Sa. Mior et al., A COMPARISON OF RADIOGRAPHIC AND ELECTROGONIOMETRIC ANGLES IN ADOLESCENT IDIOPATHIC SCOLIOSIS, Spine (Philadelphia, Pa. 1976), 21(13), 1996, pp. 1549-1555
Study Design. This was a cross-sectional study of a consecutive group
of adolescent patients presenting to a scoliosis clinic for routine as
sessment or monitoring of their scoliosis, excluding postsurgical pati
ents. Summary of Background Data. In vitro studies suggested electrogo
niometry could be useful in the evaluation of scoliosis. No prior in v
itro study had been performed. Objectives. To determine the reliabilit
y and validity of an electrogoniometric instrument, the Metrecom Skele
tal Analysis System, in assessing adolescent idiopathic scoliosis. Met
hods. Thirty-one patients were examined, radiographed, and scanned wit
h the Metrecom Skeletal Analysis System twice by two different examine
rs. The magnitudes of the curves derived from the Metrecom Skeletal An
alysis System scans were compared with each other and with the Cobb an
gles measured from standing radiographs. Results. The intraclass corre
lation coefficient (a measure of agreement, ranging fro 0 to 1, where
1 represents complete agreement) for the intraexaminer reliability of
the Metrecom Skeletal Analysis System ranged from 0.71 to 0.83. The in
terexaminer reliability intraclass correlation coefficient of the Metr
ecom Skeletal Analysis System was 0.58, with a mean difference between
examiners of 5.5 degrees (SD = 5 degrees), and limits of agreement (m
ean difference +/-2 SD) ranging from -4.5 degrees to 15.6 degrees. The
Metrecom Skeletal Analysis System and the radiographically derived Co
bb angle correlation was 0.64, but the mean difference between the met
hods was 3.7 degrees (SD = 11.1), with limits of agreement from 18.4 d
egrees to 25.9 degrees. Conclusion. The Metrecom Skeletal Analysis Sys
tem does not provide sufficient clinical precision to substitute for t
he Cobb angle measured from spinal radiographic measurements in the ma
nagement of adolescents with scoliosis.