Presentation Abstract

Session: 54-Adult Reconstruction Knee VII
Date/Time: Friday, Feb 10, 2012, 4:06 PM - 4:12 PM
Presentation Number: 797
Title: How Many Americans are Currently Living with Total Knee Replacement?
Classification: Adult Reconstruction Knee
Keywords: Total Knee Arthroplasty / Other Clinical Conditions; Basic Science; Economic / Cost Analysis; Research / Clinical; Revision Total Knee Arthroplasty
Author(s): Alexander M. Weinstein, BA, Boston, Massachusetts, United States
Benjamin Rome, BA, Boston, Massachusetts, United States
William M. Reichmann, MA, Boston, Massachusetts, United States
Jamie E. Collins, MA, Boston, Massachusetts, United States
Sara A. Burbine, BA, Boston, Massachusetts, United States
Thomas S. Thornhill, MD, Boston, Massachusetts, United States
John J. Wright, MD, Boston, Massachusetts, United States
Jeffrey N. Katz, MD, Brookline, Massachusetts, United States
Elena Losina, MD, Boston, Massachusetts, United States
Abstract: INTRODUCTION In the last decade, the number of total knee replacements (TKRs) performed in the U.S. doubled, exceeding 600,000 in 2009. The vast majority are done for osteoarthritis (OA). The growth in TKR use has been greatest among younger individuals, and as a result the average age at which patients receive TKR has decreased over time. The rapid growth in TKR utilization among younger individuals, coupled with increased life expectancy, may lead to increased healthcare costs due to periprosthetic fractures, prosthetic infections, and symptomatic loosening, with the need for revision TKR. While changes in annual rates of TKR over time have been described, estimates of the number of persons in the U.S. living with knee implants have not been reported.
METHODSWe used the OAPol Model, a state-transition, computer-simulation model, to estimate the prevalence of primary TKR stratified by age and sex. We combined these prevalence estimates with 2009 U.S. Census data to calculate the number of Americans currently living with an intact primary TKR. The incidence and prevalence of symptomatic knee OA were derived using data from the National Health Interview Survey. The annual incidence of TKR among persons with advanced knee OA (Kellgren-Lawrence grade 3 or 4) was derived using the data from two national longitudinal studies of persons with knee OA (Multicenter Osteoarthritis Study and Osteoarthritis Initiative). Input parameters related to mortality, obesity, comorbidities, non-surgical OA treatments, and prosthesis failure were obtained from national survey data and published literature.
RESULTSOver 4.5 million Americans currently have an intact primary TKR, representing 4.7% of the population aged 50 years or older. The prevalence of TKR is higher in females (5.3%) than males (4.1%). Among persons 60-69 years of age, 4.1% of men and 4.9% of women have had at least one knee replaced. Among those 70-79 years of age, 7.1% of men and 8.2% of women have had at least one knee replaced. Approximately 10% of those older than 80 years have had at least one knee replaced. (Figure)
DISCUSSION AND CONCLUSIONFive percent (5%) of females and 4% of males older than 50 years are living with TKR. Among persons older than 50 years of age, TKR has become considerably more prevalent than rheumatoid arthritis or congestive heart failure. Knowledge of TKR prevalence is useful in planning health services specific to the population living with TKR. This includes the prevention and management of periprosthetic fractures and infections, as well as planning for adequate capacity for revision TKR.

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