A validated, subjectspecific knee model for predicting tibiofemoral force distribution from interseg

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A validated, subject-specific knee model for
predicting tibiofemoral force distribution from
intersegmental forces

• Rose Riemer

Advisors Dr. Tammy Haut Donahue Dr. Kenton
Kaufman
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Normal subjects

• 20-50 years of age
• No pain and/or stiffness in either knee during
  weight-bearing activities
• Full functional activity
• Recruited 17 individuals
• age 29 8.8 years
• 12 Female, 5 Male

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Gait Analysis

• 10 Camera motion system with forceplates
• 22 markers placed on body
• Collected
• level walking
• ascending stairs
• descending stairs

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Gait Analysis
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Conditions Studied

• Level walking
• Upstairs
• Downstairs

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Ground reaction forces
Image from Neumann, DA. Kinesiology of the
Musculoskeletal system. 2002
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Creating a model Geometry

• Canny edge detection, Matlab 6.5

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How it works Part 1
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Muscle groups
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Forces added to the model
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Muscle force
EMG
Muscle stresses
Image source http//www.marquette.edu/chs/pt/mpm/
Research/ EMG_of_Leg_Muscle_While_Walkin/2A.jpg
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Input/Output

• Input
• Geometry of person
• Gait of person (external forces and moments)
• Muscle forces
• Output
• Load distribution across the plateau

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Joint Load
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Creating a model Input forces

• Varus, valgus and axial loading
• Use pressure sensors inserted in the knee
• Measure pressure output and compare to program
  output.