Long Term Foundation Knee Study

Inclusion Criteria: * Subject must have received a cruciate-retaining Foundation Knee system during or prior to the year 2000. * Surgery must have been a primary knee replacement. * Subject must have received only one primary knee replacement per hospitalization * Subject must have had a primary diagnosis of osteoarthritis of the operative knee. * Subject is able and willing to sign the informed consent document Exclusion Criteria: * Subject must not have had any previous knee implants (unicondylar or total joint replacements) * Subject has a mental condition that may interfere with the subject's ability to give an informed consent or willingness to fulfill the study requirements (i.e., severe mental retardation such that the Subject cannot understand the informed consent process, global dementia, prior strokes that interfere with the Subject's cognitive abilities, senile dementia, and Alzheimer's Disease) * Subject is a prisoner