Patellofemoral Joint Arthroplasty: Early Results and Functional Outcome of the Zimmer Gender Solutions Patello-Femoral Joint System

Background: Improved knee prosthesis designs have led to an increase in the use of patellofemoral arthroplasty as a primary treatment option in recent times. We report the early results and outcomes of the Zimmer Gender Solutions Patello-Femoral Joint (PFJ) system used to treat isolated patellofemoral osteoarthritis (PFA). Methods: We retrospectively reviewed and analysed data of patients who underwent PFJ replacement (PFJR) at our institution with a minimum follow-up of 2 years. Results: Median Oxford Knee score (OKS) was 38 (interquartile range, 28 to 42) at the latest follow-up with a significant improvement from preoperative scores (p < 0.0005). Median OKS was 40 for unilateral PFJRs and 39 for nonobese patients (body mass index [BMI] < 30 kg/m(2)). There was no significant difference in OKS between unilateral and bilateral procedures (p = 0.462). Likewise, there was no significant difference in OKS between obese and nonobese patients (p = 0.272). Two knees (4%) were revised for progression of osteoarthritis. No complications were reported related to infectious or thromboembolic causes. Conclusions: Our study showed good early results of the PFJ system, at least equal to those of other leading brands in the National Joint Registry for England, Wales and Northern Ireland (NJR). There have been no complications related to either the implantation technique or prosthetic design for this new implant. Progression of tibiofemoral arthritis remains a major concern. Our study also suggests that PFJR in obese patients and bilateral procedures can have good results.