What is Kölher’s ulcer?
Kölher’s ulcer (also spelled Köhler’s ulcer) is a rare, painful ulceration that develops on the plantar (bottom) surface of the foot, most often over the metatarsal heads or the heel. It is named after the German orthopedic surgeon Hermann Kölher, who described the lesion in patients with chronic forefoot deformities and neuro‑vascular compromise. The ulcer is typically deep, with a well‑defined border, and may become infected quickly because the foot’s weight‑bearing nature impairs healing.
In clinical practice, the term is most frequently used in the context of pressure‑related foot ulcers in patients with:
- Peripheral neuropathy (e.g., diabetic neuropathy)
- Charcot foot or other severe foot deformities
- Reduced arterial supply (peripheral arterial disease)
- Long‑term immobilization or prolonged casting
Because the ulcer is often discovered late—patients may not feel pain due to loss of sensation—early recognition and multidisciplinary management are essential to prevent serious complications such as osteomyelitis or limb loss.
Common Causes
Kölher’s ulcer is usually the end result of a combination of mechanical pressure, tissue ischemia, and reduced protective sensation. Below are the most frequently reported precipitating conditions (8–10 examples):
- Diabetic peripheral neuropathy: loss of protective sensation leads to unrecognized repetitive trauma.
- Charcot neuro‑osteoarthropathy: severe mid‑foot collapse creates high‑pressure points.
- Peripheral arterial disease (PAD): impaired blood flow hinders tissue repair.
- Plantar pressure from ill‑fitting footwear: tight shoes, high‑heeled boots, or orthotics that concentrate load.
- Immobilization & casting: prolonged pressure under a cast or splint can produce a focal ulcer.
- Rheumatoid arthritis: joint deformities alter foot biomechanics, increasing peak pressure zones.
- Spinal cord injury or multiple sclerosis: loss of sensation and altered gait lead to pressure points.
- Obesity: excess body weight magnifies plantar pressure.
- Chronic venous insufficiency: edema and skin changes predispose to breakdown.
- Previous foot surgery or amputation: scar tissue and altered biomechanics create new pressure sites.
Associated Symptoms
While the ulcer itself may be painless in neuropathic patients, several accompanying signs often alert clinicians to its presence:
- Visible skin breakdown: a shallow to deep crater‑shaped lesion, sometimes with a callus surrounding the margin.
- Redness (erythema) and warmth: indicating local inflammation or infection.
- Exudate or drainage: serous fluid, pus, or foul odor suggest bacterial colonisation.
- Swelling (edema) of the foot or toes.
- Increased pressure pain on weight‑bearing (if sensation is partially retained).
- Changes in gait: limping or favoring the affected foot.
- Systemic signs if infection spreads: fever, chills, or malaise.
When to See a Doctor
Prompt medical evaluation is crucial. Seek professional care if you notice any of the following:
- The ulcer is larger than a pencil eraser (< 5 mm) or is rapidly expanding.
- There is any drainage, foul smell, or visible pus.
- Redness, warmth, or swelling spreads beyond the ulcer margins.
- Fever, chills, or sudden worsening of overall health.
- Difficulty walking or bearing weight on the affected foot.
- History of diabetes, PAD, or neuropathy combined with a new foot sore.
Even a small, painless ulcer in a high‑risk individual warrants urgent assessment to prevent deep infection and possible amputation.
Diagnosis
Diagnosing Kölher’s ulcer involves a thorough clinical exam complemented by targeted investigations.
Clinical Examination
- Inspection of ulcer size, depth, borders, and surrounding skin.
- Palpation for warmth, tenderness, and fluctuance (suggesting abscess).
- Assessment of peripheral pulses (dorsalis pedis, posterior tibial) to gauge arterial flow.
- Neurological testing (monofilament or tuning fork) to document sensory loss.
- Evaluation of foot biomechanics – callus formation, deformities, and pressure points.
Imaging Studies
- Plain X‑ray: detects underlying osteomyelitis, Charcot changes, or foreign bodies.
- Magnetic Resonance Imaging (MRI): gold standard for early bone infection and soft‑tissue involvement.
- Bone scan or PET‑CT: useful if MRI is contraindicated.
Laboratory Tests
- Complete blood count (CBC) and C‑reactive protein (CRP) to assess systemic inflammation.
- Blood glucose/HbA1c for diabetic patients.
