Background: The purpose of this study was to quantify the procedural
rate and revision burden of total hip and knee arthroplasty in the United
States and to determine if the age or gender-based procedural rates and
overall revision burden are changing over time.
Methods: The National Hospital Discharge Survey (NHDS) for 1990
through 2002 was used in conjunction with United States Census data to
quantify the rates of primary and revision arthroplasty as a function of age
and gender within the United States with use of methodology published by the
American Academy of Orthopaedic Surgeons. Poisson regression analysis was used
to evaluate the procedural rate and to determine year-to-year trends in
primary and revision arthroplasty rates as a function of both age and
gender.
Results: Both the number and the rate of total hip and knee
arthroplasties (particularly knee arthroplasties) increased steadily between
1990 and 2002. Over the thirteen years, the rate of primary total hip
arthroplasties per 100,000 persons increased by approximately 50%, whereas the
corresponding rate of primary total knee arthroplasties almost tripled. The
rate of revision total hip arthroplasties increased by 3.7 procedures per
100,000 persons per decade, and that of revision total knee arthroplasties, by
5.4 procedures per 100,000 persons per decade. However, the mean revision
burden of 17.5% for total hip arthroplasty was more than twice that for total
knee arthroplasty (8.2%), and this did not change substantially over time.
Conclusions: The number and prevalence of primary hip and knee
replacements increased substantially in the United States between 1990 and
2002, but the trend was considerably more pronounced for primary total knee
arthroplasty.
Clinical Relevance: The reported prevalence trends have important
ramifications with regard to the number of joint replacements expected to be
performed by orthopaedic surgeons in the future. Because the revision burden
has been relatively constant over time, we can expect that a greater number of
primary replacements will result in a greater number of revisions unless some
limiting mechanism can be successfully implemented to reduce the future
revision burden.