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Prevention of Diabetic Foot Ulcers and Lower Extremity Amputation

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1 Prevention of Diabetic Foot Ulcers and Lower Extremity Amputation
Barry Stults, MD Scott A. Clark, DPM Thomas Miller, MD © American College of Physicians. All rights reserved. This content has been excerpted from the ACP Clinical Skills Module, "Diabetic Foot Ulcers." For more information visit:

2 “…the enormity of the global burden of diabetic foot disease…this much neglected, but potentially devastating, complication of a disease that is reaching epidemic proportions…Someone, somewhere, loses a leg because of diabetes every 30 seconds of everyday…” Lancet. 2005;366:1674 The enormity of the problem of diabetic foot ulcer and lower extremity amputation is well summarized in this quotation from a 2005 Lancet editorial honoring World Diabetes Day and its focus on diabetic foot disease. (Lancet 2005; 366:1674)

3 Case Study 64-year-old obese man Type 2 DM (15 yrs)
BP  (18 yrs) Dyslipidemia (18 yrs) CABG (10 yrs ago) Claudication (today; 25 yds) Insulin/Metformin/Statin/ACEI/HCTZ/ASA “Sore on my left foot, Doc” Mr. M.C. is a 64-year-old obese man who had not been seen for 12 month because of missed appointments. He had type 2 diabetes for 15 years, hypertension and dyslipidemia for 18 years, and coronary artery bypass grafting 10 years ago. On this particular visit he also noted left calf claudication on walking 25 yards that had been present for several months. What brings him to clinic is an ulcer on his left heel.

4 This is Mr. M. C. ’s left heel ulcer
This is Mr. M.C.’s left heel ulcer. Note the maggots infesting – but perhaps also debriding – this wound.

5 Case Study (continued)
Clinical evaluation of heel ulcer: Probe reached bone Extensive subcutaneous abscess MRI: extensive osteomyelitis ABI: 0.2 Angiography: Inoperable severe vascular disease Uncontrolled infection Amputation necessary Using a sterile metallic probe, the wound was explored. The probe easily reached bone indicating a high likelihood of osteomyelitis. Extensive subcutaneous abscess formation was also apparent. The patient was admitted to the hospital where an MRI study of the left foot confirmed extensive osteomyelitis of the calcaneous. No pedal pulses were present in the left foot, and a left leg ankle-brachial index (ABI) study performed the day of admission showed was = 0.2, indicating critical ischemia. Angiography revealed severe suprapopliteal and infrapopliteal obstruction at multiple levels not amenable to revascularization. Despite parenteral antibiotics and several drainage procedures, the infection remained uncontrolled. A below-the-knee amputation was required.

6 Amputations in Diabetes
Common: U.S.A. – 80,000 amputations/year (2002) Costly: $60,000/amputation $2 billion total costs annually Lancet. 2005;366:1719 Diabetes Care. 2004;27:1598 Diabetes Care. 2003;26:495 Worldwide, there is an amputation secondary to diabetes every 30 seconds, and there are at least 80,000 amputations/year in the United States. Amputation rates are higher in men and in members of racial and ethnic minority groups, particularly Native-Americans and Hispanic-Americans. Amputations are costly at $60,000/case, resulting in a total cost to U.S. healthcare payers of $2 billion/y.

7 Tragic “Rule of 50” 50% of amputations 50% of patients
Transfemoral/ transtibial level 2nd amputation in  5 years Die in  5 years However, more important than expense, amputations have tragic consequences for the individual that can be summarized by the “Rule of 50”: 50% of diabetic amputations occur at the very disabling transfemoral or transtibial levels. 50% of these patients will require a second amputation within just 5 years. 50% of these patients will die within 5 years, most from concurrent coronary artery disease or cerebrovascular disease. Clinical Care of the Diabetic Foot, 2005

8 Tragic “Rule of 15” 15% of diabetes Foot ulcer in lifetime patients
15% of foot ulcers Osteomyelitis 15% of foot ulcers Amputation Clinical Care of the Diabetic Foot, 2005 Foot ulcers precipitate about 85% of diabetic amputations. Key epidemiologic points about diabetic foot ulcer can be summarized by the “Rule of 15”: 15% of diabetes patients will experience a foot ulcer during their lifetime. 15% of these foot ulcers will progress to osteomyelitis. Even with optimal multidisciplinary care, 15% of diabetic foot ulcers will result in a lower extremity amputation at some level.

9 Team Care Identification of high-risk patients
Detection of early problems Educate/motivate self-care behaviors Prophylactic nail/skin care Therapeutic footwear Prompt, multidisciplinary treatment of ulcers Lancet. 2005;366:1676 Fortunately, five clinical trials have demonstrated that multidisciplinary team care can significantly reduce diabetic ulcer and amputation rates. These trials all included integrated, risk-stratified interventions. The first step in these programs was to identify patients at high-risk for foot ulceration by history and physical examination. High risk patients had frequent follow-up to detect early foot problems. They were intensively educated – and motivated - to perform self-foot care behaviors. They had regular prophylactic nail and skin care by podiatrists, and if needed, they were provided with therapeutic footwear. The second essential step in these programs was prompt, multidisciplinary treatment of any foot ulcers that occurred despite attempts at prevention.

