“The Emperor’s New Clothes” “The Emperor’s New Clothes” “The Emperor’s New Clothes” “The Emperor’s New Clothes” The Emperor s New Clothes The Emperor s New Clothes The Emperor s New Clothes The Emperor s New Clothes Do we have a similar phenomenon in the Do we have a similar phenomenon in the musculoskeletal modeling community? musculoskeletal modeling community? • Many publications that predict muscle and Many publications that predict muscle and Of course, the answer depends in part on contact forces using contact forces using unvalidated unvalidated methods. methods. the question we are trying to answer, but q y g • Significant research funding going to Significant research funding going to g g g g g g g g should we be more critical of our own work? projects that are making projects that are making unvalidated unvalidated predictions. predictions. • Statements being made about clinical Statements being made about clinical Statements being made about clinical Statements being made about clinical conditions and treatments based on conditions and treatments based on unvalidated unvalidated predictions. predictions. Motivation Motivation at Scripps Clinic
Workshop Objective Workshop Objective Workshop Objective Workshop Objective Workshop Objective Workshop Objective Workshop Objective Workshop Objective To introduce you to a “grand challenge” competition to To introduce you to a “grand challenge” competition to To introduce you to a “grand challenge” competition, to To introduce you to a “grand challenge” competition, to be held next summer at the SBC, to critically evaluate be held next summer at the SBC, to critically evaluate in vivo in vivo muscle and contact force predictions at the knee muscle and contact force predictions at the knee during gait using data collected from a patient with a during gait using data collected from a patient with a force force- -measuring knee replacement. measuring knee replacement. Motivation Motivation at Scripps Clinic
Big Picture Big Picture Big Picture Big Picture Big Picture Big Picture Big Picture Big Picture • We provide the We provide the in vivo in vivo data (minus the implant loads). data (minus the implant loads). • You predict the muscle and contact forces. You predict the muscle and contact forces. • We evaluate the contact force predictions quantitatively. We evaluate the contact force predictions quantitatively. • Best predictions are presented in a special session. Best predictions are presented in a special session. • Actual contact forces are revealed in the session. Actual contact forces are revealed in the session. • Winner is closest to the measured contact forces • Winner is closest to the measured contact forces. Winner is closest to the measured contact forces Winner is closest to the measured contact forces. Motivation Motivation at Scripps Clinic
Rationale Rationale Rationale Rationale Rationale Rationale Rationale Rationale In vivo In vivo measurement of muscle forces would be measurement of muscle forces would be required for direct quantitative validation of muscle required for direct quantitative validation of muscle required for direct quantitative validation of muscle required for direct quantitative validation of muscle force predictions. force predictions. Though indirect, Th Th Though indirect, in vivo h i di h i di t t i i in vivo measurement of contact forces i i measurement of contact forces t t f f t t t f t f is the next best option for quantitative validation, since is the next best option for quantitative validation, since muscle forces are the primary determinants of joint muscle forces are the primary determinants of joint p p y y j j contact forces (Herzog contact forces (Herzog et al et al ., 2003). ., 2003). Motivation Motivation at Scripps Clinic
Workshop Outline Workshop Outline Workshop Outline Workshop Outline Workshop Outline Workshop Outline Workshop Outline Workshop Outline 1. 1. Motivation for Competition (B.J. Motivation for Competition (B.J. Fregly Fregly) ) 2 Instrumented Implant Designs and Accuracy 2. 2. Instrumented Implant Designs and Accuracy Instrumented Implant Designs and Accuracy Instrumented Implant Designs and Accuracy (Darryl (Darryl D’Lima D’Lima) ) 3. 3. Experimental Data Collection (Thor Experimental Data Collection (Thor Besier Besier) ) 4. 4. Modeling Results To Date (B.J. Modeling Results To Date (B.J. Fregly Fregly) 5. 5. Logistics of Competition ( Logistics of Competition (Darryl Darryl D’Lima D’Lima) ) 6. 6. Questions and Answers (All) Questions and Answers (All) at Scripps Clinic
Reminder Reminder Reminder Reminder Reminder Reminder Reminder Reminder Please sign the attendance sheet if you Please sign the attendance sheet if you want to receive e want to receive e- -mail updates about mail updates about organization of the competition. organization of the competition. at Scripps Clinic
Workshop Outline Workshop Outline Workshop Outline Workshop Outline Workshop Outline Workshop Outline Workshop Outline Workshop Outline 1. 1. Motivation for Competition (B.J. Motivation for Competition (B.J. Fregly Fregly) ) 2 Instrumented Implant Designs and Accuracy 2. 2. Instrumented Implant Designs and Accuracy Instrumented Implant Designs and Accuracy Instrumented Implant Designs and Accuracy (Darryl (Darryl D’Lima D’Lima) ) at Scripps Clinic
2. Instrumented Implant 2. Instrumented Implant D D Design and Accuracy Design and Accuracy i i d A d A Darryl D. Darryl D. D’Lima y D’Lima, M.D., Ph.D. , M.D., Ph.D. Director, Orthopaedic Director, Orthopaedic Research Laboratories Research Laboratories Shiley Shiley Center for Center for Orthopaedic Orthopaedic Research & Education Research & Education Scripps Clinic, La Jolla, CA Scripps Clinic, La Jolla, CA pp pp , , , , at Scripps Clinic
