New Guidelines Stress Need for Diabetic Foot Ulcer Offloading

Miriam E Tucker

December 26, 2014

Offloading is essential to diabetic foot ulcer healing, according to new podiatry consensus guidelines.

The new guidance, published in the November/December 2014 issue of the Journal of the American Podiatric Association, was written by a nine-member panel of podiatrists, surgeons, and other experts in diabetic foot care.

The group reviewed the literature using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system to make eight evidence-based recommendations about management of diabetic foot ulcers, with an emphasis on the use of offloading.

The guidance also makes clear that total contact casting — not shoe gear or removable casts — is the optimal offloading method.

Offloading of diabetic foot ulcers is critical to healing but often neglected in primary and even specialty care, lead author Dr Robert J Snyder (Barry University School of Podiatric Medicine, Miami, Florida) told Medscape Medical News.

"Predominantly, diabetic foot ulcers occur on the bottom of the foot, under the metatarsal head or in the heel. It's very, very important that those areas be offloaded. Unfortunately, there are large numbers of physicians, both generalists and specialists, who don't really offload to the extent that they should, or in fact, in some cases don't offload or take pressure off these wounds at all."

Dr Jan Ulbrecht (Mount Nittany Medical Center, State College, Pennsylvania) agreed. "Adequate offloading absolutely has to be at the core of care of every single foot ulcer," he told Medscape Medical News.

Dr Ulbrecht praised the consensus statement. "They did a pretty good job of reviewing what's known and making recommendations based on where maybe the evidence is incomplete but is the best we've got. I basically agree with everything they say."

Total Contact Casts Are "Gold Standard"

Based on the GRADE review of 66 papers, the panel made the following eight consensus statements.

1) Vascular management, infection management and prevention, and pressure relief are essential to diabetic foot ulcer healing (evidence quality high/recommendation strong). Often denoted in the wound-care literature as VIP, this is the overall aggressive approach the panel deems necessary for diabetic foot ulcer healing.

Vascular assessment requires a combination of physical examination and laboratory tests. Blood-pressure indices such as the ankle-brachial index have poor reliability in patients with diabetes, so should not be used as the only assessment, according to the guidelines.

For infection diagnosis and treatment, the panel endorses the clinical-practice guidelines of the Infectious Diseases Society of America (Clin Infect Dis. 2012;54:e132-e173).

The third VIP component, pressure relief, is addressed throughout the rest of the guidelines.

2) Adequate offloading increases the likelihood of diabetic foot ulcer healing (moderate/strong). Several studies suggest that offloading facilitates healing by reducing both pressure on the foot and strain rate (Ostomy Wound Manage. 2010;56:S1-S24). The authors review the literature that suggests limitations of custom-made footwear and note that surgical offloading may be appropriate for some patients.

3) For guidance on offloading the Charcot foot, the panel endorses the Charcot Foot in Diabetes consensus report (low/strong) (Diabetes Care. 2011;34:2123-2129).

4) Total contact casting is the preferred method for offloading plantar diabetic foot ulcers because it has most consistently demonstrated the best healing outcomes and is a cost-effective treatment (moderate/strong).

In a study, total contact casting reduced plantar pressure by 32%, 63%, and 69% on the fifth, fourth, and first metatarsal heads, respectively, and by 65% on the great toe and 45% on the heel (J Rehabil Res Dev. 1995;32:205-209). The modality also reduces stride length, which decelerates the foot and reduces the applied force.

Although both removable cast walkers and total contact casts can achieve this, the panel agreed that the total contact cast is ideal because it ensures constant use.

The total contact cast has also been found to be cost-effective, with data from the US Wound Registry showing that the average per-patient cost of treatment with the cast was $11,946 vs $22,494 when it wasn't used (Wound Repair Regen. 2010;18:154-158).

Dr Snyder told Medscape Medical News, "There was very strong agreement that total contact casting should be the gold standard....It was very clear from the literature that the devices that could not be removed were far and away better because [they] forced compliance."