10 Team Care Reduces Ulcers/Amputations
50%-80% reductions in ulcers/amputations Economic modeling studies Cost-effective if 25%-40% reduction in ulcer rate Cost-saving if > 40% reduction in ulcer rate Lancet ;366:1719 Diabetes Care. 2004;27:901 Five trials demonstrated 50-80% reductions in ulcer and amputation rates. Economic modeling studies have suggested that such programs are cost-effective if they reduce ulcer/amputation rates 25-40% and may even be cost-saving if greater reductions are possible, provided that the programs include only those patients with risk factors for diabetic foot ulceration.

11 Causal Pathways for Foot Ulcers
Neuropathy % Causal Pathways Neuropathy: % Minor trauma: 79% Deformity: 63% Behavioral ? Deformity Minor Trauma - Mechanical (shoes) - Thermal - Chemical Prospective studies have investigated the causal pathways leading to diabetic foot ulcer. The most common pathway involved a combination of sensory neuropathy, foot deformities secondary to motor neuropathy, and minor trauma caused by poor self-foot care practices. Sources of minor trauma included ill-fitting shoes, thermal trauma (hot water, sand, or pavement) and chemical trauma (over-the-counter corn plasters). Poor self-foot care ULCER Diabetes Care. 1999; 22:157

12 Detecting Feet-at-risk
History: Prior amputation or foot ulcer Peripheral artery disease (PAD) Exam: Insensate Foot deformities Absent pulses Prolonged venous filling time Reduced ABI Pre-ulcerative cutaneous pathology Arch Intern Med. 1998;158:157 Diabetic patients at risk for ulceration and amputation can be detected using just three historical and four examination features. Key historical features include a prior history of lower extremity amputation or foot ulcer and a history of known peripheral arterial disease or claudication walking less than one block. Key examination features include inability to sense the 5.07/10g monofilament, major foot deformities, and peripheral arterial disease diagnosed by absent pedal pulses, a prolonged venous filling time, or by a reduced Ankle-Brachial Index. Although not part of the most commonly used risk stratification scheme, pre-ulcer cutaneous pathology also identifies feet-at-risk for ulcer and amputation

13 Risk Stratify for Ulcer Risk
Risk Level Foot Ulcer %/yr % Office Patients (diabetes clinics) 3: Prior amputation Prior ulcer 28.1% 18.6% 7% 2: Insensate and foot deformity or absent pedal pulses 6.3% 10% 1: Insensate 4.8% 17%-30% 0: All normal 1.7% 66% Diabetic patients can be stratified into one of four risk levels for subsequent foot ulceration. Risk level 3 patients with either a prior lower extremity amputation or foot ulcer are at greatest risk as their annual risk of foot ulceration is 18-28%; about 7% of office patients are at this level of risk. Risk level 2 patients are insensate to the 10g monofilament, and in addition, they have either major foot deformities or absent pedal pulses; annual risk of foot ulcer is about 6%. Risk level 1 patients are insensate to the 10g monofilament; annual risk of foot ulcer is 4.8%/year risk; they comprise 17-30% of the diabetic patients seen in the office practice. Note that risk level 0 patients who have no risk factors may still have an increased risk of foot ulceration of 1-2%/year. Diabetes Care. 2001;24:1442 Diabetes Metab. 2003;29:261

14 Annual Diabetic Foot Exams
2000 Behavioral Risk Factor Surveillance System, CDC Total Private Insurance Medicaid- Medicare VA Uninsured % with foot exam in past year 63 64 65 84* 48* Too few annual diabetic foot examinations are completed in the U.S., and so risk stratification does not occur. In the year 2000 only 63% of diabetic persons reported having had a foot exam in the past year. Foot examination rates were significantly higher in the VA healthcare system and significantly lower in diabetic persons with no health insurance. *p < 0.01 Health Services Research. 2005;40:361

15 Physical Examination of the Feet in Persons with Diabetes
Let’s review the key components of the physical examination of the feet in persons with diabetes mellitus.

16 Sensory Neuropathy in Diabetes
Loss of protective sensation in feet Detect with 5.07/10-g Semmes-Weinstein monofilament 50% of insensate patients have no symptoms Diabetes Care. 2006;29(Suppl 1):S24 Diabetes Care. 2004;27:1591 Sensory neuropathy from diabetes can lead to a loss of protective sensation in the feet sufficient to allow painless skin injury, and as such is a major risk factor for foot ulcer and amputation. This loss of protective sensation can be quickly and accurately detected using the 5.07/10 gram Semmes-Weinstein monofilament. Recent studies suggest that among persons with diabetes the prevalence of insensate feet to the 10g monofilament is 30% over age 40 years and 50% over age 60 years. Up to 50% of these persons are asymptomatic with respect to neuropathic symptoms.

17 The monofilament is imbedded in a plastic handle, a sturdy piece of cardboard, or a pen-like device.
The cardboard monofilaments are disposable but can be reused. Four suppliers of accurate monofilaments are listed in the Tool-Kit. The accuracy of monofilaments provided by pharmaceutical companies is unknown.

