Assessment of scapular positioning and function as future effect measure of shoulder interventions – an inter-examiner reliability study of the clinical assessment methods

Assessment of scapular positioning and function as future effect measure of shoulder interventions – an inter-examiner reliability study of the clinical assessment methods
Eshøj H1, Ingwersen KG1, Larsen CM1, 2, Søgaard K1, Juul-Kristensen B1, 3
1 University of Southern Denmark, Institute of Sports Science and Clinical Biomechanics, Odense M, Denmark
2 University College Lillebaelt, Odense, Denmark
3 Bergen University College, Institute of Occupational Therapy, Physiotherapy and Radiography, Bergen, Norway


Email: [email protected]

Introduction and objectives
Scapular dyskinesis, defined as an abnormal positioning, and/or altered function of the scapular is often present in subacromial impingement syndrome (SIS). SIS is one of the most common shoulder disorders, potentially leading to degenerative conditions and/or osteoarthritis in the glenohumeral joint. Treatment of SIS primarily consists of physical therapy aiming at reducing signs of scapular dyskinesis. However, no consensus exists regarding which clinical tests to use for identifying and measuring scapular positioning and function. As a first step acceptable clinimetric measures of reliability is important, although, several tests have only been tested for intra-examiner reliability. The objective was to investigate the inter-examiner reliability of an extended battery of clinical tests for assessing scapular positioning and function.
Methods
A standardized three-phase protocol for clinical reliability studies was conducted, containing a training, an overall agreement and a study phase. The index condition (scapular dyskinesis) was defined as a clearly obvious scapular winging (pseudo or margo medialis winging) observed during bilateral repeated active flexion’s of the upper extremity. A total of 24 clinical assessment variables were compiled into three categories; static (6), semi-dynamic (7) and dynamic assessment variables (9), besides assessment of external rotational strength (2). Testers were blinded to the status of subjects, the results of each test round and each others´ test results. Intra-class correlation coefficients (ICC) and kappa values were interpreted as: 0.0-0.40 (poor); 0.40-0.75 (fair to good); and 0.75-1.00 (good to excellent).
Results
A total of 41 subjects (23 males, yrs 25±9), were recruited among adult overhead athletes from the municipality of Odense, DK. Prevalence of the index condition was 54 %. Data was tested and found to have normal distribution for all continuous variables and Bland Altman plots showed no funnel effects. Bland Altman plots found no systematic bias and good to excellent ICC values in four of the static assessment variables. The ICC values ranged from “fair to good” (n=2 assessment variables, av) and “good to excellent” (n=6 av) in the static and external shoulder rotation strength av; from “poor” (n=3 av) to “fair to good” (n=4 av) in the semi-dynamic av, with; from “poor” (n=4 av) to “fair to good” (n=3 av) in the dynamic av, and no kappa statistics computed at all in three tests due to constant measurements from one of the testers.
Conclusion
An extended assessment battery to investigate the inter-examiner reliability for assessing the scapular positioning and function were compiled. Systematic bias between testers appeared in some, but not all assessment methods, questioning the overall accuracy. However, within the static assessment methods, four of these had ICC values within “good to excellent” and no systematic bias. Improvements of clinimetric properties of assessment methods for measuring scapular dyskinesis are needed.