A Direct Comparison of Biplanar Videoradiography and Optical Motion Capture for Foot and Ankle Kinematics

Abstract

Measuring motion of the human foot presents a unique challenge due to the large number of closely packed bones with congruent articulating surfaces. Optical motion capture (OMC) and multi-segment models can be used to infer foot motion, but might be affected by soft tissue artifact (STA). Biplanar videoradiography (BVR) is a relatively new tool that allows direct, non-invasive measurement of bone motion using high-speed, dynamic x-ray images to track individual bones. It is unknown whether OMC and BVR can be used interchangeably to analyse multi-segment foot motion. Therefore, the aim of this study was to determine the agreement in kinematic measures of dynamic activities. Nine healthy participants performed three walking and three running trials while BVR was recorded with synchronous OMC. Bone position and orientation was determined through manual scientific-rotoscoping. The OMC and BVR kinematics were co-registered to the same coordinate system, and BVR tracking was used to create virtual markers for comparison to OMC during dynamic trials. Root mean square (RMS) differences in marker positions and joint angles as well as a linear fit method (LFM) was used to compare the outputs of both methods. When comparing BVR and OMC, sagittal plane angles were in good agreement (ankle: R 2 = 0.947, 0.939; Medial Longitudinal Arch (MLA) Angle: R 2 = 0.713, 0.703, walking and running, respectively). When examining the ankle, there was a moderate agreement between the systems in the frontal plane (R 2 = 0.322, 0.452, walking and running, respectively), with a weak to moderate correlation for the transverse plane (R 2 = 0.178, 0.326, walking and running, respectively). However, root mean squared error (RMSE) showed angular errors ranging from 1.06 to 8.31° across the planes (frontal: 3.57°, 3.67°, transverse: 4.28°, 4.70°, sagittal: 2.45°, 2.67°, walking and running, respectively). Root mean square (RMS) differences between OMC and BVR marker trajectories were task dependent with the largest differences in the shank (6.0 ± 2.01 mm) for running, and metatarsals (3.97 ± 0.81 mm) for walking. Based on the results, we suggest BVR and OMC provide comparable solutions to foot motion in the sagittal plane, however, interpretations of out-of-plane movement should be made carefully.

The Reliability of Foot and Ankle Bone and Joint Kinematics Measured With Biplanar Videoradiography and Manual Scientific Rotoscoping

“…The experimental protocol was approved by The University of Queensland and the Providence VA Medical Center Ethics Committee and conducted according to the Declaration of Helsinki. This data set has been used in a previous publication, see Kessler et al (2019).…”

“…The position and orientation of each bone was determined via scientific rotoscoping using the open source software package, Autoscoper (Brainerd et al, 2010) (Autoscoper V2, Brown University, Providence, RI, United States), as previously detailed in Kessler et al (2019). In brief, for each frame, the partial volume of the bone of interest is used to create a digitally reconstructed radiograph (DRR) that is projected onto the two calibrated x-ray images.…”

“…Biplanar videoradiography has provided valuable insights into the function of the wrist (Akhbari et al, 2019), shoulder (Bey et al, 2006(Bey et al, , 2008, hip (Dimitriou et al, 2015), and knee (Akbarshahi et al, 2010;Miranda et al, 2013) during dynamic tasks. Recently, it has also been shown to accurately capture 3D skeletal motion of the bones in the foot (Ito, 2015;Wang et al, 2015) and subsequently used to calculate their foot kinematics (Roach et al, 2016(Roach et al, , 2017Kessler et al, 2019).…”

Intrinsic foot joints adapt a stabilized‐resistive configuration during the stance phase

“…The development of three-dimensional (3D) multi-segment foot models partially tackled this major shortcoming of the established 3D lower limb models and showed their clinical value through the detection of intrinsic foot mobility impairments [1]. During the last decade, foot and ankle biomechanics were essentially described through the kinematics of the gait cycle as determined from cadaver, invasive bone pins, biplanar videoradiography and noninvasive surface marker studies, and plantar pressure measurements [2][3][4][5][6][7][8]. Recently, multi-segment kinetic foot models have received increasing attention in methodological and clinical studies providing new insights into how the intrinsic joints of the foot can have individual power distributions [9][10][11][12].…”

In vitro study of foot bone kinematics via a custom-made cadaveric gait simulator

“…Previous studies conducted for the measurement of 3D kinematics of the foot bones during gait can be classi ed into four categories [1][2][3][4][5][6][7][8][9][10] , including skin marker-based motion capture system, uoroscopy study, in-vivo measurement with bone pins and measurement through cadaver gait simulators. However, some limitations are found in previous research methods.…”