18 When the 5.07/10g monofilament is bowed into a C-shape for one second, approximately 10 grams of force are applied at the site of contact.

19 Monofilament Testing Test characteristics:
Negative predictive value = 90%-98% Positive predictive value = 18%-36% Prospective observational study: 80% of ulcers and 100% of amputations occur in insensate feet Superior predictive value vs. other test modalities J Fam Pract. 2000;49:S30 Diabetes Care. 1992;15:1386 Testing for sensory neuropathy with the 5.07/10g monofilament has been demonstrated to predict ulcer and amputation risk in five prospective studies. For foot ulceration, the negative predictive value of normal sensing varied from 90-98%, that is, only a small percentage of patients who can sense the monofilament will develop a foot ulcer. The positive predictive value for foot ulcer of failure to sense the monofilament was 18-36%, that is, 18-36% of the patients who could not feel the monofilament developed an ulcer. In a prospective 32 month observational study, 80% of foot ulcers and 100% of amputations occurred in patients with insensate feet to the 5.07/10g monofilament. Monofilament testing has superior predictive value as compared to other test modalities such as the 128Hz tuning fork, pin-prick, cotton wisps, or the presence or absence of neuropathic symptoms.

20 Using the Monofilament
Demonstrate on forearm or hand Place monofilament perpendicular to test site Bow into C-shape for 1 second Test 4 sites/foot Heel testing does not predict ulcer Avoid calluses, scars, and ulcers Test with the monofilament using the following protocol: Place the patient in the supine position with shoes and socks removed. Demonstrate sensation of the filament on the patient’s forearm or hand, bowing the monofilament into a C-shape for one second. Ask the patient to close their eyes. Proceed to bow the monofilament into a C-shape for one second at each of four test sites on the plantar surface of each foot: the plantar surface of the distal phalanx of the great toe and the plantar surfaces of the 1st, 3rd, and 5th metatarsal heads. In one study testing these four sites as compared to eight sites still detected 95% of ulcer formers; in particular, heel testing does not discriminate ulcer formers. Avoid testing calluses, scars, or ulcers; if these lesions are present, test at adjacent sites on the plantar surface of the foot.

21 Monofilament Testing Tips
Insensate at 1 site = insensate feet Falsely insensate with edema, cold feet Test annually when sensation normal Use monofilament < 100 times day Replace if bent Replace every 3 months Inability to accurately sense the monofilament at just one site on one foot still diagnoses the patient as having insensate feet. Cold or edematous feet may be falsely insensate. If patients accurately sense the monofilament, they should be tested annually; if they are insensate, retesting annually is not necessary, although some clinicians choose to do so to remind the patient of this important deficit. The monofilament should be used for less than 100 applications per 24 hours; more frequent use fatigues the filament so that it no longer applies 10g of force, and it should then be rested for 24 hours. In general, monofilaments should be replaced every three months, or immediately if they are bent.

22 Vibration Testing Biothesiometer 128-Hz tuning fork at halluces
Best predictor of foot ulcer risk 128-Hz tuning fork at halluces Equivalent to 10-g monofilament Newly recommended by ADA Diabetes Care. 2006;29(Suppl 1):S25 Diabetes Res Clin Pract. 2005;70:8 Testing for vibration sense also detects diabetic sensory neuropathy and may accurately predict the risk of foot ulcer. An instrument, the Biothesiometer, quantitatively assesses vibration sense and may be the most sensitive predictor of foot ulcer; however, the instrument is relatively expensive and less available. Recent data suggests that the 128 Hz tuning fork tested at each hallux may be similarly sensitive and specific as compared to the 10g monofilament tested at 4 sites on each foot. The 2006 ADA Clinical Practice Recommendations now suggest testing with both the 10g monofilament and the 128 Hz tuning fork. The technique for using the 128 Hz tuning fork is described in the Tool-Kit.

23 Motor Neuropathy and Foot Deformities
Hammer toes Claw toes Prominent metatarsal heads Hallux valgus Collapsed plantar arch Diabetic motor neuropathy contributes to the development of several important foot deformities including hammer toes, claw toes, prominent metatarsal heads with inadequate plantar soft tissue cushioning, hallux valgus, and a collapsed plantar arch because they are common and lead to areas of especially high pressure over bony prominences, claw toes and prominent metatarsal heads are probably the most important deformities.

