CAREER: Virtual Prototyping of Artificial Knees

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0239042FreglyThis CAREER proposal seeks to develop an integrated educational and research foundation in computational modeling of artificial knees. The two main objectives are (1) develop a virtual prototyping environment that can be used to improve wear and functionality in artificial knees, and (2) create two exhibits on engineering analysis of knee function for the largest science museum in the southern U.S. An estimated 375,000 total knee replacements (TKRs) were performed in the USA in 2002, and if current trends continue, over 10 million will be performed between now and the year 2020. The ability to improve the longevity and functionality of these implants would make a significant impact on the quality of life for the millions of knee osteoarthritis sufferers worldwide who will receive knee replacements in the coming years. Current experimental and computational methodologies for studying TKR functionality and wear have significant limitations. Knee simulator machines used to measure wear are costly and time consuming, while dynamic finite element methods that predict motion and contact pressures simultaneously require hours or days of CPU time. Consequently, neither is appropriate for design sensitivity and optimization studies of knee implant design and surgical positioning issues. Furthermore, neither allows the study artificial knee function within the in vivo loading environment of the larger musculoskeletal system. This study proposes a fundamentally new approach for studying TKR functionality and wear. The approach integrates elastic contact theory with multibody dynamics theory to produce a hybrid simulation environment that possesses the advantages of both - fast dynamic movement simulation from multibody dynamics and accurate contact pressure prediction from elasticity. The method is fast enough to be integrated into a larger dynamic systems model of the musculoskeletal system, providing a unique in vivo computational environment for virtual prototyping of artificial knees. The environment will be extensively evaluated in four stages against existing and new experimental data to ensure that the final product is predictive. Paralleling these activities is the development of two exhibits on knee mechanics for the Museum of Science and Industry in Tampa, FL. The exhibits will take the engineering concepts and methods investigated in the research plan and make them accessible to the general public. One exhibit will be a bank of knee models that visitors can manipulate to study natural, injured, arthritic, and artificial knee mechanics, and the other will be a multimedia exhibit at which visitors can create and analyze simple knee models using the same engineering software as in the research plan. Minority and economically disadvantaged children participating in museum programs will serve as exhibit evaluators to expose them to the use of engineering in medicine.