title: Accuracy and feasibility of high-speed dual fluoroscopy and model-based tracking to measure in vivo ankle arthrokinematics.
abstract: The relationship between altered tibiotalar and subtalar kinematics and development of ankle osteoarthritis is unknown, as skin marker motion analysis cannot measure articulations of each joint independently. Here, we quantified the accuracy and demonstrated the feasibility of high-speed dual fluoroscopy (DF) to measure and visualize the three-dimensional articulation (i.e., arthrokinematics) of the tibiotalar and subtalar joints. Metal beads were implanted in the tibia, talus and calcaneus of two cadavers. Three-dimensional surface models of the cadaver and volunteer bones were reconstructed from computed tomography images. A custom DF system was positioned adjacent to an instrumented treadmill. DF images of the cadavers were acquired during maximal rotation about three axes (dorsal-plantar flexion, inversion-eversion, internal-external rotation) and simulated gait (treadmill at 0.5 and 1.0 m/s). Positions of implanted beads were tracked using dynamic radiostereometric analysis (DRSA). Bead locations were also calculated using model-based markerless tracking (MBT) and compared, along with joint angles and translations, to DRSA results. The mean positional difference between DRSA and MBT for all frames defined bias; standard deviation of the difference defined precision. The volunteer was imaged with DF during treadmill gait. From these movements, joint kinematics and tibiotalar and subtalar bone-to-bone distance were calculated. The mean positional and rotational bias (±standard deviation) of MBT was 0.03±0.35 mm and 0.25±0.81°, respectively. Mean translational and rotational precision was 0.30±0.12 mm and 0.63±0.28°, respectively. With excellent measurement accuracy, DF and MBT may elucidate the kinematic pathways responsible for osteoarthritis of the tibiotalar and subtalar joints in living subjects.
authors: Department of Orthopaedics, University of Utah, 590 Wakara Way, Salt Lake City, UT 84108, USA; Department of Orthopaedics, Shanghai Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China. Electronic address: Bibo_Wang@outlook.com.
authors: Bibo
authors: B
authors: Wang
authors: Department of Orthopaedics, University of Utah, 590 Wakara Way, Salt Lake City, UT 84108, USA; Department of Bioengineering, University of Utah, 36 S. Wasatch Drive, Room 3100, Salt Lake City, UT 84112, USA. Electronic address: Koren.Roach@utah.edu.
authors: Koren E
authors: KE
authors: Roach
authors: Department of Orthopaedics, University of Utah, 590 Wakara Way, Salt Lake City, UT 84108, USA. Electronic address: Ashley.Kapron@utah.edu.
authors: Ashley L
authors: AL
authors: Kapron
authors: Department of Orthopaedics, University of Utah, 590 Wakara Way, Salt Lake City, UT 84108, USA. Electronic address: Niccolo.Fiorentino@utah.edu.
authors: Niccolo M
authors: NM
authors: Fiorentino
authors: Department of Orthopaedics, University of Utah, 590 Wakara Way, Salt Lake City, UT 84108, USA. Electronic address: Charles.Saltzman@hsc.utah.edu.
authors: Charles L
authors: CL
authors: Saltzman
authors: Department of Bioengineering, University of Utah, 36 S. Wasatch Drive, Room 3100, Salt Lake City, UT 84112, USA. Electronic address: Maddie.Singer@hsc.utah.edu.
authors: Madeline
authors: M
authors: Singer
authors: Department of Orthopaedics, University of Utah, 590 Wakara Way, Salt Lake City, UT 84108, USA; Department of Bioengineering, University of Utah, 36 S. Wasatch Drive, Room 3100, Salt Lake City, UT 84112, USA; Department of Physical Therapy, University of Utah, 520 Wakara Way, Suite 240, Salt Lake City, UT 84108, USA; Scientific Computing and Imaging Institute, 72 S Central Campus Drive, Room 3750, Salt Lake City, UT 84112, USA. Electronic address: Andrew.Anderson@hsc.utah.edu.
authors: Andrew E
authors: AE
authors: Anderson
mesh_terms: D000369:Aged, 80 and over; D000843:Ankle Joint / Q000000981:diagnostic imaging / Q000502:physiology*; D001696:Biomechanical Phenomena; D002102:Cadaver; D003198:Computer Simulation; D005240:Feasibility Studies; D005260:Female; D005471:Fluoroscopy / Q000379:methods*; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000502:physiology*; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed / Q000379:methods
keywords: Dual fluoroscopy; In vivo; Kinematics; Subtalar joint; Tibiotalar joint