24 Hammer Toes Claw Toes © 2002 American Diabetes Association
Diabetic motor neuropathy leads to atrophy of the intrinsic musculature of the foot with consequent dorsiflexion of the proximal phalanx to form a hammer toe. Dorsiflexion of the middle phalanx and a flexion contracture of the distal phalanx convert the hammer toe into a claw toe. Note the increasingly prominent metatarsal heads with these two deformities. These deformities result in areas of high pressure and subsequent callus formation over the metatarsal head and the tip of the toe when walking, and over the distal end of the proximal phalanx from shoe gear. [PATRICK AND TED: I DO NOT HAVE PERMISSION TO USE THIS DIAGRAM IN A MONOGRAPH THAT IS FOR SALE, AND I DOUBT IT WILL BE GRANTED BY THE AMERICAN DIABETES ASSOCIATION. DO YOU HAVE ARTISTS TO DRAW A SIMILAR PICTURE?] Claw Toes © 2002 American Diabetes Association From The Uncomplicated Guide to Diabetes Complications Reprinted with permission from The American Diabetes Association

25 Hallux Valgus © 2002 American Diabetes Association
Hallux valgus deformities are more common in persons with diabetes and result in high pressure points from shoe gear at the distal end of the proximal phalanx. [PATRICK AND TED: FROM SAME REFERENCE, NO PERMISSION] © 2002 American Diabetes Association From The Uncomplicated Guide to Diabetes Complications Reprinted with permission from The American Diabetes Association

26 The pes cavus deformity – a “high” plantar arch – leads to areas of high pressure over the heel, the metatarsal heads, and the plantar surface of the toes. The pes planus or midfoot collapse deformity resulting from a Charcot foot creates an area of high pressure on the plantar surface of the midfoot. All of the shaded areas on the foot deformities in this diagram are at risk for callus formation and subsequent ulceration. [PATRICK AND TED: I DO NOT HAVE PERMISSION TO REPRODUCE THIS] Boulton, et al. Guidelines for Diagnosis of Outpatient Management of Diabetic Peripheral Neuropathy. Diabetic Medicine 1998, 15:

27 Pre-ulcer Cutaneous Pathology
Persistent erythema after shoe removal Callus Callus with subcutaneous hemorrhage Fissure Interdigital maceration, fungal infection Nail pathology In addition to major foot deformities it is also essential for clinicians to recognize pre-ulcerative cutaneous pathology. Combinations of sensory, motor, and autonomic neuropathy and inappropriate footwear can lead to several cutaneous lesions. The earliest abnormality is an area of persistent erythema following removal of the shoe indicating excessive pressure at the site. Without intervention, callus and later callus with subcutaneous hemorrhage – the “pre-ulcer” – may develop. Autonomic neuropathy and consequent reduced sweating leads to excessively dry skin on the feet. Dry skin augments callus formation and can also fissure and progress to frank ulceration. Poor self-foot care behaviors can lead to fungal infection and subsequent interdigital maceration along with several types of nail pathology that can progress to foot ulceration.

28 Pre-ulcer The diagram shows a common sequence of events leading from a foot deformity to an ulcer complicated by deep soft tissue infection and osteomyelitis. A hammer toe deformity results in increased pressure and callus formation on the plantar surface of an excessively prominent metatarsal head. The callus further increases the subcutaneous pressure beneath it, eventually resulting in a subcutaneous hemorrhage and the formation of a pre-ulcer (callus with subcutaneous hemorrhage). With continued pressure and no therapeutic intervention, the pre-ulcer is converted to a frank ulcer. If untreated, the ulcer may progress to deep soft tissue infection and osteomyelitis. [PATRICK AND TED: I DO NOT HAVE PERMISSION FOR THIS DIAGRAM WHICH COMES FROM The Foot in Diabetes, edited by AJM Boulton, H Connor, PR Cavanagh, J Wiley and Sons 2000 AJM Boulton, H Connor, PR Cavanagh, The Foot in Diabetes, 2002

29 Areas of erythema that persist after removal of the shoe are an indication of excessive pressure from inappropriately fitted shoe gear. Over time, these areas of erythema are sites for callus and ulcer formation. Also note the excessively dry skin.

30 A marked Hallux valgus deformity and early hammer-toe deformities from diabetic motor neuropathy.
Note the areas of persistent erythema over pressure points on the first MTP joint and on the dorsum of the proximal phalanges. This patient requires a modification of shoe gear to relieve pressure and prevent callus and ulcer formation.

31 Early hammer and claw-toe deformities.
There are areas of persistent erythema on the dorsum of the proximal phalanges caused by excessive pressure from poorly-fitted shoe gear.

32 Severe hammer and claw-toe deformities.
There are areas of persistent erythema on the dorsum of the fourth and fifth toes. The consequences of the ill-fitting shoe gear have now progressed to marked callus formation at the peak of the hammer toe deformities on the dorsum of the second and third toes.

33 Significant hammer and claw-toe deformities.
The claw-toes have resulted in the build-up of significant callus on the tips of the toes. Unless the patient’s shoe gear is modified, these calluses are at high risk to ulcerate in the future.

34 Diabetic motor neuropathy has resulted in hammer and claw-toe deformities and very prominent metatarsal heads on the plantar surface of the foot. Excessive pressure on the metatarsal heads and inadequate shoe gear have resulted in marked callus build-up that is further accelerated by the dry skin. The patient is at high risk for ulceration at these sites. Ted: Can we remove background and put neutral color or blue background instead so foot shows up better?

