Edge loading of patellar components after total knee arthroplasty

Patellofemoral joint kinematics, contact areas, contact pressures, and cont act patterns were assessed after total knee arthroplasty (TKA) using human cadaver knees. Two contemporary TKA systems with, anatomic patellofemoral j oints were implanted and tested under anatomically based loading conditions . An electromagnetic tracking system was used to evaluate patellofemoral ki nematics, and Fuji pressure-sensitive film was used to determine contact ar eas, pressures, and patterns. Edge loading of patellar components was obser ved at higher knee flexion angles with both TKA systems. Peak contact press ures seen at the regions of edge loading exceeded the yield strength of ult ra-high-molecular weight polyethylene. Efforts to reduce edge loading and c ontact pressures may decrease the incidence of patellofemoral joint complic ations and component failure after TKA.