KNEEMO – ESR 3
Biofeedback: intervention & evaluation
Jaap Harlaar & Josien van den Noort
VU medical center, dept Rehabilitation medicine
MOVE Research Institute Amsterdam
Dieter Rosenbaum, Münster
Department of
Rehabilitation Medicine
... to make people walk better
Clinical Gait
Analysis
?
Intervention
Motion Capture in a gait lab > joint kinematics
GroundReactionForce vector
Quantifying Knee load:
Measuring the Knee Adduction Moment
Asymp
Severe
Knee OsteoArthritis
9
From Force to Tissue Stress
10
The simple case
FMed = FGRF x (1 + RGRF / RBF)
RBF = 0.09m
FGRF
FBF
FGRF = 800N
2,5
Fmed (BW)
2
1,5
RKAdM
1
RBF
0,5
RGRF
12
11
10
9
8
7
6
5
4
3
2
1
0
0
Rgrf (cm)
FMed
KAdM = FGRF x RKAdM
Lateral
Medial
Advanced Musculoskeletal modelling
- Aim: precise quantitative data on:
cartilage load intensity; location;and
dynamics
- alignment (> external load)
+ shape
+cartilage properties
+ EMG (> muscle forces)
 cartilage loading
KAdM is a proxy for Knee Load
Asymp
Severe
Baliunas et al. 2002, Mundermann et al. 2005, Thorp et al. 2006,
Rutherford et al. 2008, Foroughi et al. 2009
Kinematic strategies
- To unload the knee
Hunt et al. 2008, Simic et al. 2011, Shull et al. 2013, van den Noort et al. 2013
- E.g. toe-angle, trunk sway, step width, hip rotation
- Effect on ground reaction force and knee position
- Change knee adduction moment
Normal
Toe-in
Trunk sway
How gait modifications affect the KAdM
Normal
Toe-in
Trunk sway
van den Noort JC, Schaffers I, Snijders J, Harlaar J.
The effectiveness of voluntary modifications of gait
pattern to reduce the knee adduction moment.
Hum Mov Sci. 2013 Jun;32(3):412-24
Toe-Out
Role of visual feedback?
- May be effective for gait retraining
Barrios et al. 2010, Hunt et al. 2010, Shull et al. 2011, Wheeler et al. 2011
Gait Analysis in an VR environment
Overground gait lab
GRAIL by
Questions
1. What is the most effective type of feedback to
reduce knee load?
2. What is the best feedback parameter ?
GRAIL
- Gait Real-time Analysis Interactive Lab
- Virtual environment with visual feedback
- Motion capture system (Vicon)
- Dual-belt instrumented treadmill
- 17 healthy subjects
4 types of Feedback using 2 variables
- Kinetic: Knee adduction moment
- Kinematic: Hip internal rotation (promotes toeing in)
- Four feedback types
KAdM feedback
- Decrease KAdM:
-
Bar 55%
Polar 56%
Color 53%
Graph 49%
- Different types feedback:
- No effect
Hip angle feedback
- Increase hip endorotation
-
Bar 9o
Polar 10o
Color 8o
Graph 7o
- Different types feedback:
- No effect
Hip angle feedback
- However…
KAdM did not decrease
significantly with increased
hip endorotation
Conclusion
- Real-time visual feedback effective to modify gait
- ↓KAdM
- ↑hip endorotation
- Feedback type made no difference
- To lower the KAdM, direct but implicit feedback
is more effective than indirect (but explicit)
kinematic feedback
How to proceed in ESR 3 ?
Part1
- What are kinematic strategies used in lowering KAdM ?
- Will KOA patients perform alike ?
- Do their kinematic strategies differ from healthy ?
Part 2
- Will this training sustain ?
- Or is permanent feedback needed ?
- >> wearable sensors – ESR11
- based on personalized kinematic strategy & tactile feedback
- Does it promote functional gain ?
- Does it decelerate joint status decline ?
Discussion – part 2
-
Training intensity
Training frequency
Evaluation
Period
outcome measures
- KAdM
- Functional Gain
- ..
- pitfalls ?
KadM feedback to modify gait in KOA
A promising approach ?
Knee instability
Fitzgerald et al. 2004, Lewek et al. 2005, Felson et al. 2007, Schmitt et al. 2008
A measure of stability..
- Definition stability
to maintain a position or control movement under differing
external loads Schipplein and Andriacchi 1991
- Via active neuromuscular system & passive restraint
- Joint laxity
- No relation with self-reported instability Schmitt et al. 2008
- Not dynamic or functional
- Varus-valgus motion van der Esch et al. 2008
- Not related to muscle strength, joint proprioception, joint laxity
and skeletal alignment
Mechanical measure of stability
Gait sensitivity norm (robotics)
Hobbelen and Wisse 2008
Knie Flexie Hoek [graden]
100
80
60
40
20
0
0
100
200
300
400
Gangcyclus [%]
500
600
700
Knie Flexie Hoek [graden]
100
80
60
40
20
0
0
100
200
300
400
Gangcyclus [%]
500
600
700