Generation I Tray Design Generation I Tray Design Generation I Tray Design Generation I Tray Design Generation I Tray Design Generation I Tray Design Generation I Tray Design Generation I Tray Design • Axial Load Cells (4) – Total Load – Mediolateral Distribution – Center of Pressure – AP/ML Moments – AP/ML Moments – Shear – Axial Moment 2. Implant Design and Accuracy 2. Implant Design and Accuracy at Scripps Clinic
Generation I Tray Design Generation I Tray Design Generation I Tray Design Generation I Tray Design Generation I Tray Design Generation I Tray Design Generation I Tray Design Generation I Tray Design Axial Load Cells (4) “eKnee” • – Total Load – Mediolateral Distribution – Center of Pressure – AP/ML Moments – AP/ML Moments – Shear – Axial Moment 2. Implant Design and Accuracy 2. Implant Design and Accuracy at Scripps Clinic
Generation I Tray Design Generation I Tray Design Generation I Tray Design Generation I Tray Design Generation I Tray Design Generation I Tray Design Generation I Tray Design Generation I Tray Design 2. Implant Design and Accuracy 2. Implant Design and Accuracy at Scripps Clinic
Generation I Generation I Generation I Generation I Calibration Accuracy Calibration Accuracy Calibration Accuracy Calibration Accuracy • NIST Load cell • R 2 > 0.99 • AAE Axial Force < 1.1% FS • Shear cross talk <0 3% • Shear cross-talk <0.3% • AAE Center of Pressure <0.25 mm Kaufman + J Biomech 1996 Kaufman +, J Biomech 1996 2. Implant Design and Accuracy 2. Implant Design and Accuracy at Scripps Clinic
Generation I Generation I Generation I Generation I Calibration Accuracy Calibration Accuracy Calibration Accuracy Calibration Accuracy 2. Implant Design and Accuracy 2. Implant Design and Accuracy at Scripps Clinic
Generation I Generation I Generation I Generation I Calibration Accuracy Calibration Accuracy Calibration Accuracy Calibration Accuracy • NIST Load cell • R 2 > 0.99 • AAE Axial Force < 1.5% FS • AAE Center of Pressure < 1.9 mm D’Lima +, J Biomech 2005 2. Implant Design and Accuracy 2. Implant Design and Accuracy at Scripps Clinic
Generation II Tray Design Generation II Tray Design Generation II Tray Design Generation II Tray Design Generation II Tray Design Generation II Tray Design Generation II Tray Design Generation II Tray Design Microprocessor Internal Power Induction Coil I t l P I d ti C il Transmitting Antenna g Kirking +, J Biomech, 2005 2. Implant Design and Accuracy 2. Implant Design and Accuracy at Scripps Clinic
Generation II Tray Design Generation II Tray Design Generation II Tray Design Generation II Tray Design Generation II Tray Design Generation II Tray Design Generation II Tray Design Generation II Tray Design Microprocessor “eTibia” I t Internal Power Induction Coil l P I d ti C il Transmitting Antenna g Kirking +, J Biomech, 2005 2. Implant Design and Accuracy 2. Implant Design and Accuracy at Scripps Clinic
Generation II Generation II Generation II Generation II Calibration Accuracy Calibration Accuracy Calibration Accuracy Calibration Accuracy Kirking +, J Biomech 2006 2. Implant Design and Accuracy 2. Implant Design and Accuracy at Scripps Clinic
Generation II Generation II Generation II Generation II Calibration Accuracy Calibration Accuracy Calibration Accuracy Calibration Accuracy Kirking +, J Biomech 2006 2. Implant Design and Accuracy 2. Implant Design and Accuracy at Scripps Clinic
Generation II Generation II Generation II Generation II Calibration Accuracy Calibration Accuracy Calibration Accuracy Calibration Accuracy Kirking +, J Biomech 2006 2. Implant Design and Accuracy 2. Implant Design and Accuracy at Scripps Clinic
Temperature Tests Temperature Tests Temperature Tests Temperature Tests Temperature Tests Temperature Tests Temperature Tests Temperature Tests • Water Bath 42 Water Bath 42° °C C • High Temperature Burn High Temperature Burn- -In 80 In 80° °C C 2. Implant Design and Accuracy 2. Implant Design and Accuracy at Scripps Clinic
Durability Tests Durability Tests Durability Tests Durability Tests Durability Tests Durability Tests Durability Tests Durability Tests • Shaker Tests Shaker Tests • Prototypes & Implantable Grade Units Prototypes & Implantable Grade Units – +12 years +12 years 2. Implant Design and Accuracy 2. Implant Design and Accuracy at Scripps Clinic
Data Transmission Data Transmission Data Transmission Data Transmission Data Transmission Data Transmission Data Transmission Data Transmission • Power Channel Power Channel • Temperature Channel Temperature Channel • 12 Data Channels 12 Data Channels • Start byte • St St Start byte t b t t b t • Checksum byte Checksum byte • 2 ms delay 2 ms delay 2 ms delay 2 ms delay 2. Implant Design and Accuracy 2. Implant Design and Accuracy at Scripps Clinic
Conclusions Conclusions Conclusions Conclusions Conclusions Conclusions Conclusions Conclusions 1. 1. High sensor accuracy High sensor accuracy 2. 2. Robust measurements Robust measurements 3 Consistent 3. 3. Consistent Consistent in vivo Consistent in vivo in vivo measurements in vivo measurements measurements measurements 2. Implant Design and Accuracy 2. Implant Design and Accuracy at Scripps Clinic
Acknowledgments Acknowledgments Acknowledgments Acknowledgments Acknowledgments Acknowledgments Acknowledgments Acknowledgments SCORE Microstrain Clifford Colwell, MD Steve Arms Shantanu Patil, MD Christopher Townsend Juan Hermida, MD Nick Steklov D’Lima Zimmer, Inc OREF 2609 Janet Krevolin NIH R21 EB004581 Todd Johnson NIH R21 AR057561 SCORE 2. Implant Design and Accuracy 2. Implant Design and Accuracy at Scripps Clinic
