Peak skeletal mass assessment in young adults with idiopathic scoliosis.

In 52 adult women with ages ranging from 20 to 35 years (mean age, 26.5 +/- 4.9 years) with scoliosis of the idiopathic type (mean, 44.7 +/- 17.4 Cobb degrees), bone density was assessed by conventional grading of the relative vertebral density (RVD) and the Singh trabecular index (STI). In vivo determinations of the bone mineral content (BMC) were performed in the radius, femur, and lumbar vertebrae by new noninvasive techniques of single (SPA)- and dual (DPA)-photon absorptiometry. Frequency distributions of scoliosis vs. control subjects with respect to RVD and STI grades showed interdependence to the P less than 0.01 level of significance. The mean BMC determinations of the radius (0.685 +/- 0.061 gm/sq cm) of the femur (0.947 +/- 0.110 gm/BA/sq cm) and of the vertebrae (1.091 +/- 0.105 gm/BA/sq cm) were markedly reduced compared with published control values (P less than 0.001). In comparison with the authors' institutional controls, mean BMC measurements were significantly lower for the radius (P less than 0.05) and for the femur (P less than 0.001). These results conclusively demonstrated that assessment of peak skeletal mass in a population of adult premenopausal women with idiopathic scoliosis showed significant decrease in average BMC measurements compared with control values. Maximal bone accretion was best evaluated at locations unaffected by deformity such as the radial diaphysis and the femoral neck.