Diabetic Foot

Recalcitrant ulceration and infection of the foot.

Epidemiology

            - 3-6% diabetics à Foot Ulceration

            - Amputation 16x in diabetics

            - ↑Age

            - Males

            - Caucasians 4x > Asians

Etiology

            - Neuropathy; particularly loss of sensory and proprioceptive elements.

            - PVD

            - Microvascular disease

            - Biomechanical

            - Infection; impaired leukocyte activity

Neuropathy

            - Nerves affected by ischaemia, gylcaemia

            - 20-50% diabetics

            - Numbness, Parasthesia, Hyperasthesia, Burning, Pain

            - Autonomic neuropathy à Warm foot, bounding pulses, dry skin

PVD

            - 20x more common in diabetics

            - More distal disease than non-diabetics

            - Often à Critical ischaemia without claudication

Biomechanical

            - Loss of sensation and Repetitive trauma --> Charcot joint / Ulceration

            - Exacerbated by ill-fitting shoes, poor vision

Microvascular

            - Thickening of capillary basement membrane

Pathology

            - Pure neuropathic 50%

            - Pure ischaemic 10%

            - Mixed 40%

Clinical

            - Numbness / Pain (neuropathic / ischaemic)

            - Joint pain / deformity

            - Ulceration

            - Osteomyelitis

            - Gangrene
Test ABIs
Complete neurovascular exam
Radiographs to assess occult Charcot bone and joint destruction / collapse.

Wagener Classification of Ulcers

Management

Principles
MDT
- surgeon, endocrine, vascular, podiatrist
- optimise diabetes
- optimise blood supply to the leg
- control any sepsis; broad spectrum required.

Neuropathy

            - Regular self-examination of feet

            - Debride callus

            - Proper footwear, Scotch cast boot

            - TCA, Gabapentin, Carbamazepine

PVD

            - Revascularise if possible

            - Debride tissue

Biomechanical

            - Rest, Immobilise in cast

- Resection of bony prominences may aid treatment and healing.

Infective Osteomyelitis

            - XR:                Sen; Spec 70%

            - Probing to bone:        Sen 66%; PPV 89%

            - WCC+Bone scan:       Sen 90%; Spec 80%

            - Prolonged AB’s, Hyperbaric O2, Dressings

            - Most need  Amputation

 
Two-stage ulcer operations
1. deep wide resection / debridement of ulcer and underlying soft tissue and any infected osseous structures
- cuture and deep biopsy
- remove all necrotic / avascular / devitalized tissues
2. Return for debridement and pulsatile irrigation and delayed closure.