35 This patient has a pes cavus or high plantar arch deformity that has resulted in pressure points and callus formation over the heels, metatarsal heads, and along the medial aspect of the great toe. Extensive callus increases the subcutaneous pressure immediately beneath the callus and can result in a subcutaneous hemorrhage, the so-called “pre-ulcer.” Note the extensive nail pathology. Ted: Can you provide a color background?

36 This is an example of a pre-ulcer, a callus beneath which is a subcutaneous hemorrhage as indicated by the visible hemosiderin deposits. With continued pressure this pre-ulcer is likely to progress to a frank ulcer. Prompt referral to podiatry is indicated.

37 Without very careful physical examination of the feet, this pre-ulcer (callus with subcutaneous hemorrhage) on the tip of the third digit with its claw-toe deformity could easily go undetected. Pre-ulcers must be promptly and carefully debrided to determine if there is already an underlying ulcer.

38 In this patient debridement did not reveal an underlying ulcer.
Debridement of callus reduces subcutaneous pressure and helps to prevent subcutaneous hemorrhage and progression to an ulcer. This patient’s socks and shoe gear will have to be modified to accommodate his claw-toe deformities.

39 Here is a less fortunate patient with a claw-toe deformity and a now debrided pre-ulcer at the tip of the third toe. An early ulceration is already apparent that will require local wound care and off-loading of pressure in order to heal.

40 Diabetic autonomic neuropathy leads to decreased sweating, very dry skin, and consequent fissure formation, as noted in this patient on the plantar surface of the first metatarsal head. Without careful physical examination such fissures easily go undetected; some will become secondarily infected and ulcerate.

41 Perhaps 50% or more of patients with diabetes are unable to reach their feet because of obesity or are unable to see their feet due to retinopathy. Severe nail abnormalities can result. Torsion of the excessively long nail on the great toe could lead to trauma to the nail bed, secondary infection, and ulceration. The nail curving over the top of the second toe has the potential to lacerate the plantar surface of the toe. Because of sensory neuropathy the patient may be unaware of any discomfort.

42 These nails are grossly hypertrophied from fungal infection in this patient with no prior access to podiatric care. Due to the increased pressure transmitted to underlying tissues, these nails can damage the nail bed which may then become secondarily infected and ulcerate.

43 It is essential to carefully examine the interdigital spaces between the toes to detect maceration that results from excessive moisture and concurrent fungal infection as these lesions can progress to ulceration. However, in this patient a pre-ulcer was discovered instead, the result of excessive pressure from an adjacent deformed toe rubbing against it.

44 This diabetic patient has multiple abnormalities: hammer and claw-toe deformities, callus formation, nail pathology, and very dry skin with early fissure formation.

45 Peripheral Artery Disease
Prevalence (ABI < 0.9): 10%-20% in type 2 diabetes at diagnosis 30% in diabetics  age 50 years 40%-60% in diabetics with foot ulcer Complications: Claudication Associated coronary and cerebral vascular disease Delayed ulcer healing Diabet Med. 2005;22:1310 Diabetes Care. 2003;26:3333 Defined as an Ankle-Brachial Index (ABI) < 0.9, peripheral artery disease (PAD) is very prevalent in patients with diabetes: 10-20% at the time of diagnosis in type 2 diabetes, 30% in diabetic patients over age 50, and 40-60% in diabetic patients with a concurrent foot ulcer. While PAD can cause claudication and is a marker for concurrent coronary artery disease and cerebrovascular disease, it also delays the healing of foot ulcers and is a major risk factor for lower extremity amputation. PAD is not an independent risk factor for foot ulcer in diabetes.

46 Pedal Pulse Examination
Absent pedal pulses predicts severe PAD Absence of a single pedal pulse does not predict PAD Presence of pedal pulses does not rule out PAD! Arch Intern Med. 1998;158:1357 Diabetes Care. 2003;26:3333 The pedal pulse exam can help to detect PAD in patients with diabetes, but it may also be misleading. The absence of both pedal pulses significantly increases the likelihood of severe PAD. In contrast, the absence of just one pedal pulse is not predictive of PAD because vessels are congenitally absent up to 8% of the population. The presence of pedal pulses does not rule out severe PAD: 30% of diabetic persons with severe PAD have a PT pulse due to collateral blood flow. Therefore patients with a high suspicion for PAD due to claudication or a foot ulcer should undergo additional vascular testing.

47 Venous Filling Time Sitting: Locate pedal vein bulging above skin
Supine: Elevate leg to 45° for 1 minute Sitting: Check time to pedal vein bulging J Clin Epidemiol. 1997;50:659 Arch Intern Med. 1998;158:1357 Measurement of venous filling time is specific but not sensitive for the detection of PAD. The test is based on the fact that once emptied, pedal veins fill more slowly in persons with PAD. The patient sits on an exam table with feet dangling and a pedal vein bulging above the skin on the dorsum of the foot is identified. The patient is then placed in the supine position, and the leg is elevated to a 45 degree angle for one minute. The patient then sits and dangles the foot while the time is measured until the pedal vein rises to the same height above the skin.

