abduction using 3-D/2-D model image registration ..... External/internal rotation of the humerus during shoulder scapular abduction. .... adults and children.
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research report
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KEISUKE MATSUKI, MD, PhD1 • KEI O. MATSUKI, MD, PhD2 • SATOSHI YAMAGUCHI, MD, PhD2 • NOBUYASU OCHIAI, MD, PhD3 TAKAHISA SASHO, MD, PhD3 • HIROYUKI SUGAYA, MD, PhD4 • TOMOAKI TOYONE, MD, PhD5 • YUICHI WADA, MD, PhD5 KAZUHISA TAKAHASHI, MD, PhD6 • SCOTT A. BANKS, PhD7
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Dynamic In Vivo Glenohumeral Kinematics During Scapular Plane Abduction in Healthy Shoulders
houlder subacromial impingement syndrome is one of the most common causes of shoulder pain and is thought to be due to inadequate space for clearance of the rotator cuff tendons during arm elevation.9 Various theories have been proposed regarding the primary mechanism of shoulder impingement, including kinematic changes, anatomic abnormality, and degeneration of the rotator cuff tendons.9,29,39 Kinematic changes are thought to occur primarily in TTSTUDY DESIGN: Controlled laboratory study. TTOBJECTIVES: To measure superior/inferior
translation and external rotation of the humerus relative to the scapula during scapular plane abduction using 3-D/2-D model image registration techniques.
TTBACKGROUND: Kinematic changes in the
glenohumeral joint, including excessive superior translation of the humeral head and inadequate external rotation of the humerus, are believed to be a possible cause of shoulder impingement. Although many researchers have analyzed glenohumeral kinematics with various methods, few articles have assessed dynamic in vivo glenohumeral motion.
TTMETHODS: Twelve healthy males with a mean
age of 32 years (range, 27-36 years) were enrolled in this study. Fluoroscopic images of the dominant shoulder during scapular plane elevation were taken, and computed tomography-derived 3-D bone models were matched with the silhouette of the bones in the fluoroscopic images using 3-D/2-D model image registration techniques. The kinematics of the humerus relative to the scapula were determined using Euler angles.
TTRESULTS: On average, there was 2.1 mm of
initial humeral translation in the superior direction from the starting position to 105° of humeral elevation. Subsequently, an average of 0.9 mm of translation in the inferior direction occurred between 105° and maximum arm elevation. The average amount of external rotation of the humerus was 14° from the starting position to 60° of humeral elevation. The humerus then rotated internally an average 9° by the time the shoulder reached maximum elevation. These changes in superior/ inferior translation and external/internal rotation were statistically significant (P
