The influence of soft tissue artifacts on multi-segment foot kinematics

Movement of skin markers with respect to their underlying bone (i.e. soft tissue artifacts (STAs)) might corrupt the accuracy marker-based movement analyses. This study aims quantify STAs in 3D for foot and effect on multi-segment kinematics as calculated by Oxford Rizzoli Foot Models (OFM, RFM). Fifteen subjects asymptomatic feet were seated a custom-made loading device computed tomography (CT) table, combined OFM RFM marker set right foot. One unloaded reference CT-scan neutral position was performed, followed 9 loaded CT-scans at different positions. The 3D-displacement STA) each coordinate system between scan other scans calculated. Subsequently, segment orientations joint angles from positions according definitions without STAs. differences degrees defined errors caused displacements. Markers lateral malleolus proximally posterior aspect calcaneus showed largest hindfoot-shank angle most affected extreme (40° plantar flexion) sagittal plane (mean: 6.7°, max: 11.8°) transverse 3.9°, 6.8°). that introduce clinically relevant kinematics. Moreover, it identified locations are STAs, suggesting use within models should be reconsidered.