An Evidence-based Assessment Model for the Comprehensive Assessment of the Scapulohumeral Complex

Abstract

A comprehensive assessment of shoulder dysfunction is currently lacking. Current shoulder assessment models often fail to address the complexity of shoulder dysfunction. The scapulohumeral complex is the anatomical complex with the most movement in the human body, however stability is compromised by the lack of inherent bony stability. Many modifiable musculoskeletal factors influence shoulder function/ dysfunction. In this study modifiable musculoskeletal factors and the influence on the shoulder complex were explored and highlighted. Current literature was extensively researched and analysed. The development of an objective assessment model for the scapulohumeral complex was the end goal. This thesis contains five original papers. The first paper, a global systematic review with meta- analyses, explores and consolidates current knowledge of 71 studies on the worldwide occurrence of modifiable musculoskeletal factors in both an athletic and non-athlete population. This study highlighted the presence of definite modifiable musculoskeletal factors in painful shoulders and identified gaps in present research. The second paper, an analytical cross-sectional study design, investigated the strength profile of the superior cuff (included the supraspinatus muscle and its tendon) and of the inferior cuff (includes the infraspinatus and teres minor muscles and their tendons) in participants aged between 18 to 75 years of age in both non-painful and painful shoulders. This study was a first of its kind to propose and to explore the force couple ratio between the supraspinatus muscle (SS) and the anterior deltoid muscle (AD) with isometric dynamometry. The force couple ratios were concluded in both the superior force couple SS:AD and in the inferior force couple between the external (ER) and the internal rotators (IR). The third paper, an analytical cross-sectional study, reported on the flexibility of the periscapular musculature in the age group 18 to 75 years of age in both non-painful and painful shoulders. It was the first study to the authors’ knowledge to explore the flexibility of the latissimus dorsi (LD), the pectoralis minor (PMm), subscapularis and the posterior capsule (PC) in terms of range of motion (ROM) in a non-athlete population group. Decreased range of external rotation (ER), internal rotation (IR), flexion, and abduction were linked to painful shoulders. v The fourth study, a nominal group technique, gauged the opinions of practicing physiotherapists (clinicians and academics) on the inclusion of various factors to be considered in an evaluation model for shoulder assessment. The fifth study, a pilot reliability study, tested the novel assessment model for the shoulder based on the findings of all the previous studies (1,2,3 and 4). The findings of this thesis identified modifiable musculoskeletal factors that were associated with shoulder dysfunction. An evidence-based scapulohumeral complex assessment model using current research is therefore proposed based on the findings of the current thesis. The guidelines provided with the present thesis can serve as a starting point for more research in the shoulder field.