Diabetic Foot Examination OSCE — Neuropathy, Vascular Assessment, and Ulcer Classification

Introduction

The diabetic foot examination is a high-yield OSCE station combining vascular, neurological, and skin assessment. Diabetic foot disease is the leading cause of non-traumatic lower limb amputation in the UK — identifying at-risk features early is life-changing for patients.

Preparation

• Introduce yourself, confirm patient identity
• Explain the examination and obtain consent
• Remove shoes, socks, and dressings from both feet
• Ask about pain before touching

1. Look — Inspection

Skin

Deformities

Ulcers — Inspect and Characterise

2. Wagner Ulcer Classification

3. Neurological Assessment

Light Touch and Protective Sensation

10-gram Semmens-Weinstein monofilament: Apply to 10 standard sites on the plantar surface. Inability to feel the monofilament at any site = loss of protective sensation = high risk of neuropathic ulceration.

Vibration Sense

Apply a 128 Hz tuning fork to the tip of the great toe. Loss of vibration sense is an early sign of peripheral neuropathy.

Pin-Prick Sensation

Test in dorsal and plantar surface — note distribution of deficit (glove-and-stocking = peripheral neuropathy).

Proprioception

Ask patient to identify direction of toe movement with eyes closed.

Ankle Reflexes

Reduced or absent ankle jerk = peripheral neuropathy.

4. Vascular Assessment

Pulses

Absent or reduced pedal pulses = peripheral arterial disease.

Capillary Refill

Press the nail bed for 2 seconds; normal refill under 2 seconds. Prolonged = poor peripheral perfusion.

Buerger's Test

Elevate legs to 45 degrees for 2 minutes. Pallor on elevation = ischaemia. Then lower legs — reactive hyperaemia (red flushing) on dependency. Positive Buerger's test = significant PAD.

ABPI (Ankle-Brachial Pressure Index)

Normal 0.9-1.2. Under 0.9 = PAD. Under 0.5 = critical ischaemia.

How to Present

"On examination of the diabetic foot, there was a 2 cm punched-out ulcer over the right first metatarsal head, with granulation tissue at the base and surrounding callus. The ulcer was painless. There was loss of protective sensation to the monofilament at 4 of 10 sites bilaterally and absent ankle jerks. Posterior tibial and dorsalis pedis pulses were present bilaterally. Buerger's test was negative. This is a Wagner grade 1 neuropathic ulcer in a patient with peripheral neuropathy and intact peripheral circulation. I would refer to the multidisciplinary diabetic foot team for podiatry review, wound care, and HbA1c optimisation."

"How do you differentiate neuropathic from ischaemic diabetic foot ulcers?"

Neuropathic ulcers develop at pressure points (metatarsal heads, heel, toe tips), are painless due to loss of protective sensation, have a punched-out edge with a granulation or slough base, and are surrounded by callus. Pulses are usually present. Ischaemic ulcers develop at the tips of toes, lateral foot, and between toes where perfusion is poorest. They are painful, have sloping edges, a necrotic base, and are associated with absent pulses and cold peripheries.

"How do you perform the 10g monofilament test?"

Apply the Semmes-Weinstein 10g monofilament perpendicular to 10 standard plantar sites on each foot until it bends (applying approximately 10g of pressure). Ask the patient, with eyes closed, whether they can feel it. Inability to detect the monofilament at any site indicates loss of protective sensation and classifies the patient as high risk for neuropathic ulceration. Document results as the number of sites felt out of 10.

"What is Charcot neuroarthropathy and how does it present acutely?"

Charcot neuroarthropathy is a progressive destruction of the bones and joints of the foot driven by peripheral neuropathy. Acute Charcot foot presents as a hot, swollen, erythematous, painful foot with radiological fractures or dislocations, often without a history of trauma. It is frequently mistaken for cellulitis or gout. The key differentiating feature is the neurological basis: the foot is warm but the patient has reduced sensation. Urgent offloading is essential to prevent joint destruction.

"What is Buerger's test and what does a positive result mean?"

Buerger's test (Buerger's angle test): elevate both legs to 45 degrees. Pallor of the foot at less than 45 degrees of elevation indicates inadequate arterial inflow (positive test). Then ask the patient to sit up and hang the legs over the edge of the bed — a positive result shows dependent rubor (reactive hyperaemia). A positive Buerger's test indicates significant peripheral arterial disease and a resting ABPI measurement should be performed.

Related guides: Peripheral Vascular Examination OSCE | Diabetes History OSCE | Ankle Examination OSCE