. She had a complex past medical history, including extensive coronary artery disease, morbid obesity, chronic osteoporosis, anemia, diabetes, and rheumatoid arthritis. She was a Jehovah's Witness and thus refused all blood products. Given her medical history, religious preferences, and fracture comminution, a spanning external fixator was used. She completed fracture union with an excellent clinical and radiographic result at 2 years.

Background: Although early aseptic mechanical failure after total knee arthroplasty has been reported in younger patients, it is unknown whether early revision due to periprosthetic joint infection is more or less frequent in this patient subgroup. The purpose of this study was to determine whether the incidence of early periprosthetic joint infection requiring revision knee surgery is significantly different in patients younger than fifty years of age compared with older patients following primary unilateral total knee arthroplasty. Methods: A large population-based study was conducted with use of the California Patient Discharge Database, which allows serial linkage of all discharge data from nonfederal hospitals in the state over time. Patients undergoing primary unilateral total knee arthroplasty during 2005 to 2009 were identified. Principal outcomes were partial or complete revision arthroplasty due to periprosthetic joint infection or due to aseptic mechanical failure within one year. Multivariate analysis included risk adjustment for important demographic and clinical variables. The effect of hospital total knee arthroplasty volume on the outcomes of infection and mechanical failure was analyzed with use of hierarchical modeling. Results: At one year, 983 (0.82%) of 120,538 primary total knee arthroplasties had undergone revision due to periprosthetic joint infection and 1385 (1.15%) had undergone revision due to aseptic mechanical failure. The cumulative incidence in patients younger than fifty years of age was 1.36% for revision due to periprosthetic joint infection and 3.49% for revision due to aseptic mechanical failure. In risk-adjusted models, the risk of periprosthetic joint infection was 1.8 times higher in patients younger than fifty years of age (odds ratio = 1.81, 95% confidence interval = 1.33 to 2.47) compared with patients sixty-five years of age or older, and the risk of aseptic mechanical failure was 4.7 times higher (odds ratio = 4.66, 95% confidence interval = 3.77 to 5.76). The rate of revision due to infection at hospitals in which a mean of more than 200 total knee arthroplasties were performed per year was lower than the expected (mean) value (p = 0.04). Conclusions: Patients younger than fifty years of age had a significantly higher risk of undergoing revision due to periprosthetic joint infection or to aseptic mechanical failure at one year after primary total knee arthroplasty. Level of Evidence: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Prophylactic parenteral antibiotics have contributed to the present low rate of surgical site infections following hip and knee arthroplasty. Over the past decade, there has been a change in the pattern of methicillin-resistant Staphylococcus aureus infections from hospital-acquired to community-acquired. The findings of recent studies on screening programs to identify carriers of methicillin-resistant Staphylococcus aureus have been equivocal, with some studies showing that such programs reduce the rate of infections and others showing no effect on infection rates. Hospitals with antibiogram data that reveal high Staphylococcus resistance should consider use of vancomycin as a prophylactic antibiotic.