Onlay vs. Inlay Patellofemoral Arthroplasty

There is currently no sufficient evidence if there is superiority of one of the two available types (onlay type, inlay type) of patellofemoral arthroplasty. Therefore, it is the aim of this study to compare the two types in a prospective comparative setting. Patients on the waiting list for patellofemoral arthroplasty are randomized to either onlay or inlay type patellofemoral arthroplasty. The KOOS - knee score serves as the primary outcome parameter. Secondary outcome parameters are the Marx Activity Scale, the HSS patella score, the Kujala Score, radiographic loosening, progression of tibiofemoral degeneration, revision surgery and parameters of patellofemoral tracking. Inferential statistics will be performed at 1-year follow up data-sets.