Clinical Practice Recommendations for Management of the Diabetic Foot in the Wound Clinic

DFUs remain the precursors to amputation, and efforts among healthcare providers must focus on prevention and expeditious treatment if amputation rates are to be reduced.

In 2009, a summit was held in Tucson, AZ, to initiate the development of an ongoing, sustainable relationship between the American Podiatric Medical Association (APMA) and the Society for Vascular Surgery (SVS). The expressed goals were to improve patient care and promote education with respect to the management of the diabetic foot. This meeting was spurred by the recognition of the profound and growing impact of the global epidemic of diabetes. Noncommunicable diseases have become, for the first time in human history, the leading cause of death.¹ Diabetes is the quintessential disease in this regard and now affects more than 422 million people worldwide.² Diabetes is also the leading cause of nontraumatic amputations — a patient who’s living with diabetes undergoes a major limb amputation every 20 seconds.³ Diabetic foot ulcers (DFUs) are common and costly, with the annual cost of diabetic foot disease in the United States estimated to be at least $6 billion. DFUs remain the precursors to amputation, and efforts among healthcare providers must focus on prevention and expeditious treatment if amputation rates are to be reduced. The first tangible results of this collaboration appeared in a joint statement from both the APMA and SVS on the role of the interdisciplinary team approach in the management of the diabetic foot⁴ in June 2010, followed by a dedicated journal supplement in September 2010 discussing strategies to prevent and heal DFUs by building partnerships for amputation prevention.^5,6 The sustainability of these collaborative efforts is further evidenced by recently published clinical practice guidelines on management of the diabetic foot. In addition to contributors from APMA and SVS, the Society for Vascular Medicine (SVM) was included in producing and reviewing guidelines prior to publication.⁷

ORGANIZATION OF GUIDELINES 

This committee, including contributors from all three collaborating organizations, made specific practice recommendations using the Grading of Recommendations Assessment, Development and Evaluation. The specific recommendations are based on five systematic reviews of the literature. Specific areas of focus included: 1) prevention of diabetic foot ulceration; 2) offloading; 3) diagnosis of osteomyelitis; 4) wound care; and 5) peripheral artery disease (PAD). It is beyond the scope of this overview article to cover all of these areas in detail, but key recommendations and a selection of those with the most potential impact in clinical practice or the highest level of evidence-based support will be highlighted. Despite the ubiquity of diabetic foot problems, as well as given the magnitude of their socioeconomic impact, only limited high-quality evidence for many of the critical questions could be identified. This state of affairs highlights the importance and necessity of increasing research efforts to obtain funding to answer these questions.⁸ Committee members used the best available evidence and considered patients’ values and preferences as well as the clinical context to develop these guidelines.

PREVENTION OF DFUs

Prevention is of key importance, so the initial recommendations focus on this important element of diabetic foot care. Patients living with diabetes should undergo annual interval foot inspections by physicians or advanced practice providers with training in foot care (Grade 1C), and foot examination should include testing for peripheral neuropathy using the Semmes-Weinstein⁹ test (Grade 1B). Given a lack of evidence of benefit, the use of specialized therapeutic footwear in average-risk patients living with diabetes is not suggested (Grade 2C). However, customized footwear is recommended in high-risk patients, including those experiencing significant neuropathy, foot deformity, or prior amputation (Grade 1B). Education of patients and their families about foot care is also highly recommended (Grade 1C). Clinicians therefore must not just have time to evaluate and treat, but also to counsel and educate.

