Age related biomechanical properties of the glenoid-anterior band of the inferior glenohumeral ligament-humerus complex.

Abstract

To quantify the biomechanical properties of the glenoid-anterior band of the inferior glenohumeral ligament-humerus complex for the two age groups. In vitro human cadaver study evaluating the biomechanical properties of the glenoid-anterior band of the inferior glenohumeral ligament-humerus complex for a younger group (n=5, mean age 38.5, SD 0.5 years) and an older group (n=7, mean age 74.8, SD 5.3 years). Glenohumeral instability is more of a problem in younger than in older individuals, primarily because recurrence is much more common at a young age. Tensile testing was performed on the glenoid-anterior band of the inferior glenohumeral ligament-humerus complex in the shoulder apprehension position using a custom jig, Instron machine and a video digitizing system. In the younger individuals disruption of the complex most often occurred at the glenoid-labrum region of the glenoid insertion site. In the older individual, disruption most often occurred at the midsubstance region. The load and the stress at failure of the glenoid-anterior band of the inferior glenohumeral ligament-humerus complex showed that the older group was only 61% and 46% of the younger group, respectively. The structural properties of the glenoid-anterior band of the inferior glenohumeral ligament-humerus complex and the material characteristics of the anterior band of the inferior glenohumeral ligament for the younger group were significantly superior than the older group. A stronger and more extensive repair, such as the traditional open technique, may be necessary for younger individuals with glenohumeral instability whereas in older individuals, a different repair technique, such as an arthroscopic technique, may be sufficient.