Moiré topography in school screening for structural scoliosis

Schoolgirls, aged 10-17 years, were screened for structural scoliosis at school using both conventional clinical screening with a forward bending test and moiré topography. Those suspected of having scoliosis were examined in an orthopaedic clinic for the presence of clinically significant scoliosis, defined as lateral deviation of 10 degrees or more measured according to Cobb. The screening revealed 41 cases of scoliosis, corresponding to a prevalence of 4.1 per cent. In 39 girls the scoliosis had not been recognized previously. In this study moiré topography revealed twice as many cases of scoliosis as did conventional clinical screening. The diagnostic sensitivity of moiré topography proved to be high (0.997). The method is, however, loaded by many false positive results. No correlation between the degree of lateral deviation, judged by X-ray examination, and the difference in contour lines, judged by moiré topography, was found.