CT, MRI and video based analysis of knee kinematics--a basis for CT based simulation

With the new computer aided surgery techniques a surgery can be split in two phases, which are pre-operative planning and intervention. The planning is frequently based on three dimensional image data and takes place in the office of the surgeon. Using this approach the surgical feeling, the physical feedback of the patient, is not available during the planning phase. However, this feedback yields information, which is helpful or necessary for the planning. This lack of information can be compensated by a simulation module, which simulates kinematic data from image volume data. To develop such a module first both image volume data and kinematic data have to be captured from a wide range of patients. In this work a new approach for kinematic analysis of the knee is presented which yields an accuracy which is necessary for such simulation. Because the analysis has to be done for many patients the degree of invasiveness is emphasized. This contactless and non invasive approach is based on external fixations, anatomical skin markers, video sequences and computer tomograms. Position tracking of femur and tibia for any motion pattern is possible. Because the individual anatomic structures extracted from the tomogram are tracked, an analysis of any point or coordinate system can be done later using the originally captured data. This gives a new degree of freedom for analysis.