Symmetry analysis of a 3D printed model of distal radius / 中华创伤骨科杂志

ABSTRACT

Objective To investigate whether a 3D printed model of the contrlateral healthy distal radius, especially its articular accuracy, helps anatomical reduction and precise reconstruction of the fractured distal radius. Methods The CT data of bilateral radii were collected from 15 normal volunteers ( 11 males and 4 females with an average age of 22. 8 years ) between November and December 2016. After 3D reconstruction of the bilateral distal 1/3 radii, solid 3D models of left radius were mirrored and generated by 3D printing. The data of right radii ( reference group ) were compared with the data of the solid 3D models of left radius acquired through a 3D scanner ( test group ) using deviation analysis. Results The maximum volume difference between the 3D printed model and the contralateral radius was 6. 86％. The average volume of the reference group was 19, 165. 82 ± 3, 250. 50 mm3 and that of the test group 19, 310. 65 ± 3, 305. 15 mm3, showing no statistically significant difference between the 2 groups ( t= -0. 941, P=0. 363 ) . The maximum surface area difference was 3. 84％ between the 2 groups. The average surface area of the reference group was 5, 075. 80 ± 549. 34 mm2 and that of the test group 5, 139. 43 ± 572. 48 mm2, showing a signifi-cant difference ( t= -2. 451, P=0. 028 ) . The 3D deviation analysis showed a mean positive deviation of 0. 37 ± 0. 10 mm and a mean negative deviation of 0. 30 ± 0. 07 mm. The maximum mean square root was 0. 65. The 3D deviation was distributed mainly within 1 mm interval, with a distribution frequency of 96. 27％. Conclusions A 3D printed model prepared by high precision equipment is accurate enough to guide reconstruction of distal radius fractures in adults. In the treatment of complex fractures of the distal radius, a 3D printed model of the contralateral healthy distal radius can be used as a reference to achieve anatomical reduction and precise reconstruction of the fractured distal radius.