title: Biplane fluoroscopy for hindfoot motion analysis during gait: A model-based evaluation.
abstract: The purpose of this study was to quantify the accuracy and precision of a biplane fluoroscopy system for model-based tracking of in vivo hindfoot motion during over-ground gait. Gait was simulated by manually manipulating a cadaver foot specimen through a biplane fluoroscopy system attached to a walkway. Three 1.6-mm diameter steel beads were implanted into the specimen to provide marker-based tracking measurements for comparison to model-based tracking. A CT scan was acquired to define a gold standard of implanted bead positions and to create 3D models for model-based tracking. Static and dynamic trials manipulating the specimen through the capture volume were performed. Marker-based tracking error was calculated relative to the gold standard implanted bead positions. The bias, precision, and root-mean-squared (RMS) error of model-based tracking was calculated relative to the marker-based measurements. The overall RMS error of the model-based tracking method averaged 0.43 ± 0.22mm and 0.66 ± 0.43° for static and 0.59 ± 0.10mm and 0.71 ± 0.12° for dynamic trials. The model-based tracking approach represents a non-invasive technique for accurately measuring dynamic hindfoot joint motion during in vivo, weight bearing conditions. The model-based tracking method is recommended for application on the basis of the study results.
authors.affiliation: Medical College of Wisconsin, 8700 Watertown Plank Road, Milwaukee, WI 53226 USA. Electronic address: jacross@mcw.edu.
authors.forename: Janelle A
authors.initials: JA
authors.lastname: Cross
authors.affiliation: Marquette University, 1515 W. Wisconsin Avenue, Milwaukee, WI 53233 USA. Electronic address: ben.mchenry@marquette.edu.
authors.forename: Benjamin D
authors.initials: BD
authors.lastname: McHenry
authors.affiliation: Marquette University, 1515 W. Wisconsin Avenue, Milwaukee, WI 53233 USA. Electronic address: rmolthen@wi.rr.com.
authors.forename: Robert
authors.initials: R
authors.lastname: Molthen
authors.affiliation: Meriter UnityPoint, 6408 Copps Avenue, Monona, WI 53716 USA. Electronic address: elexten@aol.com.
authors.forename: Emily
authors.initials: E
authors.lastname: Exten
authors.affiliation: Marquette University, 1515 W. Wisconsin Avenue, Milwaukee, WI 53233 USA. Electronic address: tal.gilat-schmidt@marquette.edu.
authors.forename: Taly Gilat
authors.initials: TG
authors.lastname: Schmidt
authors.affiliation: Marquette University, 1515 W. Wisconsin Avenue, Milwaukee, WI 53233 USA. Electronic address: gerald.harris@marquette.edu.
authors.forename: Gerald F
authors.initials: GF
authors.lastname: Harris
mesh_terms: D000328:Adult; D005471:Fluoroscopy; D005528:Foot / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000502:physiology*; D005684:Gait; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008953:Models, Anatomic; D014057:Tomography, X-Ray Computed
keywords: Biomechanics; Biplane fluoroscopy; Gait; Hindfoot; Model-based