LIGAMENT LOADING DURING CLINICAL EXAMINATIONS

Abstract

Many different clinical examinations are used to assess instability of the glenohumeral joint. Validation of these includes clinical data, follow-up, imaging, and arthroscopy. In spite of these many works, there currently exists no clear unique method for identifying and validation novel clinical examinations. The aim of this study was to use a computational tool to quantify the specificity of clinical examinations in assessing glenohumeral ligament (GHL) pathology. Five GHLs were modelled according to the literature [1]. Physiological kinematics data [2] were applied to simulate 23 clinical examination manoeuvres for the glenohumeral joint. Individual ligament forces were computed as a percentage of the total ligamentous restraint. The 0° abduction anterior-laxity test was most specific for the superior GHL (82.3%). The anterior apprehension in the coronal plane and 90° anterior-laxity tests were specific for the anterior band of the inferior GHL (abIGHL – 100%). Pure scapular plane abduction and the 90° abduction inferior-laxity tests were specific for the axillary pouch of the IGHL (apIGHL – 100%, 89.6%). Specific tests for posterior band of the IGHL were posterior apprehension (95.1%), 0° and 20° abduction posterior-laxity, and 30° to 45° flexion Norwood and Terry test (100% each). The middle GHL did not exhibit any exclusive loading pattern for any of the tests. A secondary insertional morphology was simulated with the abIGHL positioned at the 4 o’clock position as opposed to the 3 o’clock position [1,2,3]. Significant loading differences were computed for the same ligaments during the same tests. This study demonstrates the sensitivity of specific tests for individual GHLs, but provides the significant caveat that ligament loading is significantly influenced by normal anatomical variations.