Three dimensional reconstruction model measuring femoral anteversion angle
ZHOU You
LU Sheng
KANG Xiao-peng
XU Xiao-shan
LI Rong
WANG Jun
LI Wei
LI Chuan
Abstract：Objective To explore the value of the three dimensional ( 3 D ) reconstruction model measuring femoral neck anteversion ( FNA ) in developmental dysplasia of the hip ( DDH ) patients with “Y” closed cartilage. Methods We analyzed 34 DDH patients diagnosed and treated in our hospital from March 2013 to June 2015. All patients had completed CT scans from the coxa joint to the caput fibular. CT data in dicom format were imported into Mimics 10.01. After the reconstruction of the 3 D model of the femur with surface shaded display, we imported the data in stl format into Geomagic 11.0 software, selected the lateral femoral head to synthesize them into a sphere with the application the best fitting ball command, and recorded the 3 D coordinate of its center. We input the center coordinate of the femoral head into Mimics software. We adjusted the femur to be translucent, and then rotated it until the center of the femoral head reached the center of the femoral neck orthographic projection area on the 3 D view. Making a straight line connect the center of the femoral head with another point which covered the center on the femoral greater trochanter side. And the line was the axis of the femoral neck. Rotating the femur until the inferior border of the greater trochanter was located in the middle of the connection point of 2 femoral condyle infra-glenoid margins. The angle formed by the line and the axis of the femoral neck was FNA. Thirty-four patients ( 68 hips ) were respectively measured. The results were analyzed by paired t-test with inspection level alpha 0.05 on both sides. Results All of the 34 patients ( 68 hips )completed the femur CT scans, and 2 testers respectively measured the FNA with the application of 3 D reconstruction mentioned before. One patient was measured twice 1 month apart. Paired t test was used for the statistical analysis. For the first time, the FNA measured by the 2 testers were respectively ( 27.83 ± 11.69 ) and ( 26.18 ± 15.21 ), with no statistically significant differences ( P = 0.193 ). The FNA measured by 1 tester 1 month later was ( 27.38 ± 11.81 ). No statistically significant differences existed compared with the first measurement results ( P =0.392 ). Conclusions The reconstruction model in 3 D can help to accurately find measurement benchmark parameters, such as the center of the femoral head, femoral neck axis etc, establishing a method of 3 D FNA measurement. The precise measurement of FNA facilitates comprehensive understanding of the anatomical deformities in patients with acetabulum hypoplasia, and provides reference for surgical plan design.
Keywords：Femur neckHip jointDysplasiahip3 D reconstructionFemoral neck anteversion
Publication Date：2016-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：4( 97-100 )