Criteria

The Society for Vascular Surgery lower extremity threatened limb classification system: risk stratification based on wound, ischemia, and foot infection (WIfI)[50][51]

The WIfI (Wound, Ischemia, Foot Infection) scoring system is widely used for classifying and describing diabetic ulcers, and to stratify the likelihood of healing and amputation risk in patients. It is endorsed for these purposes by the International Working Group on the Diabetic Foot (IWGDF), European Society for Vascular Surgery, Society for Vascular Surgery, and American Heart Association.​[10][18][52]​​​ It can also be used to describe infected ulcers; however the the IWGDF/Infectious Diseases Society of America (IDSA) classification (see below) is recommended as first-choice for this scenario.[52]

When using the WIfI system, it is recommended that clinicians report the individual variables, rather than giving a total score.

Wound (W):

  • 0: no ulcer or gangrene

  • 1: mild - small, shallow ulcer(s) on distal leg or foot; no exposed bone (unless limited to distal phalanx); no gangrene

  • 2: moderate - deeper ulcer with exposed bone, joint, or tendon; generally not involving the heel; shallow heel ulcer without calcaneal involvement; gangrenous changes limited to digits

  • 3: severe - extensive, deep ulcer involving forefoot and/or midfoot; deep, full thickness heel ulcer ± calcaneal involvement; extensive gangrene involving forefoot and/or midfoot; full thickness heel necrosis ± calcaneal involvement

Ischemia (I):

  • 0: ankle-brachial index (ABI) ≥0.80; ankle systolic pressure >100 mmHg; toe pressure (TP)/transcutaneous oximetry (TcPO₂) ≥60 mmHg

  • 1: mild - ABI 0.6 to 0.79; ankle systolic pressure 70 to 100 mmHg; TP/TcPO₂ 40 to 59 mmHg

  • 2: moderate - ABI 0.4 to 0.59; ankle systolic pressure 50 to 70 mmHg; TP/TcPO₂ 30 to 39 mmHg

  • 3: severe - ABI ≤0.39; ankle systolic pressure <50 mmHg; TP/TcPO₂ <30 mmHg

Foot infection (FI):

  • 0: no symptoms or signs of infection

  • 1: mild - infection present, as defined by the presence of at least 2 of the following:

    • Local swelling or induration

    • Erythema >0.5 cm to ≤2 cm around ulcer

    • Local tenderness or pain

    • Local warmth

    • Purulent discharge

  • 2: moderate - local infection (as described above) with erythema >2 cm, or involving structures deeper than skin and subcutaneous tissues (e.g., abscess, osteomyelitis, septic arthritis, fasciitis); no systemic inflammatory response signs

  • 3: severe (limb and/or life-threatening) - local infection (as described above) with signs of systemic inflammatory response syndrome as manifested by at least 2 of the following:

    • Temperature >100.5°F (38°C) or <96.8°F (36°C)

    • Heart rate >90 bpm

    • Respiratory rate >20 breaths/minute or PaCO₂ <32 mmHg

    • WBC count >12,000/mm³ or <4000/mm³ or 10% immature (band) forms

    A simple Venn diagram has been designed to assist clinicians in defining which specific factor is dominant. [Figure caption and citation for the preceding image starts]: Diabetic foot problems can be related to the presence of a wound, ischemia, or infection (WIfI). Which of these parameters is dominant may vary, and a flexible long-term management approach is needed. The Venn diagram shows intersecting rings of dominance for these three parameters, with gradings listed for each. The shaded areas represent combinations of these parameters of dominanceFrom the collection of Dr David G. Armstrong and Dr Joseph L. Mills Sr; used with permission [Citation ends].com.bmj.content.model.Caption@70670025

International Working Group on the Diabetic Foot (IWGDF): diabetic foot ulcer classification[52]​​

The SINBAD (Site, Ischemia, Neuropathy, Bacterial Infection, Area, and Depth) System is a descriptive tool for assessing and classifying diabetic foot ulcers, as well as for audit, benchmarking, and communication between healthcare professionals. It uses a scoring system with a maximum of 6 points. A score of 3 or more is associated with an increased time to healing and greater risk of eventual failure to heal. When using the SINBAD system, clinicians should describe the individual variables rather than a total score.

Site

  • Forefoot (0 points)

  • Midfoot and hindfoot (1 point)

Ischemia

  • Pedal blood flow intact: at least one palpable pulse (0 points)

  • Clinical evidence of reduced pedal flow (1 point)

Neuropathy

  • Protective sensation intact (0 points)

  • Protective sensation lost (1 point)

Bacterial infection

  • None (0 points)

  • Present (1 point)

Area

  • Ulcer <1 cm² (0 points)

  • Ulcer ≥1 cm² (1 point)

Depth

  • Ulcer confined to skin and subcutaneous tissue (0 points)

  • Ulcer reaching muscle, tendon, or deeper (1 point)

International Working Group on the Diabetic Foot and Infectious Diseases Society of America: classification system for foot infections in people with diabetes[41]

A diabetic foot infection is defined by the presence of at least two of the following:

  • Local swelling or induration

  • Erythema (>0.5 cm around the wound)

  • Local tenderness or pain

  • Local warmth

  • Purulent discharge

Once an infection is diagnosed, the IWGDF/IDSA classification system should be used to describe the severity of infection and to guide management, in particular to identify which patients require hospital admission for intravenous antibiotics.

Infection severity

  • 1: Uninfected

    • No systemic or local symptoms or signs of infection

  • 2: Mild

    • Presence of ≥2 of the following: local swelling or induration, erythema 0.5 cm to <2 cm around the wound, local tenderness or pain, local increased warmth, or purulent discharge (exclude other causes of inflammatory response, such as trauma, gout, acute Charcot neuro-osteoarthropathy, fracture, thrombosis, and venous stasis)

  • 3: Moderate: add “O” for any infection involving bone (osteomyelitis)

    • Infection (as for mild severity above) with no systemic manifestations and involving erythema extending ≥2 cm from the wound margin, and/or tissue deeper than skin and subcutaneous tissues (e.g., tendon, muscle, joint, and bone). Add “O” for any infection involving bone (osteomyelitis)

  • 4: Severe: add “O” for any infection involving bone (osteomyelitis)

    • Any foot infection with associated manifestations of systemic inflammatory response syndrome, as manifested by ≥2 of the following: temperature >100.5°F (38°C) or <96.8°F (36°C), heart rate > 90 beats/minute, respiratory rate >20 breaths/minute or PaCO₂ <32 mmHg, WBC count >12,000/mm³ (leukocytosis) or <4000/mm³ (leukopenia); or a normal WBC count with >10% immature (band) forms

University of Texas: diabetic wound classification[26]

Stages:

  • A: no infection or ischemia present

  • B: infection present

  • C: ischemia present

  • D: infection and ischemia present

Grades:

  • 0: epithelialized (healed) ulcer

  • 1: superficial ulcer (epithelium with or without dermis)

  • 2: ulcer penetrates to tendon or capsule

  • 3: ulcer penetrates to bone or joint

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