A new method for estimating three-dimensional movement of the patella using a surface mapping method and computed tomography
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Updated: Dec 9, 2025
Four-Dimensional CT Analysis Using Sequential 3D-3D Registration
Published on: November 23, 2019
Takuma Inai1, Tomoya Takabayashi1, Satoshi Watanabe2
1Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare, Niigata, Japan.
Introduction:
A previous study reported a method called the 2D-3D registration technique to examine three-dimensional movement of the patella. However, that method requires a biplane fluoroscopy system. In the present study, the aim was to establish a new method (CT-based surface mapping method) to estimate three-dimensional positions and angles of the patella with a motion capture system and CT.
Methods:
In Study 1, the most appropriate parameters for the CT-based surface mapping method (i.e., target edge length, threshold of thickness of the soft tissue, and minimum distance between markers) were explored and determined. In Study 2, three-dimensional movement (i.e., positions and angles) of the patella using the CT-based surface mapping method and the most appropriate parameters were determined, and they were compared with the true positions and angles obtained by CT.
Results:
The results of Study 1 showed that the most appropriate conditions were as follows: (1) target edge length, 3 mm; (2) threshold of thickness of the soft tissue, 0-20 mm; and (3) minimum distance between markers, 10 mm. The results of Study 2 showed that the errors of the positions and angles were less than approximately 10 mm and 10° at most, respectively (both supine and sitting positions).
Conclusion:
The CT-based surface mapping method may be useful for a future study to clarify differences in three-dimensional movements of the patella between patients with patellar tendinitis and healthy subjects.
