I recently participated in a study to perform a retrieval analysis with clinical correlation to look at high rates of infection after conversion of patellofemoral arthroplasty (PFA) to total knee arthroplasty (TKA) seen in an earlier study. That study was limited by a small sample size, so analyzing it on an expanded group of patients provided more information.
We used the following method: A retrospective review of an implant retrieval registry identified 62 conversions of PFA to TKA between 2004-2021. Implants were analyzed for wear pattern and cement fixation. Patient charts were reviewed for demographic information, perioperative data, prior and subsequent surgical procedures, complications and outcomes. Radiographs performed prior to index PFA and conversion procedures were assessed for KL grading.
We concluded that the most common reason for PFA conversion to TKA was progression of osteoarthritis. PFA conversion to TKA is technically similar to primary TKA, but complication rates are more consistent with revision TKA in this study.