Measuring foot and ankle kinematics using a bi-plane fluoroscopic system
KeywordsStance Phase Knee Kinematic Registration Result Polystyrene Foam Manual Registration
The walkway was made of high density polystyrene foam, whose size was 1.2 m, 0.6 m and 4.0 m for height, width and length, respectively. The target foot position was marked on the walkway and the directions of the two X-ray imaging systems were carefully determined to capture the silhouettes of talus, calcaneus, navicular and tibia during the stance phase of walking. The study was approved by the IRB at Chung-Ang University. An informed consent was obtained from each volunteer prior to testing. Subjects walked on the walkway at their self-selected normal speed and the bi-plane fluoroscopic images were taken for 2 seconds. Images for calculating geometric calibration of the imaging system were taken. The subjects underwent computed tomographic (CT) imaging and three-dimensional bone models were obtained. A semi-automatic and manual registration methods were used to determine the positions and orientations of the four target bones for each frame of the bi-plane images during the stance phase of walking. The quality of silhouettes of the bones varied throughout the stance phase.
Ten subjects (age 21.5±1.9, all males, BMI 21.7±1.9) volunteered for the study. The registration results showed some degrees of vibration of the bones, motion noise. The general trend of foot and ankle kinematics could be observed.
Foot and ankle skeletons could be imaged during the stance phase of walking using a bi-plane fluoroscopic system set-up along a polystyrene foam walkway. The positions and orientations of the foot and ankle bones could be calculated from the bi-plane images but the results showed some degrees of noise in their motions.
This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Future Planning (MSIP) (No. 2013R1A2A2A03015668).
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