Lee, Seok Beom

Abstract The prevalence of rotator cuff disease among the elderly population and the greatest incidence of acute dislocations will continue to provide challenging patient management decisions. Stability of the shoulder is critical to successful upper extremity function. The GH joint is stabilized by passive capsuloligamentous restraints as well as by active dynamic stabilizers through concavity compression. The compression of the convex humeral head (HH) into the concave glenoid fossa (GF) counteracts against translational shear forces (Matsen et. al 1994). The major compressive load across the joint is provided by the action of the surrounding musculature, especially the rotator cuff. The muscles may generate both compressive and shear force components as well as moments. The purpose of this study is to describe a new testing methodology of how to estimate the contribution of individual rotator cuff muscles to the dynamic stability of the GH joint at a given joint position.