Application of musculoskeletal modelling to evaluate movement and muscle activity patterns in shoulder instability

Seyres, Martin Augustin

Abstract

Shoulder instability is a complex impairment that presents as the shoulder sliding out of its support. It challenges current clinical practice in its definition, assessment, classification and long-term outcome. An improved understanding of its mechanisms, as well as the identification of specific biomarkers may inform treatment allocation which motivated this body of work.

Data was analysed from an established cohort study to examine paterns of shoulder instability. A kinematic and electromyography analysis was performed on fifteen young subjects with shoulder instability and fifteen healthy age equivalent controls. Shoulder instability participants were found to have characteristic paterns of compensation, both in the way they move and in the way their muscles contract, which adds valuable information to the current literature.

A novel study design is presented to examine a subgroup of pathological individuals that presented with normal kinematics and muscle contraction paterns, and were virtually indistinguishable from the healthy control group using a standard motion analysis approach. Using musculoskeletal modelling techniques, static optimisation and statistical analyses, a new approach was demonstrated that provided indication of non-obvious compensatory paterns that inherently characterise this impairment.

One of the main challenges that this pathology can present is the assessment of small compensatory paterns that are linked to this condition and are likely to create long term complications and ultimately prevent full recovery. By assessing the neuromuscular behaviour based on the individual kinematics, strong indication can be provided of an impaired muscle control behaviour. This important information provides an insight that is currently lacking or not observable in the assessment of patients that could otherwise appear healthy based on the current evaluation methods. Therefore, it could prove to be an important objective marker in their rehabilitation.

Finally, the results of this study advocate for the streamlining of the use of modelling techniques in clinical settings, to assess both joint angles and muscle control in this population. This thesis provides a groundwork for longer term goals in upper limb biomechanics in general, and patient-specific modelling approaches.

Citation

Seyres, M. A. Application of musculoskeletal modelling to evaluate movement and muscle activity patterns in shoulder instability. (Thesis). Keele University. https://keele-repository.worktribe.com/output/1109341

• Thesis Type: Thesis
• Deposit Date: Mar 20, 2025
• Publicly Available Date: Mar 20, 2025
• Public URL: https://keele-repository.worktribe.com/output/1109341
• Award Date: 2025-03