BioMechanics
November 2007
By: Michael B. Strauss, MD, and Stuart S. Miller, MD
There are many myths, fallacies, and misconceptions about the skin of the feet and the toenails of patients with diabetes, and the care that they require. Physicians who understand the reality behind these misconceptions are better equipped to address them and provide improved patient care.
Common myths include:
- If a foot skin integrity or toenail problem in a patient is not noted early, it is nothing to worry about.
- Management of a foot skin or toenail problem may be futile or have only short-term benefits.
- Neuropathy is the direct cause of diabetic foot wounds and the reason why healing is so difficult.
- Amputation is a sign of management failure.
- Patient noncompliance is always the patient's fault.
Objective evaluation, appropriate management, and rational prevention of injury to the foot skin and toenails in diabetic patients can expose the myths and misinformation and help keep these patients healthy.
Out of sight, out of mind
Ignoring a problem is almost never a good idea.
Myth: Because a problem in the skin integrity of the feet or toenails is not noted immediately, it is OK to assume that the problem is not important.
Reality: Almost all problems that become limb-threatening in patients with diabetes begin with a minor foot skin or toenail problem. Patients probably have less awareness of what is happening in these structures than in any other external portion of their bodies. The feet and toenails are the most remote from vision and smell, the senses most likely to detect the earliest problems, and they are covered with socks, footwear, and bedding materials almost all the time. Because they are remote from the hands, the feet and toenails are often difficult for the patient to examine and initiate care measures, a problem compounded by restrictions in mobility resulting from obesity, arthritis, and aging. Sensory neuropathy may delay diagnosis of foot skin and toenail problems because pain perception associated with injury or infection is absent in these structures.
Advice: Patients who have diabetes, and their caregivers, need to examine the skin of their feet and their toenails routinely (Table 1). They should do so before they don socks and shoes, after they remove them, and after they bathe.
Physicians should ask patients who have significant sensory neuropathies to wear white socks so that any break in skin integrity may be recognized immediately because of the resulting stain visible on the sock. Patients should be advised to bring the first sign of a problem in these structures to the attention of their primary care physician, diabetes educator, or foot surgeon. Physicians may use visual inspection to start their evaluation of foot skin and toenail problems.
An exercise in futility?
Management is a constant challenge.
Myth: Once a problem in the foot skin or toenail is identified, management may be futile or result in only short-term benefits.
Reality: Several factors contribute to this misconception. Because the foot skin and toenails are at the most distal portions of the circulatory system, they have the poorest blood supply, especially when concomitant peripheral arterial disease is present. In addition, they are in the part of the body most likely to be affected by neuropathy.
Although skin and toenail problems may be slow to heal because of peripheral arterial disease, most eventually do heal. The following are five potential management strategies:
- surgical management of the wound base and, if necessary, correction of deformities;
- appropriate immobilization and protection of the wound site;
- optimal medical management, especially involving diabetes care;
- selection of the most suitable agents to cover the wound; and
- enhancement of wound oxygenation, which may require hyperbaric oxygen treatments as an adjunct to management.1
Advice: Healing the wound and correcting toenail disease are primary goals. However, preventing new or recurring wounds is also important. An effective four-strategy program includes:
- patient education;
- skin and toenail care;
- appropriate footwear choices; and
- proactive surgeries.
The importance of the last strategy cannot be overemphasized. Deformities are a prime reason, along with inadequate blood supply and refractory osteomyelitis, why the wounds do not heal and why they recur after healing.2 If attention is not paid to this essential strategy, unsatisfactory treatment results or recurrences of problems after nonoperative management, including total contact casting, are likely.
Neuropathy-bane and boon
Sensory loss can compound other problems.
Myth: Neuropathy is the direct cause of diabetic foot wounds and toenail problems and the reason why healing is so difficult.
Reality: This is probably the most widely propagated misconception about diabetic wounds. Neuropathy itself is not a direct cause of wounds and toenail problems.3 Neuropathy may delay diagnosis of a wound or toenail problem, lead to a deformity, or contribute to making the skin more vulnerable to stresses (Table 2), but it does not interfere with healing. In addition, in almost all situations, diabetic neuropathy is not a correctable condition.
