Dr. Metin Yavuz is one of the leading researchers on the biomechanical forces causing diabetic foot ulcers. He started his work at the Cleveland Clinic and has continued it at the Ohio College of Podiatric Medicine. Dr. Yavuz contributed a superb article to the May, 2010 issue of Lower Extremity Review entitled: Plantar Shear: Casting Light on Dark Matter. The article discusses a number of concepts. A critical one is that shear forces cause callusing, and calluses often are early warning signs of an ulcer. What makes matters worse is that a callus acts a “stress riser” – much like a pebble in a shoe. A person with a healthy foot notices the rise in stress. A person with diabetic neuropathy does not, and hence an ulcer can form.
Dr. Yavuz’s article also poses this dilemma: friction causes shear; however, friction is also necessary for ambulation – if your feet don’t grip you will slide as you do when walking on ice. That is precisely why we recommend that ShearBan® be used strategically at trouble spots and not on the entire plantar surface. We generally know where those trouble spots are – where calluses are forming. If shear offloading is strategically placed in those hotspots, gait efficiency can be maintained.