However, Dr Ulbrecht said that although he agrees that total contact casting is the ideal, he still offers patients a choice of offloading device.

If a patient can use a removable device and refrain from putting the foot on the ground when they are not wearing it, they'll do fine, he said. "I have a conversation with my patients. Interestingly enough, many patients choose the cast because they know themselves...they won't be able to adhere to [a removable offloading method]. But I absolutely make it a patient choice."

For physicians who decide to use removable casts or other offloading methods such as crutches, Dr Ulbrecht advised that "you've got to be tracking your healing rate and making sure it at least matches what is achieved with the total contact cast."

The guidelines advise that total contact casting is contraindicated in certain situations, such as untreated infection, osteomyelitis, severe peripheral arterial disease, severe obesity, and blindness.

Gap Between Evidence and Clinical Practice

The statement continues, describing the disconnect between the ideal scenario and real-world practice.

5) There currently exists a "gap" between the evidence supporting the efficacy of diabetic foot ulcer offloading and what is performed in clinical practice (moderate/strong).

In the US Wound Registry study, which involved 108,000 patient visits to 18 wound centers in 16 states, just 6% of patients with diabetic foot ulcers were treated with total contact casts (Wound Repair Regen. 2010;18:154-158).

And in a survey of 895 foot clinics, only 1.7% reported using total contact casting in more than half of patients. Shoe modification was used in 51% of patients, and no offloading was used in 45% (Diabetes Care. 2008;31:2118-2119).

"There is a disconnect between the evidence and what clinicians are actually doing," Dr Snyder told Medscape Medical News.

He added, "We realized a large number of patients were not getting the advantage of utilizing this technology, but we didn't realize until we looked at the literature how low a number it actually was. And this was in wound-care centers....We realized we had to get the message to the specialist and generalist that this is really mandatory."

Dr Ulbrecht said that clinicians will often debride the ulcer but fail to take the next step.

"As they say in the article, if you don't adequately offload the wound, it won't heal, and anything else you do won't do anything."

The guidelines address the fact that total contact casting is perceived to be technically difficult, complex, time-consuming, and without adequate reimbursement but notes that these obstacles can be overcome with better education and newer casting techniques that make the application easier and faster.

"I think a lot of the new techniques available to allow us to more simply apply these casts will really neutralize a lot of the barriers out there," Dr Snyder commented.

6) The likelihood of diabetic foot ulcer healing is increased with offloading adherence (moderate/strong).

Here, the authors cite several studies linking device adherence to healing outcomes and also note that "the panel agreed that wound clinicians should ensure that patients never leave the clinic wearing the shoe that allowed the ulcer to occur."

7) Advanced therapeutics are unlikely to succeed in improving wound-healing outcomes unless effective offloading is obtained (moderate/strong).

Several studies support the use of advanced therapies, such as cellular or tissue-based wound-healing products as adjunctive wound care treatments, but only if offloading is also achieved.

8) The panel supports the development of a per-visit offloading quality measure to address the gap between the evidence of offloading and its current use in clinical practice (low/strong).

The increasing use of wound-care registries and electronic health records could facilitate the development of such measures and promote their implementation, say the authors.

"I think it makes great sense to make [offloading] a quality measure," Dr Ulbrecht said, but he added that it might be difficult to come up with an appropriate metric, particularly if modalities other than total contact casting are used.

"It would require a lot of thought exactly how to make it a quality measure. I think you would need to use a device that is known to be effective....If you use a removable one, you'd have at least to document in the record that you've had the conversation....The quality measure part of this is a challenge, but it's doable."

The consensus panel's work was supported by Derma Sciences, which manufactures kits to aid application of contact casts. Dr Snyder is a consultant for Derma Sciences, as well as Acelity, MacroCure, and MiMedx. Disclosures for the coauthors are listed in the article. Dr  Ulbrecht is part owner of DIApedia, a research and development company active in the field of diabetes-related foot problems that has developed offloading orthoses for at-risk patients with diabetes that are currently being sold in the US and Europe.

J Am Podiatr Med Assoc. 2014;104:555-567. Abstract

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