Advice: Accept neuropathy for what it is: a bane-it causes loss of protective sensation, muscle imbalances, and autonomic dysfunction-and a boon-sensory neuropathy facilitates almost painless wound care with consideration to dressing changes and debridements and requires minimal anesthesia when proactive surgeries are performed. Autonomic neuropathy also may contribute to increased blood flow, an essential element for wound healing. Almost all patients with diabetes who use the appropriate prevention strategies avoid future wound and toenail problems and maintain functional use of their feet, even if they have profound neuropathies.
Amputation-a measure of success?
The decision to amputate is complex and involves a myriad of factors.
Myth: The need to amputate is a sign of failure in the management of disease.
Reality: Lower extremity amputations, ranging from partial toe to hip disarticulations, must be placed in proper perspective. They do not necessarily reflect a lack of management success, especially if the five management strategies have been used. Amputations may bring closure to long-standing problems and allow the patient to resume functional activities that were not otherwise possible. There are five major reasons for lower limb amputations: nonmanageable ischemia, uncontrolled infection, structural problems that prevent functional use of the extremity, coexisting collagen vascular diseases, and intractable pain.1
Advice: Determination of the level of amputation is usually obvious when one or more of the five reasons are present. When alternatives exist as to the level of amputation, the surgeon needs to provide probability for healing and functional recovery to the patient or designated healthcare proxy. With an infected toe joint, for example, the probability of healing when the joint is removed and the toe is shortened may be 50%, but with a toe amputation, the probability of healing would approach 100%. With the proper selection of footwear, no differences in function are likely to be noted with either approach. Special consideration must be given for performing amputations when intractable pain is present, even if the wound is remediable. To maximize function, amputation should be performed at the most distal level where healing is likely to occur.
Patient compliance in perspective
Practitioners must consider their patients' abilities and limitations when expecting them to manage their own disease.
- Myth: Poor patient compliance is the reason for failures in managing and preventing foot skin and toenail wounds in patients who have diabetes.
- Reality: Like amputations, patient compliance must be placed in proper perspective. Labeling a patient as noncompliant because management and prevention recommendations are not followed may be inappropriate. Use of these measures may be impossible for some patients because they have limitations in mobility (e.g., in donning and removing elastic support hose to control edema), a lack of resources for supplies and help, or a combination of these difficulties. Patients' care providers should appreciate these compliance issues and explore all possible measures for resolving them-the cost of a single day of hospitalization will cover many weeks of home healthcare or homemaker services.4
- Advice: Physician and diabetes educators need to make measures for ensuring compliance with all aspects of diabetes care-including care of the skin of the feet and the toenails-an integral part of their encounters with patients and their caregivers. Simplified assessments for skin and toenail evaluation and management provide objective criteria for determining which interventions need to be carried out. In addition, calculating a goal-aspiration score that quantifies patient goal-related assessments offers information about compliance and provides guidelines for determining how often follow-up visits are needed.
Michael B. Strauss, MD, is medical director and Stuart S. Miller, MD, is education coordinator of the hyperbaric medicine department at the Long Beach Memorial Medical Center in Long Beach, CA.
A version of this article originally appeared in our sister publication, the Journal of Musculoskeletal Medicine, in August 2007.
References
- Strauss MB, Pinzur MS. Treatment strategies for managing problem diabetic foot wounds. In: 68th Annual Meeting Proceedings, American Academy of Orthopaedic Surgeons, 2001;2:675-676.
- Strauss MB. Diabetic foot problems: keys to prompt, aggressive therapy. Consultant 2002;42:81-93.
- Strauss MB, Miller SS. Diabetic foot problems: keys to effective, aggressive prevention. Consultant 2007;47:245-252.
- Consensus Development Conference on Diabetic Foot Wound Care: April 7-8, 1999, Boston. American Diabetes Association. Diabetes Care 1999;22:1359-1360.
Patient Do's and don'ts to prevent foot skin and toenail problems in the diabetic foot
Do
Inspect feet for pressure sores and skin irritation after removing shoes
Inspect socks for stains when they are removed; if sensation in feet is reduced, wear white socks
Use the appropriate footwear as recommended by healthcare professional
Perform daily foot skin care
Maintain an "open line" to a primary care physician to discuss the first signs of any foot skin or toenail problems
Don't
Walk barefoot
Use heating devices on feet
Soak feet in hot water
Use chemicals or sharp instruments to trim calluses
Trim toenails if sensation in feet is reduced, vision is impaired, or mobility is limited