Friday, March 3, 2017

Assessing shoulder function: subjective, objective or both?

Relationship Between Patient-Reported Assessment of Shoulder Function and Objective Range-of Motion Measurements

These authors asked three questions:
(1) How does subjective patient assessment of shoulder function correlate with objectively measured active shoulder range of motion? 
(2) What is the difference in active motion between shoulders that can and those that cannot be used to perform each of the functions of the Simple Shoulder Test (SST see this link)? and
(3) Does the relationship between subjective and objective assessment of shoulder function differ between male and female patients?

In 74 male and 30 female patients with osteoarthritis they analyzed the relationship between the SST patient self-assessments of shoulder function  and objective range-of-motion measurements recorded by the observer-independent Kinect motion capture system

For both female and male patients, they found a poor correlation between objective measurements of active abduction and the total SST scores of osteoarthritic shoulders (square symbols). The relationships between active abduction and total SST score were closer for the contralateral shoulders (diamond symbols).

For all shoulders combined there was essentially no difference in these relationships for female (square symbols) and male (diamond symbols). 

They found a significant difference in active abduction between the osteoarthritic shoulders that allowed and those that did not allow the patient to perform the individual SST functions for only 4 of the 12 functions in the female group and 5 of 12 in the male group because of the highly variable relationship between self-assessed function and active abduction. 

In contrast, when the contralateral shoulders were assessed, this difference was found to be significant for 10 of the 12 functions in the female group and all 12 of the functions in the male group. 

Comment: One of the challenges in the measurement of passive and active shoulder motion is that these "objective" measurements have been shown to be observer-dependent. This study used an observer-independent method for measuring the range of active shoulder motion. 

The key finding in this study was that the active range of motion correlated poorly with the patients' self-assessed function of their osteoarthritic shoulders, meaning that the shoulder function was dependent on characteristics of the shoulder and the patient other than the active range of motion.