48 Venous Filling Time Interpretation
Normal <20 sec Abnormal/collaterals sec Severe PAD >40 sec Filling time > 20 sec predicts ABI < 0.5 Sensitivity, 22%; Specificity, 94%; LR, 3.9 J Clin Epidemiol. 1997;50:659 Arch Intern Med. 1998;158:1357 A venous filling time of seconds suggests PAD with protective collateral blood flow. A filling time of greater than 40 seconds suggests especially severe vascular disease. In one study, a venous filling time over 20 seconds predicted an ABI < 0.5 (severe ischemia) with a sensitivity of 22%, specificity of 94%, and a likelihood ratio of 3.9.

49 A much more useful noninvasive test to diagnose PAD in diabetes is the Ankle-Brachial Index (ABI). The (ABI) is performed with a handheld Doppler Flow meter to measure systolic blood pressure in both arms and in the DP and PT arteries. The ABI is calculated by dividing the highest pressure measured at the ankle by the highest brachial pressure. [PATRICK AND TED: DO NOT HAVE PERMISSION TO USE. REFERENCE IS: Norman PE, Eikelboom JW, Hankey GJ. Peripheral arterial disease: prognostic significance and prevention of atherothrombotic complications. Medical Journal of Australia 2004; 181: Figure 1, p.151 Adapted from: Norman PE, Eikelboom JW, Hankey GJ. Peripheral arterial disease: prognostic significance and prevention of atherothrombotic complications. Medical Journal of Australia 2004; 181: Figure 1, p.151

50 Ankle-Brachial Index Screening: 2004 ADA recommendation Diagnosis:
“Consider” at age 50 years and every 5 years Diagnosis: Claudication, absent DP/PT pulses, foot ulcer Limitations: Underestimates severity in calcified arteries Diabetes Care. 2005;28:2206 Diabetes Care. 2004;27(Suppl 1):S15-S35 In 2004 the American Diabetes Association (ADA) recommended that physicians consider screening diabetic patients with an ankle/brachial index (ABI) measurement to detect peripheral artery disease (PAD) beginning at age 50 years with repeat measurements every five years thereafter. Screening can begin even earlier if multiple cardiovascular disease risk factors are present. ABI should certainly be performed for diagnosis in diabetic patients with claudication, absence of both pedal pulses, or with a foot ulcer irrespective of other physical exam findings. ABI measurements may underestimate the severity of PAD in diabetic patients due to the frequent presence of medial calcification of the artery and poor compressibility. In patients at high risk for PAD because of the presence of claudication or foot ulcer, vascular consultation should be obtained with consideration of additional vascular testing such as qualitative wave form analysis and systolic toe blood pressures.

51 Interpretation of the ABI
Interpretation ABI Normal Mild obstruction Moderate obstruction* Severe obstruction* <0.40 Poorly compressible** >1.30 2° to medial calcification *Poor ulcer healing with ABI < 0.50 **Further vascular evaluation needed A normal ABI is Most patients with claudication have an ABI between An ABI below is consistent with severe obstruction and a poor prognosis for the healing of a foot ulcer without revascularization. ABI values above 1.3 are usually due to poorly compressible arteries from medial calcification; further vascular evaluation is needed.

52 Risk-stratified Management of the Diabetic Foot
Let’s now review a risk-stratified approach to management of the diabetic foot.

53 Low Risk Annual comprehensive foot examination
Questionnaire completed by patient Examination Self-management and footwear education Brief counseling Written handout JAMA. 2005;293:217 Low risk, Category 0 patients have intact protective sensation to the 10-gram monofilament, no major foot deformities, pedal pulses are present, and there is no prior history of foot ulcer or amputation. Category 0 patients require an annual comprehensive foot examination. This examination can be facilitated by a questionnaire that patients complete in the waiting room and a decision-supported diabetic foot examination form (SEE TOOL-KIT). Category 0 patients at higher risk of foot ulcer-persons from racial minority groups or persons who are homeless or suffer from alcoholism – should additionally have a visual inspection of their feet at every visit. Category 0 patients should have basic foot care education about self-management of their feet and appropriate footwear. This can be accomplished with brief counseling and a short, written patient education handout (SEE TOOL-KIT).

54 High Risk Annual comprehensive foot exam
Inspect feet every office visit Podiatry care as needed Intensive patient education Detect/manage barriers to foot care Therapeutic footwear, as needed High risk category 1-3 patients, who have sensory neuropathy and one or more of the other key risk factors of major skeletal deformity, peripheral arterial disease, and/or prior foot ulcer or amputation, require a more aggressive approach to prevention. In addition to an annual comprehensive foot examination, the feet should be carefully inspected at every office visit, and patients should be referred to podiatry at a frequency necessitated by their risk level. Intensive patient education is essential, and any barriers preventing optimal foot care should be detected and managed. Finally, select patients may benefit from the use of therapeutic footwear.

