Abstract/Details

Analysis of in vitro and in vivo function of total knee replacements using dynamic contact models


2006 2006

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Abstract (summary)

Despite the high incidence of osteoarthritis in human knee joint, its causes remain unknown. Total knee replacement (TKR) has been shown clinically to be effective in restoring the knee function. However, wear of ultra-high molecular weight polyethylene has limited the longevity of TKRs. To address these important issues, it is necessary to investigate the in vitro and in vivo function of total knee replacements using dynamic contact models. A multibody dynamic model of an AMTI knee simulator was developed. Incorporating a wear prediction model into the contact model based on elastic foundation theory enables the contact surface to take into account creep and wear during the dynamic simulation. Comparisons of the predicted damage depth, area, and volume lost with worn retrievals from a physical machine were made to validate the model.

In vivo tibial force distributions during dynamic and high flexion activities were investigated using the dynamic contact model. In vivo medial and lateral contact forces experienced by a well-aligned instrumented knee implant, as well as upper and lower bounds on contact pressures for a variety of activities were studied. For all activities, the predicted medial and lateral contact forces were insensitive to the selected material model. For this patient, the load split during the mid-stance phase of gait and during stair is more equal than anticipated.

The external knee adduction torque has been proposed as a surrogate measure for medial compartment load during gait. However, a direct link between these two quantities has not been demonstrated using in vivo measurement of medial compartment load. In vivo data collected from a subject with an instrumented knee implant were analyzed to evaluate this link. The subject performed five different overground gait motions (normal, fast, slow, wide, and toe out) while instrumented implant, video motion, and ground reaction data were simultaneously collected. The high correlation coefficient results support the hypothesis that the knee adduction torque is highly correlated with medial compartment contact force and medial to total force ratio during gait.

Indexing (details)


Subject
Mechanical engineering;
Aerospace materials;
Biomedical research
Classification
0548: Mechanical engineering
0538: Aerospace materials
0541: Biomedical research
Identifier / keyword
Applied sciences; Contact pressure; Dynamic contact; Knee; Total knee replacements
Title
Analysis of in vitro and in vivo function of total knee replacements using dynamic contact models
Author
Zhao, Dong
Number of pages
81
Publication year
2006
Degree date
2006
School code
0070
Source
DAI-B 67/08, Dissertation Abstracts International
Place of publication
Ann Arbor
Country of publication
United States
ISBN
9780542808388
Advisor
Fregly, Benjamin J.
University/institution
University of Florida
University location
United States -- Florida
Degree
Ph.D.
Source type
Dissertations & Theses
Language
English
Document type
Dissertation/Thesis
Dissertation/thesis number
3228882
ProQuest document ID
305328059
Copyright
Database copyright ProQuest LLC; ProQuest does not claim copyright in the individual underlying works.
Document URL
http://search.proquest.com/docview/305328059
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