Measurement of morphological indexes of talus of Chinese population with three-dimensional CT and its significance

Objective: To measure and anlyze the morphological indexes of talus of the Chinese population with three-dimensional measurement method and to provide the accurate data of morphological parameters of talus, and to pvovide basis for designing the talar prostheses. Methods: Forty male and 40 female volunteers applied for this study and 4 of them were excluded. At last, 76 volunteers of 39 males and 37 females were included. The ankle joints of 76 subjects were scanned by CT and the CT images were reconstructed to three-dimensional model with Mimics software. A total of 13 indexes were measured including talar length, breadth, height, and volume, length, breadth, and radian of medial and lateral malleolus articular surfaces, anterior, middle, and posterior breadth of trochlea; among 13 indexes, 9 indexes were measured through Mimics software, and the other 4 indexes were measured through Magics software. Results: All the indexes of the subjects were normally distributed. There were no significant differences in the morphological indexes between left and right talus in either males or females (P > 0.05). The talar length, breadth, and height in the males were (60.85 ± 2.82), (42.96 ± 2.59), and (33.76 ± 1.73)mm, respectively, and in the females they were (54.41 ± 2.49), (39.76 ± 1.78), and (29.72 ± 1.20)mm, respectively. Most of the indexes were larger in the males than the females (P < 0.05), whereas radian of medial malleolus articular surface was larger in the females than the males (P < 0.05). The radian of lateral malleolus articular surface and the posterior breadth of trochlea of the males and the females had no significant differences (P > 0.05). Conclusion: CT measurement method to measure the morphological indexes of talus is more convenient and fast, its measurement error is small, and its erpeatability is high. Left and right sides of talus show strong degree of symmetry, thus the morphological indexes of the contralateral talus can be adopted as a reference for designing talus prosthesis. (authors)