A CAD-to-Simulink framework for evaluating impingement-free motion in reverse total shoulder arthroplasty

Area of Science:

• Biomedical Engineering
• Orthopedic Surgery
• Computational Mechanics

Background:

• Accurate range of motion (ROM) prediction is crucial for reverse total shoulder arthroplasty (RTSA) implant design and surgical planning.
• Current computational methods for ROM estimation have limitations in geometric accuracy.
• A novel, high-resolution approach is needed to overcome these limitations.

Purpose of the Study:

• To introduce and validate a CAD-to-Simulink computational pipeline for predicting impingement-free ROM in RTSA.
• To assess the impact of varying neck-shaft angles on impingement-free ROM.
• To provide a kinematically accurate tool for optimizing RTSA implant geometry and surgical positioning.

Main Methods:

• Developed a CAD-to-Simulink pipeline using point-cloud-based collision detection.
• Modeled shoulder anatomy and RTSA components, performing humeral motion sweeps.
• Evaluated three neck-shaft angles (155°, 145°, 135°) and validated the 155° configuration experimentally.

Main Results:

• Decreasing neck-shaft angle from 155° to 135° increased impingement-free ROM by up to 23%.
• This improvement was linked to delayed inferior impingement during adduction.
• Experimental validation closely matched computational predictions for impingement angles.

Conclusions:

• The CAD-to-Simulink framework offers a validated, reproducible, and Finite Element Method-independent method for predicting impingement-free ROM.
• This tool enhances kinematic accuracy for RTSA implant design and surgical planning.
• Optimizing neck-shaft angles can significantly improve functional outcomes in RTSA patients.