In spite of efforts to control diabetes and improve limb salvage rates, the number of diabetes-related amputations continues to rise in the United States. Over 80,000 amputations are performed each year, with approximately one-half being partial foot procedures and one-half being transtibial or higher amputations.1 By evaluating and identifying patients at risk for amputation, podiatrists may initiate simple, preventive interventions that can help lower these dismal statistics.
Patients with diabetes suffer from macrovascular and microvascular complications. Any of these complications can increase the risk of serious foot problems. Accordingly, podiatric physicians should be aware of these systemic disorders and encourage their patients to comply with measures to control these disease processes.2
Macrovascular complications affect the larger vessels and include coronary artery disease (CAD) and peripheral vascular disease (PVD). Although patients with diabetes are believed to be more susceptible to these conditions than the non-diabetic population, glucose control alone may not alter the course of these diseases. Medical interventions include exercise, the prevention of thrombosis with aspirin or other medications, control of hypertension and lipid management.
During the podiatric office visit, one should provide hypertension screening and encourage compliance with blood pressure control measures. One can refer undiagnosed or uncontrolled blood pressure to the internist for intervention. Any blood pressure in excess of 130/80 requires further evaluation.
Podiatrists can also provide screening for peripheral arterial disease (PAD) via a Doppler examination and determining the patient’s ankle-brachial artery index (ABI) can facilitate the detection of coronary artery disease (CAD). There is a 20 percent risk of a non-fatal cardiac event within five years in patients with PAD and a 30 percent mortality risk within five years of diagnosis in these patients even if they have not suffered from critical limb ischemia or amputation.3
Microvascular complications include retinopathy, renal disease and neuropathy. These appear to be directly related to hyperglycemia. Tight glucose monitoring and control is now the standard of care for both type 1 and type 2 diabetes. Encouraging compliance with such a regimen should be part of the podiatric office visit.
Severe signs of neuropathy, such as profound numbness or ulceration, are indicators of poor control. Office evaluation of blood glucose or hemoglobin A1c may provide laboratory evidence of poor control. One must encourage patients to monitor and report their glucose levels to their physicians and obtain appropriate management to optimize their blood glucose levels. Referring the patient to an endocrinologist may be appropriate if the primary physician is unable to normalize the glucose levels.
The clinic or office visit consists of identifying patient complaints and obtaining a pertinent history. Clinicians must document foot complaints and comorbidities such as renal disease or CAD, review the patient’s current medications and assess his or her glucose control. The podiatric physical should include at least a brief vascular and sensory evaluation. While a detailed examination of these systems is not necessary at every visit, one should perform it once or twice a year depending on the individual patient. In particular, note the presence or absence of ulcer or ulcerative lesion. Be sure to document the diagnosis and risk assessment.
Focal Pressure Keratosis: A Common Precursor To Ulceration
In a position statement on diabetic foot care, the American Diabetes Association (ADA) has identified four conditions that are associated with an increased risk of amputation.4 These conditions include:
• Peripheral neuropathy
• Altered biomechanics (i.e., pressure callus, limited joint mobility, bony deformity or severe nail pathology)
• Peripheral vascular disease
• History of ulcer or amputation
Patients exhibiting any of these conditions have an abnormality that requires regular podiatric evaluation and management. In particular, a pressure callus or focal pressure keratosis frequently can lead to ulcerations that fail to heal in the neuropathic patient. These patients can have even more problems healing if they have PAD as well.
In 2001, our group at Loyola University Chicago and Hines VA Hospital published a study in the Journal of the American Podiatric Medical Association (JAPMA) in which we reviewed 233 cases of diabetic foot ulceration admitted to our hospitals over a seven-year period.5 We found that 82 percent of these ulcers were preceded by a focal pressure keratosis. Those patients who had frequent outpatient podiatric care had significantly lower grade ulcerations and were significantly less likely to require any form of surgical intervention. Conversely, the worst ulcerations were those without documentation of any prior podiatric care.
The frequency of podiatric visits depends on the severity of the abnormality and the degree of intervention necessary to control the ulcer risk. Some patients with severe hemorrhagic keratosis under an isolated metatarsal head may require monthly debridement of the keratosis or perhaps biweekly debridement in order to prevent ulceration. In my experience, debridement is extremely effective in preventing ulceration, infection, hospitalization and amputation.
Managing a focal pressure keratosis is critical. Debridement of chronic pressure keratosis at appropriate intervals can prevent ulceration and decrease hospitalizations and amputations. The natural history of untreated pressure callus in a diabetic neuropathic patient is ulceration, infection and amputation. The minor trauma associated with focal pressure callus leading to ulceration, faulty healing, infection and amputation is a classic example of Pecoraro’s triad, which he suggested is responsible for 80 percent of all diabetes-related amputations.4
Emphasizing Appropriate Shoegear And Patient Education
In addition to debridement of the keratosis or ulcer, we found in the aforementioned JAPMA review that the prescription of protective shoes and patient education were effective in decreasing ulcer grade.5 One should provide each of these elements of care during the podiatric evaluation and management visit.
