Workshop on Grand Challenge Competition Workshop on Grand Challenge - - PowerPoint PPT Presentation

Workshop on Grand Challenge Competition Workshop on Grand Challenge Competition t P di t I Vi K L d t P di t I Vi K L d

B.J. Fregly B.J. Fregly1, Darryl D. D’Lima , Darryl D. D’Lima2, and Thor Besier , and Thor Besier3

to Predict In Vivo Knee Loads to Predict In Vivo Knee Loads

g y g y y

1University of Florida, Gainesville, FL

University of Florida, Gainesville, FL

2Shiley Center at Scripps Clinic, La Jolla, CA

Shiley Center at Scripps Clinic, La Jolla, CA

3Stanford University, Stanford, CA

Stanford University, Stanford, CA

at Scripps Clinic

The Ultimate Goal The Ultimate Goal The Ultimate Goal The Ultimate Goal The Ultimate Goal The Ultimate Goal The Ultimate Goal The Ultimate Goal

• Why are we here this morning?

Why are we here this morning?

• What do we hope to achieve?

What do we hope to achieve?

Our ultimate goal is clinical utility of musculoskeletal computer models.

at Scripps Clinic

Motivation Motivation

The Ultimate Goal The Ultimate Goal The Ultimate Goal The Ultimate Goal The Ultimate Goal The Ultimate Goal The Ultimate Goal The Ultimate Goal

Osteoarthritis Stroke Muscle loads Cartilage loads Ligament loads Cerebral palsy Ligament loads Bone loads Motion patterns P l i Paraplegia

at Scripps Clinic

Motivation Motivation

Standard Treatment Design Standard Treatment Design Standard Treatment Design Standard Treatment Design Standard Treatment Design Standard Treatment Design Standard Treatment Design Standard Treatment Design

Currently, treatment design for Currently, treatment design for neuromusculoskeletal neuromusculoskeletal disorders involves the following steps: disorders involves the following steps: 1.

• 1. Observe what has worked well for previous patients.

Observe what has worked well for previous patients. 2.

• 2. Create implicit, mental model of patient.

Create implicit, mental model of patient. 3 G b t t t t t f t ti t G b t t t t t f t ti t 3.

• 3. Guess best treatment parameters for current patient.

Guess best treatment parameters for current patient. 4.

• 4. Apply treatment and iterate if possible/necessary.

Apply treatment and iterate if possible/necessary. T t t l i i hi hl T t t l i i hi hl bj ti bj ti Treatment planning is highly Treatment planning is highly subjective subjective and outcome is often and outcome is often variable variable for different patients. for different patients.

at Scripps Clinic

Motivation Motivation

Standard Treatment Design Standard Treatment Design Standard Treatment Design Standard Treatment Design Standard Treatment Design Standard Treatment Design Standard Treatment Design Standard Treatment Design

Currently, treatment design for Currently, treatment design for neuromusculoskeletal neuromusculoskeletal disorders involves the following steps: disorders involves the following steps: 1.

• 1. Observe what has worked well for previous patients.

Observe what has worked well for previous patients. 2.

• 2. Create implicit, mental model of patient.

Create implicit, mental model of patient. 3 G b t t t t t f t ti t G b t t t t t f t ti t

“One size fits none”

3.

• 3. Guess best treatment parameters for current patient.

Guess best treatment parameters for current patient. 4.

• 4. Apply treatment and iterate if possible/necessary.

Apply treatment and iterate if possible/necessary. T t t l i i hi hl T t t l i i hi hl bj ti bj ti Treatment planning is highly Treatment planning is highly subjective subjective and outcome is often and outcome is often variable variable for different patients. for different patients.

at Scripps Clinic

Motivation Motivation

Personalized Treatment Design Personalized Treatment Design Personalized Treatment Design Personalized Treatment Design Personalized Treatment Design Personalized Treatment Design Personalized Treatment Design Personalized Treatment Design

In the future, treatment design for In the future, treatment design for neuromusculoskeletal neuromusculoskeletal disorders could involve the following steps: disorders could involve the following steps: 1.

• 1. Observe what has worked well for previous patients.

Observe what has worked well for previous patients. 2.

• 2. Create explicit, computational model of patient.

Create explicit, computational model of patient. 3 P f i t l t t t ti t P f i t l t t t ti t ifi d l ifi d l 3.

• 3. Perform virtual treatments on patient

Perform virtual treatments on patient-specific model. specific model. 4.

• 4. Apply optimized treatment to patient.

Apply optimized treatment to patient. T t t l i b T t t l i b bj ti bj ti Treatment planning becomes Treatment planning becomes objective

• bjective

and outcome can be and outcome can be optimized

• ptimized for each patient.

for each patient.

at Scripps Clinic

Motivation Motivation

Personalized Treatment Design Personalized Treatment Design Personalized Treatment Design Personalized Treatment Design Personalized Treatment Design Personalized Treatment Design Personalized Treatment Design Personalized Treatment Design

In the future, treatment design for In the future, treatment design for neuromusculoskeletal neuromusculoskeletal disorders could involve the following steps: disorders could involve the following steps: 1.

• 1. Observe what has worked well for previous patients.

Observe what has worked well for previous patients. 2.

• 2. Create explicit, computational model of patient.

Create explicit, computational model of patient. 3 P f i t l t t t ti t P f i t l t t t ti t ifi d l ifi d l

The National Academy of Engineering has identified “personalized medicine” as one of

3.

• 3. Perform virtual treatments on patient

Perform virtual treatments on patient-specific model. specific model. 4.

• 4. Apply optimized treatment to patient.

Apply optimized treatment to patient. T t t l i b T t t l i b bj ti bj ti

p the 10 grand challenges of the 21st century.

