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Australian Diabetes Foot Network: management of diabetes-related foot ulceration — a clinical update

Shan M Bergin, Joel M Gurr, Bernard P Allard, Emma L Holland, Mark W Horsley, Maarten C Kamp, Peter A Lazzarini, Vanessa L Nube, Ashim K Sinha, Jason T Warnock, Jan B Alford and Paul R Wraight
Med J Aust 2012; 197 (4): 226-229. || doi: 10.5694/mja11.10347
Published online: 20 August 2012

In 2005, over 1000 people with diabetes died as a direct result of lower limb ulceration; this represented 8% of all diabetes-related deaths.1 Annually, there are about 10 000 hospital admissions for diabetes-related foot ulcers (DRFUs) in Australia, with lower limb amputation a common outcome.1,2

Most DRFUs occur in the presence of peripheral sensory neuropathy, foot deformity and/or trauma, with peripheral arterial disease (PAD) and infection being further complicating factors that prevent or delay ulcer healing.3-5 Therefore, for successful management of DRFUs, all interdependent factors affecting healing should be addressed simultaneously.6 Health professionals without the resources, time and/or clinical skills to appropriately manage these individuals must refer them to others that do have the resources and skills. People with complex or non-healing DRFUs should be referred to a multidisciplinary foot care team (MFCT) comprising medical, surgical, nursing, podiatry and other allied health professionals with appropriate skills and knowledge, for immediate management.

Assessment

All individuals with a DRFU should be clinically assessed for aetiology and factors that may prevent wound healing. A comprehensive foot and wound assessment (Box 1), complemented by a more general assessment, will help guide investigation and management strategies.6,7 Published wound classification systems are a useful adjunct to clinical assessment and can assist with wound documentation and assessing progress over time. The Wagner and University of Texas classification systems are two readily available examples.8,9

The initial response to treatment can be a robust predictor of wound healing.10 In the absence of clear benchmarks for DRFU healing times, we suggest that wounds demonstrating a lack of progress in healing after 4 weeks of appropriate treatment should be referred to an MFCT. Indicators for more immediate referral to an MFCT or emergency department include gangrene, limb-threatening ischaemia, deep ulcers (bone, joint or tendon in the wound base), ascending cellulitis, systemic symptoms of infection and abscesses.

Management recommendations

General management recommendations are summarised in Box 2.

Debridement

Debridement of DRFUs is an essential component of wound bed preparation, as it removes non-viable tissue, allows comprehensive examination of the wound bed and assessment of actual wound size, has the potential to convert a chronic wound to an acute wound, and reduces local pressure on the ulcer.10,11 Surgical sharp debridement is required for management of deep necrotic tissue, gangrene, drainage of collections, deep infections or when pain necessitates the use of an anaesthetic.12,13 Non-surgical sharp debridement is generally required every 1–2 weeks to remove non-viable tissue, including the surrounding callus.12 Non-sharp debridement (enzymatic, autolytic and biological) can be used as an adjunct to sharp debridement and can be especially helpful for adherent slough, or when pain limits non-surgical sharp debridement.14

In the presence of PAD, debridement could potentially create a larger non-healing wound, therefore vascular investigations are indicated before debridement. One exception is for an abscess, which requires immediate drainage to reduce tissue pressures, control infection and prevent further tissue loss. Same-day vascular review is then recommended.

Dressing selection

Ulcers should be regularly inspected and cleaned with saline or clean water.7 Cleaning with surface antiseptics (eg, chlorhexadine) is not recommended, as this may be harmful to granulation tissue.11

There is no evidence showing that one type of dressing is better than another, or that one type of dressing can be used on all wounds. Dressing choice will generally change as the wound characteristics change during healing. Dressing selection is based on the principles of “moist wound healing”, where inflammation, infection and exudate are controlled while maintaining an adequate moisture balance at the wound bed.7,11 In general, foam dressings meet the objectives of moist wound healing and will suit a wide variety of wounds.

An exception to the creation of a moist wound environment is when a dry, non-infected ulcer is present in the setting of ischaemia. These ulcers should be kept dry and covered with a non-adherent, non-occlusive dressing until a vascular referral and management plan is arranged.

There is some evidence supporting the use of new technologies such as negative pressure wound therapy and hyperbaric oxygen for healing DRFUs. However, the specific knowledge and skills required for these technologies generally limits their use to MFCTs,15 and they would form only a part of the comprehensive wound management plan.

