Patellar button wear patterns in well-functioning total knee arthroplasty retrievals.

One of the common reasons for early revision or poor outcome in total knee arthroplasty is due to patellar maltracking, loosening, or pain. The analysis of how the patellofemoral mechanism operates and wears in vivo has not been a focus of many retrieval studies. This paper describes the wear pattern observed on patellar buttons from well-functioning TKA specimens that were harvested as part of a donor program. The attempt was to describe the variations in wear patterns to see if any commonalities existed that may predict a well-functioning patellofemoral mechanism after TKA.