Workshop Outline Workshop Outline Workshop Outline Workshop Outline Workshop Outline Workshop Outline Workshop Outline Workshop Outline 1. 1. Motivation for Competition (B.J. Motivation for Competition (B.J. Fregly Fregly) ) 2. Instrumented Implant Designs and Accuracy 2 Instrumented Implant Designs and Accuracy 2. Instrumented Implant Designs and Accuracy Instrumented Implant Designs and Accuracy (Darryl (Darryl D’Lima D’Lima) ) 3. 3. Experimental Data Collection (Thor Experimental Data Collection (Thor Besier Besier) ) at Scripps Clinic
3. Experimental Data Collection 3. Experimental Data Collection Thor Thor Besier Besier, Ph.D. , Ph.D. Research Director, Human Performance Lab Research Director, Human Performance Lab Department of Orthopaedics Department of Orthopaedics Stanford University, Stanford, CA Stanford University, Stanford, CA y, y, , , at Scripps Clinic
Organizers Organizers Organizers Organizers Organizers Organizers Organizers Organizers Main Organizers Main Organizers • Darryl Darryl D’Lima D’Lima, , Shiley Shiley Center at Scripps Clinic Center at Scripps Clinic • B.J B.J. . Fregly Fregly, University of Florida , University of Florida EMG EMG Data Data • Th • Thor Th Thor Besier B B Besier, Stanford University i i , Stanford University St St f f d U i d U i it it • David Lloyd, University of Western Australia David Lloyd, University of Western Australia Strength Data Strength Data Strength Data Strength Data • Marcus Marcus Pandy Pandy, University of Melbourne , University of Melbourne 3. Experimental Data Collection 3. Experimental Data Collection at Scripps Clinic
Subject Description Subject Description Subject Description Subject Description Subject Description Subject Description Subject Description Subject Description • Subject: JW Subject: JW • Gender: Male Gender: Male • A • Age: 83 yrs A Age: 83 yrs 83 83 • Height: 166 cm Height: 166 cm • Mass: 64 6 kg Mass: 64 6 kg Mass: 64.6 kg Mass: 64.6 kg • Right knee, generation I implant design Right knee, generation I implant design • Anthropometric data available from Anthropometric data available from p calibrated subject calibrated subject- -specific skeletal specific skeletal model ( model (Reinbolt Reinbolt et al et al ., 2008) ., 2008) 3. Experimental Data Collection 3. Experimental Data Collection at Scripps Clinic
Session Description Session Description Session Description Session Description Session Description Session Description Session Description Session Description • Gait Gait and other motion data collected in the morning. G it G it and other motion data collected in the morning. d d th th ti ti d t d t ll ll t d i t d i th th i i • Strength data collected in the afternoon. Strength data collected in the afternoon. • Fluoroscopic motion data reported previously (Zhao • Fluoroscopic motion data reported previously (Zhao Fluoroscopic motion data reported previously (Zhao Fluoroscopic motion data reported previously (Zhao et al et al ., 2007). ., 2007). 3. Experimental Data Collection 3. Experimental Data Collection at Scripps Clinic
Task Summary Task Summary Task Summary Task Summary Task Summary Task Summary Task Summary Task Summary • St ti t i l • Static trials St ti t i l Static trials • Inverse dynamic model calibration Inverse dynamic model calibration – Hip, knee, and ankle isolated motion Hip, knee, and ankle isolated motion Hip, knee, and ankle isolated motion Hip, knee, and ankle isolated motion Session 1: Gait Session 1: Gait Laboratory • Musculoskeletal model calibration Musculoskeletal model calibration • Medial Medial- -lateral load manipulation lateral load manipulation • Gait trials (4 types) Gait trials (4 types) • Isometric • Isometric, Session 2: Session 2: Isometric isokinetic Isometric, isokinetic isokinetic and passive isokinetic, and passive , and passive and passive Dynamometer dynamometry dynamometry Laboratory 3. Experimental Data Collection 3. Experimental Data Collection at Scripps Clinic
Gait Lab Data Gait Lab Data Gait Lab Data Gait Lab Data Gait Lab Data Gait Lab Data Gait Lab Data Gait Lab Data • Marker trajectories Marker trajectories M M k k t t j j t t i i – 8- -camera Motion Analysis system camera Motion Analysis system – Modified Cleveland Clinic marker set Modified Cleveland Clinic marker set • Ground reaction forces Ground reaction forces – 3 3 Bertec Bertec force plates force plates • Surface EMG S S Surface EMG f f G G – 14 muscles 14 muscles – Delsys Delsys Bagnoli y Bagnoli EMG system g EMG system y • Joint contact forces Joint contact forces – eKnee eKnee: : as described previously as described previously 3. Experimental Data Collection 3. Experimental Data Collection at Scripps Clinic
Dynamometer Lab Data Dynamometer Lab Data Dynamometer Lab Data Dynamometer Lab Data Dynamometer Lab Data Dynamometer Lab Data Dynamometer Lab Data Dynamometer Lab Data • Knee flexion angle Knee flexion angle – Goniometer Goniometer & & Biodex Biodex angle angle • Joint torque ( • Joint torque ( Joint torque ( gravity corrected Joint torque ( gravity corrected gravity corrected ) gravity corrected ) ) – Biodex Biodex • Surface EMG Surface EMG – 14 muscles 14 muscles – Delsys Delsys Bagnoli Bagnoli EMG system EMG system • Joint contact forces Joint contact forces – as described previously as described previously Biodex dynamometer 3. Experimental Data Collection 3. Experimental Data Collection at Scripps Clinic
