Clinical and Computational Evaluation of an Anatomic Patellar Component.

Area of Science:

• Orthopedic Surgery
• Biomedical Engineering
• Biomechanical Analysis

Background:

• Anatomic patellar components in total knee arthroplasty (TKA) offer favorable in vivo kinematics.
• A novel failure mechanism necessitates investigation into factors affecting anatomic patellar component performance.

Purpose of the Study:

• To identify patient- and implant-related factors associated with suboptimal performance of anatomic patellar components in TKA.
• To compare outcomes between anatomic and medialized dome patellar components.

Main Methods:

• Retrospective evaluation of 100 TKA patients with anatomic components versus 100 matched patients with dome components.
• Radiographic assessment and finite-element analysis of bone strain energy density were performed.

Main Results:

• Anatomic components showed significantly higher rates of anterior knee pain, chronic effusions, and superior patellar pole fragmentation.
• Increased lateral patellar subluxation and tilt were observed with anatomic components.
• Computational analysis revealed higher bone strain energy density at the superior patellar pole with anatomic components, exacerbated by specific resection parameters.

Conclusions:

• Anatomic patellar components are associated with increased adverse outcomes including pain, effusion, and fragmentation.
• Surgical factors like high resection angles and excessive patellar resection significantly increase stress on the superior patellar pole.
• Modifying surgical technique regarding patellar resection may enhance the performance and longevity of anatomic patellar components.