Diabetic Foot Wound Assessment

It should not be assumed that a foot wound is a diabetic foot ulcer without ruling out other causes that can include venous ulcers (caused by improper functioning of venous valves, usually of the legs), ischemic ulcers (caused by arterial insufficiency), vasculitic ulcers (caused by inflammatory destruction of blood vessels), and malignancies.

A full examination and documentation of findings must be completed prior to a diagnosis of a foot wound. This ensures that the proper treatment plan is established. Foot ulcer evaluation should include assessment of neurological status, vascular status, and evaluation of the wound itself. This includes vital information such as wound size, shape, location, depth, base, and border, as well as signs of infection and deterioration.

Neurological status can be checked by using 10-gram monofilaments. This is an effective method of testing for the presence or absence of “protective sensation.” Patients are deemed to have lost their protective sensation if they cannot feel a 10-gram monofilament pressed against their skin. As a result of this lack of sensation, their foot is now “at risk.” This means the patient is more likely to damage their foot without feeling it. However, it is also necessary to test for vibratory sensation since approximately 10% of high risk patients can feel a monofilament, but have lost their vibratory perception. This can be done using a 128-Hz Tuning Fork. Both of these tests can be performed fairly quickly in any office setting. There are more in-depth analyses that can be performed in a neurological laboratory. These include using a vibrometer (a device designed to more accurately measure vibratory sense), assessing temperature sense, performing nerve conduction studies, and checking position sense and balance.

Vascular assessment is also an essential component in the evaluation of diabetic ulcers. This includes checking pedal pulses, the dorsalis pedis on the dorsum of the foot, and the posterior tibial pulse behind the medial malleolus. Patients with a non-palpable pedal pulse should seek further testing at a noninvasive vascular laboratory. The capillary filling time must also be assessed by pressing on a toe until the skin blanches, then timing the skin while it restores its color. A prolonged capillary filling time is considered anything greater than 5 seconds.