Treatment planning becomes Treatment planning becomes objective

• bjective

and outcome can be and outcome can be optimized

• ptimized for each patient.

for each patient.

at Scripps Clinic

Motivation Motivation

Virtual Prototyping Virtual Prototyping Virtual Prototyping Virtual Prototyping Virtual Prototyping Virtual Prototyping Virtual Prototyping Virtual Prototyping

at Scripps Clinic

Motivation Motivation

Barriers to Clinical Utility Barriers to Clinical Utility Barriers to Clinical Utility Barriers to Clinical Utility Barriers to Clinical Utility Barriers to Clinical Utility Barriers to Clinical Utility Barriers to Clinical Utility

1) 1) Model Creation Model Creation )

• Automated patient

Automated patient-

• specific calibration

specific calibration

• No special engineering/programming skills

No special engineering/programming skills

• Computationally “fast”

Computationally “fast” Computationally fast Computationally fast 2) 2) Model Utilization Model Utilization

• “Clinically useful locomotion measures”

“Clinically useful locomotion measures”

• Identification of such measures

Identification of such measures

• Identification of such measures

Identification of such measures

• Calculation of such measures

Calculation of such measures 3) 3) Model Validation Model Validation

• Accuracy of calculated measures

Accuracy of calculated measures

• Challenge of

Challenge of unmeasurable unmeasurable quantities quantities

• Limitations in modeling capabilities

Limitations in modeling capabilities

at Scripps Clinic

g p g p

Motivation Motivation

“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 contact forces using contact forces using unvalidated unvalidated methods. methods.

• Significant research funding going to

Significant research funding going to g g g g g g g g 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.

at Scripps Clinic

Motivation Motivation

“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 contact forces using contact forces using unvalidated unvalidated methods. methods.

• Significant research funding going to

Significant research funding going to

Of course, the answer depends in part on the question we are trying to answer, but

g g g g g g g g projects that are making projects that are making unvalidated unvalidated predictions. predictions.

• Statements being made about clinical

Statements being made about clinical

q y g should we be more critical of our own work?

Statements being made about clinical Statements being made about clinical conditions and treatments based on conditions and treatments based on unvalidated unvalidated predictions. predictions.

at Scripps Clinic

Motivation Motivation

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.

at Scripps Clinic

Motivation Motivation

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.

at Scripps Clinic

Motivation Motivation

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. Th h i di t Th h i di t i i i i t f t t f t f t t f Though indirect, Though indirect, in vivo in vivo measurement of contact forces measurement of contact forces 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 y j p y j contact forces (Herzog contact forces (Herzog et al et al., 2003). ., 2003).

at Scripps Clinic

Motivation Motivation

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 Instrumented Implant Designs and Accuracy 2.

• 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) ) 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

• rganization of the competition.
• rganization 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 Instrumented Implant Designs and Accuracy 2.

• 2. 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 i d A D i d A

Darryl D. Darryl D. D’Lima D’Lima, M.D., Ph.D. , M.D., Ph.D.

Design and Accuracy Design and Accuracy

y Director, Director, Orthopaedic 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

at Scripps Clinic

• 2. Implant Design and Accuracy
• 2. Implant Design and Accuracy

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

at Scripps Clinic

• 2. Implant Design and Accuracy
• 2. Implant Design and Accuracy

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

at Scripps Clinic

• 2. Implant Design and Accuracy
• 2. Implant Design and Accuracy

Generation I Generation I Generation I Generation I Calibration Accuracy Calibration Accuracy Calibration Accuracy Calibration Accuracy

• NIST Load cell
• R2 > 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

at Scripps Clinic

• 2. Implant Design and Accuracy
• 2. Implant Design and Accuracy

Generation I Generation I Generation I Generation I Calibration Accuracy Calibration Accuracy Calibration Accuracy Calibration Accuracy

at Scripps Clinic

• 2. Implant Design and Accuracy
• 2. Implant Design and Accuracy

Generation I Generation I Generation I Generation I Calibration Accuracy Calibration Accuracy Calibration Accuracy Calibration Accuracy

• NIST Load cell
• R2 > 0.99
• AAE Axial Force < 1.5% FS

D’Lima +, J Biomech 2005

• AAE Center of Pressure < 1.9 mm

at Scripps Clinic

• 2. Implant Design and Accuracy
• 2. Implant Design and Accuracy

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 I t l P I d ti C il Internal Power Induction Coil Transmitting Antenna

Kirking +, J Biomech, 2005

g

at Scripps Clinic

• 2. Implant Design and Accuracy
• 2. Implant Design and Accuracy

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 I t l P I d ti C il

“eTibia”

Internal Power Induction Coil Transmitting Antenna

Kirking +, J Biomech, 2005

g

at Scripps Clinic

• 2. Implant Design and Accuracy
• 2. Implant Design and Accuracy

Generation II Generation II Generation II Generation II Calibration Accuracy Calibration Accuracy Calibration Accuracy Calibration Accuracy

at Scripps Clinic

• 2. Implant Design and Accuracy
• 2. Implant Design and Accuracy

Kirking +, J Biomech 2006

Generation II Generation II Generation II Generation II Calibration Accuracy Calibration Accuracy Calibration Accuracy Calibration Accuracy

Kirking +, J Biomech 2006

at Scripps Clinic

• 2. Implant Design and Accuracy
• 2. Implant Design and Accuracy

Generation II Generation II Generation II Generation II Calibration Accuracy Calibration Accuracy Calibration Accuracy Calibration Accuracy

Kirking +, J Biomech 2006

at Scripps Clinic

• 2. Implant Design and Accuracy
• 2. Implant Design and Accuracy

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

at Scripps Clinic

• 2. Implant Design and Accuracy
• 2. Implant Design and Accuracy

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

at Scripps Clinic

• 2. Implant Design and Accuracy
• 2. Implant Design and Accuracy

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

• St

t b t St t b t

• Start byte

Start byte

• Checksum byte

Checksum byte

• 2 ms delay

2 ms delay 2 ms delay 2 ms delay

at Scripps Clinic

• 2. Implant Design and Accuracy
• 2. Implant Design and Accuracy

Conclusions Conclusions Conclusions Conclusions Conclusions Conclusions Conclusions Conclusions

1.

