Risk Stratification and Classification

Risk Stratification/Classification

Several systems and methods have been described in the literature and are used to classify the diabetic foot to aid communication, research, teaching and plan interventions. The purpose of risk stratification is to stratify those with diabetes, so management programs can be implemented and outcomes predicted. Little work has been done to validate the available systems or classifications.

International Working Group of the Diabetic Foot Classification
Based on perfusion, extent/size, depth/tissue loss, infection and sensation:
a) Perfusion:
 Grade 1
o No symptoms of peripheral arterial disease (PAD) in the affected foot, in combination with:
 Palpable dorsal pedal and posterior tibial artery or
 Ankle-brachial index .9 to 1.1 or
 Toe-brachial index >0.6 or
 Transcutaneous oxygen pressure >60 mmHg
 Grade 2
o Symptoms or signs of PAD, but not critical limb ischaemia (CLI):
 Presence of intermittent claudication or
 Ankle-brachial index <0.9, but with and ankle pressure >50mmHg or
 Toe-brachial index <0.6, but with systolic toe blood pressure >30 mmHg or
 TcP02 30- to 60 mmHg or
 Other abnormalities on non-invasive testing, compatible with PAD, (but not CLI)
 Grade 3
o Critical limb ischaemia:
 Systolic ankle pressure <50 mmHg or
 Systolic toe blood pressure <30 mmHg or
 TcP02 <30 mmHg
b) Extent/Size:
Measured in square centimetres after debridement

c) Depth/tissue loss:
Grade 1
Superficial full-thickness ulcer, not penetrating any structure deeper than the dermis
Grade 2
Deep ulcer, penetrating below the dermis to the subcutaneous structures, involving fascia, muscle or tendon
Grade 3
All subsequent layers of the foot involved including bine and/or joint

d) Infection:
Grade 1:
o no symptoms or signs of infection
• Grade 2:
o infection involving the skin and subcutaneous tissue only, with no involvement of deeper tissues and no systemic signs and symptoms. No other causes of an inflammatory response (eg gout, trauma, etc).
o at least two of the following manifestations are present;
 localised swelling or induration
 erythema >0.5-2cm around the ulcer
 local tenderness or pain
 local warmth
 purulent discharge
• Grade 3:
o infection involving structures deeper than the skin and subcutaneous tissues (eg abscesses, osteomyelitis, septic arthritis, or necrotizing fasciitis
o erythema (cellulitis) extending >2cm around and ulcer in addition to one of the following: oedema, tenderness, heat, purulent discharge
• Grade 4:
o Any foot infection with signs o a systemic inflammatory response syndrome, manifested by two or more of the following:
 Temperature <360C or >380C
 Heart rate >90 beats/min
 Respiratory rate >20 beats/min
 PaC02 <32 mmHg
 White blood cell count >12 000 or <4000 cells/mm3
 >10% immature (band) forms

e) Sensation:
 Grade 1:
o No loss of protective sensation on the affected foot detected, defined as the presence of sensory modalities listed below
 Grade 2:
o Loss of protective sensation on the affected foot is defined as the absence of perception of one of the following tests in the affected foot:
 Absent pressure sensation, determined with a 10g monofilament, on two out of three sites on the plantar side of the foot.
 Absent vibration sensation (determined with a 128-Hz tuning fork) or vibration threshold >25V, both tested on the hallux

Wagner

University of Texas Health Science Centre (UTHSC) System :

Diabetic Foot Category 0 (minimal pathology):
• Patient diagnosed with diabetes mellitus
• Sensorium intact
• Ankle brachial index of > 0.80 and toe systolic pressure >45mmHg
• Foot deformity may be present
• No history of ulceration
Treatment:
Triannual visits to assess neurovascular status, dermal thermometry and foci of stress
Possible shoe accommodation
Patient education

Diabetic Foot Category 1 (insensate foot):
Patient diagnosed with diabetes mellitus
Sensorium absent
Ankle brachial index >0.80 and toe systolic pressure >45mmHg
No history of ulceration
No history of diabetic neuropathic osteoarthropathy
No foot deformity
Treatment:
Same as category ), including:
Possible shoe accommodation
Dermal thermometry monitoring every 2-3 months
Yearly dynamic pressure updates

Diabetic Foot Category 2 (insensate foot with deformity):
• Patient diagnosed with diabetes mellitus
• Sensorium absent
Ankle brachial index >0.80 and toe systolic pressure >45mmHg
No history of ulceration
• No history of diabetic neuropathic osteoarthropathy
• Foot deformity present (focus of stress)
Treatment:
• Same as category 1, including:
• Consultation for possible custom molded or extra-depth shoe accommodation
• Possible prophylactic surgery to alleviate focus of stress

