Evaluating coracoid graft geometry for glenoid bone loss: a comparative study of stress distribution and contact mechanics.

Abstract

<h4>Background</h4>This study aimed to investigate the biomechanical differences between natural coracoid (NC) and modified coracoid (MC) grafts (with a flattened surface to optimize contact with the glenoid cavity), focusing on their impact on contact area, contact volume, and stress distribution in scenarios of glenoid bone loss. The objective was to determine how graft configuration influences biomechanical stability and force distribution under varying conditions of bone loss.<h4>Methods</h4>Three-dimensional models of the glenoid cavity and coracoid process were developed using population-based anatomical averages. Two graft configurations were analyzed: NC and MC. Simulations incorporated progressive glenoid bone loss (0%-20%). Biomechanical analyses evaluated contact area, contact volume, stress distribution, and deformation under a compressive force of 700 N using finite element analysis.<h4>Results</h4>NC grafts demonstrated superior adaptation and a larger contact area in anatomically intact glenoid (0% bone loss). However, as bone loss increased beyond 2%, MC grafts provided more consistent contact areas, better stress distribution, and reduced stress concentration. The flattened surface of MC grafts optimized the biomechanical interaction, particularly under conditions of advanced bone loss, ensuring enhanced stability and reduced risk of localized deformation.<h4>Conclusion</h4>The findings highlight the importance of graft configuration in addressing glenoid bone loss. While NC grafts are preferable for intact or minimally compromised glenoids, MC grafts are more effective in scenarios with bone loss, providing improved biomechanical stability and optimized force distribution. This study underscores the need for tailored surgical strategies to achieve optimal outcomes based on individual anatomical and clinical conditions.