XIMIT - X-Ray Migration Measurement Using Implant Models and Image Templates

XIMIT is a newly developed method for precisely measuring the 2D migration of a hip socket implant using standard radiographs. 2D migration is the change of the 2D distance between implant and bone observable in the x-ray image. It is measured in order to judge the fixation of the implant in the bone. The proposed method is based on a carefully designed measurement of the 2D distance minimizing the influence of different sources of errors. The magnitude of the entering errors is minimized by estimating the implant’s 3D orientation and position using the CAD model of the implant and by involving a state of the art template matching algorithm. According to the first error estimate, the new method makes a migration measurement with a standard deviation of about 0.2mm possible.