Tissue Volumizing: Can We Create An Internal Orthotic?

By Stephanie C.S. Wu, DPM, MS, Nicholas J. Bevilacqua, DPM, Lee C. Rogers, DPM, and David G. Armstrong, DPM, PhD

     The rapid rise in the incidence of diabetes, a serious lifelong condition, is of alarming concern to healthcare professionals. Recent data from the Centers of Disease Control and Prevention (CDC) estimate that approximately 20.8 million people, roughly 7 percent of the United States population, have diabetes.1 In 2005 alone, 1.5 million new cases of diabetes were diagnosed in people aged 20 years or older.1 Diabetes mellitus is a multifaceted disease and foot ulceration, which often results in lower extremity amputations, is one of the most common complications.2-5      The lifetime risk of a person with diabetes developing a foot ulcer has been estimated at 15 percent.6 However, recent studies have shown the annual population-based incidence ranges from 1.0 to 4.1 percent and the prevalence ranges from 4 to 10 percent, suggesting the incidence may be as high as 25 percent.3 Diabetic foot ulcers frequently become infected and are a major cause of hospital admissions.4,5 They also account for more than half of non-traumatic lower limb amputations in this patient population.4 Diabetic foot ulcers impose tremendous medical and financial burdens on our healthcare system with costs conservatively estimated up to $45,000 per patient. These estimates, however, do not include the deleterious psychosocial effects on the patient’s quality of life because of impaired mobility and substantial loss of productivity.8-11      The etiology of foot ulcerations in people with diabetes is generally associated with the presence of peripheral neuropathy and cycles of repetitive stress generated by normal ambulatory activities.12 During ambulation, the foot is exposed to moderate or high pressure and shear forces. Foot deformities, limited joint mobility, partial foot amputations and other structural deformities often predispose patients with diabetic peripheral neuropathy to abnormal weightbearing, areas of concentrated pressure and abnormal shear forces that significantly increase their risk of ulceration.13-15 Patients with previous foot ulcerations can withstand fewer cycles of stress to their feet before reulcerating.16 Peripheral neuropathy is usually profound before leading to a loss of protective sensation (LOPS). The consequent vulnerability to physical and thermal trauma thereby increases the risk of foot ulceration sevenfold.17-18      In one study of patients with peripheral neuropathy, 28 percent with high plantar pressure developed a foot ulcer during a 2.5 year follow-up, compared to none with normal plantar pressure.19 The frequency, magnitude and duration of forces to the plantar aspect of the foot comprise the etiologic criteria to assess ulcer formation and consider strategies to prevent and heal plantar foot ulcerations.12 Subsequently, many studies have linked plantar pressures to the sites of ulceration in neuropathic patients.20-23

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