• 1. High sensor accuracy

High sensor accuracy 2.

• 2. Robust measurements

Robust measurements 3 Consistent Consistent in vivo in vivo measurements measurements 3.

• 3. Consistent

Consistent in vivo in vivo measurements measurements

at Scripps Clinic

• 2. Implant Design and Accuracy
• 2. Implant Design and Accuracy

Acknowledgments Acknowledgments Acknowledgments Acknowledgments Acknowledgments Acknowledgments Acknowledgments Acknowledgments

SCORE Clifford Colwell, MD Shantanu Patil, MD Microstrain Steve Arms Christopher Townsend Juan Hermida, MD Nick Steklov D’Lima OREF 2609 NIH R21 EB004581 Zimmer, Inc Janet Krevolin Todd Johnson NIH R21 AR057561 SCORE

at Scripps Clinic

• 2. Implant Design and Accuracy
• 2. Implant Design and Accuracy

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 Instrumented Implant Designs and Accuracy 2.

• 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 Department of Orthopaedics 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

Th B i B i St f d U i it St f d U i it

• Thor

Thor Besier Besier, Stanford University , Stanford University

• 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

at Scripps Clinic

• 3. Experimental Data Collection
• 3. Experimental Data Collection

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

83 A 83

• Age: 83 yrs

Age: 83 yrs

• 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)

at Scripps Clinic

• 3. Experimental Data Collection
• 3. Experimental Data Collection

Session Description Session Description Session Description Session Description Session Description Session Description Session Description Session Description

G it G it d th ti d t ll t d i th i d th ti d t ll t d i th i

• Gait

Gait and other motion data collected in the morning. and other motion data collected in the morning.

• 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).

at Scripps Clinic

• 3. Experimental Data Collection
• 3. Experimental Data Collection

Task Summary Task Summary Task Summary Task Summary Task Summary Task Summary Task Summary Task Summary

• St ti t i l

St ti t i l

• Static trials

Static trials

• Inverse dynamic model calibration

Inverse dynamic model calibration

– Hip, knee, and ankle isolated motion

Hip, knee, and ankle isolated motion

Session 1: Gait

Hip, knee, and ankle isolated motion Hip, knee, and ankle isolated motion

• Musculoskeletal model calibration

Musculoskeletal model calibration

• Medial

Medial-

• lateral load manipulation

lateral load manipulation

Session 1: Gait Laboratory

• Gait trials (4 types)

Gait trials (4 types)

Session 2:

• Isometric

Isometric isokinetic isokinetic and passive and passive

Session 2: Dynamometer Laboratory

• Isometric,

Isometric, isokinetic isokinetic, and passive , and passive dynamometry dynamometry

at Scripps Clinic

• 3. Experimental Data Collection
• 3. Experimental Data Collection

Gait Lab Data Gait Lab Data Gait Lab Data Gait Lab Data Gait Lab Data Gait Lab Data Gait Lab Data Gait Lab Data

M k t j t i M k t j t i

• Marker trajectories

Marker trajectories

– 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

S f G S f G

• Surface EMG

Surface EMG

– 14 muscles

14 muscles

– Delsys

Delsys Bagnoli Bagnoli EMG system EMG system y g y

• Joint contact forces

Joint contact forces

– eKnee

eKnee: : as described previously as described previously

at Scripps Clinic

• 3. Experimental Data Collection
• 3. Experimental Data Collection

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 (gravity corrected

gravity corrected)

• Joint torque (

Joint torque (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

at Scripps Clinic

• 3. Experimental Data Collection
• 3. Experimental Data Collection

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 2 : Shoulder 1-2 : 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 33 : Heel 32 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)

at Scripps Clinic

• 3. Experimental Data Collection
• 3. Experimental Data Collection

( y) ( y)

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 S i b S i b 9 Tibi li Tibi li t i t i 1. 1. Semimembranosus Semimembranosus 2. 2. Biceps Biceps femoris femoris 3. 3. Vastus Vastus medialis medialis 9. 9. Tibialis Tibialis anterior anterior 10.

• 10. Peroneus

Peroneus longus longus 11.

• 11. Soleus

Soleus 4. 4. Vastus lateralis Vastus lateralis 5. 5. Rectus Rectus femoris femoris* * 6 Medial Medial gastrocnemius gastrocnemius 12.

• 12. Adductor

Adductor magnus magnus 13.

• 13. Gluteus

Gluteus maximus maximus 14 14 Gluteus Gluteus medius medius* 6. 6. Medial Medial gastrocnemius gastrocnemius 7. 7. Lateral Lateral gastrocnemius gastrocnemius 8. 8. Tensor fascia Tensor fascia latae latae* * 14.

