Abstract

Background/Objectives: The morphology of the glenoid cavity is increasingly recognized as a key factor influencing joint mechanics and clinical outcomes, particularly in the context of shoulder instability. However, the specific effects of glenoid shape on the contact pressure distribution and humeral head displacement remain insufficiently explored. This study examined the impact of five glenoid morphotypes—pear, oval, teardrop, calabash, and inverted comma—on contact pressure patterns and humeral head displacement. Methods: Using three-dimensional models of the glenoid cavity derived from anatomical landmarks, we simulated cartilage compression and computed pressure fields using an elastic foundation model under a 700 N joint reaction force applied in various orientations. Results: Our results demonstrate that the glenoid morphology significantly influences both the magnitude and spatial distribution of contact pressures, particularly under eccentrically directed loads. Notably, pressure and humeral displacement were more pronounced when the force was inclined in the antero-posterior direction compared with the supero-inferior axis. Discussion: Among the morphotypes, the pear-shaped glenoid, the most prevalent in the general population, exhibited the greatest susceptibility to variations in glenohumeral loading. This suggests a potential evolutionary trade-off in shoulder morphology, favoring increased mobility at the expense of joint stability. Conclusions: These findings underscore the biomechanical relevance of patient-specific glenoid anatomy and advocate for its consideration in diagnostic and therapeutic strategies targeting shoulder instability and cartilage degeneration.

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