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Sensitivity of Musculoskeletal Models to Scaled-Generic Knee Kinematic Errors
M. Williams1, S. Martelli1, N. Sancisi2, M. Conconi2, V. Parenti-Castelli2, K. Reynolds1 1Medical Device Research Institute, School of Computer Science, Engineering and Mathematics, Flinders University, South Australia 2Department of Industrial Engineering, University of Bologna, Bologna, Italy
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Musculoskeletal forces during activity
[1] Increasingly used to study human motion in healthy and pathological conditions [1]. Increasing field Modelling the mechanical system Non-invasive [1] Hicks et al., J Biomech Eng Feb 1;137(2):
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Creating confidence on model calculations
Verification, validation and sensitivity studies in computational biomechanics [1,2]. No study has assessed the sensitivity of musculoskeletal model calculation to common scaled-generic knee kinematic assumptions. Increasing field Modelling the mechanical system Non-invasive [1] Anderson & Weiss, Comp meth biomech and biomed eng, 2007, 10 (3) [2] Viceconti et al., Clin Biomech, 2005, 20 (5).
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Aim To assess the effect of scaled-generic knee kinematic errors on calculation of muscle and joint forces and knee ligaments elongation
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Participants and data collection
Participants: 13 healthy women of year of age Motion capture (10-cameras VICON system, Oxford Metrics Group, Oxford, U.K., 120Hz): walking, jumping, stair ascent, stair descent, chair up and down, fast walking GRF (3 AMTI,Watertown, MA, USA, 1000 Hz) CT (Aquilon CT, Toshiba, 0.5 x 0.5 x 0.5 mm, 120kV, 200mA) including pelvis and proximal tibia Scaled-generic models validated [1] against published joint angles [2,3], hip contact forces [4] and muscle firing patterns [5] [1] Martelli et al., J Biomech., 2015, In Press [2] Kadaba et al., Journal of Orthop. Res., 1989, 7, 849–60. [3] Stacoff et al., Gait Posture 21,2005, 24–38. [4] Bergmann et al., J Biomech., 2001, 34, 859–871 [5] Inman et al., 1981, Human Walking. MD: Williams & Wilkins, Baltimore
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Knee kinematic models 3D model with physiological constraints [4,5]
RMSE < 2.3º & 1.6 mm The common type of model… scaled Scaling of random subject from 90’s – produces kinematic errors What is the effect of these errors? Recent protocol identifies subject-specific knee motion, can now find out these effects by creating model C We developed a method… Planar-scaled model [1,2,3] [1] Delp et al., IEEE Trans Biom Eng, 1990, 37 (8) [2] Yamaguchi & Zajac, J . Biomech., 1989 , 21:1-10 [3] Martelli et al., J Biomech., 2015, In Press [4] Ottoboni et al., P I Mech Eng H, 2010 [5] Conconi et al., IDETC/CIE 2013, Portland, USA, 2013
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Study design Scaled-generic models from [1]
Joint Angles Joint Moments Muscle Forces Joint Contact Forces Ligament length Scaled-generic models from [1] Subject-specific model [2,3] 13 healthy women. Age: 60-78; 2 stages of input, motion data: Activities? Scaled-generic vs subject-specific (6 of 13 analysed) [2] Ottoboni et al., P I Mech Eng H, 2010 [3] Conconi et al., IDETC/CIE 2013, Portland, USA, 2013 [1] Martelli et al., J Biomech, 2015, In Press .
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The calculated 3D knee kinematics
[1] Sheehan et al., J Biomech, 2007
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Comparison of joint angles
N = 3600 (6 subjects x 6 tasks x 100 frames) Explain data analysis Further work is accumulating data for more subjects Comparing ligament extension across models
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Comparison of joint moments
Explain data analysis Further work is accumulating data for more subjects Comparing ligament extension across models
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Comparison of muscle Force
Explain data analysis Further work is accumulating data for more subjects Comparing ligament extension across models
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Comparison of joint forces
Explain data analysis Further work is accumulating data for more subjects Comparing ligament extension across models
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Scaled-generic ligament length
Explain data analysis Further work is accumulating data for more subjects Comparing ligament extension across models
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Conclusions Scaled-generic models are a valid solution (R2 > 0.97) for calculating patterns of joint angles, muscle and joint forces, although localized high force errors (<2105 N) have been shown. Scaled-generic knee kinematics induce unrealistic ligament elongation (Dl/l < 60%). Explain data analysis Further work is accumulating data for more subjects Comparing ligament extension across models
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Thank you Explain data analysis
Further work is accumulating data for more subjects Comparing ligament extension across models
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Knee Modelling Results
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