Surface Marker Data Surface Marker Data Surface Marker Data Surface Marker Data Surface Marker Data Surface Marker Data Surface Marker Data Surface Marker Data 1-2 : Shoulder 1 2 : Shoulder 2 : Shoulder 2 : Shoulder 3- -4 : Elbow 4 : Elbow 5- -6 : Wrist 6 : Wrist 7- -8 : ASIS 8 : ASIS 9 : Sacrum 9 : Sacrum 10 10- -15 : Thigh superior, inferior, lateral 15 : Thigh superior, inferior, lateral 16 16- -19: Knee medial and lateral 19: Knee medial and lateral (static only) (static only) 20 20- -21 : Patella 21 : Patella 22 22- -27 : Shank superior, inferior, lateral 27 : Shank superior, inferior, lateral 28 28- -31: Ankle medial and lateral 31: Ankle medial and lateral (static only) (static only) 32 32-33 : Heel 32 33 : Heel 32 33 : Heel 33 : Heel 34 34- -37 : 37 : Midfoot Midfoot lateral and superior lateral and superior 38 38- -39 : Toe tip 39 : Toe tip 40 40- -43 : Toes medial and lateral 43 : Toes medial and lateral (static only) (static only) ( ( y) y) 3. Experimental Data Collection 3. Experimental Data Collection at Scripps Clinic
Surface EMG Data Surface EMG Data Surface EMG Data Surface EMG Data Surface EMG Data Surface EMG Data Surface EMG Data Surface EMG Data 1. 1 1. S Semimembranosus Semimembranosus S i i b b 9. 9 9. Tibi li Tibialis anterior Tibialis Tibi li anterior t t i i 2. 2. Biceps femoris Biceps femoris 10. 10. Peroneus Peroneus longus longus 3. 3. Vastus medialis Vastus medialis 11. Soleus 11. Soleus 4. 4. Vastus lateralis Vastus lateralis 12. 12. Adductor Adductor magnus magnus 5. 5. Rectus femoris Rectus femoris* * 13. 13. Gluteus Gluteus maximus maximus 6. 6 6. Medial Medial gastrocnemius Medial gastrocnemius Medial gastrocnemius gastrocnemius 14. Gluteus 14. 14 Gluteus 14 Gluteus medius Gluteus medius medius medius* 7. 7. Lateral Lateral gastrocnemius gastrocnemius 8. 8. Tensor fascia latae Tensor fascia latae* * Electrode placement consistent Electrode placement consistent with with Perotto Perotto & & Delagi Delagi (1980) (1980) * Indicates double Indicates double Indicates double-differential electrode Indicates double differential electrode differential electrode differential electrode 3. Experimental Data Collection 3. Experimental Data Collection at Scripps Clinic
EMG Preparation Trials EMG Preparation Trials EMG Preparation Trials EMG Preparation Trials EMG Preparation Trials EMG Preparation Trials EMG Preparation Trials EMG Preparation Trials • Skin shaved and • Skin shaved and Skin shaved and abrased Skin shaved and abrased abrased with gauze and then rubbed abrased with gauze and then rubbed with gauze and then rubbed with gauze and then rubbed with alcohol prior to electrode placement with alcohol prior to electrode placement • Manual restraint of subject during maximum isometric Manual restraint of subject during maximum isometric voluntary contractions (3 repetitions): voluntary contractions (3 repetitions): l l t t t t ti ti (3 (3 titi titi ) ) – – Hip flexion Hip flexion- -extension (standing) extension (standing) extension (seated w knee @ 80 ° ) – – Knee flexion Knee flexion- -extension (seated w knee @ 80 (seated w knee @ 40 ° ; ankle @ 0 ; ankle @ 0 ° – – Ankle Ankle dorsiflexion dorsiflexion (seated w knee @ 40 dorsiflexion dorsiflexion) ) (seated w knee @ 40 ° and standing tip – Ankle – Ankle plantarflexion plantarflexion (seated w knee @ 40 and standing tip- - toes) toes) (seated w knee @ 40 ° ) – – Ankle inversion Ankle inversion- -eversion eversion (seated w knee @ 40 ) • Resting signals obtained during quiet sitting Resting signals obtained during quiet sitting Resting signals obtained during quiet sitting Resting signals obtained during quiet sitting 3. Experimental Data Collection 3. Experimental Data Collection at Scripps Clinic
Static Trials Static Trials Static Trials Static Trials Static Trials Static Trials Static Trials Static Trials • Standing (toes forward, toes in, toes out) Standing (toes forward, toes in, toes out) Standing (toes forward, toes in, toes out) Standing (toes forward, toes in, toes out) • Sitting Sitting • Maximum isometric contraction Maximum isometric contraction 3. Experimental Data Collection 3. Experimental Data Collection at Scripps Clinic
Model Calibration Trials Model Calibration Trials Model Calibration Trials Model Calibration Trials Model Calibration Trials Model Calibration Trials Model Calibration Trials Model Calibration Trials • Passive seated leg rest Passive seated leg rest Passive seated leg rest Passive seated leg rest • Unloaded seated leg extension Unloaded seated leg extension • Loaded seated leg extension Loaded seated leg extension • One One- -legged standing legged standing • Two Two- -legged squat legged squat • Chair rise • Chair rise Chair rise Chair rise • Calf raise Calf raise 3. Experimental Data Collection 3. Experimental Data Collection at Scripps Clinic
Load Manipulation Trials Load Manipulation Trials Load Manipulation Trials Load Manipulation Trials Load Manipulation Trials Load Manipulation Trials Load Manipulation Trials Load Manipulation Trials • Varus • Varus Varus-valgus Varus-valgus valgus stress test valgus stress test stress test stress test • Stance initiation tests Stance initiation tests 3. Experimental Data Collection 3. Experimental Data Collection at Scripps Clinic
Gait Trials Gait Trials Gait Trials Gait Trials Gait Trials Gait Trials Gait Trials Gait Trials • Normal gait • Normal gait Normal gait Normal gait • Medial thrust gait Medial thrust gait • Walking pole gait Walking pole gait g p g p g g • Trunk sway gait Trunk sway gait 3. Experimental Data Collection 3. Experimental Data Collection at Scripps Clinic
Dynamometer Trials Dynamometer Trials Dynamometer Trials Dynamometer Trials Dynamometer Trials Dynamometer Trials Dynamometer Trials Dynamometer Trials • Isometric, passive, and Isometric, passive, and isokinetic isokinetic knee knee flexion/extension flexion/extension • Isometric, passive, and Isometric, passive, and isokinetic , p , p , , isokinetic ankle ankle plantarflexion plantarflexion/ /dorsiflexion dorsiflexion 3. Experimental Data Collection 3. Experimental Data Collection at Scripps Clinic
