Influence of rotator cuff tears on glenohumeral stability during abduction tasks

Abstract

One of the main goals in reconstructing rotator cuff tears is the restoration of glenohumeral joint stability, which is subsequently of utmost importance in order to prevent degenerative damage such as superior labral anterior posterior (SLAP) lesion, arthrosis, and malfunction. The goal of the current study was to facilitate musculoskeletal models in order to estimate glenohumeral instability introduced by muscle weakness due to cuff lesions. Inverse dynamics simulations were used to compute joint reaction forces for several static abduction tasks with different muscle weakness. Results were compared with the existing literature in order to ensure the model validity. Further arm positions taken from activities of daily living, requiring the rotator cuff muscles were modeled and their contribution to joint kinetics computed. Weakness of the superior rotator cuff muscles (supraspinatus; infraspinatus) leads to a deviation of the joint reaction force to the cranial dorsal rim of the glenoid. Massive rotator cuff defects showed higher potential for glenohumeral instability in contrast to single muscle ruptures. The teres minor muscle seems to substitute lost joint torque during several simulated muscle tears to maintain joint stability. Joint instability increases with cuff tear size. Weakness of the upper part of the rotator cuff leads to a joint reaction force closer to the upper glenoid rim. This indicates the comorbidity of cuff tears with SLAP lesions. The teres minor is crucial for maintaining joint stability in case of massive cuff defects and should be uprated in clinical decision-making. ß

Relationship Between Deltoid and Rotator Cuff Muscles During Dynamic Shoulder Abduction: A Biomechanical Study of Rotator Cuff Tear Progression

“…1,21 To compensate for SSC or ISP tears, the anterior and posterior deltoid, respectively, needed greater amounts of force to restore glenohumeral mechanics. 11 Perhaps the teres minor muscle, which aids with posterior concavity-compression, 8 reduces the required force needed from the posterior deltoid, muting the clinical effect on abduction of ISP tears. On the other hand, only the SSC is responsible for humeral head compression anteriorly.…”

“…In the presence of RTC tears, the joint-reaction forces necessary for glenohumeral stability are significantly altered. 2,18 With dysfunction of the ISP and subscapularis (SSC), the joint-reaction forces and glenohumeral contact point are displaced superiorly on the glenoid, 8 leading to superior humeral head translation and glenohumeral instability. 15,16 Dynamic magnetic resonance imaging of shoulders with and without cuff tears has been able to correlate the degree of humeral head translation with the extent of RTC tears.…”

Effect of Rotator Cuff Deficiencies on Muscle Forces and Glenohumeral Contact Force After Anatomic Total Shoulder Arthroplasty Using Musculoskeletal Multibody Dynamics Simulation

“…Musculoskeletal multibody dynamics modeling provides a non-invasive strong platform for understanding in vivo biomechanics of the shoulder and the effects of joint replacement on function. Most of the previous 3D anatomic shoulder musculoskeletal models address GH loading in the light of rotator cuff tears ( Holscher et al, 2016 ; Klemt et al, 2018 ; Vidt et al, 2018 ), and these outcomes can be transferable to ATSA. Lemieux et al (2013) and De Wilde et al (2004) predicted the GH force and deltoid force of ATSA using musculoskeletal models.…”

Evidence-Based Review of Clinical Diagnostic Tests and Predictive Clinical Tests That Evaluate Response to Conservative Rehabilitation for Posterior Glenohumeral Instability: A Systematic Review

“…This approach may be the best current diagnostic strategy available to clinicians. Recognized risk factors are pertinent to the clinical diagnosis of PI, including glenoid retroversion, 6,10,13,20,22,25,27 rotator cuff strength, 8,12,26 and GH joint laxity. 16…”