Lower extremity ulcerations: Presenting the facts

Compromises to the epidermis, dermis or subcutaneous tissue pose significant health issues, especially in patients who have diabetes or venous insufficiency.

Ulcers can arise from myriad pathology including, but not limited to, diabetes, venous insufficiency, collagen vascular disease, peripheral arterial disease, foot infections and trauma. This dermatological derangement may extend to the muscle and tendon or even as far as the joint capsule or bone. Ulcers deeply extending to soft tissue or bone display increased risk for infection as the ulcer extends deeper, particularly in the presence of arterial disease/ischemia.

The following medical conditions listed below have been attributed as risk factors for the development of lower extremity ulcerations primarily in the diabetic population. Aggressive preventive measures should rely on attentive visual inspection of the lower extremities of patients by their primary care physician, podiatrist/limb preservationist, endocrinologist, vascular surgeon and other first-line health care provider.

Patris Toney

Risk factors explained

Peripheral neuropathy is the most common risk factor and is seen in almost 30% of people with diabetes aged 40 and older. It leads to structural foot changes such as Charcot and intrinsic minus foot and to dry skin and muscle wasting.

Hyperglycemia is another risk factor; 7% (20.87 million) of the U.S. population has type 2 diabetes. In 2005, 1.5 million new cases were diagnosed. Hyperglycemia is linked to 60% of nontraumatic amputations. In 2002, 82,000 amputations were performed.

Peripheral vascular disease has a 45.4% prevalence rate among individuals aged 65 and older. Eighty-five percent of prior amputations are preceded by ulcer. People with diabetes have 10 times the risk for amputation.

The prevalence of presence or history of ulcer was 11.8% between 2000 and 2002 and increased incidence correlated to duration of diabetes. It correlates with increased plantar pressure gradient and increased plantar pressures, and has a 25% projected lifetime risk among people with diabetes.

Abnormal foot shape is also a risk factor. Lesser toe deformity presents in 60% of individuals aged 65 or older. Patients with this condition are 1.5 times more likely to be subjected to increased plantar pressures and have a 143% increase in plantar pressure gradient in forefoot vs. rearfoot.

Diabetes is the number one cause of new cases of visual impairment in individuals aged 20 to 74 years. Data have shown a correlation between diabetic retinopathy and increased risk for lower extremity amputation independent of glucose control.

Onychomycosis has a 74.9% prevalence rate in individuals aged 65 and older. Tinea pedis, another risk factor, has a 36.3% prevalence in individuals aged 65 and older. Calluses or corns are associated with 2.4 times increased plantar pressures and have a 58.2% prevalence in individuals aged 65 and older. Finally, diabetic foot infections lead to a 55.7 times greater risk for hospitalization, and 154.5 times increased risk for amputation, and are associated with 60% of diabetic foot ulcers resulting in amputation.

Comprehensive programs useful

Comprehensive foot care programs can help to achieve a 45% to 85% reduction in lower extremity amputation rates. Although prevention is the ultimate goal, treatment of existing ulcers depends heavily on early detection by the patient and physician. Patients need to be educated on home self-assessments with daily foot examinations. Examinations must involve looking at the feet and shoe gear.

Foot examinations may be enhanced by use of a mirror to facilitate inspection of the bottom of the feet. Most plantar ulcers, especially in neuropathic individuals, go unnoticed until it is too late and infection has occurred. Associated redness and drainage from the infection are both potential indicators. Equally important is diligent watchfulness of calluses, as the associated increase in pressure can cause erosion of the underlying skin leading to hidden ulceration and even infection. Although the presence of a callus seems innocent and trimming of such is viewed as menial, aggressive treatment of calluses is one of the first steps in prevention followed by external alleviation of the contributing pressure source by changing shoe gear or adding offloading padding.