Data To Be Made Available Data To Be Made Available Data To Be Made Available Data To Be Made Available Data To Be Made Available Data To Be Made Available Data To Be Made Available Data To Be Made Available • EMG preparation trials EMG preparation trials • Static trials • Static trials Static trials Static trials • Model calibration trials Model calibration trials • Gait trials Gait trials Gait trials Gait trials • Dynamometer trials Dynamometer trials minus the minus the eKnee eKnee contact forces for competition contact forces for competition t i l t i l trials. trials. 3. Experimental Data Collection 3. Experimental Data Collection at Scripps Clinic
Additional Available Data Additional Available Data Additional Available Data Additional Available Data Additional Available Data Additional Available Data Additional Available Data Additional Available Data • Pre • Pre Pre and post Pre- and post and post surgery CT scans of knee region and post-surgery CT scans of knee region surgery CT scans of knee region surgery CT scans of knee region • Fluoroscopic motion measurements for Fluoroscopic motion measurements for treadmill gait (Zhao treadmill gait (Zhao et al et al ., 2007) ., 2007) 3. Experimental Data Collection 3. Experimental Data Collection at Scripps Clinic
Data Synchronization Data Synchronization Data Synchronization Data Synchronization Data Synchronization Data Synchronization Data Synchronization Data Synchronization Ground Reaction Forces EMG [3840Hz] [3840H ] [1000H ] [1000Hz] Marker Trajectories Joint Contact Forces Common sync signals – vertical GRF and [120Hz] [~50Hz] vastus lateralis EMG vastus lateralis EMG MATLAB MATLAB -Cubic spline interpolation -Cubic spline interpolation LP: Low pass cutoff frequency LP: Low pass cutoff frequency -Cross-correlation -Cross-correlation C C l l i i HP: High pass cutoff frequency -Filtering [4 th order Butterworth] -Filtering [4 th order Butterworth] LP:15Hz LP:15Hz Marker Trajectories Marker Trajectories j j LP:100Hz LP:100Hz Joint Contact Forces Joint Contact Forces Joint Contact Forces Joint Contact Forces HP:30Hz HP 30H [200Hz] [200Hz] [200Hz] [200Hz] Ground Reaction Forces Ground Reaction Forces EMG EMG [1000Hz] [1000Hz] [ [ ] ] [ [1000Hz] [ [1000Hz] ] ] 3. Experimental Data Collection 3. Experimental Data Collection at Scripps Clinic
Acknowledgments Acknowledgments Acknowledgments Acknowledgments Acknowledgments Acknowledgments Acknowledgments Acknowledgments D’Lima D’Lima Fregly Fregly Besier 3. Experimental Data Collection 3. Experimental Data Collection at Scripps Clinic
Workshop Outline Workshop Outline Workshop Outline Workshop Outline Workshop Outline Workshop Outline Workshop Outline Workshop Outline 1. 1. Motivation for Competition (B.J. Motivation for Competition (B.J. Fregly Fregly) ) 2. 2. Instrumented Implant Designs and Accuracy 2 Instrumented Implant Designs and Accuracy Instrumented Implant Designs and Accuracy Instrumented Implant Designs and Accuracy (Darryl (Darryl D’Lima D’Lima) ) 3. Experimental Data Collection (Thor 3. Experimental Data Collection (Thor Besier Besier) ) 4. 4. Modeling Results To Date (B.J. Modeling Results To Date (B.J. Fregly Fregly) at Scripps Clinic
4. Modeling Results to Date 4. Modeling Results to Date B.J. B.J. Fregly Fregly, Ph.D. g y g y , Ph.D. Department of Mechanical & Aerospace Engineering, Department of Mechanical & Aerospace Engineering, Department of Biomedical Engineering, and Department of Biomedical Engineering, and Department of Department of Orthopaedics Orthopaedics & Rehabilitation & Rehabilitation University of Florida, Gainesville, FL University of Florida, Gainesville, FL at Scripps Clinic
Previous Studies Previous Studies Previous Studies Previous Studies Previous Studies Previous Studies Previous Studies Previous Studies 1) 1) First First eKnee eKnee Data Data Set Set Study 1 Study 1 - Correlation between the knee adduction y Correlation between the knee adduction moment and medial contact force within the gait cycle moment and medial contact force within the gait cycle Study 2 Study 2 - Estimation of muscle and contact forces in Estimation of muscle and contact forces in the knee during gait the knee during gait the knee during gait the knee during gait 2) 2) Second Second eKnee eKnee Data Data Set Set Study 3 Study 3 Study 3 - Do changes in peak knee adduction moment Study 3 Do changes in peak knee adduction moment Do changes in peak knee adduction moment Do changes in peak knee adduction moment predict changes in peak medial contact force? predict changes in peak medial contact force? 4. Modeling Results to Date 4. Modeling Results to Date at Scripps Clinic
First First eKnee First eKnee First First eKnee First eKnee First First eKnee Data Set eKnee Data Set eKnee Data Set eKnee Data Set Data Set Data Set Data Set Data Set • Fluoroscopic motion data for treadmill gait, step Fluoroscopic motion data for treadmill gait, step p p g g , , p p up/down, kneel, and lunge up/down, kneel, and lunge • Video motion and ground reaction data for step Video motion and ground reaction data for step up/down and 5 gait patterns (normal, fast, slow, up/down and 5 gait patterns (normal fast slow up/down and 5 gait patterns (normal, fast, slow, up/down and 5 gait patterns (normal fast slow toe out, wide) toe out, wide) 4. Modeling Results to Date 4. Modeling Results to Date at Scripps Clinic
Study 1 Overview Study 1 Overview Study 1 Overview Study 1 Overview Study 1 Overview Study 1 Overview Study 1 Overview Study 1 Overview Gait Dynamic Analysis Contact Model In vivo kinematic In vivo kinematic measurement R Regression i Model In vivo load measurement Medial contact Adduction force moment 4. Modeling Results to Date 4. Modeling Results to Date at Scripps Clinic
