k d aout - plantar pressure - dfsi 2006

1. Plantar pressure distributionPlantar pressure distribution
in the normal and in the diabetic foot.in the normal and in the diabetic foot.
An introduction to the use of plantar
pressure data in clinical and scientific research.
Kristiaan D’Août, PhD.
University of Antwerp, Belgium and
Centre for Research and Conservation, Belgium.
in collaboration with
Jain Institute of Vascular Sciences, Bangalore, India.
Dr. Suresh, Dr. Vivekanand, Dr. Vinaya
Diabetic Foot Society of India
Mumbai, 13-15 October 2006

2. Biomechanics of the foot (healthy & diabetic)Biomechanics of the foot (healthy & diabetic)
1. Kinematics: movements, gait patterns
2. Kinetics: forces involved
3. Tissue properties
4. Plantar pressures
• important in the diabetic foot
Ulcer formation through ischemia and/or tissue damage
• can be measured directly in a clinical setting

3. Pressure plate
• mobile plate (approx. 42 x 56 x 1 cm)
• contains discrete pressure sensors (0.5 x 0.7 cm)
• static and dynamic measurements (300 fps)
The « normal » human foot
Pressure insoles
• practical problems
• mainly for footwear testing
How to measure plantar pressure?How to measure plantar pressure?

4. Overview sequence (each 33th frame)
Analysis: visual overview or focus on areas of interest

5. Time (s)
Pressure(kPa)
2. loading time
3.
pressure
impulse
1. peak pressure

6. The three main pressure-related variables - clinical importanceThe three main pressure-related variables - clinical importance
1. Peak pressure
May be most responsible for tissue damage.
2. Loading time
May be most important in prolonged ischemia.
Brief ischemia can not be avoided.
3. Pressure impulse
Combines both; is recently shown to play a role in stress injuries,
along with loading rate.

7. Pressure results with healthy subjects and with patientsPressure results with healthy subjects and with patients
Three trials of the same subject
There is considerable
variation even within
a standard protocol!

8. slow
walking
normal
walking
fast
walking
running turn
left
turn right standing sitting
plantar
sitting
ball
Peak P
Time
Impulse
A case: First Metatarsal head during various tasksA case: First Metatarsal head during various tasks
There is huge variation between different daily activities

10. Peak pressure
Loading time
pressure impulse
Peak pressure seems high at the hallux only
The metatarsal region is loaded longer
Impulses at 3rd metatarsal are close
to those of the hallux!

11. #141 #156 #022
Indian, barefoot Indian, barefoot Indian, shod

12. Discussion and conclusionsDiscussion and conclusions
A pressure plate is a practical and highly useful tool in diabetic care:
in prevention, treatment and follow-up. Yet, it is a recent technique
and much research should be done.
It is also very valuable in orthotic and prosthetic tuning.
When time allows, normal daily behaviour of the patient should
be mimicked.
When time allows, peak pressure, loading time and pressure impulse
are all informative.
For a first screening, normal walking can be analysed in 5 minutes
(one trial per foot, visual evaluation of the pressure profile).
Plantar pressures are but one tool for the physician. Measurements
should be combined with other data (e.g. sensitometry), as there
are no unequivocal threshold « safe pressure » data to date.

13. kristiaan.daout@ua.ac.be
Acknowledgements
Dr. Suresh, Dr. Vivekanand, Dr. S. Praet, Dr. Rajendrakumar,
Dr. Vinaya, Ms. Usha, Mr. Uday, Mr. Albert.
The entire staff of the Jain Institute of Vascular Sciences, Bangalore.
Thank you!Thank you!