• 14. Gluteus

Gluteus medius medius Electrode placement consistent Electrode placement consistent with with Perotto Perotto & & Delagi Delagi (1980) (1980) * Indicates double

Indicates double-differential electrode differential electrode

at Scripps Clinic

• 3. Experimental Data Collection
• 3. Experimental Data Collection

Indicates double

Indicates double differential electrode differential electrode

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 abrased abrased with gauze and then rubbed with gauze and then rubbed

• Skin shaved and

Skin shaved and abrased abrased 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 l t t ti (3 titi ) l t t ti (3 titi ) voluntary contractions (3 repetitions): voluntary contractions (3 repetitions):

– – Hip flexion

Hip flexion-

• extension (standing)

extension (standing)

– – Knee flexion

Knee flexion-

• extension (seated w knee @ 80

extension (seated w knee @ 80°)

– – Ankle

Ankle dorsiflexion dorsiflexion (seated w knee @ 40 (seated w knee @ 40°; ankle @ 0 ; ankle @ 0° dorsiflexion dorsiflexion) )

– – Ankle

Ankle plantarflexion plantarflexion (seated w knee @ 40 (seated w knee @ 40° and standing tip and standing tip-

• toes)

toes)

– – Ankle inversion

Ankle inversion-

• eversion

eversion (seated w knee @ 40 (seated w knee @ 40°) )

• Resting signals obtained during quiet sitting

Resting signals obtained during quiet sitting

at Scripps Clinic

• 3. Experimental Data Collection
• 3. Experimental Data Collection

Resting signals obtained during quiet sitting Resting signals obtained during quiet sitting

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

at Scripps Clinic

• 3. Experimental Data Collection
• 3. Experimental Data Collection

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

at Scripps Clinic

• 3. Experimental Data Collection
• 3. Experimental Data Collection

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-valgus valgus stress test stress test

• Varus

Varus-valgus valgus stress test stress test

• Stance initiation tests

Stance initiation tests

at Scripps Clinic

• 3. Experimental Data Collection
• 3. Experimental Data Collection

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 g p g

• Trunk sway gait

Trunk sway gait

at Scripps Clinic

• 3. Experimental Data Collection
• 3. Experimental Data Collection

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 isokinetic , p , , p , ankle ankle plantarflexion plantarflexion/ /dorsiflexion dorsiflexion

at Scripps Clinic

• 3. Experimental Data Collection
• 3. Experimental Data Collection

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.

at Scripps Clinic

• 3. Experimental Data Collection
• 3. Experimental Data Collection

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 and post and post surgery CT scans of knee region surgery CT scans of knee region

• Pre

Pre- and post and post-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)

at Scripps Clinic

• 3. Experimental Data Collection
• 3. Experimental Data Collection

Data Synchronization Data Synchronization Data Synchronization Data Synchronization Data Synchronization Data Synchronization Data Synchronization Data Synchronization

EMG [1000H ] Ground Reaction Forces [3840H ] [1000Hz] Marker Trajectories [120Hz] [3840Hz] Joint Contact Forces [~50Hz]

Common sync signals – vertical GRF and vastus lateralis EMG

MATLAB

• Cubic spline interpolation

C l i MATLAB

• Cubic spline interpolation

C l i

LP: Low pass cutoff frequency vastus lateralis EMG

• Cross-correlation
• Filtering [4th order Butterworth]
• Cross-correlation
• Filtering [4th order Butterworth]

Joint Contact Forces Joint Contact Forces Marker Trajectories Marker Trajectories

LP:15Hz HP 30H LP:15Hz LP:100Hz LP: Low pass cutoff frequency HP: High pass cutoff frequency

Joint Contact Forces [200Hz] Joint Contact Forces [200Hz] Ground Reaction Forces [1000Hz] Ground Reaction Forces [1000Hz] EMG [1000Hz] EMG [1000Hz] j [200Hz] j [200Hz]

HP:30Hz LP:100Hz

at Scripps Clinic

• 3. Experimental Data Collection
• 3. Experimental Data Collection

[ ] [ ] [ ] [ ]

Acknowledgments Acknowledgments Acknowledgments Acknowledgments Acknowledgments Acknowledgments Acknowledgments Acknowledgments

D’Lima D’Lima Fregly Fregly Besier

at Scripps Clinic

• 3. Experimental Data Collection
• 3. Experimental Data Collection

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 Instrumented Implant Designs and Accuracy 2.

• 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) ) 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. , Ph.D. g y g y

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 Correlation between the knee adduction y 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 - Do changes in peak knee adduction moment Do changes in peak knee adduction moment Study 3 Study 3 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?

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

First First eKnee eKnee Data Set Data Set First First eKnee eKnee Data Set Data Set First First eKnee eKnee Data Set Data Set First First eKnee eKnee Data Set Data Set

• Fluoroscopic motion data for treadmill gait, step

Fluoroscopic motion data for treadmill gait, step p g , p p g , 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)

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

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 Analysis Dynamic Contact Model In vivo kinematic In vivo kinematic measurement

R i

In vivo load measurement

Regression Model

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

Adduction moment Medial contact force

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 In vivo knee motion data Dynamic contact model Contact conditions

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

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

Simulation closely matches eKnee total contact force, eKnee A/P and M/L center of pressure, and fluoroscopic motion measurements.

In vivo knee motion data Dynamic contact model Contact conditions Zhao et al., 2007a, Journal of Orthopaedic Research

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

Orthopaedic Research

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?

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

External External Internal Correlation Internal Correlation External External Internal Correlation Internal Correlation External External-Internal Correlation Internal Correlation External External-Internal Correlation Internal Correlation

2 3 4 e (%BW*H)

Best Worst

3

• 1

1 2 Adduction Torque 1 2 3 Force (BW) Total Medial 60 75 tio (%) 15 30 45 Medial Force Rat 20 40 60 80 100 20 40 60 80 100

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

20 40 60 80 100 Gait Cycle (%) 20 40 60 80 100 Gait Cycle (%)

Correlation Correlation Coefficients Coefficients Correlation Correlation Coefficients Coefficients Correlation Correlation Coefficients Coefficients Correlation Correlation Coefficients Coefficients

2

Best Worst

1 1.5 Force (BW) R = 0.96 p < 0.001 R = 0.83 p < 0.001 0.5 Medial 1 1 2 3 4 1 1 2 3 4

• 1

1 2 3 4 Adduction Torque (%BW*H)

• 1

1 2 3 4 Adduction Torque (%BW*H)

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

Correlation Coefficients Correlation Coefficients Correlation Coefficients Correlation Coefficients Correlation Coefficients Correlation Coefficients Correlation Coefficients Correlation Coefficients

