||Determination of In-vivo Glenohumeral Translation during Loaded and Unloaded Arm Elevation
NISHINAKA Naoya:筆頭著者:責任著者 ,
MATSUHISA Takayuki ,
TAKAHASHI Yuji ,
TSUTSUI HiroakiSANBE Takeyuki
315 , 2016-12 , Showa University Society
An understanding of normal joint kinematics is essential to develop treatments that restore normal joint mechanics; however, reports of kinematics during dynamic motion are rare. This study thus investigated glenohumeral (GH) translation in vivo during loaded and unloaded shoulder abduction. Nine healthy shoulders were studied from our patient cohort (average age, 31 years). We created 3D models of the scapula and humerus using computed tomography (CT) images and recorded fluoroscopic images during active abduction in neutral rotation in the plane of the scapula using a hand-held 3kg weight or no additional load. 3D motions were determined using model-based 3D-to-2D registration. Glenohumeral translation was determined by finding the location on the humeral head with the smallest separation from the plane of the glenoid. The humerus moved an average of 2 mm during arm abduction, from inferior to the center of the glenoid. There were no statistically significant differences between the unloaded and loaded conditions. Variability in humeral translation decreased with abduction using both 3-kg and 0-kg conditions, with significantly lower variability showing above a 70° GH abduction. We showed that humeral translation to the center of the glenoid maximizes joint congruency for optimal shoulder function and joint longevity. This data should lead to better strategies for shoulder injury prevention, enhanced rehabilitation, and improved surgical treatments.