Dynamic Contact Simulation Dynamic Contact Simulation Dynamic Contact Simulation Dynamic Contact Simulation Dynamic Contact Simulation Dynamic Contact Simulation Dynamic Contact Simulation Dynamic Contact Simulation In vivo knee force data Dynamic contact model Contact conditions In vivo knee motion data 4. Modeling Results to Date 4. Modeling Results to Date at Scripps Clinic
Dynamic Contact Simulation Dynamic Contact Simulation Dynamic Contact Simulation Dynamic Contact Simulation Dynamic Contact Simulation Dynamic Contact Simulation Dynamic Contact Simulation Dynamic Contact Simulation Simulation closely matches eKnee total contact In vivo knee force data force, eKnee A/P and M/L center of pressure, and fluoroscopic motion measurements. Dynamic contact model Contact conditions Zhao et al ., 2007a, Journal of In vivo knee motion data Orthopaedic Research Orthopaedic Research 4. Modeling Results to Date 4. Modeling Results to Date at Scripps Clinic
Knee Adduction Moment Knee Adduction Moment Knee Adduction Moment Knee Adduction Moment Knee Adduction Moment Knee Adduction Moment Knee Adduction Moment Knee Adduction Moment Are knee adduction moment changes within the Are knee adduction moment changes within the gait cycle highly correlated with changes in gait cycle highly correlated with changes in medial contact force? medial contact force? 4. Modeling Results to Date 4. Modeling Results to Date at Scripps Clinic
External External External Internal Correlation External External Internal Correlation External-Internal Correlation External External-Internal Correlation Internal Correlation Internal Correlation Internal Correlation Internal Correlation 4 e (%BW*H) Best 3 Worst Adduction Torque 2 2 1 0 -1 3 3 Total Medial Force (BW) 2 1 0 75 tio (%) 60 Medial Force Rat 45 30 15 0 0 0 20 20 40 40 60 60 80 80 100 100 0 0 20 20 40 40 60 60 80 80 100 100 Gait Cycle (%) Gait Cycle (%) 4. Modeling Results to Date 4. Modeling Results to Date at Scripps Clinic
Correlation Correlation Correlation Coefficients Correlation Correlation Coefficients Correlation Coefficients Correlation Coefficients Correlation Coefficients Coefficients Coefficients Coefficients Best Worst 2 R = 0.96 R = 0.83 Force (BW) 1.5 p < 0.001 p < 0.001 1 Medial 0.5 0 -1 1 0 0 1 1 2 2 3 3 4 4 -1 1 0 0 1 1 2 2 3 3 4 4 Adduction Torque (%BW*H) Adduction Torque (%BW*H) 4. Modeling Results to Date 4. Modeling Results to Date at Scripps Clinic
Correlation Coefficients Correlation Coefficients Correlation Coefficients Correlation Coefficients Correlation Coefficients Correlation Coefficients Correlation Coefficients Correlation Coefficients Best Worst 75 %) R = 0 95 R = 0.95 R = 0 73 R = 0.73 orce Ratio (% 60 p < 0.001 p < 0.001 45 Medial Fo 30 30 15 0 -1 1 0 0 1 1 2 2 3 3 4 4 -1 1 0 0 1 1 2 2 3 3 4 4 Adduction Torque (%BW*H) Adduction Torque (%BW*H) Zhao et al ., 2007b, Journal of Orthopaedic Research Orthopaedic Research 4. Modeling Results to Date 4. Modeling Results to Date at Scripps Clinic
Correlation Coefficients Correlation Coefficients Correlation Coefficients Correlation Coefficients Correlation Coefficients Correlation Coefficients Correlation Coefficients Correlation Coefficients Best Worst 75 %) R = 0.95 R = 0 95 R = 0 73 R = 0.73 orce Ratio (% 60 p < 0.001 p < 0.001 For all 15 trials analyzed together, R = 0.88 for 45 medial force and 0.83 for medial force ratio. medial force and 0 83 for medial force ratio Medial Fo 30 30 15 0 -1 1 0 0 1 1 2 2 3 3 4 4 -1 1 0 0 1 1 2 2 3 3 4 4 Adduction Torque (%BW*H) Adduction Torque (%BW*H) Zhao et al ., 2007b, Journal of Orthopaedic Research Orthopaedic Research 4. Modeling Results to Date 4. Modeling Results to Date at Scripps Clinic
Contact Force Sensitivity Contact Force Sensitivity Contact Force Sensitivity Contact Force Sensitivity Contact Force Sensitivity Contact Force Sensitivity Contact Force Sensitivity Contact Force Sensitivity Should highly accurate fluoroscopic kinematic Should highly accurate fluoroscopic kinematic measurements be directly input into contact measurements be directly input into contact models to calculate models to calculate in vivo in vivo contact forces? contact forces? 4. Modeling Results to Date 4. Modeling Results to Date at Scripps Clinic
Contact Force Sensitivity Contact Force Sensitivity Contact Force Sensitivity Contact Force Sensitivity Contact Force Sensitivity Contact Force Sensitivity Contact Force Sensitivity Contact Force Sensitivity 4. Modeling Results to Date 4. Modeling Results to Date at Scripps Clinic
Contact Force Sensitivity Contact Force Sensitivity Contact Force Sensitivity Contact Force Sensitivity Contact Force Sensitivity Contact Force Sensitivity Contact Force Sensitivity Contact Force Sensitivity Fregly et al ., 2008, Journal of Orthopaedic Research 4. Modeling Results to Date 4. Modeling Results to Date at Scripps Clinic
Study 2 Overview Study 2 Overview Study 2 Overview Study 2 Overview Study 2 Overview Study 2 Overview Study 2 Overview Study 2 Overview Muscle Forces Geometric Model Contact Forces Combined Model Inverse Dynamic Model 4. Modeling Results to Date 4. Modeling Results to Date at Scripps Clinic
Muscle & Contact Force Estimation Muscle & Contact Force Estimation Muscle & Contact Force Estimation Muscle & Contact Force Estimation Muscle & Contact Force Estimation Muscle & Contact Force Estimation Muscle & Contact Force Estimation Muscle & Contact Force Estimation No contact No contact 4. Modeling Results to Date 4. Modeling Results to Date at Scripps Clinic
Muscle & Contact Force Estimation Muscle & Contact Force Estimation Muscle & Contact Force Estimation Muscle & Contact Force Estimation Muscle & Contact Force Estimation Muscle & Contact Force Estimation Muscle & Contact Force Estimation Muscle & Contact Force Estimation No contact No contact Contact Contact Assumptions required about contact contributions t to inverse dynamic loads i d i l d 4. Modeling Results to Date 4. Modeling Results to Date at Scripps Clinic
