There are an estimated 23.6 million people in the United States with diabetes, which is roughly 7.8% of the population.1 Although comprising less than 8% of the total population, people with diabetes account for more than 60% of nontraumatic lower limb amputations. In the year 2004, approximately 71,000 nontraumatic lower-limb amputations were performed in people with diabetes.2 The total annual economic cost of diabetes in 2004 was estimated to be $174 billion dollars.1 One of the major complications of diabetes is lower extremity amputation, which is often preceded by ulcer formation. It can be difficult to identify the cause of complications because there are so many factors that play a role in the development of foot problems. As the number of people diagnosed with diabetes and the number of foot complications associated with it continues to rise, it is becoming even more important to develop an understanding of the factors leading to ulceration and, ultimately, strategies to correct them.
This chapter reviews the management of diabetic foot ulceration. The etiology of diabetic foot complications and the evaluation and management of the diabetic foot are discussed. Treatment focuses on prevention of complications and managing complications that do occur.
In order to understand the development of diabetic foot ulceration, there must be a general understanding of the relationship between diabetes and neuropathy. Neuropathy associated with diabetes is referred to as polyneuropathy because it affects sensory, motor, and autonomic nerves. The nerve damage is typically symmetrical and starts with the feet, but it can also affect the hands. Neuropathy progresses from distal to proximal in what is referred to as a stocking and glove distribution. Sensory neuropathy is considered to be the leading cause of the development of diabetic foot ulcers.3 A prospective study by Boyko and colleagues showed loss of protective sensation (LOPS) to be independently related to foot ulcer risk.4 A person without sensation is at a much greater risk of developing an ulceration of the foot than a person with intact sensation. In some studies, LOPS was present in over 80% of diabetic patients with foot wounds.5 The cause of neuropathy in diabetics appears to be multifactorial. The basis for these changes appears to be related to hyperglycemia. Increased blood sugars are thought to damage the nerve directly and cause indirect damage by decreasing blood flow to the nerves.6 Evidence for nerve damage has been substantiated by nerve conduction studies that showed that diabetics had significantly more abnormalities than nondiabetics.7
There are several quick and easy ways to assess for protective sensation in the diabetic foot, including monofilament testing, tuning forks, and bioesthesiometers. These are discussed in detail in Chapter 7.
The second component of the peripheral nervous system that is affected by ...