Individuals with neuropathy, prior amputations, prior ulcers, or arterial disease should be closely monitored with regard to foot inspections since they have increased risk for ulceration. Even more menacing is hyperglycemia. Patients must be made aware that regardless of how well-controlled their blood glucose is, excessive circulating glucose over time continues to affect the body. Therefore, neuropathy and microvascular and macrovascular disease may occur. The thought of well-controlled hyperglycemia is not only deceiving to patients, but also confusing and frustrating, especially when the negative sequela of hyperglycemia manifests.

It has been calculated that every 30 seconds somewhere in the world an amputation is performed. With the prevalence of diabetes anticipated to escalate, its profound devastation will continue to be astounding. As physicians, treating our patients is not sufficient; we must be an advocate for our patients and impress upon them the absolute importance of prevention.

Patris Toney, DPM, MPH, is a Fellow at the Center for Lower Extremity Ambulatory Research and a Fellow at the National Center for Limb Preservation.

For more information:

• Boyko EJ, Ahroni JH, Cohen V, et al. Prediction of diabetic foot ulcer occurrence using commonly available clinical information. Seattle Diabetic Foot Study. Diabetes Care. 2006;29:1202-1207.
• Caselli A, Pham H, Giurini JM, et al. The forefoot-to-rearfoot plantar pressure ratio is increased in severe diabetic neuropathy and can predict foot ulceration. Diabetes Care. 2002;25:1066-1071.
• Centers for Disease Control and Prevention. History of foot ulcer among persons with diabetes - United States, 2000–2002. MMWR. 2003;52:1098-1102.
• Complications of diabetes in the United States. American Diabetes Association Web site.
• Dunn JE, Link CL, Felson DT, et al. Prevalence of foot and ankle conditions in a multicenter community sample of older adults. Am J Epidemiol. 2004;159:491-498.
• Fromy B, Abraham P, Bouvet C, et al. Early decrease of skin blood flow in response to locally applied pressure in diabetic subjects. Diabetes. 2002;51:1214-1217.
• Harrington C, Zagari MJ, Corea J, Klitenic J. A cost analysis of diabetic lower-extremity ulcers. Diabetes Care. 2000;23:1333-1338.
• Lavery LA, Armstrong DG, Wunderlich RP, et al. Predictive value of foot pressure assessment as part of a population-based diabetes disease management program. Diabetes Care. 2003;26:1069-1073.
• Lavery LA, Armstrong DG, Wunderlich RP, et al. Risk factors for foot infections in individuals with diabetes. Diabetes Care. 2006;29:1288-1293.
• Lipsky BA. A report from the international consensus on diagnosing and treating the infected diabetic foot. Diabetes Metab Res Rev. 20(suppl 1):S68-S77.
• Moss SE, Klein R, Klein B, Wong TY. Retinal vascular changes and 20-year incidence of lower extremity amputations in a cohort with diabetes. Arch Intern Med. 2003;163:2505-2510.
• Moulik PK, Mtonga R, Gill GV. Amputation and mortality in new-onset diabetic foot ulcers stratified by etiology. Diabetes Care. 2003;26:491-494.
• Mueller MJ, Zou D, Lott DJ. “Pressure gradient” as an indicator of plantar skin injury. Diabetes Care. 2005;28:2908-2912.
• Oyibo SO, Jude EB, Ngyuent HC, et al. The effects of ulcer size and site, patient’s age sex and type and duration of diabetes on the outcome of diabetic foot ulcers. Diabet Med. 2001;18:133-138.
• Pham H, Armstrong DG, Harvey C, et al. Screening techniques to identify people at high risk for diabetic foot ulceration. A prospective multicenter trial. Diabetes Care. 2000;23:606-611.
• Reiber GE, Vileikyte L, Boyko EJ, et al. Causal pathways for incident lower-extremity ulcers in patients with diabetes from two settings. Diabetes Care. 1999;22:157-162.
• Singh N, Armstrong DG, Lipsky BA. Preventing foot ulcers in patients with diabetes. JAMA. 2005;293:217-228.
• Tan MJ, Tan JS. Managing foot infections in patients with diabetes. Infect Med. 2006;23:168-173.