Sequential Contact Force Sequential Contact Force Sequential Contact Force Sequential Contact Force Sequential Contact Force Sequential Contact Force Sequential Contact Force Sequential Contact Force Fast Normal Slow 2500 Medial Force (N) 2000 1500 1000 500 M 0 0 2500 eral Force (N) Experiment 2000 Model 1500 1000 500 500 Late 0 2500 Force (N) 2000 1500 1000 1000 Total 500 0 0 20 40 60 80 100 0 20 40 60 80 100 0 20 40 60 80 100 Gait Cycle (%) Gait Cycle (%) Gait Cycle (%) 4. Modeling Results to Date 4. Modeling Results to Date at Scripps Clinic
Sequential Contact Force Sequential Contact Force Sequential Contact Force Sequential Contact Force Sequential Contact Force Sequential Contact Force Sequential Contact Force Sequential Contact Force Fast Normal Slow 2500 Medial Force (N) 2000 1500 1000 500 M 0 0 Excellent contact force estimates, BUT 2500 eral Force (N) Experiment 2000 Model 1500 lateral collateral ligament tension tuned 1000 500 500 Late to match measured lateral contact forces. 0 2500 Force (N) 2000 1500 1000 1000 Total 500 0 0 20 40 60 80 100 0 20 40 60 80 100 0 20 40 60 80 100 Gait Cycle (%) Gait Cycle (%) Gait Cycle (%) Kim et al ., 2009, Journal of , , Orthopaedic Research 4. Modeling Results to Date 4. Modeling Results to Date at Scripps Clinic
Muscle & Contact Force Estimation Muscle & Contact Force Estimation Muscle & Contact Force Estimation Muscle & Contact Force Estimation Muscle & Contact Force Estimation Muscle & Contact Force Estimation Muscle & Contact Force Estimation Muscle & Contact Force Estimation Contact Contact No assumptions required about contact contributions t to inverse dynamic loads i d i l d 4. Modeling Results to Date 4. Modeling Results to Date at Scripps Clinic
Knee Contact Model Knee Contact Model Knee Contact Model Knee Contact Model Knee Contact Model Knee Contact Model Knee Contact Model Knee Contact Model + surrogate contact models of TF and PF joints 4. Modeling Results to Date 4. Modeling Results to Date at Scripps Clinic
Inverse Dynamic Model Inverse Dynamic Model Inverse Dynamic Model Inverse Dynamic Model Inverse Dynamic Model Inverse Dynamic Model Inverse Dynamic Model Inverse Dynamic Model • Full • Full Full body model Full-body model body model body model • Three Three- -dimensional dimensional • Engineering joints Engineering joints g g g j g j • Calibrated lower body joints Calibrated lower body joints • Calibrated full body masses Calibrated full body masses Reinbolt et al ., 2005, Journal of Biomechanics ; Reinbolt et al ., 2008, Medical Engineering & Physics 4. Modeling Results to Date 4. Modeling Results to Date at Scripps Clinic
Model Registration Model Registration Model Registration Model Registration Model Registration Model Registration Model Registration Model Registration 4. Modeling Results to Date 4. Modeling Results to Date at Scripps Clinic
Complete Knee Model Complete Knee Model Complete Knee Model Complete Knee Model Complete Knee Model Complete Knee Model Complete Knee Model Complete Knee Model • 11 muscles controlled by 8 11 muscles controlled by 8 activation signals activation signals • Muscle force = peak isometric Muscle force = peak isometric Muscle force peak isometric Muscle force peak isometric force x activation force x activation • Patellar ligament modeled as Patellar ligament modeled as 3 parallel springs 3 parallel springs 3 parallel springs 3 parallel springs • Grounded femur Grounded femur • 6 DOF 6 DOF patellofemoral patellofemoral joint (6 p joint (6 j j ( ( free DOFs) free DOFs) • 6 DOF 6 DOF tibiofemoral tibiofemoral joint (3 free joint (3 free and 3 prescribed DOFs) and 3 prescribed DOFs) and 3 prescribed DOFs) and 3 prescribed DOFs) 4. Modeling Results to Date 4. Modeling Results to Date at Scripps Clinic
Optimization Problems Optimization Problems Optimization Problems Optimization Problems Optimization Problems Optimization Problems Optimization Problems Optimization Problems “Constrained” formulations – in vivo contact forces used as additional constraints. “Unconstrained” formulations – in vivo contact forces not used as additional constraints. 4. Modeling Results to Date 4. Modeling Results to Date at Scripps Clinic
Predicted Motion Predicted Motion Predicted Motion Predicted Motion Predicted Motion Predicted Motion Predicted Motion Predicted Motion 4. Modeling Results to Date 4. Modeling Results to Date at Scripps Clinic
Load Decomposition Load Decomposition Load Decomposition Load Decomposition Load Decomposition Load Decomposition Load Decomposition Load Decomposition How do muscle and contact forces contribute How do muscle and contact forces contribute to the six inverse dynamic loads at the knee to the six inverse dynamic loads at the knee during gait? during gait? 4. Modeling Results to Date 4. Modeling Results to Date at Scripps Clinic
Load Decomposition Load Decomposition Load Decomposition Load Decomposition Load Decomposition Load Decomposition Load Decomposition Load Decomposition 300 30 150 15 Tx (Nm) Fx (N) 0 0 -150 -15 -300 300 -30 30 2000 30 y Net 1000 15 y (Nm) Fy (N) 0 0 x x Ty F -1000 -15 -2000 -30 z 300 30 150 15 ) Tz (Nm Fz (N) 0 0 -150 -15 -300 -30 0 25 50 75 100 0 25 50 75 100 Gait cycle (%) Gait cycle (%) 4. Modeling Results to Date 4. Modeling Results to Date at Scripps Clinic
Load Decomposition Load Decomposition Load Decomposition Load Decomposition Load Decomposition Load Decomposition Load Decomposition Load Decomposition 300 30 150 15 Tx (Nm) Fx (N) 0 0 -150 -15 -300 300 -30 30 2000 30 y Net 1000 15 Contact y (Nm) Fy (N) 0 0 x x Ty F -1000 -15 -2000 -30 z 300 30 150 15 ) Tz (Nm Fz (N) 0 0 -150 -15 -300 -30 0 25 50 75 100 0 25 50 75 100 Gait cycle (%) Gait cycle (%) 4. Modeling Results to Date 4. Modeling Results to Date at Scripps Clinic