Diabetic Foot Category 3 (demonstrated pathology):
• Patient diagnosed with diabetes mellitus
• Sensorium absent
Ankle brachial index >0.80 and toe systolic pressure >45mmHg
History of neuropathic ulceration
• History of diabetic neuropathic osteoarthropathy
Foot deformity present (focus of stress)
Treatment:
Same as category 2 including:
• Consultation for possible custom molded or extra-depth shoe accommodation
• Possible prophylactic surgery to alleviate focus of stress
• More frequent visits may be indicated for monitoring

Diabetic Foot Category 4A (neuropathic ulceration):
• Patient diagnosed with diabetes mellitus
• Sensorium may or may not be intact
Ankle brachial index >0.80 and toe systolic pressure >45mmHg
Noninfected neuropathic ulceration
• No acute diabetic neuropathic osteoarthropathy (Charcot’s)
Foot deformity normally present
Treatment:
Same as category 3 including:
• Off weightbearing program instituted (possible total contact casts)
• Dressing change program instituted
• Debridement program instituted
• Dermal thermometric monitoring
• Weekly to biweekly visits as needed
• Possible prophylactic surgery

Diabetic Foot Category 5 (infected diabetic foot):
• Patient diagnosed with diabetes mellitus
• Sensorium may or may not be intact
• Infected wound
• Charcot’s joint may be present
Treatment:
• Same as category 4, including:
• Debridement of infected non viable necrotic tissue and bone
• Possible hospitalisation
• Antibiotic therapy
• Medical management
• Contact casting generally contraindicated until diabetic foot category drops to 4

Diabetic Foot Category 4B (acute Charcot’s joint):
• Patient diagnosed with diabetes mellitus
• Sensorium absent
Ankle brachial index >0.80 and toe systolic pressure >45mmHg
Noninfected neuropathic ulceration may be present
• Acute diabetic neuropathic osteoarthropathy (Charcot’s) is present
Treatment:
Same as category 3 including:
• Off weightbearing program instituted (possible total contact casts)
• Dermal thermometric and radiographic monitoring
• Weekly to biweekly visits as needed

Diabetic Foot Category 6 (dysvascular foot):
• Patient diagnosed with diabetes mellitus
• Sensorium may or may not be intact
• Ankle brachial index of <0.80 or toe systolic pressure <45mmHg or pedal transcutaneous oxygen tension of <40mmHg
• Ulceration may be present
Treatment:
• Vascular consult, possible revascularisation (if successful, patient reverts to a lower category)
• If infection is present, treatment same as for category 5
• Vascular consultation concomitant with control of sepsis
• Contact casting generally contraindicated.

Jeffcoate et al (1993):
1. Infection:
a. Cellulitis
i. Complicating and obvious ulcer
ii. N obvious ulcer
iii. Associated with pre-existing gangrene
iv. Caused by trauma
b. Osteomyelitis
i. Complicating an obvious ulcer
ii. No obvious precipitating ulcer
iii. Associated with gangrene
2. Ischaemia:
a. Symptomatic ischaemia without an ulcer
i. Claudication
ii. Rest pain
b. Painless scabbed lesions of the skin
i. Single
ii. Multiple
c. Gangrene
i. Of a digit or digits
ii. Of the forefoot
d. Persistent unhealing ischaemic lesions
i. Neuroischaemic ulcers
ii. Following surgery
iii. Following other trauma
iv. With no known cause
e. Ischaemic heel ulcers
i. Small
ii. Large
iii. Painful cracks
f. Blisters (epidermis intact)
i. Caused by definable trauma
ii. No know cause
3. Neuropathy:
a. Ulcers with surrounding callus over an area of increased pressure
i. Under metatarsal head
ii. On toe
iii. Complicating Charcot deformity
iv. Complicating surgery
v. Complicating other deformity
b. Neuropathic ulcers under the calcaneus
c. Ulcers caused by unnoticed trauma
d. Acutely evolving Charcot deformity

Seattle Wound Classification System of Diabetic Foot Ulcers :
1. Intact skin
1.1 Without lesions
1.2 Superficial minor lesion(s) with no functional interruption of the protective cutaneous barrier
1.3 Non ulcerated minor lesion(s) less than four weeks duration with ? evidence of healing progress sufficient to close previous interruption of the cutaneous barrier
2. Acute ulcer or preulcerative soft tissue infection
2.1 Subcutaneous abscess or acute localised cellulitis without rupture of the overlying cutaneous envelope
2.2 Inflamed red oedematous ulcer with exudate
3. Partial thickness ulcer involving epidermis and dermis. Clean, moist, granulating, superficial
3.1 Ulcer with partial or early granulations
3.2 Ulcer with exuberant granulations
4. Ulcer penetrating to subcutaneous tissue (full thickness)
5. Ulcer covered by an adherent film of necrotic material
6. Ulcer covered by a hard, black eschar
7. Ulcer with superficial loss of tissue, penetrating to tendon, ligament, joint capsule or bone
8. Ulcer with deep tissue infection
9. Gangrene involving a portion of the foot
10. Entire foot (or leg) gangrenous

Other risk assessment and classification strategies are available (eg Carville Foot Risk Assessment)

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