What is a Diabetic Foot Ulcer?

Diabetic foot ulcers (DFUs) are open sores or wounds caused by a combination of factors that include neuropathy (lack of sensation), poor circulation, foot deformities, friction or pressure, trauma, and duration of diabetes with complication risks.

DFUs occur in 34% of people with diabetes,¹ and approximately 14% to 24 % of patients with diabetes who develop a DFU will require an amputation. Diabetic complications cause 40% to 60% of nontraumatic lower limb amputations worldwide, and 80% of these amputations follow DFUs.² However, a DFU is a preventable condition, despite being the leading cause of nontraumatic lower extremity amputations in the United States.

Diabetic Foot Ulcer Etiology: Neuropathy, Trauma, and Arterial Occlusive Disease

DFUs are soft tissue skin sores affecting the lower extremity and caused by a triad of sensory neuropathy, trauma, and, in many patients, arterial occlusive disease.³ The infected wounds heal slowly because of diabetes, thus increasing the risk of wound chronicity and infection complications. About 60% of patients with diabetes will develop neuropathy, which is also the leading cause of DFUs. Neuropathy is damage to nerves, usually in the feet and hands, that results in tingling, pain, and numbness or loss of sensation in the affected area. One of the most common causes of neuropathy is diabetes, but other conditions and events that lead to neuropathy include:

• Metabolic problems
• Injuries
• Inherited causes
• Exposure to toxins

The lack of sensation created by neuropathy leaves patients vulnerable to blisters, cuts, or sores that are not felt as they occur. The lack of attention to these wounds and the absence of proper care can result in infections when the wounds are left untreated. DFUs can have a multifactorial etiology with contributing factors that include:

• Poor glycemic control
• Foot deformities
• Calluses and hyperkeratosis
• Improper foot care
• Ill-fitting footwear
• Neuropathy
• Poor circulation
• Dry skin

Patients and caregivers should be aware of the signs of a DFU, which include irritation or swelling around a wound, seepage of discharge, or a warm sensation close to the affected area. Any brown or black tissue present around the wound can cause serious problems. This discolored tissue is known as eschar and is one of the most common signs of a DFU.

What Are the Core Principles of Diabetic Foot Ulcer Prevention?

Patients with a DFU have a high recurrence rate of injury after the initial ulcer has healed; approximately 40% of patients have a recurrence within 1 year after ulcer healing, almost 60% within 3 years, and 65% within 5 years.⁴ Various factors contribute to repeated injury and reinfection of the ulcer. Given the prevalence of these complications, prevention is more effective than treating DFUs. To prevent DFUs, patients and health care providers should familiarize themselves with the core principles of DFU prevention.

How to Implement Glycemic Control in patients with Diabetic Foot Ulcers

Patients with diabetes must manage and monitor their blood glucose levels from the earliest stages of diabetes. This scrutinizing management is one method that helps prevent diabetic neuropathy. It can reduce the risk of nerve damage by over 50%⁵ because high glucose levels impede circulation, and impaired circulation is a leading cause of neuropathy.

Recent studies showed that wound healing rates were higher when hemoglobin A1c (HbA1c) was controlled between 7.0% and 8.0% during treatment than when HbA1c was controlled at less than 7.0%.⁶ Patients with diabetes should strictly manage their blood glucose levels because studies showed a 57% reduction in the incidence of clinical neuropathy in patients who managed their blood glucose levels with scrutiny compared with conventional glycemic treatment.

How to Involve Patients and Caregivers in Diabetic Foot Ulcer Care: Foot Checks and Education

Vigilance in proper foot care and a regimen of regular foot checks, either by a patient or a caregiver, are vital steps to prevent DFUs and undetected foot injuries. With the strain that COVID-19 has placed on hospital staffing, it is important to involve patients and caregivers in DFU prevention, if possible. The following is a list of treatments and care that can be carried out by either a patient or a caregiver:

• Check feet daily for any changes. Patients can use a mirror to check themselves
• Keep toenails trimmed straight across to avoid ingrown toenails and infection. Podiatrists or foot care nurses are trained in routine foot care
• Smooth corns or calluses
• Advise patients to maintain blood flow to feet through ambulation or changing positions if possible
• Wash feet daily in lukewarm water. Dry feet entirely, and add a lotion to the tops and bottom of the feet; however, never add lotion in between toes, where bacteria are harbored