Load Decomposition Load Decomposition Load Decomposition Load Decomposition Load Decomposition Load Decomposition Load Decomposition Load Decomposition 300 30 150 15 Tx (Nm) Fx (N) 0 0 -150 -15 -300 300 -30 30 2000 30 y Net 1000 15 Contact y (Nm) Fy (N) Muscle 0 0 x x Ty F -1000 -15 -2000 -30 z 300 30 150 15 ) Tz (Nm Fz (N) 0 0 -150 -15 -300 -30 0 25 50 75 100 0 25 50 75 100 Gait cycle (%) Gait cycle (%) Fregly et al ., 2009, SBC 4. Modeling Results to Date 4. Modeling Results to Date at Scripps Clinic
Muscle & Contact Force Estimates Muscle & Contact Force Estimates Muscle & Contact Force Estimates Muscle & Contact Force Estimates Muscle & Contact Force Estimates Muscle & Contact Force Estimates Muscle & Contact Force Estimates Muscle & Contact Force Estimates Does inclusion of explicit contact models in Does inclusion of explicit contact models in a musculoskeletal knee model improve the a musculoskeletal knee model improve the estimation of muscle and contact forces estimation of muscle and contact forces estimation of muscle and contact forces estimation of muscle and contact forces during gait? during gait? 4. Modeling Results to Date 4. Modeling Results to Date at Scripps Clinic
“Constrained” Contact Forces “Constrained” Contact Forces “Constrained” Contact Forces “Constrained” Contact Forces Constrained Contact Forces Constrained Contact Forces Constrained Contact Forces Constrained Contact Forces 4. Modeling Results to Date 4. Modeling Results to Date at Scripps Clinic
“Constrained” Contact Forces “Constrained” Contact Forces “Constrained” Contact Forces “Constrained” Contact Forces Constrained Contact Forces Constrained Contact Forces Constrained Contact Forces Constrained Contact Forces 100 N 100 N 100 N 100 N RMSE RMSE 4. Modeling Results to Date 4. Modeling Results to Date at Scripps Clinic
“Constrained” Contact Forces “Constrained” Contact Forces “Constrained” Contact Forces “Constrained” Contact Forces Constrained Contact Forces Constrained Contact Forces Constrained Contact Forces Constrained Contact Forces 4. Modeling Results to Date 4. Modeling Results to Date at Scripps Clinic
“Constrained” Muscle Forces “Constrained” Muscle Forces “Constrained” Muscle Forces “Constrained” Muscle Forces Constrained Muscle Forces Constrained Muscle Forces Constrained Muscle Forces Constrained Muscle Forces 4. Modeling Results to Date 4. Modeling Results to Date at Scripps Clinic
“Constrained” Muscle Forces “Constrained” Muscle Forces “Constrained” Muscle Forces “Constrained” Muscle Forces Constrained Muscle Forces Constrained Muscle Forces Constrained Muscle Forces Constrained Muscle Forces 4. Modeling Results to Date 4. Modeling Results to Date at Scripps Clinic
“Constrained” Muscle Forces “Constrained” Muscle Forces “Constrained” Muscle Forces “Constrained” Muscle Forces Constrained Muscle Forces Constrained Muscle Forces Constrained Muscle Forces Constrained Muscle Forces 4. Modeling Results to Date 4. Modeling Results to Date at Scripps Clinic
“Unconstrained” Contact Forces “Unconstrained” Contact Forces “Unconstrained” Contact Forces “Unconstrained” Contact Forces Unconstrained Contact Forces Unconstrained Contact Forces Unconstrained Contact Forces Unconstrained Contact Forces 4. Modeling Results to Date 4. Modeling Results to Date at Scripps Clinic
“Unconstrained” Contact Forces “Unconstrained” Contact Forces “Unconstrained” Contact Forces “Unconstrained” Contact Forces Unconstrained Contact Forces Unconstrained Contact Forces Unconstrained Contact Forces Unconstrained Contact Forces 4. Modeling Results to Date 4. Modeling Results to Date at Scripps Clinic
“Unconstrained” Contact Forces “Unconstrained” Contact Forces “Unconstrained” Contact Forces “Unconstrained” Contact Forces Unconstrained Contact Forces Unconstrained Contact Forces Unconstrained Contact Forces Unconstrained Contact Forces 4. Modeling Results to Date 4. Modeling Results to Date at Scripps Clinic
“Unconstrained” Contact Forces “Unconstrained” Contact Forces “Unconstrained” Contact Forces “Unconstrained” Contact Forces Unconstrained Contact Forces Unconstrained Contact Forces Unconstrained Contact Forces Unconstrained Contact Forces 4. Modeling Results to Date 4. Modeling Results to Date at Scripps Clinic
“Unconstrained” Muscle Forces “Unconstrained” Muscle Forces “Unconstrained” Muscle Forces “Unconstrained” Muscle Forces Unconstrained Muscle Forces Unconstrained Muscle Forces Unconstrained Muscle Forces Unconstrained Muscle Forces 4. Modeling Results to Date 4. Modeling Results to Date at Scripps Clinic
“Unconstrained” Muscle Forces “Unconstrained” Muscle Forces “Unconstrained” Muscle Forces “Unconstrained” Muscle Forces Unconstrained Muscle Forces Unconstrained Muscle Forces Unconstrained Muscle Forces Unconstrained Muscle Forces 4. Modeling Results to Date 4. Modeling Results to Date at Scripps Clinic
“Unconstrained” Muscle Forces “Unconstrained” Muscle Forces “Unconstrained” Muscle Forces “Unconstrained” Muscle Forces Unconstrained Muscle Forces Unconstrained Muscle Forces Unconstrained Muscle Forces Unconstrained Muscle Forces Fregly et al ., 2009, SBC 4. Modeling Results to Date 4. Modeling Results to Date at Scripps Clinic
Study 3 Overview Study 3 Overview Study 3 Overview Study 3 Overview Study 3 Overview Study 3 Overview Study 3 Overview Study 3 Overview Gait Analysis Regression Regression Model In vivo load measurement M di l Medial contact t t Add Adduction ti force moment 4. Modeling Results to Date 4. Modeling Results to Date at Scripps Clinic
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