OFFLOADING

For those patients experiencing plantar DFUs, the guidelines recommend offloading with a total contact cast (TCC) or irremovable fixed ankle walking boot (Grade 1B). This recommendation has critical implications for wound care clinics. Despite an abundance of efforts supporting TCC as the most effective method of offloading, data show they are used infrequently in wound care clinics, especially in the U.S. TCCs reduce plantar pressure up to 87% and randomized trials show they are far more efficacious than standard therapeutic shoes and removable devices both in the most clinically relevant endpoints: proportion of patients’ healing and time to healing.¹⁰

DIAGNOSIS OF OSTEOMYELITIS

Osteomyelitis is a frequent accompaniment of DFUs and its diagnosis remains challenging. In patients with a new infection of a DFU, the guidelines recommend the probe-to-bone (PTB) test and serial plain radiographs to identify bony abnormalities (deformity, destruction), soft tissue gas, and radio-opaque foreign bodies. PTB is inexpensive and poses minimal patient risk. The accuracy of the PTB test is influenced by pretest probability and is most useful with initial infections in patients who have not had recent foot surgery. These simple examinations are less costly and easy to obtain, and may eliminate the need for more expensive testing in many patients. An MRI should be considered (Grade 1B) if a soft tissue abscess is suspected or the diagnosis of osteomyelitis is uncertain (PTB inconclusive, radiographs equivocal). Bone cultures should be obtained, when possible, in uncertain cases and whenever bone is surgically debrided to treat presumptive osteomyelitis (Grade 1C).

DFUs & PAD

In patients living with DFUs who may have comorbid PAD, the group recommends routine assessment of foot perfusion¹¹ and application of a classification system such as the SVS Lower Extremity Threatened Limb Classification system based on Wound, Ischemia, and foot Infection (WIfI) to select patents who would benefit from revascularization by either surgical bypass or endovascular therapy.¹² Toe waveforms and pressures are highly recommended given the inherent limitations of ankle-brachial index measurements in these patients (Grade 1B); transcutaneous oxygen measurements are also useful.^11,12 Perfusion assessment is thus a routine component of the initial evaluation of DFUs, reassessment for those whose wounds fail to respond, and is suggested as a routine component of annual follow up in the highest risk group of patients, including those with a history of DFUs, PAD, prior PAD intervention or bypass, or known atherosclerotic cardiovascular disease (Grade 2C).

WOUND CARE

Patients living with DFUs must be seen frequently to ensure optimal treatment and to be certain that response to clinical care is appropriate. Standard comprehensive care should always include local wound debridement, offloading, control of edema, control of bioburden, and maintenance of wound moisture balance with appropriate dressings. If these techniques are routinely employed, adjunctive therapies will only be required in a minority of patients. The number of visits required to properly care for DFUs has major implications for staffing of wound care clinics. The guidelines recommend frequent evaluation (at 1-4-week intervals) to measure the wound; monitor for the appropriate, expected reduction in wound size; and assess healing progress (Grade 1 C). Sharp wound debridement of all infected ulcers should be performed urgently (Grade 1B). For non-infected DFUs, sharp debridement of all devitalized tissue and surrounding callus should be performed at 1-4-week intervals to speed healing (Grade 1B). There is insufficient evidence to recommend specific dressings for DFUs, but the principle of maintaining a moist wound bed while avoiding maceration of adjacent tissue is well supported by the evidence (Grade 1B). For DFUs that fail to improve as manifested by at least a 50% wound area reduction after four weeks of standard wound therapy, the guidelines recommend use of adjunctive wound therapy options including negative pressure, biologics, living cellular therapy, and extracellular matrix products. Specific agents are discussed in broader detail in the full document.⁷ The three most likely reasons for failure of a wound to respond are inadequate offloading, ischemia, and infection. Before proceeding with complex or adjunctive wound therapies, it is recommended that the wound care practitioner reassess adequacy and patient adherence with offloading, vascular status, and presence and control of infection (Grade 1B). Superimposed infection is a key driver of amputation and the risk of amputation in a patient living with a DFU correlates directly with severity of the infection. In addition, the presence of PAD in association with infection triples the amputation risk. Coordinated care to recognize infection early, drain and control it promptly and aggressively, administer appropriate antibiotics, and perform timely revascularization as soon as infection has been controlled is essential to minimize the risk of major amputation in these patients, as they generally fall within the group at highest risk for amputation (stage IV) in the SVS Lower Extremity Threatened Limb Classification system based on WIfI.¹²

