150 likes | 309 Views
Impact of Orthotics on the Knee. Sara Mrowzinski. http://www.wmgh.net/article/foot-orthotics-72.asp. Introduction. Many people think of orthotics based on the off-the-shelf brands and do not realize how the orthotic works. What is an Orthotic?. Prevents abnormal movement
E N D
Impact of Orthotics on the Knee Sara Mrowzinski http://www.wmgh.net/article/foot-orthotics-72.asp
Introduction • Many people think of orthotics based on the off-the-shelf brands and do not realize how the orthotic works
What is an Orthotic? • Prevents abnormal movement • Various conditions can be relieved • Back, hip, knee, and ankle pain • Increase stability in joints • Increase biomechanical efficiency Right leg posterior view http://www.wellfeet.com/orthoticswork.htm
The Knee • Anatomically designed to flex and extend in the sagital plane (hinge joint) • Abnormal alignment at the foot can alter the forces when standing, walking, running, etc. to a transverse component
Pronation • 70% have over-pronation • Low arches • Effects travel up http://healthyfeetforlife.com/
Components Example: 150 lb person standing with the foot 20⁰ over-pronated Vertical Component: cos 20⁰ = (v / 150) v = 140.95 lb Transverse Component: sin 20⁰ = (t / 150) t = 51.3 lb
Correction • Force directed at the ankle into the posted orthotic http://www.orthoticsandal.com/AboutOS_Technology.html
Correction http://www.wellfeet.com/orthoticswork.htm http://www.trcc.com/au/solution/orthotics.html
“Effect of Inverted Orthoses on Lower-Extremity Mechanics in Runners” • Authors: • Dorsey S. Williams III • Irene McClay Davis • Stephen P. Baitch • Journal: • Medicine & Science in Sports & Exercise
Methods • 11 runners participated • All previously wore standard orthotics • Inversion orthotics posted at 15⁰ or 25⁰ • 3-D gait analysis • Joint motion • Joint kinetics • Ran at 3.35 m/s
Results • Results • Eversion moment not present before • Peak inversion moment significantly decreased • Increase in peak knee adduction • Other factors • Takes 5⁰ of change in post in order to have 1⁰ change effect
Example • Corrected with 54% improvement 20⁰ x .54 = 10.8⁰ cos 10.8⁰ = (vc / 150) vc = 147.34 lb Sin 10.8⁰ = (tc / 150) tc = 28.11 lb (28.11-51.3) x 100% = 45% decrease 51.3
Discussion • Impact of Padding • Decreases the force due to the compression of the padding • Orthotics have various amounts of padding depending on the person’s needs • At the ankle • Muscles affect stability • Rear foot movement and stress on the lateral knee needs to be studied more
Conclusions • These results suggest that an inversion orthotic may be more suitable than a standard orthotic for those with excess pronation http://www.syracuseorthotics.com/