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

Abstract

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. 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. 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. 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 III, retrospective cohort study.