75 %) R = 0 95 R = 0 73

Best Worst

30 45 60

• rce Ratio (%

R = 0.95 p < 0.001 R = 0.73 p < 0.001 15 30 Medial Fo 1 1 2 3 4 1 1 2 3 4

• 1

1 2 3 4 Adduction Torque (%BW*H)

• 1

1 2 3 4 Adduction Torque (%BW*H)

Zhao et al., 2007b, Journal of Orthopaedic Research

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

Orthopaedic Research

Correlation Coefficients Correlation Coefficients Correlation Coefficients Correlation Coefficients Correlation Coefficients Correlation Coefficients Correlation Coefficients Correlation Coefficients

75 %) R = 0 95 R = 0 73

Best Worst

30 45 60

• rce Ratio (%

R = 0.95 p < 0.001 R = 0.73 p < 0.001

For all 15 trials analyzed together, R = 0.88 for medial force and 0 83 for medial force ratio

15 30 Medial Fo 1 1 2 3 4 1 1 2 3 4

medial force and 0.83 for medial force ratio.

• 1

1 2 3 4 Adduction Torque (%BW*H)

• 1

1 2 3 4 Adduction Torque (%BW*H)

Zhao et al., 2007b, Journal of Orthopaedic Research

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

Orthopaedic Research

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?

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

Contact Force Sensitivity Contact Force Sensitivity Contact Force Sensitivity Contact Force Sensitivity Contact Force Sensitivity Contact Force Sensitivity Contact Force Sensitivity Contact Force Sensitivity

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

Contact Force Sensitivity Contact Force Sensitivity Contact Force Sensitivity Contact Force Sensitivity Contact Force Sensitivity Contact Force Sensitivity Contact Force Sensitivity Contact Force Sensitivity

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

Fregly et al., 2008, Journal of Orthopaedic Research

Study 2 Overview Study 2 Overview Study 2 Overview Study 2 Overview Study 2 Overview Study 2 Overview Study 2 Overview Study 2 Overview

Geometric Model Muscle Forces Combined Model Contact Forces Inverse Dynamic Model

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

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

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

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 Contact No contact Contact Assumptions required about contact contributions t i d i l d

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

to inverse dynamic loads

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 500 1000 1500 2000 2500 Medial Force (N) Experiment Model M 500 1000 1500 2000 2500 eral Force (N) 500 Late 1000 1500 2000 2500 Force (N) 500 1000 Total 20 40 60 80 100 Gait Cycle (%) 20 40 60 80 100 Gait Cycle (%) 20 40 60 80 100 Gait Cycle (%)

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

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 500 1000 1500 2000 2500 Medial Force (N) Experiment Model M 500 1000 1500 2000 2500 eral Force (N)

Excellent contact force estimates, BUT lateral collateral ligament tension tuned

500 Late 1000 1500 2000 2500 Force (N)

to match measured lateral contact forces.

500 1000 Total 20 40 60 80 100 Gait Cycle (%) 20 40 60 80 100 Gait Cycle (%) 20 40 60 80 100 Gait Cycle (%)

Kim et al., 2009, Journal of

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

, , Orthopaedic Research

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 i d i l d

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

to inverse dynamic loads

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

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

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 body model body model

• Full

Full-body model body model

• Three

Three-

• dimensional

dimensional

• Engineering joints

Engineering joints g g j g 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

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

Model Registration Model Registration Model Registration Model Registration Model Registration Model Registration Model Registration Model Registration

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

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 joint (6 p 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)

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

and 3 prescribed DOFs) and 3 prescribed DOFs)

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.

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

Predicted Motion Predicted Motion Predicted Motion Predicted Motion Predicted Motion Predicted Motion Predicted Motion Predicted Motion

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

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?

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

Load Decomposition Load Decomposition Load Decomposition Load Decomposition Load Decomposition Load Decomposition Load Decomposition Load Decomposition

300

• 150

150 300 Fx (N) 30

• 15

15 30 Tx (Nm) Net

• 300

1000 2000 Fy (N)

• 30

15 30 y (Nm)

x y

• 2000
• 1000

F 150 300

• 30
• 15

Ty 15 30 )

x z

25 50 75 100

• 300
• 150

Gait cycle (%) Fz (N) 25 50 75 100

• 30
• 15

Gait cycle (%) Tz (Nm

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

Load Decomposition Load Decomposition Load Decomposition Load Decomposition Load Decomposition Load Decomposition Load Decomposition Load Decomposition

300

• 150

150 300 Fx (N) 30

• 15

15 30 Tx (Nm)

x y

Net Contact

• 300

1000 2000 Fy (N)

• 30

15 30 y (Nm)

x z

• 2000
• 1000

F 150 300

• 30
• 15

Ty 15 30 ) 25 50 75 100

• 300
• 150

Gait cycle (%) Fz (N) 25 50 75 100

• 30
• 15

Gait cycle (%) Tz (Nm

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

Load Decomposition Load Decomposition Load Decomposition Load Decomposition Load Decomposition Load Decomposition Load Decomposition Load Decomposition

300

• 150

150 300 Fx (N) 30

• 15

15 30 Tx (Nm)

x y

Net Contact Muscle

• 300

1000 2000 Fy (N)

• 30

15 30 y (Nm)

x z

• 2000
• 1000

F 150 300

• 30
• 15

Ty 15 30 ) 25 50 75 100

• 300
• 150

Gait cycle (%) Fz (N) 25 50 75 100

• 30
• 15

Gait cycle (%) Tz (Nm

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

Fregly et al., 2009, SBC

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?

