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Plantar pressure distribution 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
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Plantar pressure distribution 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
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
The « normal » human foot How to measure plantar pressure? • 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) • Pressure insoles • practical problems • mainly for footwear testing
Overview sequence (each 33th frame) Analysis: visual overview or focus on areas of interest
1. peak pressure 3. pressure impulse 2. loading time Pressure (kPa) Time (s)
The 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.
Pressure results with healthy subjects and with patients Three trials of the same subject There is considerable variation even within a standard protocol!
A case: First Metatarsal head during various tasks slow walking normal walking fast walking running turn left turn right standing sitting plantar sitting ball Peak P Time Impulse There is huge variation between different daily activities
Peak pressure Peak pressure seems high at the hallux only Loading time The metatarsal region is loaded longer pressure impulse Impulses at 3rd metatarsal are close to those of the hallux!
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Discussion 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. For a first screening, normal walking can be analysed in 5 minutes (one trial per foot, visual evaluation of the pressure profile). 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. 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.
Thank you! 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.