Technical Advice for Patellofemoral Arthroplasty

Background: Isolated patellofemoral arthroplasty (PFA) is a bone-preserving intervention for localized compartment disease, offering rapid mobilization and high functional recovery. Despite these advantages, historical data indicate revision rates significantly higher than those of total knee arthroplasty, often attributed to suboptimal implant design and exacting surgical requirements.

Objective: This article aims to delineate specific surgical techniques, preoperative planning strategies, and intraoperative considerations essential for optimizing clinical outcomes and reducing failure rates in PFA.

Key Points: Successful PFA requires stringent patient selection, excluding those with tibiofemoral degeneration or regional pain syndromes. Precise patella preparation must maintain a minimum bone thickness of 12 mm and replicate the native apex position to prevent soft tissue over-tensioning. Trochlea component positioning is critical; current evidence supports an anatomical "inlay" approach to match the patient’s natural tracking rather than adhering to traditional total knee arthroplasty alignment landmarks. Rotational alignment should prioritize lateral marginal congruence to prevent patellar clunking or instability. Intraoperative assessment must evaluate the need for tibial tuberosity osteotomy—specifically distalization for patella alta—and titrated lateral release or medial soft tissue reconstruction to ensure stable tracking from full extension through deep flexion.

Conclusion: While technically demanding, PFA can achieve revision rates comparable to total knee arthroplasty when surgeons prioritize anatomical trochlear orientation and precise soft tissue balancing. Mastery of extensor mechanism realignment and component congruence is fundamental to avoiding common complications such as instability, persistent effusion, and chronic anterior knee pain.