Transitioning To Advanced Therapies For DFUs: Are Four Weeks And 50 Percent The Magic Numbers?

Chanel Houston, DPM, Samirah Mohammed, DPM, and Peter A. Blume, DPM, FACFAS

   Infection also impedes wound healing and is usually a consequence, rather than a cause, of ulceration. Infection allows the entry of microorganisms and subsequent multiplication of these microorganisms. In view of the fact that a diabetic foot infection has the potential to threaten the limb, appropriate diagnosis and therapy are urgently required. Having a way to evaluate healing potential for a particular therapy may help physicians change to more aggressive therapies earlier in the treatment process in efforts to drastically lower infection risks and prevent lower extremity amputations.

   While the understanding of the etiology of diabetic foot ulcers continues to progress, treatment therapies are advancing and amputation rates are declining.

Essential Diagnostic Considerations

Patients with diabetes who present with ulcerations on the foot usually have arterial insufficiency as evidenced by weakly or non-palpable pedal pulses, ischemic changes in the setting of gangrene, or skin atrophy.2 The ulcerations are typically located on the plantar aspect of the foot in weightbearing areas such as plantar metatarsal head regions. One may also find ulcerations at the distal aspect of pedal digits. This is due to the effects of motor neuropathy leading to retrograde buckling, which results in hammertoe formation, creating callosities and subsequent ulceration. Sensory neuropathy in the patient with diabetes can be characterized by a decreased or absent light touch sensation when one tests specific pedal areas with a 10-gram Semmes-Weinstein monofilament.2

   Osteomyelitis is always an underlying concern in the face of any ulceration, especially ulcerations that are chronic in nature. Radiographs, magnetic resonance imaging and triphasic bone scans are excellent diagnostic modalities, and can help tailor treatment protocols. Clinicians may also obtain wound cultures from infected wounds in efforts to optimize appropriate antibiotic therapy.2

   Vascular insufficiency is another consideration when dealing with diabetic ulcers.2,3 Various vascular studies can help assess the hemodynamics of vascular insufficiency. Unfortunately, one vascular study that is not very beneficial to the patient with diabetes is the ankle-brachial pressure index (ABI), which is often falsely elevated since patients with diabetes have calcified vessels that will not compress. Pulse volume recordings (PVRs) may prove more accurate in determining the significance of arterial disease in patients with diabetes than an ABI.2

   Magnetic resonance angiography is another useful tool for imaging atherosclerotic disease. Healing cannot occur in the presence of hypoxia, which can still persist even post-revascularization.1 Measuring the transcutaneous oxygen tension (TcPO2) proves helpful in these cases since a value above 30 mmHg suggests a high healing potential.2

A Pertinent Overview Of Treatment Options For Diabetic Foot Ulcerations

The cost to manage foot disorders is estimated at several billion dollars annually.4,5 Researchers have estimated that in the United States, 4.6 to 13.7 billion dollars are spent every year for the treatment of diabetic peripheral neuropathy and its complications. This dollar amount accounts for approximately 27 percent of the direct medical costs of diabetes.6 Successful clinical management of diabetic foot ulcers not only has the potential to reduce the cost of caring for these patients, it can improve the patient’s quality of life by reducing comorbidities.

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