Effects of soft tissue artefacts on computed segmental and stifle kinematics in canine motion analysis

Abstract

Skin marker-based motion analysis has been widely used to evaluate the functional performance of canine gait and posture. However, the interference of soft tissues between markers and the underlying bones (soft tissue artefacts, STAs) may lead to errors in kinematics measurements. Currently, no optimal marker attachment sites and cluster compositions are recommended for canine gait analysis. The current study aims to evaluate cluster-level STAs and the effects of cluster compositions on the computed stifle kinematics. Ten mixed-breed healthy dogs affixed with 19 retroreflective markers on the thigh and shank were enrolled. During isolated stifle passive extension, the marker trajectories were acquired with a motion capture system, and the skeletal poses were determined by integrating fluoroscopic and CT images of the bones. The cluster-level STAs were assessed, and clusters were paired to calculate the stifle kinematics. A selection of cluster compositions was useful for deriving accurate sagittal and frontal plane stifle kinematics with flexion angles below 50 per cent of the range of motion. The findings contribute to improved knowledge of canine STAs and their influence on motion measurements. The marker composition with the smallest error in describing joint kinematics is recommended for future applications and study in dogs during dynamic gait assessment.

Evaluation of a multibody kinematics optimization method for three-dimensional canine pelvic limb gait analysis

“…However, this approach is considered suboptimal since local marker displacements are derived based on the estimated body segment poses using the SO. The SOdetermined segment poses are indeed subject to a rigid error component of STAs [20], which leads the local marker displacements to substantially underestimate the magnitude of STAs. Nonetheless, the computed weightings of the pelvis, thigh, and crus seem to follow a tendency that the thigh marker should be assigned lower weightings owing to greater STAs [15].…”

“…5), for which the pelvic and tibial AFs were determined following the reported recommendation [14], and the femoral AF was constructed in reference to the definition proposed by Cappozzo et al [34]. The position vectors of the markers were then expressed in their corresponding AFs to form "marker templates" of the pelvic, femoral and tibial segments [20].…”

“…Single-body optimization estimates the corresponding segment by minimizing the deformation of the measured marker array from its initial shape [14,18], addressing the nonrigid error component of the STA. However, SO cannot correct the STA error composited by rigid movement components [19], and residual errors in stifle angle estimation have been observed in dogs [15,20]. While other strategies, such as traditional filtering, dynamic calibration and point cluster techniques, have been reported in human motion analysis to compensate for the STA [21], they either were not able to accurately estimate 3-D knee kinematics or may not be feasible for dogs.…”

“…Computed tomography model-based fluoroscopic analysis has also been reported for estimating STA-free segment and joint kinematics in dogs [2,8,11,15]. It integrates CT-based models and fluoroscopy images [29] and can serve as the reference standard for evaluating other motion measurements [15,20,30]. While CT model-based fluoroscopic analysis is advantageous in obtaining a relatively accurate spatial pose of the body segments (accuracy: 0.77 mm and 3.06 mm for translations and 1.13°for rotations [29]), its major disadvantages are radiation exposure, the need for CT scanning and reconstruction, additional costs, and the narrow field of view of fluoroscopy imaging, which limits the motion measurement to a single joint (or 2-3 adjacent body segments).…”

Description of soft tissue artifacts and related consequences on hindlimb kinematics during canine gait

“…However, it is acknowledged that markers attached to the skin surface become displaced with respect to the underlying skeleton along with movement of the body (Leardini et al, 2005). Such skin marker movement results in "soft tissue artifacts" of clusters in determining canine stifle joint angles have also been quantified (Lu et al, 2020).…”