Pressure off-loading

Pressure off-loading is an essential component of DRFU management, particularly in the case of plantar neuropathic ulcers.11,16 Total contact casting has been shown to heal more plantar wounds, but it requires proficient staff for safe application and removal, and is contraindicated with significant PAD and spreading infection. Casting is not always appropriate, and has the potential to cause iatrogenic ulcers, muscle wasting and increase the risk of falls.17

Removable ambulatory walkers (eg, controlled ankle movement walkers and air casts) have been shown to off-load pressure from ulcers by an equivalent amount to total contact casting.16 However, their efficacy in healing wounds is generally less than total contact casting, as they can be removed. An individual’s compliance can be improved by making an ambulatory walker irremovable by applying a cable tie or adhesive bandage around it.18 Other pressure off-loading devices, such as postoperative shoes and felt padding, should be considered when total contact casts and ambulatory walkers are either unavailable or contraindicated.17

In the presence of significant underlying deformity, people with ulcers that fail to heal using conservative pressure off-loading techniques should be assessed by an orthopaedic surgeon and/or an MFCT to determine if they would benefit from surgical intervention. Procedures such as tendoachilles lengthening, arthroplasties, metatarsal head resection and tenotomies may improve healing time and reduce the risk of ulcer recurrence.19 Surgery of this type should not be considered in the presence of PAD without input from a vascular specialist.

Ongoing relief of pressure is important for secondary prevention in people with healed foot ulceration, particularly in the presence of a foot deformity. In the absence of a foot deformity, most individuals with a healed ulcer can be accommodated in off-the-shelf footwear (unmodified comfort or sports shoes). Medical-grade footwear is generally required for people with a foot deformity as it provides extra depth, multiple-width fittings and features designed for a broader range of foot types. Medical-grade footwear may also be fitted with custom-made orthoses to redistribute plantar pressure and reduce the risk of future foot ulceration. Medical-grade footwear should be purchased from suppliers with trained staff. Medical-grade footwear can be expensive, so health professionals should be aware of government-funded schemes to support such purchases (eg, the Department of Veterans Affairs “gold cards”).

Infection
Soft tissue infection

Soft tissue infection is a common complication of DRFUs and must be treated immediately with systemic antibiotics. Clinical signs and laboratory markers typically associated with infection can be blunted or absent in people with diabetes, so should not be relied on in isolation to assess infection severity.20 An increase in skin pigmentation may be a sign of inflammation and/or infection in individuals with pigmented skin.

Clinically infected wounds should be cultured by deep tissue swabs taken after debridement or by tissue samples, for identification of microorganisms and antibiotic sensitivities.21 Mild, acute wound infections (characterised by < 2 cm of surrounding cellulitis) can usually be managed by primary health care professionals, using oral antibiotics effective for gram-positive cocci (eg, Staphylococcus aureus and streptococci). Infections characterised by systemic toxicity, more than 2 cm of cellulitis, a deep abscess or osteomyelitis require immediate referral to hospital or an MFCT.

Wound chronicity, prior antibiotic use, renal impairment and hospitalisation are all risk factors for polymicrobial infections with gram-positive cocci, gram-negative bacilli and/or anaerobes. When these risk factors are present, broad-spectrum antibiotic therapy should immediately be commenced and then modified according to culture results.22 Clinically non-infected wounds require neither wound culture nor antimicrobial therapy.21

Osteomyelitis

Osteomyelitis can complicate DRFUs, increasing the risk of amputation. A positive “probe to bone” test is highly suggestive of osteomyelitis and should be performed routinely by inserting a sterile instrument into the ulcer to determine whether bone can be probed at the base.21,23 Plain x-ray is a valuable baseline investigation when osteomyelitis is suspected, and will also identify foreign bodies and tissue gas. The radiological signs of osteomyelitis may be delayed, so a normal x-ray should not be interpreted as definitive when there is a high level of clinical suspicion for osteomyelitis. Magnetic resonance imaging has a higher sensitivity and specificity for osteomyelitis than plain x-ray, so is the imaging modality of choice, and may help differentiate the condition from Charcot neuroarthropathy.21 Bone scans and white cell scans generally lack specificity for diagnosing osteomyelitis.

Although surgery has been the mainstay of treatment for pedal osteomyelitis, there is evidence supporting medical management of focal osteomyelitis with antibiotics or antibiotics combined with limited surgical resection.24-26 It is difficult to predict which cases will or will not respond to antibiotic therapy, so this strategy should be undertaken with the guidance and supervision of an MFCT.

