Trochlear Replacement Alone Without Patella Resurfacing in Patellofemoral Osteoarthritis: A Single Tertiary Centre Clinical Series

Background Patellofemoral arthroplasty (PFA) is an established treatment for isolated patellofemoral joint osteoarthritis (PFJ OA). The procedure involves resurfacing the degenerated trochlear as well as the articular surface of the patella. In some patients with severe patellofemoral joint arthritis, the patella bone stock can be too thin to hold a plastic button. The patella in these cases could have a high fracture risk if resurfaced. We present the clinical outcome of a series of patients with severe patellofemoral joint arthritis where the trochlear alone was resurfaced, and the patella was too thin to be resurfaced. Methods All patients between January 2019 and December 2024 undergoing patellofemoral joint replacement in our unit were reviewed. All the patients who had trochlear replacement alone (without resurfacing of the patella) with a minimum follow-up of one year were included in this study. Six patients met the inclusion criteria. Functional outcomes were assessed using the Oxford Knee Score (OKS) and Knee Injury and Osteoarthritis Outcome Score (KOOS). Implant survivorship was determined through hospital records and cross-referenced with the National Joint Registry (NJR). Results The total number of patellofemoral joint replacements in our unit undertaken by a single surgeon (TA) was 51 from January 2019 to December 2024. Patella was not resurfaced (isolated trochlear replacement) in seven cases; six were included in our study, as one was lost to follow-up. The mean age at surgery was 54.7 years, and the mean follow-up was 39 months. All patients received Zimmer Gender Solutions (Zimmer Inc., Warsaw, IN) prosthesis. No patient required revision surgery until the last follow-up. Mean OKS at the last review was 34.16 (range 15-41), and mean KOOS was 39.78 (range 9.19-69.9). All patients experienced clinically significant improvement. No complications, reoperations, or radiographic progression of tibiofemoral osteoarthritis were observed. Conclusion Isolated trochlear replacement for severe patellofemoral arthritis without patella resurfacing is a safe option with reasonable short-midterm results. Larger prospective studies are needed to confirm long-term results.