What causes a hammer toe to swell?

Causes of Hammer Toe Swelling

Hammer toe swelling is most commonly caused by inflammation due to pressure and friction from ill-fitting footwear, which leads to the development of calluses, corns, and potential pre-ulcerative lesions at pressure points, particularly at the apex or distal part of the affected toe.

Common Causes of Hammer Toe Swelling

Mechanical Factors

• Pressure and friction: The deformed position of the toe creates abnormal pressure points, particularly at the apex of the toe and distal tip 1
• Ill-fitting footwear: Shoes with narrow toe boxes compress the deformed toe, causing irritation and inflammation 2
• Callus formation: Excess callus develops at pressure points, further increasing pressure and inflammation 2, 1

Inflammatory Responses

• Bursitis: Inflammation of the small fluid-filled sacs that cushion the bones, tendons, and muscles near joints
• Capsulitis: Inflammation of the joint capsule surrounding the proximal interphalangeal joint
• Synovitis: Inflammation of the synovial membrane lining the joint

Structural Factors

• Muscle-tendon imbalance: The underlying cause of hammer toe involves an imbalance between intrinsic and extrinsic muscles that control toe movement 3, 4
• Joint degeneration: As the deformity progresses, the joint may develop arthritic changes, contributing to swelling 5
• Limited joint mobility: Reduced mobility of the joints can exacerbate pressure points and inflammation 2

Pathological Conditions

• Infection: Open lesions or breaks in the skin can lead to soft tissue infection or even osteomyelitis 2
• Neuropathy: Particularly in diabetic patients, loss of protective sensation allows continued pressure and trauma without pain awareness 2
• Charcot neuroarthropathy: In severe cases, especially with diabetes, this can cause significant swelling and deformity 2

Clinical Assessment of Hammer Toe Swelling

Warning Signs Requiring Urgent Attention

• Unexplained swelling with warmth and redness: May indicate infection or Charcot process 2
• Open ulceration: Requires immediate attention to prevent infection progression 2
• Temperature difference >2.2°C between corresponding regions of left and right foot for two consecutive days 2

Diagnostic Approach

1. Visual inspection: Look for erythema, swelling, callus formation, and skin breakdown
2. Radiography: Initial imaging to assess bone structure and joint alignment 2
3. Temperature monitoring: To detect early inflammation, especially in diabetic patients 2
4. Image-guided aspiration: If infection is suspected, to obtain fluid for culture 2

Management Strategies

Conservative Management

• Appropriate footwear: Extra-depth shoes with wide toe boxes to accommodate the deformity 2, 1
• Orthotic devices: Silicone or semi-rigid orthotic devices to reduce callus formation 2, 1
• Regular callus debridement: Professional removal of excess callus to reduce pressure 1
• Emollients: Application to dry skin and nail plate to maintain skin integrity 1

Interventional Options

• Digital flexor tenotomy: Highly recommended for non-rigid hammer toes with nail changes, excess callus, or pre-ulcerative lesions 2, 1
  • Has high healing rate (97%)
  • Significantly reduces plantar pressure
  • Decreases infection risk
  • Can be performed in outpatient setting

Surgical Considerations

• Proximal interphalangeal joint arthrodesis: For fixed deformities that don't respond to conservative measures 5
• Arthroplasty: Alternative to arthrodesis that allows some motion 5
• Metatarsal head resection: For cases with associated metatarsalgia 1

Prevention and Monitoring

Patient Education

• Daily foot inspection: Especially important for patients with neuropathy 2
• Proper footwear selection: Avoid thin-soled slippers, walking barefoot, or wearing only socks 1
• Monitoring schedule: Based on risk stratification (every 1-3 months for high-risk patients) 2, 1

Common Pitfalls to Avoid

• Delayed treatment: Early intervention prevents progression to ulceration and infection
• Self-treatment of calluses: Can lead to skin breakdown and infection
• Inadequate footwear modification: Proper footwear is essential for preventing pressure-related swelling
• Overlooking temperature monitoring: Temperature differences can detect inflammation before visible swelling occurs

By addressing the underlying causes of hammer toe swelling through appropriate footwear, orthotic devices, and when necessary, surgical intervention, patients can experience significant relief from symptoms and prevent serious complications such as ulceration and infection.