2018 journal article

Modeling a rotator cuff tear: Individualized shoulder muscle forces influence glenohumeral joint contact force predictions

CLINICAL BIOMECHANICS, 60, 20–29.

By: M. Vidt*, A. Santago*, A. Marsh*, E. Hegedus*, C. Tuohy*, G. Poehling*, M. Freehill*, M. Miller*, K. Saul n

author keywords: Muscle forces; Rotator cuff; Computational model; Glenohumeral; Kinematics; Older adult
MeSH headings : Aged; Biomechanical Phenomena; Computer Simulation; Female; Humans; Male; Middle Aged; Rotator Cuff / physiopathology; Rotator Cuff Injuries / physiopathology; Shoulder Joint / physiopathology
TL;DR: Outcomes suggest predicted joint contact force following rotator cuff tear is sensitive to including individualized muscle forces, and individualized computational models enable more relevant joint force predictions. (via Semantic Scholar)
UN Sustainable Development Goal Categories
5. Gender Equality (Web of Science)
Source: Web Of Science
Added: December 31, 2018

Background Rotator cuff tears in older individuals may result in decreased muscle forces and changes to force distribution across the glenohumeral joint. Reduced muscle forces may impact functional task performance, altering glenohumeral joint contact forces, potentially contributing to instability or joint damage risk. Our objective was to evaluate the influence of rotator cuff muscle force distribution on glenohumeral joint contact force during functional pull and axilla wash tasks using individualized computational models. Methods Fourteen older individuals (age 63.4 yrs. (SD 1.8)) were studied; 7 with rotator cuff tear, 7 matched controls. Muscle volume measurements were used to scale a nominal upper limb model's muscle forces to develop individualized models and perform dynamic simulations of movement tracking participant-derived kinematics. Peak resultant glenohumeral joint contact force, and direction and magnitude of force components were compared between groups using ANCOVA. Findings Results show individualized muscle force distributions for rotator cuff tear participants had reduced peak resultant joint contact force for pull and axilla wash (P ≤ 0.0456), with smaller compressive components of peak resultant force for pull (P = 0.0248). Peak forces for pull were within the glenoid. For axilla wash, peak joint contact was directed near/outside the glenoid rim for three participants; predictions required individualized muscle forces since nominal muscle forces did not affect joint force location. Interpretation Older adults with rotator cuff tear had smaller peak resultant and compressive forces, possibly indicating increased instability or secondary joint damage risk. Outcomes suggest predicted joint contact force following rotator cuff tear is sensitive to including individualized muscle forces.