Validation of a Kinematic Functional Shoulder Score Including Only Essential Movements

Overview

A lot of shoulder function evaluation scores exist but none has been universally accepted as a gold standard. Recent studies have demonstrated the potential of computerized movement analysis with embedded sensors for objective evaluation of shoulder functional outcome following surgery. A very simple testing procedure is possible as just a few repetitions of two simple shoulder movements are sufficient. This could potentially facilitate implementation of shoulder function movement analysis in current clinical practice. However, at the present stage of development, the method needs to be extensively validated. This means that the research will intend to determine precisely for which current shoulder pathology it can be applied, what the outcome of healthy people is, what the reliability of the score is and how it can monitor patient evolution.

Measurement of shoulder function is a controversial issue. There is a great variety of measurement tools but none of them has been universally accepted. There is therefore a need to develop extensively validated and convenient measurement tools. Embedded computerized movement analysis can potentially meet these requirements for measurement of shoulder function. Ambulatory measurement devices allow application in various clinical conditions, display adequate precision and accuracy, and are considerably more straightforward than laboratory-based systems. Using a Physilog ® II embedded system, Coley (2007) developed a relatively simple score of shoulder function (P Score). The method is based on arm power measurement by three-dimensional accelerometers and gyroscopes during seven consecutive shoulder movements. It demonstrated reliability, responsiveness and criterion-based validity. However, additional knowledge and technological progress could now contribute to further simplification of the testing procedure. Indeed, a secondary analysis of Coley's study data based on principal component analysis and multiple regressions highlighted that a procedure including only two selected movements produces comparable results to P Score. Moreover, the development of wireless systems considerably simplifies set up. Consequently, simpler but equivalent measurement procedure can now be considered. A pilot study (ClinicalTrials.gov identifier: NCT01281085) has been conducted to prepare this study. it contributed to determine the number of replications of movements needed and to refine the testing procedure. The aim of this study is to proceed to an extensive validation study of the simplified testing procedure. Kinematic measurements will be carried out with four groups of patients presenting with frequent shoulder conditions (rotator cuff condition, shoulder instability, diaphyseal or subcapital humerus fracture, frozen shoulder) and a group of healthy people. Measurement procedure includes two consecutive measurements, alternatively conducted by two evaluators and measured simultaneously by two different movement analysis systems. Currently used functional questionnaires will be completed at both stages for comparison. Measurement will be performed at baseline and 6 months later. Statistical analysis will address reproducibility, responsiveness, minimal clinically important difference and correlation with current clinical scores.