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

“Constrained” Contact Forces “Constrained” Contact Forces “Constrained” Contact Forces “Constrained” Contact Forces Constrained Contact Forces Constrained Contact Forces Constrained Contact Forces Constrained Contact Forces

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

“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 RMSE 100 N RMSE

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

“Constrained” Contact Forces “Constrained” Contact Forces “Constrained” Contact Forces “Constrained” Contact Forces Constrained Contact Forces Constrained Contact Forces Constrained Contact Forces Constrained Contact Forces

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

“Constrained” Muscle Forces “Constrained” Muscle Forces “Constrained” Muscle Forces “Constrained” Muscle Forces Constrained Muscle Forces Constrained Muscle Forces Constrained Muscle Forces Constrained Muscle Forces

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

“Constrained” Muscle Forces “Constrained” Muscle Forces “Constrained” Muscle Forces “Constrained” Muscle Forces Constrained Muscle Forces Constrained Muscle Forces Constrained Muscle Forces Constrained Muscle Forces

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

“Constrained” Muscle Forces “Constrained” Muscle Forces “Constrained” Muscle Forces “Constrained” Muscle Forces Constrained Muscle Forces Constrained Muscle Forces Constrained Muscle Forces Constrained Muscle Forces

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

“Unconstrained” Contact Forces “Unconstrained” Contact Forces “Unconstrained” Contact Forces “Unconstrained” Contact Forces Unconstrained Contact Forces Unconstrained Contact Forces Unconstrained Contact Forces Unconstrained Contact Forces

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

“Unconstrained” Contact Forces “Unconstrained” Contact Forces “Unconstrained” Contact Forces “Unconstrained” Contact Forces Unconstrained Contact Forces Unconstrained Contact Forces Unconstrained Contact Forces Unconstrained Contact Forces

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

“Unconstrained” Contact Forces “Unconstrained” Contact Forces “Unconstrained” Contact Forces “Unconstrained” Contact Forces Unconstrained Contact Forces Unconstrained Contact Forces Unconstrained Contact Forces Unconstrained Contact Forces

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

“Unconstrained” Contact Forces “Unconstrained” Contact Forces “Unconstrained” Contact Forces “Unconstrained” Contact Forces Unconstrained Contact Forces Unconstrained Contact Forces Unconstrained Contact Forces Unconstrained Contact Forces

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

“Unconstrained” Muscle Forces “Unconstrained” Muscle Forces “Unconstrained” Muscle Forces “Unconstrained” Muscle Forces Unconstrained Muscle Forces Unconstrained Muscle Forces Unconstrained Muscle Forces Unconstrained Muscle Forces

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

“Unconstrained” Muscle Forces “Unconstrained” Muscle Forces “Unconstrained” Muscle Forces “Unconstrained” Muscle Forces Unconstrained Muscle Forces Unconstrained Muscle Forces Unconstrained Muscle Forces Unconstrained Muscle Forces

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

“Unconstrained” Muscle Forces “Unconstrained” Muscle Forces “Unconstrained” Muscle Forces “Unconstrained” Muscle Forces Unconstrained Muscle Forces Unconstrained Muscle Forces Unconstrained Muscle Forces Unconstrained Muscle Forces

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

Fregly et al., 2009, SBC

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

In vivo load measurement

Regression Model

Add ti M di l t t Adduction moment Medial contact force

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

Joint Contact Forces Joint Contact Forces Joint Contact Forces Joint Contact Forces Joint Contact Forces Joint Contact Forces Joint Contact Forces Joint Contact Forces

How do medial thrust and walking pole gait How do medial thrust and walking pole gait affect medial and lateral contact force? affect medial and lateral contact force? affect medial and lateral contact force? affect medial and lateral contact force?

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

Medial Contact Force Medial Contact Force Medial Contact Force Medial Contact Force Medial Contact Force Medial Contact Force Medial Contact Force Medial Contact Force

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

Medial Contact Force Medial Contact Force Medial Contact Force Medial Contact Force Medial Contact Force Medial Contact Force Medial Contact Force Medial Contact Force

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

Medial Contact Force Medial Contact Force Medial Contact Force Medial Contact Force Medial Contact Force Medial Contact Force Medial Contact Force Medial Contact Force

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

Medial Contact Force Medial Contact Force Medial Contact Force Medial Contact Force Medial Contact Force Medial Contact Force Medial Contact Force Medial Contact Force

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

Medial Contact Force Medial Contact Force Medial Contact Force Medial Contact Force Medial Contact Force Medial Contact Force Medial Contact Force Medial Contact Force

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

Lateral Contact Force Lateral Contact Force Lateral Contact Force Lateral Contact Force Lateral Contact Force Lateral Contact Force Lateral Contact Force Lateral Contact Force

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

Lateral Contact Force Lateral Contact Force Lateral Contact Force Lateral Contact Force Lateral Contact Force Lateral Contact Force Lateral Contact Force Lateral Contact Force

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

Lateral Contact Force Lateral Contact Force Lateral Contact Force Lateral Contact Force Lateral Contact Force Lateral Contact Force Lateral Contact Force Lateral Contact Force

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

Lateral Contact Force Lateral Contact Force Lateral Contact Force Lateral Contact Force Lateral Contact Force Lateral Contact Force Lateral Contact Force Lateral Contact Force

Fregly et al 2009 Journal of

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

Fregly et al., 2009, Journal of Orthopaedic Research

Knee Adduction Moment Knee Adduction Moment Knee Adduction Moment Knee Adduction Moment Knee Adduction Moment Knee Adduction Moment Knee Adduction Moment Knee Adduction Moment

Does the knee adduction moment predict no Does the knee adduction moment predict no change in the first peak and a significant reduction change in the first peak and a significant reduction in the second peak of medial contact force? in the second peak of medial contact force?

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

Knee Adduction Moment Knee Adduction Moment Knee Adduction Moment Knee Adduction Moment Knee Adduction Moment Knee Adduction Moment Knee Adduction Moment Knee Adduction Moment

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

Knee Adduction Moment Knee Adduction Moment Knee Adduction Moment Knee Adduction Moment Knee Adduction Moment Knee Adduction Moment Knee Adduction Moment Knee Adduction Moment

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

Medial Contact Force Medial Contact Force Medial Contact Force Medial Contact Force Medial Contact Force Medial Contact Force Medial Contact Force Medial Contact Force

Inconsistent with adduction moment changes !