CONCLUSION

It is clear after considering the broad scope of these recommendations that diabetic foot care is best provided by an organized, cohesive team in which the breadth of knowledge extends beyond the scope of most individual specialties. The SVS, APMA, and now SVM collaboration resulting in the publication of various dedicated literature and joint guidelines represents a coordinated effort to encourage the development of such limb salvage teams across the nation.^4-6 The complete guidelines are available online.⁷ All five areas in which recommendations have been made were preceded by five systematic reviews of the literature, which have been individually published and to which the interested reader is referred. This management of the diabetic foot guidelines and all SVS clinical practice guidelines are also available as a set of an interactive practice guidelines application that can be downloaded from both iTunes and Google Play.¹³ The app includes calculators for the SVS WIfI Threatened Limb Classification System as well as the CEAP Classification (clinical, etiologic, anatomic, and pathophysiologic) and Venous Clinical Severity, which should prove very useful for busy clinicians working in wound care clinics and other venues for the provision of wound care.¹⁰ 

Joseph L. Mills is professor of surgery in the Michael E. DeBakey Department of Surgery and chief of the division of vascular surgery and endovascular therapy at Baylor College of Medicine, Houston, TX. He may be reached at joseph.mills@bcm.edu.

References 

1. Reddy KS, Hunter DJ. Noncommunicable diseases. N Engl J Med. 2013;369(26): 2563.

2. NCD Risk Factor Collaboration (NCD-RisC). Worldwide trends in diabetes since 1980: a pooled analysis of 751 population-based studies with 4.4 million participants. Lancet. 2016;387(10027):1513-30. 

3. International Diabetes Federation. IDF Diabetes Atlas. 6th ed. Brussels, Belgium. 2015. 

4. Sumpio BE, Armstrong DG, Lavery LA, Andros G. The role of interdisciplinary team approach in the management of the diabetic foot: a joint statement from the Society for Vascular Surgery and the American Podiatric Medical Association. J Vasc Surg. 2010;51(6):1504-6.

5. Mills JL Sr, Armstrong DG, Andros G SVS/APMA writing group. Rescuing sisyphus: the team approach to amputation prevention. J Vasc Surg. 2010;52(3 suppl):1S-2S.

6. Rogers LC, Andros G, Caporusso J, Harkless LB, Mills JL, Armstrong DG. Toe and flow: essential components and structure of the amputation prevention team. J Vasc Surg. 2010;52(3 Suppl):23S-27S.

7. 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 of Vascular Medicine. J Vasc Surg. 2016;63(2 Suppl):3S-21S.

  8. Armstrong DG, Kanda VA, Lavery LA, Marston W, Mills JL, Sr Boulton AJ. Mind the gap: disparity between research funding and costs of care for diabetic foot ulcers. Diabetes Care. 2013;36(7):1815-7.

  9. Feng Y, Schlösser FJ, Sumpio BE. The Semmes Weinstein monofilament examination as a significant predictor of the risk of foot ulceration and amputation in patients with diabetes mellitus.. J Vasc Surg. 2011;53(1):220-6.

10. Cavanaugh PR, Bus SA. Off-loading the diabetic foot for ulcer prevention and healing. J Vasc Surg. 2010;52(3 Suppl);37S-43S.

11. Wang Z, Hasan R, Firwana B, et al. A systematic review and meta-analysis of tests to predict wound healing in diabetic foot. J Vasc Surg. 2016;63(2S):22S-28S.

12. Mills JL Sr, Conte MS, Armstrong DG, et al. The Society for Vascular Surgery lower extremity threatened limb classification system: risk stratification based on Wound, Ischemia and foot Infection (WIfI). J Vasc Surg. 2014;59(1):220-34.

13. Society for Vascular Surgery. Interactive Practice Guidelines App. Accessed online: https://vascular.org/research-quality/clinical-practice-documents/interactive-practice-guidelines-app