[Adaptive planing model for osteosynthesis of femoral neck fracture]

To investigate how surgeons can be supported in planning of screws for femoral neck fracture fixation reducing incidents of misplaced screws, a system was developed which makes use of a deformable model to be adapted to the femoral head/neck. The accuracy and usability of the system was checked against planning support systems mimicking the conventional positioning of screws within bi-planar x-rays. All designs were evaluated and compared by N = 7 test user. Checking the rate of misplaced screws a) at the femoral neck yielded rates of 8% or up to 42%, b) at the femoral head yielded rates of 0% or up to 11% for model-based or conventional planning, respectively. It is thus suggested to constrain the planning and navigation space by means of deformable models of the bone.