Document Detail


Quantifying skin motion artifact error of the hindfoot and forefoot marker clusters with the optical tracking of a multi-segment foot model using single-plane fluoroscopy.
MedLine Citation:
PMID:  21498078     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
The trajectories of skin-mounted markers tracked with optical motion capture are assumed to be an adequate representation of the underlying bone motions. However, it is well known that soft tissue artifact (STA) exists between marker and bone. This study quantifies the STA associated with the hindfoot and midfoot marker clusters of a multi-segment foot model. To quantify STA of the hindfoot and midfoot marker clusters with respect to the calcaneus and navicular respectively, fluoroscopic images were collected on 27 subjects during four quasi-static positions, (1) quiet standing (non-weight bearing), (2) at heel strike (weight-bearing), (3) at midstance (weight-bearing) and (4) at toe-off (weight-bearing). The translation and rotation components of STA were calculated in the sagittal plane. Translational STA at the calcaneus varied from 5.9±7.3mm at heel-strike to 12.1±0.3mm at toe-off. For the navicular the translational STA ranged from 7.6±7.6mm at heel strike to 16.4±16.7mm at toe-off. Rotational STA was relatively smaller for both bones at all foot positions. For the calcaneus they varied between 0.1±2.2° at heel-strike to 0.2±0.6° at toe-off. For the navicular, the rotational STA ranged from 0.6±0.9° at heel-strike to 0.7±0.7° at toe-off. The largest translational STA found in this study (16mm for the navicular) was smaller than those reported in the literature for the thigh and the lower leg, but was larger than the STA of individual spherical markers affixed to the foot. The largest errors occurred at toe-off position for all subjects for both the hindfoot and midfoot clusters. Future studies are recommended to quantify true three-dimensional STA of the entire foot during gait.
Authors:
R Shultz; A E Kedgley; T R Jenkyn
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2011-4-15
Journal Detail:
Title:  Gait & posture     Volume:  -     ISSN:  1879-2219     ISO Abbreviation:  -     Publication Date:  2011 Apr 
Date Detail:
Created Date:  2011-4-18     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9416830     Medline TA:  Gait Posture     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Copyright Information:
Copyright © 2011. Published by Elsevier B.V.
Affiliation:
Division of Sports Medicine, Department of Orthopaedic Surgery, Stanford University School of Medicine, USA; Wolf Orthopaedic Biomechanics Laboratory, Fowler Kennedy Sport Medicine Clinic, The University of Western Ontario, Canada.
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