IRUS Total

A biomechanical confirmation of the relationship between critical shoulder angle (CSA) and articular joint loading

File Description SizeFormat 
CSA manuscript JSES final.docAccepted version220.5 kBMicrosoft WordView/Open
Table 1.docxAccepted version13.35 kBMicrosoft WordView/Open
Fig. 1.jpgAccepted version43.6 kBJPEGView/Open
Fig. 2.jpgAccepted version82.53 kBJPEGView/Open
Fig. 3.jpgAccepted version251.82 kBJPEGView/Open
Title: A biomechanical confirmation of the relationship between critical shoulder angle (CSA) and articular joint loading
Authors: Villatte, G
Van der Kruk, E
Asim, B
Zumstein, M
Moor, B
Emery, R
Bull, AMJ
Reilly, P
Item Type: Journal Article
Abstract: Background: The Critical Shoulder Angle (CSA) has been shown to be correlated with shoulder disease states. The biomechanical hypothesis to explain this correlation is that the CSA changes the shear and compressive forces on the shoulder. The objective of this study is to test this hypothesis by use of a validated computational shoulder model. Specifically, this study assesses the impact on glenohumeral biomechanics of modifying the CSA. Methods: An inverse dynamics three-dimensional musculoskeletal model of the shoulder was used to quantify muscle forces and glenohumeral joint forces. The CSA was changed by altering the attachment point of the middle deltoid into a normal CSA (33°), a reduced CSA of 28°, and an increased CSA of 38°. Subject-specific kinematics of slow and fast speed abduction in the scapular plane, and slow and fast forward flexion measured by a 3D motion capture system were used to quantify joint reaction shear and compressive forces. Results: Increasing the CSA results in increased superior-inferior forces (shearing forces; integrated over the range of motion; p<0.05). Reducing CSA results in increased latero-medial (compressive) forces for both the maximum and integrated sum of the forces over the whole motion; p<0.01). Discussion/Conclusion: Changes in the CSA modify glenohumeral joint biomechanics with increasing CSA producing higher shear forces that would contribute to rotator cuff overuse, whereas reducing the CSA results in higher compressive forces which contribute to joint wear.
Issue Date: 1-Oct-2020
Date of Acceptance: 2-Mar-2020
URI: http://hdl.handle.net/10044/1/78671
DOI: 10.1016/j.jse.2020.03.002
ISSN: 1058-2746
Publisher: Elsevier
Start Page: 1967
End Page: 1973
Journal / Book Title: Journal of Shoulder and Elbow Surgery
Volume: 29
Issue: 10
Copyright Statement: Crown Copyright © 2020 All rights reserved. This manuscript is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International Licence http://creativecommons.org/licenses/by-nc-nd/4.0/
Keywords: Critical shoulder angle (CSA)
computational shoulder model
glenohumeral joint
joint wear
rotator cuff
1103 Clinical Sciences
Publication Status: Published
Online Publication Date: 2020-06-01
Appears in Collections:Bioengineering
Department of Surgery and Cancer
Faculty of Medicine
Faculty of Engineering

This item is licensed under a Creative Commons License Creative Commons