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

Optimal Axial Rotation Optimal Axial Rotation Optimal Axial Rotation Optimal Axial Rotation Optimal Axial Rotation Optimal Axial Rotation Optimal Axial Rotation Optimal Axial Rotation

Consistent with medial contact force changes

Optimal rotation: 20 deg

• 5 deg

15 deg Optimal R2 value: 0 57 0 70 0 74

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

Optimal R value: 0.57 0.70 0.74

Knee Extension Moment Knee Extension Moment Knee Extension Moment Knee Extension Moment Knee Extension Moment Knee Extension Moment Knee Extension Moment Knee Extension Moment

Walter et al., 2009, SBC

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

Conclusions Conclusions Conclusions Conclusions Conclusions Conclusions Conclusions Conclusions

1.

• 1. Inclusion of explicit contact models in a

Inclusion of explicit contact models in a musculo musculo-

• skeletal knee model allows additional inverse

skeletal knee model allows additional inverse skeletal knee model allows additional inverse skeletal knee model allows additional inverse dynamic loads to be used as constraints and dynamic loads to be used as constraints and alters the muscle and contact force estimates. alters the muscle and contact force estimates. 2.

• 2. The second

The second eKnee eKnee data set provides the unique data set provides the unique

• pportunity to evaluate muscle and contact force
• pportunity to evaluate muscle and contact force

predictions for gait patterns that modulate medial predictions for gait patterns that modulate medial predictions for gait patterns that modulate medial predictions for gait patterns that modulate medial contact force. contact force.

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

Acknowledgments Acknowledgments Acknowledgments Acknowledgments Acknowledgments Acknowledgments Acknowledgments Acknowledgments

NSF CAREER award CBET 0239042 and NSF CAREER award CBET 0239042 and NSF award CBET 0602996 NSF award CBET 0602996

at Scripps Clinic

• 4. Modeling Results to Date
• 4. Modeling Results to Date

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 Instrumented Implant Designs and Accuracy 2.

• 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) ) 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) )

at Scripps Clinic

• 5. Logistics of Competition
• 5. Logistics of Competition

Darryl D. Darryl D. D’Lima D’Lima, M.D., Ph.D. , M.D., Ph.D. y Director, Director, Orthopaedic 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

Announcement of Competition Announcement of Competition Announcement of Competition Announcement of Competition Announcement of Competition Announcement of Competition Announcement of Competition Announcement of Competition

Focus on the musculoskeletal modeling community: Focus on the musculoskeletal modeling community:

• BIOMCH

BIOMCH-

• L Newsgroup

L Newsgroup

• ISB Technical Group on Computer Simulation

ISB Technical Group on Computer Simulation Newsgroup Newsgroup

• ASME Summer Bioengineering Conference

ASME Summer Bioengineering Conference g g g g

• American Society of Biomechanics Newsletter

American Society of Biomechanics Newsletter

• International Society of Biomechanics Newsletter

International Society of Biomechanics Newsletter

• SimTK.org e

SimTK.org e-

• mail list

mail list

• Personal invitation

Personal invitation

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• 5. Logistics of Competition
• 5. Logistics of Competition

Journal of Journal of Orthopaedic Orthopaedic Research Research Journal of Journal of Orthopaedic Orthopaedic Research Research Journal of Journal of Orthopaedic Orthopaedic Research Research Journal of Journal of Orthopaedic Orthopaedic Research Research

• Publication

Publication

– Make data available

Make data available

– Announce competition

Announce competition

– Peer reviewed

Peer reviewed

– Tim Wright, PhD (Editor)

Tim Wright, PhD (Editor)

• Data

Data A th t i t A th t i t

– Anthropometric measurements

Anthropometric measurements

– Marker positions

Marker positions

– Ground reaction forces

Ground reaction forces

– EMG signals

EMG signals

– Limited

Limited tibial tibial contact forces contact forces

– OpenSim

OpenSim model of subject and model of subject and

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• 5. Logistics of Competition
• 5. Logistics of Competition

p j j implant geometry implant geometry

www SimTK org www SimTK org www SimTK org www SimTK org www.SimTK.org www.SimTK.org www.SimTK.org www.SimTK.org

• Registration

Registration g

• Data published in

Data published in J J Orthop Orthop Research Research

• Contact models of implant components

Contact models of implant components

• Videos of data collection

Videos of data collection

• Post

Post-

• competition implant contact forces

competition implant contact forces

• Special requests

Special requests

• Special requests

Special requests

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• 5. Logistics of Competition
• 5. Logistics of Competition

Predicted Quantities Predicted Quantities Predicted Quantities Predicted Quantities Predicted Quantities Predicted Quantities Predicted Quantities Predicted Quantities

Time histories of Time histories of Time histories of Time histories of

• Medial contact force

Medial contact force

• Lateral contact force

Lateral contact force Lateral contact force Lateral contact force for selected gait trials for selected gait trials

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• 5. Logistics of Competition
• 5. Logistics of Competition

Abstract Submission Abstract Submission Abstract Submission Abstract Submission Abstract Submission Abstract Submission Abstract Submission Abstract Submission

• Introduction

Introduction Introduction Introduction

• Methods

Methods

• Results

Results

• Discussion

Discussion

• Predictions

Predictions – – upload to SimTK.org upload to SimTK.org

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• 5. Logistics of Competition
• 5. Logistics of Competition

Review Criteria Review Criteria Review Criteria Review Criteria Review Criteria Review Criteria Review Criteria Review Criteria

• Reviewers

Reviewers

• Significance (0

Significance (0-3 points) 3 points) Significance (0 Significance (0 3 points) 3 points)

• Technical content (0

Technical content (0-

• 5 points)

5 points)

• Completeness (0

Completeness (0-

• 2 points)

2 points) p ( p ( p ) p )

• Accuracy (0

Accuracy (0-

• 5 points

5 points -

• new)

new)

• Novelty (0

Novelty (0-

• 5 points

5 points -

• new)

new)

• Max 20 points

Max 20 points

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• 5. Logistics of Competition
• 5. Logistics of Competition

Special Session Special Session Special Session Special Session Special Session Special Session Special Session Special Session

• Top scoring papers given podium presentations

Top scoring papers given podium presentations in a special session at next year’s conference. in a special session at next year’s conference.

