Geometry-Driven Glenohumeral Joint Biomechanical Analysis: Simultaneous Evaluation of the Capsule and Muscles

Glenohumeral joint stability is provided by complex interaction between the passive (bony geometry, capsule, and ligaments) and active (muscles) stabilizers [1]. The functional roles of geometry, capsule, ligaments, and muscles have been evaluated by sequential cutting studies [2–4] or direct measurements [5–7]. However these isolated function of individual stabilizer does not replicate in vivo glenohumeral joint biomechanics where the joint stability is controlled by interaction between passive and active stabilizers. Direct measurement device instrumentation on the soft tissue do not allow entire capsular strain measurement during rotational range of motion. Sequential cutting of the soft tissue can result in alteration in the synergy of passive and active stabilizers. To replicate in vivo interaction between passive and active stabilizers it is required to minimize the measurement device instrumentation on the glenohumeral joint capsule while the joint stability is provided by both passive and active stabilizers. Therefore, the objective of this study was to quantify the simultaneous contribution of the capsule and muscles using a geometry-driven biomechanical analysis.