Objectives: To reconstruct the morphology of the proximal femur and measure the parameters of them by means of the computer-aided design (CAD) in order to provide help to the design and research of the domestic prosthesis, event for the selection of the adapted implant for the doctors before operation.
Methods: The data of 160 healthy Chinese proximal femur images were obtained by the PHLLIP SR7000 computer tomography. The correlative parameters were measured exactly by medical imaging software. Then the imaging data were input into an computerized contouring program which generates the three dimensional coordinates representing periosteal and endosteal contours of the femur for each CT slice. Though the computer-aided design (CAD) software, the three-dimensional solid model was reconstructed by the vectorisation of image contours. In the circumstance of CAD system, the bone axis is defined as the line across the geometric center of the cross-section of the isthmus and 20 mm above the lesser trochanter mid-point. We measured the parameters of the endosteal and periosteal dimensions of the medullary canal.
Results: The parameters of the medullary canal measured with the reconstructed normal Chinese femur have significant difference from that measured with the Caucasian's. The extracortical and endosteal parameters of male have significant differences from most of female's. However, there were no significant differences in endosteal width between different age groups in two gender groups. From the proximal to the distal femur, the intersection angles between the longest mediolateral endosteal diameters of the slices and the plane of the femoral neck were increased.
Conclusions: The reconstructive femur contains more information and can be cut at arbitrary levels which means it is facility to the research of the Morphology of the Proximal femur and the measurement of relative parameters. It is necessary to design the prosthesis which fit anatomic parameters of the Chinese femur. It needs to further study whether the gender factor will be considered in the prosthesis design. The angle between the anteversion and the helitorsion at the level 20 mm above the lesser trochanter midpoint should be noticed by the implant designers and doctors.