55 High Risk: Nursing Tasks
Place “High-Risk Feet” stickers on each chart Remove patient’s shoes/socks Determine if patient can reach/see soles of feet Stock 10-g monofilament in each room Consider training to perform monofilament exam Provide patient education forms J Gen Intern Med. 2003;18:258 Nurses and medical assistants can facilitate the performance of foot examinations in the office setting, first by identifying high risk patients with a chart sticker (SEE TOOL-KIT). They can remove the patient’s shoes and socks prior to the clinician entering the room; in a randomized clinical trial this simple maneuver was shown to significantly increase the number of foot exams performed on diabetic patients. They should determine that the patient can both reach and see the soles of their feet. They should keep each exam room well-stocked with 10-gram monofilaments, and it may be reasonable to train them to accurately perform the monofilament examination. Finally, they should provide the patient with written education materials appropriate to their level of literacy and language needs.

56 High Risk: Podiatry Care
Provide nail and skin care Assess footwear needs Visit frequency not evidence-based Diabetes Care. 2003;26:1691 J Fam Practice. 2000;49(Suppl):S30 High risk category 1-3 patients should be referred to podiatry for regular prophylactic care of their skin and nails and for assessment of their footwear needs. A randomized clinical trial demonstrated a 48% relative risk reduction for recurrent foot ulceration in patients who had regular podiatric care. The optimal frequency of visits to podiatry has not been determined. Some investigators suggest that category 1 patients be seen every 3-6 months while category 2 and especially category 3 patients be seen more frequently.

57 High Risk: Patient Education
Reinforce frequently – low retention Patient demonstrates self-care knowledge Evidence: May reduce foot ulcer/amputation rates Cochrane Database Syst Rev Jan 25;(1)CD001488 Foot Ankle Int. 2005;26:38 High risk category 1-3 patients should receive intensive education from primary care clinicians, podiatrists, and diabetes educators. This education should be reinforced frequently as clinical studies have demonstrated low retention of this information. In particular, patients should be asked to demonstrate their self-care knowledge, and this can be efficiently accomplished using available questionnaires (SEE TOOL-KIT). A systematic overview of clinical trials suggests that patient education may reduce the rate of foot ulcer and amputation although the quality of available studies is low.

58 Basic Foot Care Concepts
Daily foot inspection May require mirror, magnification, or caregiver Patient able to recognize/report: Persistent erythema Enlarging callus Pre-ulcer (callus with hemorrhage) A central concept of basic foot care is daily inspection of the feet. This may require use of a mirror by patients who cannot reach their feet or a magnification glass by patients who cannot see their feet. In some patients the exam may need to be done by a caregiver. Patients should be educated to recognize important foot lesions and report them immediately including areas of persistent erythema following shoe removal, enlarging callus, and pre-ulcers (callus with hemorrhage).

59 Basic Foot Care Concepts
Commitment to self-care Wash/dry daily Lubricate daily (not between toes) Debride callus/corn (low-risk patients) No self-cutting of nails if: Neuropathy PAD Poor vision Diabetic patients must make a commitment to self-care of the feet including daily cleansing with care to avoid excessively hot water and to dry thoroughly between the toes. The feet should be lubricated daily but not between the toes, a site for excessive moisture and maceration. Debridement of callus with a callus file, emory board, or pumice stone may reduce plantar pressure by 25%, but debridement should not be accomplished with sharp instruments like razor blades or over-the-counter corn plasters that can cause a chemical burn. Patients should not cut their own nails if they have significant sensory neuropathy, peripheral arterial disease, or poor vision.

60 Basic Foot Protective Behaviors
Avoid temperature extremes No walking barefoot/stocking-footed Appropriate exercise for insensate feet Inspect shoes for foreign objects Optimal footwear at all times Patient foot care education should include cautions to avoid temperature extremes (walking barefoot in hot water or on hot sand, pavement or in snow) as well as to never walk barefoot or stocking-footed, a source of many traumatic injuries. Appropriate exercise is important for patients with diabetes, but patients with significant sensory neuropathy and loss of protective sensation may be better served by bicycling or swimming than by walking or treadmill exercise. Patients with significant neuropathy should inspect their shoes for foreign objects before they put them on. Optimal footwear is effective only if it is worn at all times; dangerous blisters may form when inappropriate footwear is used for special occasions.

61 Basic Footwear Education
Avoid: Pointed toes Slip-ons Open toes High heels Plastic Black color Too small Favor: Broad-round toes Adjustable (laces, buckles, Velcro) Athletic shoes, walking shoes Leather, canvas White/light colors ½” between longest toe and end of shoe With respect to basic footwear education, shoes with broad-round toes are favored over shoes with pointed toes to reduce pressure on the lateral edges of the foot. Shoes with adjustable laces, buckles, or Velcro can compensate for end-of-day foot swelling as compared to slip-ons. Athletic or walking shoes are favored over shoes with open toes or high heels, the latter resulting in high plantar pressure on the forefoot. Leather or canvas shoes with white or light colors result in less heat and sweating than plastic shoes, especially if their color is black. Patients should purchase their shoes at the end of the day when swelling is greatest and allow one-half inch between the longest toe and the end of the shoe. An excellent, highly readable patient education handout is available in the reference listed on the slide. Diabetes Self-Management. 2005;22:33

62 Barriers to Foot Care Depression Alcoholism
Social isolation if unable to inspect feet Financial barriers Diab Metab Res Rev. 2004;20(Suppl 1):S13 It is essential to detect and manage any barriers that might prevent optimal foot care. The prevalence of depression may be as high as 15-25% in persons with diabetes, and it may reduce patient motivation to care for their feet. The Patient Health Questionnaire-9 (PHQ-9) is a validated tool to screen for major depression in primary care and may be administered annually or as needed. Similarly, alcoholism should be detected and appropriately managed. Social isolation is a significant issue in diabetic patients who are unable to reach and/or see their feet if they are unsuccessful with mirrors and/or magnifying glasses; home health aides may be a solution for some patients. Diabetes is an expensive disease, and financial barriers can interfere with optimal foot care. As will be discussed, Medicare will certify certain diabetic patients for therapeutic shoe benefits.

