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Ligamentous and bone injuries in the wrist affect tens of thousands of adults per year and leads to abnormal function. Surgical procedures as well as physical therapy intended to restorefunction have room for improvement. Measuring wrist kinematics of the small carpal bones is necessary to understand the effect of ligamentous injury during normal motion.Currently there are motion analysis systems that are used to track large scale movementfor total body kinematics such as gait analysis. The accuracy of these systems is catered toward capturing gross movement and cannot precisely measure on the order of millimeters necessary for carpal kinematics. There are some devices currently on the market that can measure the kindematics of a cadaveric wrist, however they either us expensive CT and X-Ray technology, or require physical contact with the specimen that might affect the accuracy of the data obtained. Additionally, these devices cannot measure the continuous motion and only determine the location of wrist and carpal bones at the beginning and end of movement.
We propose a non-contact system for measuring wrist kinematics that can accurately and precisely measure the three dimensional movement of the scaphoid and lunate. Three designs for markers were considered; passive, active, and magnetic. Initially we decided active LED markers would be the best option for our project needs. However, after working with active LED markers we determined limitations associated with the markers like wiring that would get in the way of measurement. Thus, we decided to develop passive (not electrical) markers for our system. We created a system of color coded passive markers in order to record three dimensional movement. In addition, we began computational analysis via Matlab to identify the active markers in an image and calculate the distance between them. We have created a three dimensional matrix on Matlab in order to map the movement of each marker. Moving forward we will create an algorithm that can calculate the relative position of these two bones in a three dimensional space.
The main deliverables of the product are a working prototype, consisting of a frame and passive markers, and the algorithm that can identify and measure the motion of the markers on a video recording to calculate the wrist kinematics. Thus far progress has been made toward creating the physical working prototype and the algorithm. In the end patents for the finished product and associated algorithm will be necessary.
biomedical engineering, wrist kinematics
Biomedical Engineering and Bioengineering | Engineering
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