What is the treatment for a stage three diabetic foot ulcer on the plantar surface of the foot?

Treatment of Stage 3 Diabetic Plantar Foot Ulcer

For a stage 3 diabetic foot ulcer on the plantar surface, immediately offload the ulcer with a non-removable knee-high device (total contact cast or removable cast walker rendered irremovable), combined with sharp debridement, appropriate wound dressings, infection control if present, and vascular assessment. 1

Primary Offloading Strategy

Use a non-removable knee-high offloading device with an appropriate foot-device interface as first-line treatment. This has the strongest evidence (high quality) for healing neuropathic plantar forefoot ulcers. 1 The non-removable nature ensures adherence, which is critical since patients often fail to consistently wear removable devices.

Alternative Offloading Options (in order of preference):

• If non-removable device is contraindicated or not tolerated: Use a removable knee-high walker, but only if the patient demonstrates reliable adherence to wearing it during all weight-bearing activities. 1

• If knee-high devices cannot be used: Consider forefoot offloading shoes, cast shoes, or custom-made temporary shoes, again only with expected adherence. 1

• If offloading devices are unavailable: Felted foam combined with appropriately fitting footwear can serve as third-line treatment. 1

• Do NOT use conventional or standard therapeutic footwear alone to heal plantar ulcers—this is ineffective. 1

Wound Management

Perform sharp debridement to remove callus, necrotic tissue, and non-viable material from the ulcer. 2, 3 This is a cornerstone of standard care and should be done regularly as needed.

Apply appropriate wound dressings to facilitate moist wound healing, though specific dressing type is less critical than offloading and debridement. 3

Infection Assessment and Control

Evaluate for infection based on clinical signs: purulence, erythema extending >2cm from wound edge, warmth, tenderness, or systemic signs. 4

• If mild infection is present: Non-removable knee-high device can still be used. 1
• If moderate infection: Consider removable offloading device for easier wound monitoring. 1
• If severe infection with purulence or deep tissue involvement: Prioritize infection control with intravenous antibiotics and surgical drainage/debridement before definitive offloading. 1, 4

Obtain cultures after debridement (not from surface swabs) to guide antibiotic selection. 4

Vascular Assessment

Assess for peripheral arterial disease through palpation of pedal pulses, ankle-brachial index, or toe pressures. 2, 5

• If mild ischemia: Non-removable offloading may still be appropriate. 1
• If moderate to severe ischemia: Vascular reconstruction may be needed before ulcer healing is possible; use removable offloading to allow vascular monitoring. 1, 5

Glycemic and Metabolic Control

Optimize blood glucose control, lipids, and blood pressure as these directly impact wound healing capacity. 5

Surgical Interventions for Refractory Ulcers

If conservative offloading fails after appropriate trial:

• For plantar metatarsal head ulcers: Consider Achilles tendon lengthening (strongest evidence) or metatarsal head resection combined with continued offloading. 1
• For hallux ulcers: Consider joint arthroplasty. 1
• For flexible toe deformities with plantar/apex ulcers on digits 2-5: Perform digital flexor tenotomy (strong recommendation). 1

Critical Pitfalls to Avoid

• Never allow the patient to walk barefoot, in socks only, or in thin slippers during treatment—this will prevent healing. 1
• Do not rely on patient adherence with removable devices unless you have strong reason to believe they will comply; non-removable is superior. 1
• Do not delay vascular assessment—ischemia will prevent healing regardless of other interventions. 5
• Do not undertreate infection—severe infections require urgent surgical intervention to prevent progression to necrosis and amputation. 4

Patient Education

Instruct the patient to: Inspect feet daily, report any temperature changes or new lesions immediately, maintain the offloading device continuously during all weight-bearing activities, and understand this is a limb-threatening condition requiring strict adherence. 1