Primary knee and hip arthroplasty among nonagenarians and centenarians in the United States

Objective. The number of individuals ages 100 years in the US is expected to increase considerably in the future along with the need for arthroplasties. This report focuses on the poorly studied epidemiology and mortality outcomes of arthroplasty among these individuals. Methods. We describe the epidemiology of knee and hip arthroplasties among centenarians using data from a large hospital discharge database in the US (the Nationwide Inpatient Sample) during the period 1993 through 2002. We used nonagenarians as the comparison group with adjustment for differences in the prevalence of congestive heart failure, neurologic diseases such as dementia and stroke, renal and hepatic diseases, obesity, anemia, malignancy, coagulopathy, and depression and other psychiatric illnesses. Cox regression models were used to study the mortality outcomes following arthroplasty. Results. Overall, there were 679 hip arthroplasties and 7 knee arthroplasties among centenarians in this database. The corresponding figures for nonagenarians were 33,975 and 2,050, respectively. A vast majority (83%) of hip arthroplasty recipients were women. Risk-adjusted mortality estimates following arthroplasty for centenarians were higher than for nonagenarians (hazard ratio 1.46, 95% confidence interval 1.10-1.95). However, this was similar to differences in overall in-hospital mortality (hazard ratio 1.36, 95% confidence interval 1.32-1.40) between these 2 age categories. Conclusion. In the US population, hip and knee arthroplasty are very rarely performed among centenarians. Our in-hospital mortality data suggest that arthroplasties should not be denied to centenarians solely because of short-term postoperative life expectancy estimates.