Three-Dimensional Analysis of Hallux Valgus Deformity
Date Issued
2012
Date
2012
Author(s)
Chen, Bo-Lun
Abstract
Hallux valgus is one of the common foot ailment, but is currently limited to two-dimensional X-ray image analysis, cannot see a real change of its structure in three-dimensional space, this study combined with CT imaging and mechanical drawing software will reorganization the foot structure, and use this software to create three-dimensional projection plane to observe the foot structure change caused by hallux valgus.
We use the principal axes as the reference axis of the bone in three-dimensional space, then to project the principal axes of the bone to three-dimensional projection plane, and measure the angle between the projection axes. To statistics correlation between 2D and 3D IMA、HVA were showing highly correlated(r>0.9,p<0.01), so validate the reliability of use the principal axes as the bone reference axis to analysis.
Analysis the three types of the lateral shape of the first metatarsal head. We find it has associated with the first metatarsal rotation. In order to verify the first metatarsal rotation will cause the shape change, we develop a method to analyze the relative rotation angle of the first metatarsal, statistics results indicated that a significant difference(p<0.05)between the rotation of the first metatarsal and its three types. Therefore, we use the relative rotation angle to distinguish the three interval of the lateral metatarsal head shape. This interval can be provided as a reference for doctor in treatment of hallux valgus to reduce the recurrence rate.
Discuss the first metatarsal and its proximal articular surface obliquity, statistics results indicate that a positive correlation with the IMA(r=0.579,p<0.05), verify that an abnormal obliquity of the proximal articular surface led to excessive medial inclination of the first metatarsal, and cause the abnormal obliquity is also related to the first metatarsal rotation.
Finally, by the reconstruction of the foot three-dimensional model, measure the height of the first to fifth metatarsal head relative to the flat. Results indicated that the height of head decreased from the first to fifth metatarsal, was an inclined linear alignment. After through the statistical analysis found that the height of the first metatarsal head will significantly decrease when the hallux valgus was severe, showing a highly correlated(r<-0.8,p<0.01).
Subjects
hallux valgus
first metatarsal
three-dimensional analysis
principal axes
Computerized Tomography(CT)
Type
thesis
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