DEFINITION OF A FLUOROSCOPIC GOLD STANDARD FOR THE EVALUATION OF MARKER-BASED FOOT PROTOCOLS

The quantification of foot-kinematics in-vivo is a critical issue for functional evaluation in several pathologies. The great clinical and research interest is demonstrated by the number of foot protocols, based on different biomechal models, reported in recent literature. The performance of only few of these protocols was experimentally assessed and only in terms of repeatability. The lack of a validation is essentially due to the lack of a methodology for the accurate in-vivo quantification of foot kinematics, taking into account deformability of foot segments. The aim of the present study is the definition of a fluoroscopic gold standard for the assessment of marker-based foot protocols. One subject performed foot and ankle motor tasks while synchronously acquired by means of stereophoeogrammetry and videofluoroscopy. 3D kinematics of foot segments was reconstructed using 3D fluoroscopy associated to a function-based definition of foot segmental models and compared with foot segmental kinematics reconstructed using stereophotogrammetry. Results show that function-based model constrained to bony segment kinematics provides a good specificity in describing the relative kinematics of foot sub- segments, while the kinematics of the different bony segments within the sub-segments can hardly be generalized, without the proposed functional approach.