What is the treatment for an osteochondral lesion of the metatarsal head?

Treatment of Osteochondral Lesions of the Metatarsal Head

For osteochondral lesions of the metatarsal head, surgical intervention with mosaicplasty (autologous osteochondral graft transplantation) is the preferred treatment, especially for lesions larger than 50 mm² or when a subchondral cyst is present. 1

Diagnostic Evaluation

Before determining treatment, proper diagnosis is essential:

• Imaging studies:

  • Initial radiographs to identify osteochondral abnormalities 2
  • MRI without IV contrast is the study of choice for assessment of cartilage abnormalities and osteochondral lesions 2
  • CT may be useful to identify cortical and subcortical involvement 2

• Key clinical findings:

  • Pain at the metatarsophalangeal joint
  • Limited joint mobility
  • Pain with weight-bearing activities

Treatment Algorithm Based on Lesion Characteristics

1. Small Lesions (<50 mm²) without Subchondral Cyst

• First-line treatment: Subchondral drilling/microfracture
  • Involves debridement of friable cartilage edges
  • Creation of perpendicular holes in subchondral bone
  • Allows for marrow elements to form fibrocartilage repair tissue 2

2. Larger Lesions (≥50 mm²) or Presence of Subchondral Cyst

• Preferred treatment: Mosaicplasty (autologous osteochondral graft transplantation)
  • Significantly better outcomes compared to subchondral drilling for larger lesions 1
  • Involves harvesting osteochondral cylindrical grafts from non-weight-bearing areas
  • Grafts typically obtained from lateral femoral condyle or ipsilateral metatarsal 3
  • Provides immediate replacement with hyaline cartilage, which has superior mechanical properties 2

3. For First Metatarsal Head Lesions

• Consider combined approach: Osteochondral graft transplantation with Moberg osteotomy
  • Particularly useful for central lesions of the first metatarsal head 4
  • Improves range of motion and functional outcomes
  • AOFAS scores improvement from 58 to 85 reported 4

Surgical Technique for Mosaicplasty

1. Measurement and preparation of the defect area
2. Debridement of friable edges to obtain stable, healthy cartilage edges
3. Creation of drill holes based on lesion size
4. Harvesting osteochondral graft from appropriate donor site
5. Implantation of graft into previously created holes 2

Advantages of Mosaicplasty

• Elimination of need for second procedure
• Replacement with hyaline cartilage (superior mechanical properties)
• Immediate or near-immediate weight bearing after surgery 2
• Better functional outcomes for larger lesions compared to drilling 1

Post-Operative Management

• Protected weight-bearing initially
• Progressive range of motion exercises
• Return to activities based on healing and symptom resolution
• Regular follow-up to assess graft incorporation

Clinical Outcomes

Research shows significant improvements following appropriate surgical management:

• AOFAS scores improve from 65.0 to 81.5 with mosaicplasty (compared to 62.9 to 73.2 with drilling) 1
• VAS pain scores decrease significantly with both techniques 1
• Activity levels can be restored to pre-injury status in many cases 3

Important Considerations and Pitfalls

• Lesion size matters: For lesions ≥50 mm², mosaicplasty shows superior outcomes compared to drilling 1
• Subchondral cyst presence: Indicates need for mosaicplasty rather than drilling 1
• Donor site selection: Must consider morbidity and appropriate size matching
• Delayed treatment risk: Untreated lesions may progress to osteoarthritis/hallux rigidus 3
• Age considerations: Techniques have been successfully used in both adolescent and adult patients 3

Prompt and appropriate treatment of osteochondral lesions of the metatarsal head is crucial to restore joint function, prevent degenerative changes, and maintain normal gait patterns.