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Institution

Exponent

CompanyMenlo Park, California, United States
About: Exponent is a company organization based out in Menlo Park, California, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 1589 authors who have published 2680 publications receiving 88140 citations.


Papers
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Journal ArticleDOI
Steven M. Kurtz1, Kevin L. Ong1, Edmund Lau1, Fionna Mowat1, Michael T. Halpern1 
TL;DR: 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.
Abstract: 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.

7,032 citations

Journal ArticleDOI
TL;DR: The extensive polymer science literature as it relates to structure, mechanical properties, and chemical resistance of PAEK biomaterials is synthesized to more readily appreciate why this family of polymers will be inherently strong, inert, and biocompatible.

1,802 citations

Journal ArticleDOI
TL;DR: Hip instability and mechanical loosening are the most common indications for revision total hip arthroplasty in the United States, and this information will be valuable in directing future research, implant design, and clinical decision-making.
Abstract: 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 $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. Level of Evidence: Prognostic Level II. See Instructions to Authors for a complete description of levels of evidence.

1,448 citations

Journal ArticleDOI
TL;DR: Implementation of a new toxicity testing paradigm firmly based on human biology by transitioning from current expensive and lengthy in vivo testing with qualitative endpoints to in vitro toxicity pathway assays on human cells or cell lines using robotic high-throughput screening with mechanistic quantitative parameters.
Abstract: With the release of the landmark report Toxicity Testing in the 21st Century: A Vision and a Strategy, the U.S. National Academy of Sciences, in 2007, precipitated a major change in the way toxicity testing is conducted. It envisions increased efficiency in toxicity testing and decreased animal usage by transitioning from current expensive and lengthy in vivo testing with qualitative endpoints to in vitro toxicity pathway assays on human cells or cell lines using robotic high-throughput screening with mechanistic quantitative parameters. Risk assessment in the exposed human population would focus on avoiding significant perturbations in these toxicity pathways. Computational systems biology models would be implemented to determine the dose-response models of perturbations of pathway function. Extrapolation of in vitro results to in vivo human blood and tissue concentrations would be based on pharmacokinetic models for the given exposure condition. This practice would enhance human relevance of test results, and would cover several test agents, compared to traditional toxicological testing strategies. As all the tools that are necessary to implement the vision are currently available or in an advanced stage of development, the key prerequisites to achieving this paradigm shift are a commitment to change in the scientific community, which could be facilitated by a broad discussion of the vision, and obtaining necessary resources to enhance current knowledge of pathway perturbations and pathway assays in humans and to implement computational systems biology models. Implementation of these strategies would result in a new toxicity testing paradigm firmly based on human biology.

1,398 citations

Journal ArticleDOI
TL;DR: The patient and clinical factors influencing the economic burden of periprosthetic joint infection (PJI) in the United States are characterized and the annual cost of infected revisions to US hospitals increased from $320 million to $566 million during the study period and was projected to exceed $1.62 billion by 2020.
Abstract: 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 $5965 greater than the mean cost for knee PJIs. The annual cost of infected revisions to US hospitals increased from $320 million to $566 million during the study period and was projected to exceed $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.

1,369 citations


Authors

Showing all 1593 results

NameH-indexPapersCitations
Hans-Olov Adami14590883473
Melvin E. Andersen8351726856
Joseph Katz8169127793
Lorna J. Gibson7517833835
Buddhima Indraratna6473515596
Barbara A. Goff6122711859
Jack S. Mandel6017122308
Antonio Gens5826914987
Ellen T. Chang5720911567
Dayang Wang551859513
Edmund Lau5218322520
Steven M. Kurtz522498066
Alfred J. Crosby512068310
Suresh H. Moolgavkar511698833
Michael T. Halpern5123716566
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
20232
20229
2021123
2020124
2019133
201888