TY - JOUR
T1 - Marker placement sensitivity of the Oxford and Rizzoli foot models in adults and children
AU - Schallig, Wouter
AU - van den Noort, Josien C.
AU - Maas, Mario
AU - Harlaar, Jaap
AU - van der Krogt, Marjolein M.
N1 - Funding Information: This research was funded by an internal grant of the Amsterdam Movement Sciences research institute. Publisher Copyright: © 2021 The Authors
PY - 2021/9/20
Y1 - 2021/9/20
N2 - Understanding the effect of individual marker misplacements is important to improve the repeatability and aid to the interpretation of multi-segment foot models like the Oxford and Rizzoli Foot Models (OFM, RFM). Therefore, this study aimed to quantify the effect of controlled anatomical marker misplacement on multi-segment foot kinematics (i.e. marker placement sensitivity) as calculated by OFM and RFM in a range of foot sizes. Ten healthy adults and nine children were included. A combined OFM and RFM marker set was placed on their right foot and a static standing trial was collected. Each marker was replaced ± 10 mm in steps of 1 mm over the three axes of a foot coordinate system. For each replacement the change in segment orientation (tibia, hindfoot, midfoot, forefoot) was calculated with respect to the reference pose in which no markers were replaced. A linear fit was made to calculate the sensitivity of segment orientation to marker misplacement in °/mm. Additionally, the effect of foot size on the sensitivity was determined using linear regressions. For every foot segment of both models, at least one marker had a sensitivity ≥ 1.0°/mm. Highest values were found for the markers at the posterior aspect of the calcaneus in OFM (1.5°/mm) and the basis of the second metatarsal in RFM (1.4°/mm). Foot size had a small effect on 40% of the sensitivity values. This study identified markers of which consistent placement is critical to prevent clinically relevant errors (>5°). For more repeatable multi-segment models, the role of these markers within the models’ definitions needs to be reconsidered.
AB - Understanding the effect of individual marker misplacements is important to improve the repeatability and aid to the interpretation of multi-segment foot models like the Oxford and Rizzoli Foot Models (OFM, RFM). Therefore, this study aimed to quantify the effect of controlled anatomical marker misplacement on multi-segment foot kinematics (i.e. marker placement sensitivity) as calculated by OFM and RFM in a range of foot sizes. Ten healthy adults and nine children were included. A combined OFM and RFM marker set was placed on their right foot and a static standing trial was collected. Each marker was replaced ± 10 mm in steps of 1 mm over the three axes of a foot coordinate system. For each replacement the change in segment orientation (tibia, hindfoot, midfoot, forefoot) was calculated with respect to the reference pose in which no markers were replaced. A linear fit was made to calculate the sensitivity of segment orientation to marker misplacement in °/mm. Additionally, the effect of foot size on the sensitivity was determined using linear regressions. For every foot segment of both models, at least one marker had a sensitivity ≥ 1.0°/mm. Highest values were found for the markers at the posterior aspect of the calcaneus in OFM (1.5°/mm) and the basis of the second metatarsal in RFM (1.4°/mm). Foot size had a small effect on 40% of the sensitivity values. This study identified markers of which consistent placement is critical to prevent clinically relevant errors (>5°). For more repeatable multi-segment models, the role of these markers within the models’ definitions needs to be reconsidered.
KW - Foot kinematics
KW - Gait analysis
KW - Measurement error
KW - Multi-segment foot models
KW - Repeatability
UR - http://www.scopus.com/inward/record.url?scp=85111056477&partnerID=8YFLogxK
U2 - https://doi.org/10.1016/j.jbiomech.2021.110629
DO - https://doi.org/10.1016/j.jbiomech.2021.110629
M3 - Article
C2 - 34320419
SN - 0021-9290
VL - 126
JO - Journal of Biomechanics
JF - Journal of Biomechanics
M1 - 110629
ER -