Ainhum (Dactylolysis Spontanea): Clinical Insights and Contemporary Management

Indroduction

Ainhum, or dactylolysis spontanea, is a rare, progressive condition characterized by fibrotic constriction bands around the digits, predominantly affecting the fifth toe, leading ultimately to auto-amputation. First described in 1867 by Brazilian physician Silva Lima, its etiology remains unclear, though genetic predisposition and vascular anomalies have been proposed. This review highlights essential clinical features, diagnostic strategies, and evolving management options relevant to orthopedic practice.

Epidemiology and Risk Factors

Ainhum primarily affects males of African descent (male-to-female ratio: 2:1), with a prevalence ranging from 0.015% to 2.2%. However, increasing reports in diverse populations, including India and Brazil, suggest associations with interethnic marriage or tropical climates. The typical onset is between 20 and 50 years, though rare pediatric cases have been documented.

Five Key Clinical Signs

Fibrotic Constriction Band: Circumferential groove at the base of the fifth toe, progressing to deep ulceration (Stage I–II). Bilateral involvement occurs in approximately 75% of cases.
Bulbous Distal Swelling: Lymphatic edema distal to the constriction produces a characteristic “potato-like” appearance.
Osteolysis: X-ray shows progressive bone resorption at the proximal interphalangeal joint, tapering, and eventual digit separation (Stage III).
Progressive Pain: Reported by approximately 78% of patients, pain intensifies due to nerve compression or pathological fracture.
Auto-Amputation: Bloodless spontaneous detachment of the digit typically occurs within 4–6 years of initial presentation (Stage IV).

Diagnostic Evaluation

Clinical diagnosis is usually clear but supported by imaging modalities:

Radiographs: Demonstrate radiolucent bands, osteolysis, and distal phalanx thinning.
Doppler Ultrasound: Evaluates compromised posterior tibial artery flow, distinguishing true Ainhum from pseudoainhum conditions such as diabetic gangrene or leprosy.
Histopathology: Rarely required but reveals dermal fibrosis and hyperkeratosis.

Latest Treatment Options

1. Early-Stage Interventions (Grade I–II):

Corticosteroid Injections: Intralesional triamcinolone effectively reduces local inflammation and fibrosis.
Surgical Z-Plasty: Fibrotic band excision using Z-shaped skin flaps to halt progression and alleviate pain.
Topical Retinoids: Emerging use of topical tretinoin to modulate keratinocyte proliferation.

2. Advanced Disease (Grade III–IV):

Disarticulation: Metatarsophalangeal joint amputation provides pain relief and maintains functional mobility.
Physical Therapy: Postoperative orthotics and targeted gait rehabilitation to minimize locomotor dysfunction.

3. Experimental Therapies:

Antifibrotic Agents: Tranilast, previously employed in keloid management, has anecdotal support as a potential antifibrotic treatment.
Biologic Agents: Investigational use of anti-TNFα drugs to modulate the inflammatory response.

Prognosis and Multidisciplinary Care

Without intervention, auto-amputation is inevitable. Associated complications include chronic infections, gait instability, and significant psychological distress. Early referral to dermatology and orthopedic specialists significantly enhances patient outcomes. Postoperative care should prioritize infection control, custom footwear, and psychological support.

Conclusion

Ainhum requires heightened clinical awareness, especially among at-risk populations. Prompt diagnosis and appropriate staged treatments—from conservative corticosteroid injections to definitive surgical intervention—are vital to preventing irreversible digit loss. Continued research into antifibrotic therapies holds potential for transformative improvements in patient management, emphasizing the importance of multidisciplinary, evidence-based approaches in orthopedic care.

About you

Dr. Christodoulos Amorgianos Orthopedic Trauma Surgeon – Specialist Hand Microsurgery & Interventional Pain Specialist

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(+30)210 6972957

Email:
x_amorgianos@yahoo.com