• More than one special session may be

More than one special session may be

• More than one special session may be

More than one special session may be possible. possible.

• Participants present models and predictions.

Participants present models and predictions.

• Actual contact force measurements revealed at

Actual contact force measurements revealed at end of special session. end of special session.

• Post

Post-mortem mini mortem mini-workshop after special workshop after special Post Post mortem mini mortem mini workshop after special workshop after special session to evaluate competition and lessons session to evaluate competition and lessons learned. learned.

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• 5. Logistics of Competition
• 5. Logistics of Competition

Award Presentation Award Presentation Award Presentation Award Presentation Award Presentation Award Presentation Award Presentation Award Presentation

• Certificate

Certificate

• Cash prize (hopefully)

Cash prize (hopefully)

• Manuscript submitted to

Manuscript submitted to J J Orthop Orthop Research Research (investigating) (investigating) (investigating) (investigating)

• Runners ups

Runners ups

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• 4. Modeling Results to Date
• 4. Modeling Results to Date

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 Instrumented Implant Designs and Accuracy 2.

• 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) ) 4.

• 4. Modeling Results To Date (B.J.

Modeling Results To Date (B.J. Fregly Fregly) 5.

• 5. Logistics of Competition (Darryl

Logistics of Competition (Darryl D’Lima D’Lima) ) 6.

• 6. Questions and Answers (All)

Questions and Answers (All)

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• 6. Questions and Answers
• 6. Questions and Answers

B.J. B.J. Fregly Fregly, Ph.D., University of Florida and , Ph.D., University of Florida and g y g y y Darryl Darryl D’Lima D’Lima, M.D., Ph.D., , M.D., Ph.D., Shiley Shiley Center at Scripps Clinic Center at Scripps Clinic

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Data Related Questions Data Related Questions Data Related Questions Data Related Questions Data Related Questions Data Related Questions Data Related Questions Data Related Questions

1.

• 1. For which tasks should

For which tasks should in vivo in vivo contact force data be contact force data be released BEFORE the competition? released BEFORE the competition?

• EMG preparation trials?

EMG preparation trials?

• Static trials?

Static trials? Static trials? Static trials?

• Model calibration trials?

Model calibration trials?

• Gait trials (4 patterns)?

Gait trials (4 patterns)? D t t i l ? D t t i l ?

• Dynamometer trials?

Dynamometer trials?

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• 6. Questions and Answers
• 6. Questions and Answers

Data Related Questions Data Related Questions Data Related Questions Data Related Questions Data Related Questions Data Related Questions Data Related Questions Data Related Questions

2.

• 2. Are the current filter cutoff and output frequencies

Are the current filter cutoff and output frequencies acceptable for the data? acceptable for the data? acceptable for the data? acceptable for the data?

Experimental Quantity Input Frequency (Hz) Filter Frequency (Hz) Output Frequency (Hz) Marker positions 120 Low pass 15 200 eKnee forces ~50 Low pass 15 200 Ground reactions 3840 Low pass 100 1000 Ground reactions 3840 Low pass 100 1000 EMG signals 1000 High pass 30 1000

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• 6. Questions and Answers
• 6. Questions and Answers

Model Related Questions Model Related Questions Model Related Questions Model Related Questions Model Related Questions Model Related Questions Model Related Questions Model Related Questions

1.

• 1. Should we provide our surrogate contact model in

Should we provide our surrogate contact model in Matlab Matlab so that every participant can calculate so that every participant can calculate tibiofemoral tibiofemoral and and patellofemoral patellofemoral contact forces easily? contact forces easily? 2.

• 2. If so, how should muscle forces be applied to it?

If so, how should muscle forces be applied to it? 3.

• 3. Should we provide an

Should we provide an O Si O Si i f th i f th OpenSim OpenSim version of the version of the geometric/inverse dynamic geometric/inverse dynamic knee model? knee model? 4.

• 4. What other modeling

What other modeling information is needed? information is needed?

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• 6. Questions and Answers
• 6. Questions and Answers

Organization Related Questions Organization Related Questions Organization Related Questions Organization Related Questions Organization Related Questions Organization Related Questions Organization Related Questions Organization Related Questions

1.

• 1. Should accuracy be the primary scoring criterion, or

Should accuracy be the primary scoring criterion, or y p y g y p y g should the proposed 5 scoring criteria (significance, should the proposed 5 scoring criteria (significance, technical content, completeness, accuracy, and technical content, completeness, accuracy, and novelty) be used? novelty) be used? novelty) be used? novelty) be used? 2.

• 2. Should selection of the winning paper be subjective

Should selection of the winning paper be subjective

• r objective? If subjective, who should do it?
• r objective? If subjective, who should do it?

j j j j

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• 6. Questions and Answers
• 6. Questions and Answers

Other Relevant Questions Other Relevant Questions Other Relevant Questions Other Relevant Questions Other Relevant Questions Other Relevant Questions Other Relevant Questions Other Relevant Questions

What questions and suggestions do you have for us? What questions and suggestions do you have for us?

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• 6. Questions and Answers
• 6. Questions and Answers