Development of trunk asymmetries and structural scoliosis in prepuberal school children in Malmö: follow-up study of children 10-14 years of age.

Trunk asymmetries were diagnosed at the age of 10 in school children (2,200 cases) in Malmö. A combined clinical-moiré screening program was used. Twenty-five percent of the girls and 19% of the boys had a positive forward bending test. A positive moiré asymmetry was seen in 13% of the girls and in 11% of the boys. More extreme moiré asymmetries were seen in 0.8% of the girls and 0.6% of the boys. All of these cases were roentgenographed and the mean Cobb angle was 14 degrees. Moiré asymmetries of one moiré fringe or more were defined as a risk group and were followed up annually until the age of 14 years by means of moiré photography. During the following 3 years, the moiré asymmetry increased markedly in 14 girls and four boys. Five of these 32 roentgenographed cases had progressive scoliosis needing brace treatment. All cases referred to as symmetric trunks at the age of 10 were also reexamined annually. In no case did the scoliosis exceed 15 degrees. This implies that adolescents with scoliosis severe enough to need treatment always had a visible trunk asymmetry at the age of 10. Consequently, progressive idiopathic scoliosis requiring some type of treatment during adolescence can be found in this risk group at the age of 10 years.