Elementary Geometrical Shapes - Hip Wear
Some hip prostheses can be represented by Elementary Geometrical Shapes (EGS). Therefore the creation of 3D prosthesis models is not necessary.
The EGS models together determine three ´markers´ which are used to calculate hip migration (18805532).
The EGS module enables you to calculate the amount and the direction of hip liner wear. It is calculated by comparing the 3D positions of the center of the femoral head and the acetabular cup models.
The fluoroscopy module enables you to easily analyze the 3D dynamic behavior of prostheses, by matching the virtual projected contours of the prosthesis with their corresponding detected contours in a fluoroscopic image sequence.
The main difference between RSA and fluoroscopy is the use of a single focus set-up.
Another difference is the presence of image (pincushion) distortion in conventional fluoroscopic systems. With a specially designed calibration box this distortion can be corrected. For digital flat panel systems this is not necessary.
The reported accuracy of Marker-based Fluoroscopic Analysis is in-plane 0.1 mm and out-of-plane 0.9 mm. The rotational accuracy is 0.1 degrees (15713311). Especially the out-of-plane accuracy must be taken into account when designing a fluoroscopy setup.