Patellofemoral arthroplasty in isolated Iwano grade IV patellofemoral osteoarthritis: 86% 10-year survival.

Purpose: Isolated patellofemoral osteoarthritis (PFOA) is a degenerative condition, typically presenting as anterior knee pain. For patients who are refractory to conservative treatment, patellofemoral arthroplasty (PFA) is a viable surgical option. Appropriate patient selection is fundamental to achieving favourable long-term outcomes. Large multicenter and registry studies have reported outcomes of PFA (under 0.45%-2% utilization). Howevever, because of the heterogenicity of indications and surgeons, those findings may not be transferable to individual surgeon practices. This study aimed to evaluate the utilization and long-term survival of PFA within a high-volume, single-surgeon arthroplasty practice. Methods: This retrospective study included consecutive cases of Patellofemoral arthroplasties performed between 2012 and 2014. Patients with prior ipsilateral knee surgery, patellar instability, or less than 10 years of follow-up were excluded. The number of primary knee arthroplasties performed within the same period was collected. Radiographic assessments included Kellgren-Lawrence grading, Iwano grading, Insall-Salvati ratio, Dejour classification, medial proximal tibial angle, joint line convergence angle, sulcus angle and anatomical lateral distal femoral angle. Implant survival rates were evaluated over a 10-year follow-up period. Results: A total of 37 patients (50 patellofemoral arthroplasties) who underwent PFA for isolated PFOA were included, alongside 2556 primary knee arthroplasties. PFAs accounted for 2.0% of the primary knee arthroplasties performed during the study period. All patients were classified as Iwano grade IV preoperatively. The 10-year survival rate was 86.0%. All seven PFA failures were due to progression of tibiofemoral osteoarthritis and were converted to total knee arthroplasty. Conclusions: PFA demonstrated a 10-year implant survival rate of 86.0% when performed under strict selection criteria in a high-volume arthroplasty centre. Achieving optimal outcomes requires careful patient selection, surgical proficiency and alignment with patient expectations. Further prospective studies are warranted to better evaluate long-term functional outcomes after PFA. Level of Evidence: Level III, retrospective cohort study.