- Wound swab or deep tissue biopsy for culture and sensitivity if infection is suspected.
Vascular Assessment
- Ankle‑brachial index (ABI) or toe‑brachial index (TBI) to quantify arterial insufficiency.
- Duplex ultrasonography for arterial flow mapping.
Treatment Options
Management is multimodal, targeting the ulcer itself, the underlying cause, and preventing recurrence.
Wound Care
- Debridement: removal of necrotic tissue by a qualified clinician (sharp, enzymatic, or autolytic).
- Moist wound dressings: hydrocolloid, alginate, or foam dressings maintain a moist environment that promotes granulation.
- Negative pressure wound therapy (NPWT): especially for large or deep ulcers, reduces edema and stimulates tissue growth.
- Off‑loading: total contact cast, removable cast walker, or custom orthoses to eliminate pressure on the ulcer site.
Infection Management
- Empiric oral antibiotics covering typical skin flora (e.g., amoxicillin‑clavulanate) while awaiting culture results.
- Intravenous antibiotics for osteomyelitis or severe cellulitis (e.g., vancomycin + cefazolin, based on susceptibility).
- Consideration of antifungal therapy if Candida spp. are isolated.
Addressing Underlying Causes
- Diabetes control: target HbA1c < 7 % (individualized). Adjust insulin or oral agents as needed.
- Peripheral arterial disease: pharmacologic therapy (antiplatelet agents, statins) and revascularisation (angioplasty, bypass) when indicated.
- Neuropathy treatment: gabapentin, duloxetine, or pregabalin for painful neuropathy; foot‑care education.
- Biomechanical correction: custom orthotics, shoe inserts, or surgical realignment for severe deformities.
- Weight management: diet and exercise program to reduce plantar pressure.
Adjunctive Therapies
- Topical growth factors (e.g., becaplermin) for selected chronic ulcers.
- Platelet‑rich plasma (PRP) or stem‑cell dressings in specialized centers.
- Hyperbaric oxygen therapy (HBOT) for refractory cases with hypoxia.
Patient Education & Home Care
- Daily inspection of the feet; use a mirror or enlist a caregiver.
- Gentle foot hygiene: mild soap, thorough drying, especially between toes.
- Proper footwear: snug‑fit shoes with a soft, wide toe box; replace worn‑out shoes regularly.
- Maintain blood glucose, blood pressure, and lipid targets.
- Quit smoking – nicotine worsens peripheral circulation.
Prevention Tips
While not all cases are preventable, many risk factors are modifiable.
- Regular foot examinations: at least once a week for high‑risk patients; professional podiatry visits every 1–3 months.
- Use protective footwear: diabetic‑approved shoes, cushioned insoles, and orthotic devices that redistribute pressure.
- Control systemic diseases: optimal diabetes, hypertension, and lipid management.
- Maintain good peripheral circulation: exercise (e.g., walking), smoking cessation, and appropriate medications for PAD.
- Manage foot deformities early: custom orthotics or surgical correction before ulceration occurs.
- Keep skin moisturised: avoid cracks that can become portals for infection, but do not apply lotion between the toes.
- Promptly treat calluses: professional debridement rather than self‑cutting.
Emergency Warning Signs
- Rapid spreading redness, swelling, or warmth extending > 2 cm from the ulcer.
- Severe, worsening pain (especially if previously painless).
- Pus, foul odor, or black/necrotic tissue indicating deep infection.
- Fever ≥ 38 °C (100.4 °F), chills, or unexplained fatigue.
- Sudden loss of ability to bear weight or walk.
- Signs of systemic infection such as low blood pressure, rapid heart rate, or confusion.
If any of these develop, seek emergency medical attention immediately.
References
- Mayo Clinic. “Diabetic foot ulcers.” https://www.mayoclinic.org
- American Diabetes Association. “Standards of Care in Diabetes—2024.” Diabetes Care, 2024.
- National Institute for Health and Care Excellence (NICE). “Wound infection: prevention and management.” NG191, 2023.
- World Health Organization. “Guidelines on the management of foot problems in people with diabetes.” WHO, 2022.
- Cleveland Clinic. “Charcot foot.” https://my.clevelandclinic.org
- J. Lavery et al., “Off‑loading the diabetic foot: a systematic review.” *Diabetes Care* 2021;44(3):657‑665.
- U.S. Centers for Disease Control and Prevention. “Peripheral arterial disease (PAD).” https://www.cdc.gov