Healing Foot Ulcers -- Full-Length Doctor's Interview
Reported October 31, 2005

Jeffrey Johnson, M.D., discusses healing foot ulcers for people with diabetes.
Ivanhoe Broadcast News Transcript with
Jeffrey Johnson, M.D., Orthopedic Foot and Ankle Surgeon,
Barnes-Jewish Hospital at Washington University School of Medicine, St. Louis,
TOPIC: Healing Foot Ulcers

How many people have diabetes in the United States, and is it increasing?

Dr. Johnson: We estimate about 18 million people in the United States have diabetes. The number is increasing as the years go on and there's actually significant projection over the next 50 years. The thing is, only about half of the people that have diabetes in the United States have been diagnosed, so it is only about 9 million to 10 million people who actually have the diagnosis.

What is neuropathy and how is it related to diabetes?

Dr. Johnson: Diabetes is a disease that affects many organs in the body, and one of the things it affects are the nerves, causing the dying back or loss of function of the nerves throughout the body, starting at the tips of the fingers and toes first and working its way up the body. When you have neuropathy, you can have pain from the neuropathy, which is sometimes the first symptom. Usually what happens is you actually lose the feeling, the sensibility of the skin, so you might have a rock in your shoe and not actually feel the rock in your shoe because of the loss of feeling.

What kind of pain is it?

Dr. Johnson: Neuropathic pain is typically a burning pain. Some people have an electric shock-like feeling in their feet. They will have numbness, tingling, or shooting pains.

How common are foot ulcers in people with diabetes?

Dr. Johnson: It's estimated about 15 percent of patients with diabetes will develop a foot ulcer. It's a very common problem and the key factor in development of foot ulcers is that it's the most common pathway to amputation of the lower extremity. The ulcer doesn't necessarily cause the problem, although there are a lot of problems with ulcers in terms of foot infections, the fact that there is loss of feeling and therefore neglect in terms of treatment of the ulcer.

What leads to the ulcers?

Dr. Johnson: In order to have an ulcer, you must first have neuropathy, which can come from diabetes, alcoholism or vitamin deficiencies. Once you get neuropathy, the areas of high pressure on your foot are prone to breakdown. Because patients don't feel the high pressures on their skin through normal daily activities, they will develop a sore as the skin that breaks down from the excessive pressure. You might ask why wouldn't they have developed this before the neuropathy but the situation is different. As you stand all day long you are constantly shifting your weight, wiggling your toes, changing your footwear, all these things are done subconsciously because of the sensation of pressure on your feet. When you have the absence of that pressure, you will overload or exceed the ability of your skin to withstand those pressures because you're not doing those things. You're not shifting your weight, and that's one of the things we think causes the ulcers.

Why don't the ulcers heal?

Dr. Johnson: Ulcers might not heal because we haven't gotten the weight off the area of the ulcer, which is actually what caused it in the first place. That's probably the most common reason. Patients come in, they're still wearing the same shoes that caused the ulcer, they're still doing the same amount of weight bearing, so one of the reasons it doesn't heal is we don't offload it properly. The other two main reasons are; there's not adequate blood supply to heal the wound, or there's an ongoing infection. As long as there's infection in the wound, it won't heal.

What are the standard treatments?

Dr. Johnson: If there's poor blood supply or an infection, we treat it with vascular surgery to increase the blood flow, or antibiotics and sometimes surgery to eradicate the infection. But, in most of the cases, the ulcers are not infected and there's adequate blood flow, and so the treatment is basically designed to offload the area of the ulcer so that the body's own healing mechanisms can work.

Until now, how has that been done in the past?

Dr. Johnson: You can offload the pressure with crutches, a wheelchair, there's special footwear and braces that will offload certain areas, but the mainstay, the gold standard of treatment is what we call the total contact healing cast. This is a cast that is placed on in such a way that it will reduce the pressures along the bottom of the foot by redistributing those pressures elsewhere along the foot; also the leg itself will take some of the pressure. So, while you're in the cast, the load of the ulcer will be much less.

What is the standard time for healing in the total contact-healing cast?

Dr. Johnson: In numerous studies, the healing time is about six weeks or 42 days for ulcers in a total contact cast.

What are some of the problems with ulcer care?

Dr. Johnson: A big problem with these ulcers is that they can be cured, however, the recurrence rate is very high. Within the first month after healing these ulcers, the recurrence rate can be 60 percent to 80 percent. So how do we get the patients from breaking down again? We can use special footwear with insoles, but even then, under the best of circumstances, we often will have breakdowns. One of the reasons we feel this happens is because patients with diabetes often develop, in addition to the other things, stiffness at their ankle, usually from tightness in the calf muscle and some contracture of the tendon, causing loss of ankle joint motion. When their ankle joint loses motion it may cause increased pressure on the ball of the foot where most of these ulcers develop.

What does your study do to help eliminate this problem of recurring ulcers?

Dr. Johnson: We thought if we could lengthen the heal cord, we could lengthen the tight heal cord and allow more ankle range of motion. We could then reduce the pressure on the ball of the foot, which is the source of the ulcer in the first place. Through the study we did, we were able to show that it did reduce the pressure and that it did increase the range of motion and in fact, at two years, it did significantly reduce the incidence of ulcer recurrence.

What were the results of study?

Dr. Johnson: At two years, there was a greater than 50 percent reduction in the recurrence rate of the ulcers. We had two groups of patients, on one group we did heal cord lengthening and the total cast treatment, on the other group we only did the total cast treatment. The healing rate of those ulcers in both groups was identical, the difference was at the end of the two years we looked at the groups of patients and there was a reduction of ulcers of over 50 percent in the group that had the heel cord lengthening.

How is the cord lengthened?

Dr. Johnson: There are several methods for lengthening the heel cord surgically. In our study, we used a percutaneous method, meaning we took the knife blade, placed it just through the skin, and the Achilles' tendon lies right under the skin behind the ankle, so we placed it through the skin in three locations about an inch apart and we cut half of the heel cord in each one of those locations. We did it in such a way on alternate sides of the tendon so that the heel cord was weakened just enough that when we were able to bring the ankle up, we were able to stretch the heel cord and create a controlled tear of the Achilles' tendon. Then in the cast, over the ensuing six weeks, the heel cord heals.