It is worth noting that acute Charcot neuroarthropathy can mimic soft tissue infection and must be considered as a differential diagnosis in anyone with diabetic neuropathy who presents with a red, hot and/or swollen foot, especially in the absence of an ulcer.

Vascular management

If pedal pulses are absent in either foot, if there is gangrene or if there is no improvement in the ulcer healing despite appropriate wound management for 4 weeks, the person should be referred to a vascular specialist or an MFCT. Vascular specialists and MFCT members are the most appropriate individuals for selecting advanced investigations (eg, arterial Doppler ultrasound, computed tomography angiogram, magnetic resonance angiogram and catheter angiogram). Revascularisation by either percutaneous angioplasty or operative bypass is recommended whenever possible.27

Glycaemic control and other cardiovascular comorbidities

As well as specific treatment for a DRFU, it is important to undertake a general assessment of the individual’s diabetes and other cardiovascular comorbidities.28 This is aimed at preventing the development or progression of other diabetes-related complications (which may further affect foot health), and at reducing mortality through modification of cardiovascular risk factors. Lipid and blood pressure control should be maximised, cessation of smoking encouraged and aspirin therapy considered.29 There is no study addressing the role of glycaemic control in the acute management of diabetes-related foot complications, but it is prudent to optimise glycaemic control at the time of acute illness, when there is infection and perioperatively. Metformin should be withdrawn when there is significant infection and/or ischaemia, when an individual is fasting for procedures and with administration of angiographic contrast.29

Multidisciplinary care

It is well documented that best-practice management of complex DRFUs need coordinated, expert interdisciplinary input in both inpatient and outpatient settings.30,31 Management by MFCTs, comprising medical, surgical, nursing, podiatry and other allied health professionals with appropriate skills and knowledge, increases the percentage of healed ulcers and reduces wound healing times, hospitalisation and amputations.32,33

Conclusion

To achieve the best clinical outcomes, all DRFUs require multifactorial management from at least a medical practitioner with a podiatrist and/or wound care nurse. The management package requires appropriate wound debridement, wound dressings, pressure off-loading, glycaemic control and, when indicated, treatment of infection and improvement of peripheral blood flow. When there is significant PAD, infection or failure to respond to appropriate treatment, all individuals should promptly be referred to an MFCT or hospital.

1 Wound and foot assessment

Both feet should be assessed for:

  • abnormal foot shape, previous amputation and new ulceration

  • signs of infection

  • peripheral sensory neuropathy

  • peripheral arterial disease

  • possible cause of ulceration (footwear)

All ulcers should be assessed for the following at each contact:

  • site, size and depth

  • probable bone in the wound base

  • presence and amount of slough, necrotic and granulation tissue

  • presence of exudate (type and amount)

  • presence or absence of pain

  • signs of clinical infection

  • condition of tissue and skin surrounding ulcer

2 Management of diabetes-related foot ulcers

All diabetes-related foot ulcers will require a management “package” comprising:

  • debridement of non-viable tissue

  • wound dressings

  • pressure off-loading

  • antibiotics when clinical infection is present

  • management of peripheral arterial disease when present

  • management of glycaemic control and other cardiovascular comorbidities

3 Superficial ulcer on third toe resulting from hammer toe deformity and ill fitting footwear (scale in cm)

4 Dorsal foot ulcer: exposed tendons surrounded by granulation tissue


Provenance: Not commissioned; externally peer reviewed.

  • Shan M Bergin1
  • Joel M Gurr2
  • Bernard P Allard3
  • Emma L Holland4
  • Mark W Horsley5
  • Maarten C Kamp6
  • Peter A Lazzarini7
  • Vanessa L Nube8
  • Ashim K Sinha9
  • Jason T Warnock10
  • Jan B Alford11
  • Paul R Wraight12

  • Australian Diabetes Foot Network, Australian Diabetes Society, Sydney, NSW.

Correspondence: paul.wraight@mh.org.au

Acknowledgements: 

The Australian Diabetes Society (ADS) receives funding from the National Diabetes Services Scheme. This guide is supported by the ADS, Australasian Podiatry Council, Australian Diabetes Educators Association, Australian and New Zealand Society for Vascular Surgery, Australian Wound Management Association and Diabetes Australia.

Competing interests:

No relevant disclosures.

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