Following glenohumeral joint dislocation, surgical repair is often advocated where the glenohumeral capsule is shifted and plicated. However, nearly 25% of patients still experience redislocations. To improve these results, functional evaluations (experimental and computational) of the glenohumeral capsule have been performed whereby isolated, discrete capsuloligamentous regions of the capsule were examined. Specifically, the capsuloligamentous region termed the anterior band of the inferior glenohumeral ligament is often examined in this way since it is frequently injured during dislocations. However, this practice may not be appropriate as recent data suggests that the glenohumeral capsule functions multiaxially. Therefore, the objective of this work was to compare the predicted strain distribution and deformed shape of the anterior band of the inferior glenohumeral ligament to that experimentally measured for two finite element models: 1) composite model including all capsuloligamentous regions and 2) discrete model including only the anterior band of the inferior glenohumeral ligament. The average maximum principal strain for the anterior band of the inferior glenohumeral ligament was 21±14%, 35±14%, and 0±1% for the experimental measurements, composite finite element model, and discrete finite element model, respectively. Thus, the predicted strain distribution in the anterior band of the inferior glenohumeral ligament was similar to that which was experimentally measured for the composite finite element model. Additionally, the predicted deformed shape in the composite finite element model was also similar to experimental data with the anterior band of the inferior glenohumeral ligament clearly wrapping around the humeral head. However, the predicted strain distribution and shape for the discrete finite element model was drastically different from that observed experimentally with the anterior band of the inferior glenohumeral ligament twisting somewhat along its longitudinal axis and buckling away from the humeral head. These differences may be attributed to neglecting the boundary conditions along the margins of the anterior band of the inferior glenohumeral ligament applied by the remaining capsuloligamentous regions. Thus, the glenohumeral capsule should be evaluated as a sheet of fibrous tissue and composite finite element models may be utilized to evaluate its function in the normal, injured, and surgically repaired state.
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