Validation of marker-based tracking with a biplanar fluoroscopy system optimized for the foot and ankle

Biplanar fluoroscopy is a powerful, maturing technique for providing clinicians and biomechanists with in vivo kinematic data of the human skeleton during a variety of tasks. Marker-based tracking with biplane systems has applications in both the in vivo and in vitro realms and serves as the established means of validating model-based tracking algorithms. We have developed a custom biplane system for dynamic imaging of the entire foot and ankle complex during gait as well as a custom software suite to perform the required data preprocessing and marker-based tracking. We demonstrate our ability to repeatably model the biplane imaging chains and then accurately and precisely reconstruct the positions of markers in the foot during static and dynamic motion trials. Finally, we simulate the effects of marker localization errors in reconstructing the poses of the calcaneus, navicular, and proximal phalanx during gait in order to contextualize the extent to which marker-based tracking may be considered ground truth compared to future model-based tracking algorithms.