Development and validation of a kinematically-driven discrete element model of the patellofemoral joint.
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ABSTRACT: Quantifying the complex loads at the patellofemoral joint (PFJ) is vital to understanding the development of PFJ pain and osteoarthritis. Discrete element analysis (DEA) is a computationally efficient method to estimate cartilage contact stresses with potential application at the PFJ to better understand PFJ mechanics. The current study validated a DEA modeling framework driven by PFJ kinematics to predict experimentally-measured PFJ contact stress distributions. Two cadaveric knee specimens underwent quadriceps muscle [215?N] and joint compression [350?N] forces at ten discrete knee positions representing PFJ positions during early gait while measured PFJ kinematics were used to drive specimen-specific DEA models. DEA-computed contact stress and area were compared to experimentally-measured data. There was good agreement between computed and measured mean and peak stress across the specimens and positions (r?=?0.63-0.85). DEA-computed mean stress was within an average of 12% (range: 1-47%) of the experimentally-measured mean stress while DEA-computed peak stress was within an average of 22% (range: 1-40%). Stress magnitudes were within the ranges measured (0.17-1.26?MPa computationally vs 0.12-1.13?MPa experimentally). DEA-computed areas overestimated measured areas (average error?=?60%; range: 4-117%) with magnitudes ranging from 139 to 307?mm2 computationally vs 74-194?mm2 experimentally. DEA estimates of the ratio of lateral to medial patellofemoral stress distribution predicted the experimental data well (mean error?=?15%) with minimal measurement bias. These results indicate that kinematically-driven DEA models can provide good estimates of relative changes in PFJ contact stress.
SUBMITTER: Gustafson JA
PROVIDER: S-EPMC7307598 | biostudies-literature | 2019 May
REPOSITORIES: biostudies-literature
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