What is the management of metatarsal abductus?

Management of Metatarsus Adductus

The management of metatarsus adductus should follow a stepwise approach based on age, severity, and flexibility of the deformity, with early intervention before 9 months of age offering the best outcomes and reducing the need for surgical intervention. 1

Assessment and Classification

• Severity Assessment: Evaluate using the heel bisector line (HBL)

  • Mild: HBL passes through 2nd or 3rd toe
  • Moderate: HBL passes between 3rd and 4th toe
  • Severe: HBL passes through or lateral to 4th toe 2

• Flexibility Assessment:

  • Flexible: Forefoot can be passively corrected beyond neutral
  • Semi-rigid: Forefoot can be corrected to neutral but not beyond
  • Rigid: Forefoot cannot be passively corrected to neutral

Treatment Algorithm

For Infants (<9 months)

1. Mild, Flexible Deformity:

   • Observation with regular monitoring
   • Parent education on proper stretching techniques
   • Avoid restrictive footwear

2. Moderate Deformity:

   • If flexible: Stretching exercises for 3-6 months
   • If no improvement by 5 months or if semi-rigid: Orthotic treatment (e.g., Universal Neonatal Foot Orthosis) for 23 hours daily 2

3. Severe or Rigid Deformity:

   • Immediate orthotic treatment or serial casting
   • Orthotic devices have shown equal effectiveness to casting with fewer complications 1
   • Continue treatment until complete correction is achieved, then begin weaning process

For Older Children (>9 months to 8 years)

1. Mild to Moderate Deformity:

   • Custom orthotic devices with appropriate footwear modifications
   • Footwear with wide toe box and straight last design
   • Regular monitoring for progression

2. Severe or Rigid Deformity:

   • Serial casting may still be attempted
   • If unsuccessful after 3-6 months of conservative treatment, consider surgical options

Surgical Management (for persistent deformities)

For children 6-8 years with persistent deformity:

• Combined approach: Base wedge osteotomies for 1st and 5th metatarsals with soft tissue releases for central metatarsals 3
• For older children/adolescents with symptomatic deformity: Metatarsal osteotomies or joint arthroplasty may be necessary 4

Follow-up Protocol

• For infants receiving orthotic treatment: Regular follow-up every 2-4 weeks during active treatment
• Continue monitoring until at least walking age to ensure maintained correction 2
• Long-term follow-up recommended to monitor for recurrence or development of skewfoot deformity

Potential Complications and Prevention

• Untreated or Undertreated Deformity: Can lead to skewfoot deformity with more significant symptoms and functional limitations 5
• Improper Footwear: Can exacerbate deformity; ensure appropriate footwear with adequate toe box width
• Skin Issues with Orthotics: Monitor for pressure points or skin irritation; minor side effects are infrequent and typically resolve with adjustments 2

Key Points for Clinical Practice

• Early intervention (before 9 months) offers the best outcomes
• Conservative treatment is highly successful for most cases when initiated early
• Novel orthotic devices allow for effective treatment without the need for specialist referral in many cases 1
• Surgical intervention should be reserved for rigid deformities that fail conservative management
• Regular follow-up is essential to ensure maintained correction and prevent recurrence

By following this structured approach to management, most cases of metatarsus adductus can be effectively treated with good long-term outcomes and minimal complications.