Pressure relieving shoes and orthotics help lower the risk of ulceration. Clinicians should also make a point of educating the patient at every visit. Explain the potential impact of neuropathy. Emphasize the importance of visual foot exams at home. Review good skin care and hygiene principles. Encourage compliance with diabetes control and cardiovascular risk reduction measures. Explain the indications for professional treatment. Recommend appropriate intervals for office visits.
Reducing The Risk Of Post-Treatment Complications
We like to tell our patients and the public that regular foot care prevents amputations and this is true to a significant extent. However, even non-invasive office care of the diabetic patient carries certain risks. Ulcerations, infections or amputations may still occur in spite of our best efforts. Unintended nicks, lacerations or abrasions can and do happen. Subsequent infection at points of treatment, such as callus or nail grooves, can develop. Subsequent blistering, ulceration or necrosis of chronic pressure points can occur after treatment, and the patient may even perceive them as the results of podiatric care. Lastly, one can uncover previously undiagnosed ulceration upon the debridement of a keratosis. If the patient is not adequately informed about the condition, he or she may think the debridement caused the ulceration.
In order to manage the risk of diabetic foot care, it is important to take a pertinent history on all patients before any treatment. Likewise, examine the foot and explain any potentially ulcerative findings to the patient. If one suspects there is an underlying ulceration beneath a hemorrhagic callus, inform the patient before debridement so he or she realizes the abnormal condition preceded the podiatric care. In the event that inadvertent injury occurs, inform the patient and provide proper treatment. This may mean nothing more than applying an antiseptic and a Band-Aid. However, more high-risk situations may require dressings and a healing shoe. Instruct the patient in home care and provide short-term follow-up until the injury heals.
Patients with diabetes who contact the office with a new problem may require urgent care. One should see patients with acute injuries or suspected infections the same day. If this is not possible, make a referral to the local emergency room. For first aid, advise the patient to keep the affected area clean and stay off the foot until he or she obtains medical evaluation. Document recommendations and patient responses. One can initiate appropriate care when seeing the patient in the office unless the condition is limb threatening and requires hospitalization.
Patients with diabetes who suffer minor trauma from causes such as focal pressure keratosis may go on to ulcerate. Faulty healing of such an ulceration may result from inadequate pressure relief due to neuropathy, vascular disease or infection. This triad of minor trauma, ulcer and faulty healing may lead to the majority of the 80,000 or more diabetes-related amputations that occur in the United States each year. Evaluation and management of minor trauma triggers like foot deformity, pressure callus and undetected injury may prevent many of these amputations not to mention hospitalizations and home bound illnesses related to diabetic foot complications.
All patients with diabetes should undergo foot screening exams once a year. Those with risk factors, such as PVD, neuropathy, foot deformity and especially focal pressure keratosis, require podiatric referral and regular evaluation and management. Patients should have appropriate interventions in order to control keratosis and protect pressure points. These interventions may include debridement, shoe and orthotic prescription, counseling and education, and corrective surgery.
When such an outpatient management program is in place, expected outcomes include a decreased need for surgery, hospitalization or amputation among patients with diabetic ulcers. A proactive program should decrease the severity of ulcers as well as the overall incidence of ulceration. This kind of proactive approach constitutes medical management of serious foot conditions and is not routine care.
Dr. Sage is a Professor and Chief of the Section of Podiatry at the Department of Orthopaedic Surgery and Rehabilitation at the Loyola University Stritch School of Medicine. He is also a Staff Podiatrist at Edward Hines Jr. Veterans Affairs Hospital.
Dr. Steinberg is an Assistant Professor in the Department of Surgery at the Georgetown University School of Medicine in Washington, D.C. He is a Fellow of the American College of Foot and Ankle Surgeons.
1. Reiber GE: Epidemiology and health care costs of diabetic foot problems. From: The Diabetic Foot: Medical and Surgical Management, edited by Veves A, Giurini JM, LoGerfo FW, Humana Press, Totowa NJ, 2002.
2. Sheehan P: Introduction to diabetes. From: The Diabetic Foot: Medical and Surgical Management, edited by Veves A, Giurini JM, LoGerfo FW, Humana Press, Totowa NJ, 2002.
3. American Diabetes Association Consensus Statement: Peripheral arterial disease in people with diabetes. Diabetes Care 26: 3333-3341, 2003.
4. Mayfield JA, Reiber GE, Sanders LJ, Janisse D, Pogach LM: Preventive foot care in people with diabetes, technical review and position statement. Diabetes Care 21: 2161-2179, 1998.
5. Sage RA, Webster JK, Fisher SG. Out patient care and morbidity reduction in diabetic foot ulcers associated with chronic pressure callus. Journal of the American Podiatric Medical Association 91: 275-291, 2001.