How to treat diabetic foot ulcers with a total contact cast

A man sits with his total contact cast elevated on a chair.

There are times when clinicians and patients have done all they can to prevent diabetic foot ulcers, and they still develop.

“The patients who develop a diabetic foot ulcer are the ones who fell through the cracks,” said Don Wollheim, MD, FAPWCA, WCC, DWC, a board-certified surgeon of the American Board of Surgery.

Wollheim has 25 years of experience in general/vascular surgery and 13 years as a wound care specialist and educator. He also is a medical-legal consultant, college science instructor and clinical instructor for the Wound Care Education Institute.

“Once a diabetic foot ulcer develops, it’s essential it is treated aggressively with proven, standardized methods, as 85% of the amputations performed on diabetic patients began as a diabetic foot ulcer,” Wollheim said.

Identify the type of diabetic foot ulcer

There are three different types of diabetic foot ulcers, according to Wollheim.

They include:

  1. Ischemic
  2. Neuroischemic
  3. Neuropathic

Ischemic ulcers occur because the patient has an underlying vascular problem, such as peripheral artery disease. These ulcers occur more often in the digits (toes) and the lateral (side) aspects of the foot.

Ischemic ulcers are typically handled by a vascular service, whether the patient has diabetes or not.

Neuroischemic ulcers are caused by a combination of two conditions — diabetic neuropathy and peripheral artery disease. These ulcers present at the metatarsal heads both medially and laterally.

Neuropathic ulcers develop as a result of peripheral neuropathy. They usually start with the presence of a callous, then bleeding occurs into the callous (pre-ulcer).

After that, an ulcer develops. These ulcers develop on the bottom of the foot (the plantar surface).

A diabetic with severe peripheral neuropathy will:

  • Walk differently
  • Experience skin changes
  • Have a loss of sensation

Neuropathic foot ulcers are more common in patients with diabetes, according to Wollheim.

“The gold standard of treatment for neuropathic ulcers is the application of a total contact cast,” he said. “Like any disease process, if you can eliminate the cause, you can promote healing.”

With a neuropathic foot ulcer, that area of the bottom of the foot is getting 80% to 90% of the pressure, friction and shearing. A total contact cast equalizes the pressure and spreads it out over the entire foot, Wollheim said.

“The goal with the total contact cast is to reduce the pressure off of the wound so it has a chance to heal,” he said. “If a total contact cast is used correctly, the healing rates are fantastic — with an average of approximately 75% to 100% of wound healing occurring within six to eight weeks.”

Important total contact cast facts

  1. A total contact cast needs to be changed once a week.
  2. With your weekly change, you also need to debride the wound and cut back on the callous.

The total contact cast is the gold standard of treatment and the standard of care for diabetic foot ulcers that are neuropathic, Wollheim said.

However, there are some alternatives to the total contact cast for off-loading (reducing the pressure on the diabetic foot ulcer).

One is the use of a product called TCC–EZ, which some clinicians feel more comfortable using because it is easier to apply.

“The healing rates of the TCC-EZ is about the same as with the use of a traditional total contact cast,” Wollheim said.

Another option is the use of a removable cast walker that is a clamshell type of structure with Velcro.

“With a removable cast walker, we typically see a 65% healing rate — not as good as a total contact cast,” Wollheim said. “However, some clinicians are more comfortable using it.”

A clinician can create an instant total contact cast, according to Wollheim, by using a removable cast walker and securing it with duct tape or rolled plaster.

“This can force compliance as the patient will not be able to take it off,” he said. “We call this an instant total contact cast and the healing rates are the same as with a total contact cast — 75% to 100%.”

The topical antimicrobial products used in wound care and the use of systemic antibiotics will vary, Wollheim said.

This depends on the severity of the wound, other conditions present in the patient, and per the Infectious Diseases Society of America’s guidelines, with some patients needing hospitalization and others treated as outpatients.

Length of time for treatment

Patients will need to come in weekly for a total contact cast change as well as if the other options are being used, along with weekly debridement of callous and soft tissue.

“In general, once the wound bed is covered with epithelialized cells, the patient needs to continue to come in for treatment for two more weeks after this point,” Wollheim said.  

The overall target for healing a wound is to see greater than a 50% reduction in its size within one month, according to Wollheim. This indicates the wound will likely heal within three months.

“If a wound has reduced its size by less than 50% in one month, there is only a 10% chance it will heal in three months,” he said.

Ongoing surveillance and prevention methods

Wollheim said it’s essential the clinician and patient control what they can. That is because once a patient has a diabetic foot ulcer, that patient is at risk for developing another one.

“An important part of care is ensuring the patient is wearing the correct shoes to prevent more diabetic foot ulcers,” he said. “Early in the treatment process and once the swelling has subsided, you’ll want to send your patient for custom-made shoes.”

Also important for clinicians is to follow the American Diabetes Association guidelines on frequency of surveillance visits according to the patient’s risk category (0, 1, 2, 3).

In addition to the above practices, other considerations when providing comprehensive care for patients with diabetic foot ulcers are as follows:

  1. Encourage patients to maintain good glycemic control with an A1C of less than 7%.
  2. Encourage good nutrition and adequate protein intake as both are needed for wound healing.
  3. Obtain a surgical consult as needed (for example, the presence of peripheral artery disease and the need for surgical revascularization).
  4. Assess the need for pneumatic compression for patients who can benefit from it.
  5. Identify smokers and encourage them to stop smoking since one cigarette causes one hour of vasoconstriction.
  6. Consider a hyperbaric/O2 consult for a wound that is not responding to treatment.
  7. Consider maggot therapy as it can stimulate fibroblasts and increase collagen production.
  8. Consider the use of Regranex since the growth factor it provides may stimulate the healing of a diabetic foot ulcer.
  9. Encourage patients to call and return to the clinic for any concerns between scheduled appointments.

“Whatever it takes, do it,” Wollheim said, “since patients who undergo an amputation have a significant mortality rate within five years of their amputation. You want to prevent the need for an amputation.”

Learn more in our Online Diabetic Skin and Wound Management Course.

Carole Jakucs

Carole Jakucs, MSN, RN, PHN, is a full-time freelance writer. Her background in nursing includes tenures in healthcare management and as a care provider. She has worked in med/surg/telemetry, pediatric emergency department and college health. 

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