Fluoroscopy Validation of Noninvasive 3D Bone-Pose Tracking via External Pressure-Foils

Precise noninvasive bone motion tracking is a topic of increasing interest, as it provides medical practitioners with important information about musculoskeletal disorders and/or their treatment. Currently, the only non-invasive method that achieves 3D tracking precision below 1 mm is Dual Fluoroscopy (DF). However, this technique is expensive, restricted to only small measuring volumes and time periods, and can only be applied sporadically due to X-ray radiation limits. In a series of previous papers, the authors presented a new concept for bone motion tracking based on external virtual palpation of typical bone protuberances via motion-tracked pressure foils. This paper presents a DF validation of the method for three basic movements of the shank: flexion/extension, abduction/adduction and internal rotation. It is shown that by simple pressure-foil palpation, bone-tracking precisions of 0.5 to 1.0 mm and 0.3\(^{\circ }\) to 0.6\(^{\circ }\) can be attained with respect to manually-registered DF, reaching the same order of magnitude as state-of-the-art model-based tracking algorithms for DF using CT volumes.