Multidirectional kinematics of the glenohumeral joint during simulated simple translation tests: Impact on clinical diagnoses

Abstract

At the end ranges of motion, the glenohumeral capsule limits translation of the humeral head in multiple directions. Since the 6-degree of freedom kinematics of clinical tests are commonly utilized to diagnose shoulder injuries, the objective of this study was to determine the magnitude and repeatability of glenohumeral joint kinematics during a simulated simple anteroposterior translation test in the anterior and posterior directions. A magnetic tracking system was used to determine the kinematics of the humerus with respect to the scapula in eight cadaveric shoulders. At 60" of glenohumeral abduction and 0" of flexionkxtension, a clinician applied anterior and posterior loads to the humerus at O", 30", and 60" of external rotation until a manual maximum (simulating a simple translation test) was achieved. Prior to each test, the reference position of the humerus shifted posteriorly 1.8 k 2.0 and 4.1 ? 3.8 mm at 30" and 60" of external rotation, respectively. Anterior translation decreased significantly (p < 0 05) from 18.2 t 5.3 mm at 0" of external rotation to 15.5 f 5.1 and 9.9k 5.5 mm at 30" and 60", respectively. However, no significant differences were detected between the posterior translations of 13.4f6.4, 17.1 2 5.0, and 15.8 k6.0 mm at O", 30", and 60" of external rotation, respectively.Coupled translations (perpendicular to the direction of loading) at 0" (6.1 k 4.0 and 3.8 ? 2.9 mm), 30" (4.7 t 2.7 and 5.9 k 3.1 mm), and 60" (2.3 2 2.3 and 5.0 k 3.5 mm) of external rotation were in the inferior direction in both the anterior and posterior directions, respectively. Based on the data obtained, performing a simulated simple translation test should result in coupled inferior translations and anterior translations that are a function of external rotation. The low standard deviations demonstrate that the observed translations should be repeatable. Furthermore, capsular stretching or injury to the anterior-inferior region of the capsule should be detectable during clinical examination if excessive coupled translations exist or no posterior shift of the reference position with external rotation is noted.

Open Shoulder Repair of Osseous Glenoid Defects

“…1,5,12,29 In our study, anterior loading yielded translations of about 5 mm after capsulotomy, compared with a range from 9 to 18 mm reported by Moore et al 29 for an intact shoulder. However, we applied a small translation force of 25 N, which is similar to the translation force used by Harryman et al 12 (30 N), but considerably smaller than the forces applied by Moore et al 29 (simple translation test: maximum manual loading) and Burkart et al 5 (50 N).…”

Effects of External Rotation on Anteroposterior Translations in the Shoulder: A Pilot Study

“…In other words, a clinician may not have to position the contralateral shoulder in the exact same position as the injured shoulder while performing the test. Although encouraging in improvement of a quantitative translation test of the shoulder, prior biomechanical studies [9,10,20] had led us to hypothesize that translations of the shoulder in the abduction and external rotation position would be less than those in the abducted and neutral rotation position that were tested previously. Moore et al [20] used a magnetic motion tracking system to assess AP glenohumeral translations in cadaveric shoulders during a simulated simple translation test.…”

“…Although encouraging in improvement of a quantitative translation test of the shoulder, prior biomechanical studies [9,10,20] had led us to hypothesize that translations of the shoulder in the abduction and external rotation position would be less than those in the abducted and neutral rotation position that were tested previously. Moore et al [20] used a magnetic motion tracking system to assess AP glenohumeral translations in cadaveric shoulders during a simulated simple translation test. They found that anterior translation decreased with the abducted shoulder positioned in 30°of external rotation compared with neutral rotation and also decreased at 60°of external rotation.…”

Methodology and sensitivity studies for finite element modeling of the inferior glenohumeral ligament complex

“…A clinician translated the humeral head to its limit in the anterior direction at 01, 301, and 601 of external rotation (ER) and 601 of abduction while joint kinematics were recorded. The reproducibility of this loading method and the accuracy of the measurements have been published previously (Moore et al, 2004b). Accuracy of the magnetic sensors is o0.3% of the distance between the sensors and o1.01 (Moore et al, 2004b;Zeminski, 2001).…”

“…The reproducibility of this loading method and the accuracy of the measurements have been published previously (Moore et al, 2004b). Accuracy of the magnetic sensors is o0.3% of the distance between the sensors and o1.01 (Moore et al, 2004b;Zeminski, 2001).…”