A semiautomatic segmentation approach to biometric measurement of the talus bone of sedentary women and ballerinas using CT images

Background: Ballet produces much stress on bones in the feet of ballerinas. Monitoring and detecting talus bone deformation is important for their quality of health and profession. Objectives: To determine differences in the talus bone between ballerinas and sedentary women. Methods: We evaluated biometric differences in the talus bone of 5 ballerinas referenced to 5 similar sedentary women recruited into the present study. We acquired 20 multidetector computed tomographic images including right and left feet. Semiautomatic region-based image processing using 3D-Doctor (Able Software Corp) was used to create three-dimensional (3D) virtual models of the talus bones. Biometric measurements were made on the 3D models and statistical analysis conducted. Results: The mean talus bone length of ballerinas was 3.37 cm (SD 0.12; range 3.11 to 3.52). The talus bone length of sedentary women was 3.29 cm (SD 0.16; range 3.04 to 3.65), and tended to be shorter than that of the ballerinas (P = 0.08, t test). However, the test was insufficiently powered. The mean volume of the talus bones from the ballerinas was 24.8 cm3 (SD 0.83) and smaller than that from the sedentary women, 26.9 cm3 (SD 1.25) at P < 0.001 (t = 4.38, 18 degrees of freedom. Difference 2.1. Two-tailed 95% confidence interval for difference of means: 1.08 to 3.08). We found less variation in the feet of ballerinas than sedentary women. Conclusions: Volumetric measurements show that feet of ballerinas are smaller and retain similar shape and size than the irregular feet of sedentary women.