Diabetic patients or caregivers should be educated on the prevention of potential foot injury and able to recognize early presentation without losing time before referrals to the proper specialists. Learning the corrective processes and the steps to take when problems arise allows patients to better manage their illness. Patients with diabetes should be able to recognize possible complications and understand the relationships among glycemic control, lifestyle, and foot problems, as well as the implications of the loss of protective sensation.⁷

How Footwear Can Help Prevent Diabetic Foot Ulcers

As discussed, neuropathy reduces the nerves’ ability to heal and sense damage to the feet. This means that injuries are not felt and therefore are not addressed. Often, sores can grow into wounds and ulcers without patients or clinicians being aware. Diabetic shoes are designed to protect the feet against forces that can cause wounds to develop and possibly become infected. These shoes prevent dangerous, life-threatening conditions, including amputation. Patients with diabetes should never go barefoot and should always check their shoes for small pebbles or anything that could cut their feet.

Why Foot Examinations Are Important for Diabetic Foot Ulcer Prevention and Care

Annual foot examinations allow providers, podiatrists, and/or clinicians to address issues that can prevent DFUs. Wound care professionals should address the following issues:

• Encourage patients to inspect their feet daily, and discuss any new or previous injuries, ulcers, or issues with their feet
• Check patients’ shoes for proper fit, and if needed, have them order custom-fitted medical shoes to prevent blisters, calluses, and ulcers
• Address skin issues on the feet, including fissures, cracking, blisters, calluses, and ulcers
• Check for fungal infections and cracks or splits in toenails
• Use Doppler ultrasound imaging to see how well blood flows to the patient’s feet

What Methods of Offloading Are There for Diabetic Foot Ulcer Prevention and Care

When treating DFUs, offloading is used to alleviate pressure at areas of high stress on the foot by using various techniques. Given the structural abnormalities of the foot and the presence of neuropathy, redistribution of constant plantar pressure is of utmost importance in managing DFUs.⁸ There are various methods of offloading, both surgical and nonsurgical, available to treat DFUs:

Nonsurgical offloading

• Removable cast walkers
• Bed rest
• Crutches
• Half shoes
• Total contact casting
• Custom footwear
• Custom splints

Surgical offloading

• Achilles tendon lengthening
• Surgical correction of skeletal abnormalities
• Plantar fat pad augmentation

Conclusion

Patients with diabetes are at an increased risk of DFUs, but studies suggest that appropriate screening and preventative measures can reduce the risk of foot ulcerations with the aid of increased patient education. Preventative measures and education of patients and caregivers can work to reduce the impact of DFUs on patient populations. Possibly one day, with enough effort and education, DFUs will no longer be the leading cause of lower limb amputations in the United States.

References

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2. Hingorani A, LaMuraglia GM, Henke P, et al. The management of diabetic foot: a clinical practice guideline by the Society for Vascular Surgery in collaboration with the American Podiatric Medical Association and the Society for Vascular Medicine. J Vasc Surg. 2016;63(2 suppl):3S-21S.
3. Clayton W, Elasy TA. A review of the pathophysiology, classification, and treatment of foot ulcers in diabetic patients. Clin Diabetes. 2009;27(2):52-58.
4. Edmonds M, Manu C, Vas P. The current burden of diabetic foot disease. J Clin Orthop Trauma. 2021;17:88-93. doi:10.1016/j.jcot.2021.01.017
5. National Institute of Diabetes and Digestive and Kidney Diseases. 2021. Blood glucose control studies for type 1 diabetes: DCCT and EDIC. Accessed May 9, 2022. https://www.niddk.nih.gov/about-niddk/research-areas/diabetes/blood-glu…
6. Xiang J, Wang S, He Y, Xu L, Zhang S, Tang Z. Reasonable glycemic control would help wound healing during the treatment of diabetic foot ulcers. Diabetes Ther. 2019;10(1):95-105. doi:10.1007/s13300-018-0536-8
7. Hasan R, Firwana B, Elraiyah T, et al. A systematic review and meta-analysis of glycemic control for the prevention of diabetic foot syndrome. J Vasc Surg. 2016;63(2 suppl):22S-28S.e1-2. doi:10.1016/j.jvs.2015.10.005
8. Cavanagh PR, Bus SA. Off-loading the diabetic foot for ulcer prevention and healing. Plast Reconstr Surg. 2011;127(suppl 1):248S-256S.