Shoulder outcome measures: a comparison of 6 functional tests.
BACKGROUND
Several shoulder function scores are used in research, with no universally adopted standard. This study compares 6 shoulder outcome scales.


OBJECTIVE
Correlations exist between shoulder outcome scales, allowing conversion between scales. Shoulder scales are correlated with age.


METHODS
Regression and correlation study.


METHODS
Seventy subjects with shoulder pain completed 6 shoulder outcome scales. Pearson correlations were calculated between the total scores of the 6 instruments, between the components of the scales, and with age. Regression equations were calculated between scales.


RESULTS
The range of r values for total scores was 0.495 < or = r < or = 0.770, P < or = .01. In general, a scale's components were themselves highly correlated and added little new information to the scale (0.260 < or = r < or = 0.705, P < or = .05). Most of the scale scores were highly correlated with age (0.291 < or = r < or = 0.582, P < or = .05). Constant's reported corrections for age reduced (from r = -0.582 to r = -0.250, P < .05) but did not eliminate age as a confounding variable.


CONCLUSIONS
Correlations exist between shoulder outcome scales, but existing shoulder scales are not equivalent in their assessments of function; they contain redundant information and, in some cases, may reflect a patient's age better than his/her shoulder function. The utility of conversion equations is minimized as a result of low to moderate correlations between scales.
Placzek
Jeff D
JD
Department of Orthopaedic Surgery, Washington University School of Medicine, St Louis, Missouri, USA. placzek@oakland.edu
Lukens
Steven C
SC
Badalanmenti
Sabrina
S
Roubal
Paul J
PJ
Freeman
D Carl
DC
Walleman
Kim M
KM
Parrot
Amy
A
Wiater
J Michael
JM
D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care / Q000379:methods*; D010147:Pain Measurement / Q000379:methods*; D016059:Range of Motion, Articular / Q000502:physiology; D012785:Shoulder Joint / Q000503:physiopathology; D020069:Shoulder Pain / Q000534:rehabilitation*; D014481:United States