Mechanical Properties of the Glenohumeral Capsule Change With Simulated Injury

The glenohumeral joint suffers more dislocations than any other joint, most of which occur in the anterior direction. The anterior band of the inferior glenohumeral ligament (AB-IGHL) is the primary restraint to these dislocations and as a result experiences the highest strains during these events. [1] Injuries to the capsule following dislocation include permanent tissue deformation that increases joint mobility and contributes to recurrent instability. [2] This deformation can be quantified by measuring nonrecoverable strain. [3] Simulated injury of the capsule results in permanently elongated tissue and nonrecoverable strain. Current surgical repair techniques are subjective and may not fully address all capsular tissue pathologies resulting from dislocation. Surgeons typically repair the injured capsule by plicating the stretched-out tissue; however, these techniques are inadequate with 23% of patients needing an additional repair. [4] Quantitative data on the changes in the biomechanical properties of the capsule following dislocation may help to predict the amount of capsular tissue to plicate for restoring normal stability. Therefore, the objectives of this study were to quantify changes in stiffness and material properties of the AB-IGHL tissue sample following simulated injury (creation of nonrecoverable strain).