63 Therapeutic Footwear Goals
Protect feet Reduce plantar pressure, shock, and shear Accommodate, stabilize, support deformities Suitable for occupation, home, leisure Diabetes Care. 2004;27:1832 Diab Metab Res Rev. 2004;20(Suppl1):S51 Therapeutic footwear may benefit selected diabetic patients. Inappropriate footwear is estimated to contribute to 21-76% of foot ulcers and subsequent lower extremity amputations. Optimal footwear should meet several criteria: Protect the feet from external injury Reduce plantar pressure and the shock and shear forces that contribute to callus and ulcer formation Accommodate, stabilize, and support any skeletal deformities of the foot, and Be suitable for use in occupational, home, and leisure settings.

64 Therapeutic Footwear Components
Padded socks (e.g., CoolMax, Duraspun, others) Shoe inserts/insoles (closed-cell foam, viscoelastic) Therapeutic shoes Padded socks are one component of therapeutic footwear, and several brands are available. Their role is to cushion the metatarsal heads and heels and reduce callus formation. Ideally, the socks should be white to facilitate detection of blood or pus from unrecognized foot ulcer, seamless to minimize pressure points, and absorbent to reduce excessive moisture. Shoe inserts and insoles are designed to reduce plantar pressure. Composed of closed-cell foam or viscoelastic materials, they can be purchased off-the-shelf for some patients, but they may have to be custom-molded for others. Therapeutic shoes can be purchased off-the-shelf with extra-depth to accommodate insoles and/or skeletal deformities, and/or with extra-width for skeletal deformities. Rigid-rocker outsoles can be added to reduce mid-foot pressure. Some patients will require custom-molded shoes.

65 Therapeutic Footwear Efficacy
Decreases plantar pressure 50%-70% Uncertain reduction in ulcer rate Diabetes Care. 2004;27:1774 The efficacy of therapeutic footwear is controversial. While therapeutic footwear clearly reduces plantar pressure 50-70%, its ability to reduce ulcer rates is less well established. No data are available concerning primary prevention of foot ulcer. For secondary prevention, analytic and descriptive studies have found 50-70% reductions in ulcer rates with therapeutic footwear. Two small randomized clinical trials have demonstrated no benefit. It is likely that benefits are greatest in patients with severe foot deformities or prior amputations who wear their therapeutic footwear consistently.

66 Medicare Requirements
Certify diabetic patient with foot at risk Prescribe therapeutic footwear Prepare/fit therapeutic footwear Pedorthist, orthotist, prosthetist, D.P.M. Foot Ankle Int. 2005;26:42 Medicare will cover much of the cost of therapeutic footwear if primary care physicians will certify that the patient has a foot-at-risk according to set criteria. Therapeutic footwear can then be prescribed by expert podiatrists, osteopaths, or M.D.’s, and the shoes can be prepared and fitted by any of several professionals. Certified pedorthists can be accessed at the website listed on the slide.

67 Amount Covered by Medicare
Medicare Coverage Medicare pays 80% of payment amount allowed: Total Amount Allowed Amount Covered by Medicare Extra-depth shoes $132.00 $105.60 Custom-made shoes $396.00 $316.00 Diabetic pre-fab insoles $67.00 $53.60 Diabetic custom insoles Medicare will pay 80% of the payment amount allowed as listed on this slide and will provide the type of shoes and number of inserts as listed. 1 pair extra-depth shoes  3 pair insoles/y, or 1 pair extra-depth shoes with modification  2 pair insoles/y, or 1 pair custom-molded shoes  2 pair insoles/y

68 This patient has multiple deformities including hammer and claw toes, prominent metatarsal heads on the plantar surface of the foot and an adductovarus deformity of the fourth toe (the toe literally curves around itself). The patient will require insoles to reduce plantar pressure and an extra-depth shoe with a deep toe box to accommodate the skeletal deformities.

69 An extra-depth shoe with a deep toe box with an off-the shelf insole

70 This patient has a Charcot deformity with extensive collapse of the skeletal architecture of the foot. Note that a toe is missing from a prior amputation. Deformities of this magnitude require custom-made insoles to reduce plantar pressure as well as a custom-made shoe to accommodate the deformities.

71 Conclusion Diabetic foot ulcer is common
Foot ulcers have devastating consequences Screening is simple Screening and team care reduce diabetic foot ulcers and amputations

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