Edmund Lau

Projections of Primary and Revision Hip and Knee Arthroplasty in the United States from 2005 to 2030

BACKGROUND Over the past decade, there has been an increase in the number of revision total hip and knee arthroplasties performed in the United States. The purpose of this study was to formulate projections for the number of primary and revision total hip and knee arthroplasties that will be performed in the United States through 2030. METHODS The Nationwide Inpatient Sample (1990 to 2003) was used in conjunction with United States Census Bureau data to quantify primary and revision arthroplasty rates as a function of age, gender, race and/or ethnicity, and census region. Projections were performed with use of Poisson regression on historical procedure rates in combination with population projections from 2005 to 2030. RESULTS By 2030, the demand for primary total hip arthroplasties is estimated to grow by 174% to 572,000. The demand for primary total knee arthroplasties is projected to grow by 673% to 3.48 million procedures. The demand for hip revision procedures is projected to double by the year 2026, while the demand for knee revisions is expected to double by 2015. Although hip revisions are currently more frequently performed than knee revisions, the demand for knee revisions is expected to surpass the demand for hip revisions after 2007. Overall, total hip and total knee revisions are projected to grow by 137% and 601%, respectively, between 2005 and 2030. CONCLUSIONS These large projected increases in demand for total hip and knee arthroplasties provide a quantitative basis for future policy decisions related to the numbers of orthopaedic surgeons needed to perform these procedures and the deployment of appropriate resources to serve this need.

The epidemiology of revision total hip arthroplasty in the United States.

BACKGROUND Understanding the causes of failure and the types of revision total hip arthroplasty performed is essential for guiding research, implant design, clinical decision-making, and health-care policy. The purpose of the present study was to evaluate the mechanisms of failure and the types of revision total hip arthroplasty procedures performed in the United States with use of newly implemented ICD-9-CM (International Classification of Diseases, Ninth Revision, Clinical Modification) diagnosis and procedure codes related specifically to revision total hip arthroplasty in a large, nationally representative population. METHODS The Healthcare Cost and Utilization Project Nationwide Inpatient Sample database was used to analyze clinical, demographic, and economic data from 51,345 revision total hip arthroplasty procedures performed between October 1, 2005, and December 31, 2006. The prevalence of revision procedures was calculated for population subgroups in the United States that were stratified according to age, sex, diagnosis, census region, primary payer class, and type of hospital. The cause of failure, the average length of stay, and total charges were also determined for each type of revision arthroplasty procedure. RESULTS The most common type of revision total hip arthroplasty procedure performed was all-component revision (41.1%), and the most common causes of revision were instability/dislocation (22.5%), mechanical loosening (19.7%), and infection (14.8%). Revision total hip arthroplasty procedures were most commonly performed in large, urban, nonteaching hospitals for Medicare patients seventy-five to eighty-four years of age. The average length of hospital stay for all types of revision arthroplasties was 6.2 days, and the average total charges were

Prevalence of primary and revision total hip and knee arthroplasty in the United States from 1990 through 2002.

54,553. However, the average length of stay, average charges, and procedure frequencies varied considerably according to census region, hospital type, and type of revision total hip arthroplasty procedure performed. CONCLUSIONS Hip instability and mechanical loosening are the most common indications for revision total hip arthroplasty in the United States. As further experience is gained with the new diagnosis and procedure codes specifically related to revision total hip arthroplasty, this information will be valuable in directing future research, implant design, and clinical decision-making.

Infection Burden for Hip and Knee Arthroplasty in the United States

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.

Economic Burden of Periprosthetic Joint Infection in the United States

We quantified the current and historical incidence of periprosthetic infection associated with hip and knee arthroplasty in the United States using the Nationwide Inpatient Sample, as well as corresponding hospitalization charges and length of stay. The rate of infected knee arthroplasties was 0.92%, significantly greater than that of infected hip arthroplasties with 0.88%. Length of stay was significantly longer for infected hip (9.7 days) and knee (7.6 days) arthroplasties compared to uninfected procedures (hip, 4.3 days; knee, 3.9 days) (P < .0001). Hospitalization charges were also significantly greater for infected joint arthroplasties than for uninfected arthroplasties (hips, 1.76 times; knees, 1.52 times) (P < .0001). Urban-non-teaching hospitals experienced the highest burden of infection with 1.18% for hips and 1.26% for knees compared to rural (0.61% for hips and 0.69% for knees) and urban-teaching hospitals (0.73% for hips and 0.77% for knees). We found an increasing number of joint arthroplasties being diagnosed with periprosthetic infection.

Future clinical and economic impact of revision total hip and knee arthroplasty

This study characterizes the patient and clinical factors influencing the economic burden of periprosthetic joint infection (PJI) in the United States. The 2001-2009 Nationwide Inpatient Sample was used to identify total hip and knee arthroplasties using International Classification of Diseases, Ninth Revision, procedure codes. The relative incidence of PJI ranged between 2.0% and 2.4% of total hip arthroplasties and total knee arthroplasties and increased over time. The mean cost to treat hip PJIs was

Impact of the economic downturn on total joint replacement demand in the United States: updated projections to 2021.

5965 greater than the mean cost for knee PJIs. The annual cost of infected revisions to US hospitals increased from

16-year trends in the infection burden for pacemakers and implantable cardioverter-defibrillators in the United States 1993 to 2008.

320 million to

Prosthetic joint infection risk after total hip arthroplasty in the Medicare population.

566 million during the study period and was projected to exceed

Prevalence and projections of total shoulder and elbow arthroplasty in the United States to 2015

1.62 billion by 2020. As the demand for joint arthroplasty is expected to increase substantially over the coming decade, so too will the economic burden of prosthetic infections.