What is the treatment for small osseous fragments of the proximal 2nd metatarsal due to avulsion or periosteal reaction from a heading injury?

Treatment for Small Osseous Fragments of the Proximal 2nd Metatarsal

The recommended treatment for small osseous fragments of the proximal 2nd metatarsal due to avulsion or periosteal reaction from a heading injury is conservative management with protected weight bearing in a controlled ankle motion (CAM) walker boot or hard-soled shoe for 4-6 weeks. 1

Initial Assessment and Imaging

• Radiographs should be the initial imaging modality to evaluate the fracture pattern and displacement; if findings are conclusive, no further imaging is needed 2
• For complex or equivocal cases, MRI is the preferred second-line study as it is extremely sensitive and can demonstrate stress abnormalities with greater specificity than other modalities 2
• CT imaging may provide better visualization of fracture fragments in complex cases, though it is less sensitive than MRI 2

Treatment Algorithm

For Non-displaced or Minimally Displaced Fragments:

• Conservative treatment with protected weight bearing in a CAM-walker boot or hard-soled shoe for 4-6 weeks 1, 3
• CAM-walker boots may lead to faster bone healing (average 7.2 weeks) compared to hard-soled shoes (average 8.6 weeks), though clinical outcomes are similar with both approaches 3
• Progressive weight bearing protocol:
  • Weeks 1-2: Non-weight bearing 4
  • Week 3: 25% weight bearing 4
  • Week 4: 50% weight bearing 4
  • Week 5: 75% weight bearing 4
  • Week 6: Full weight bearing 4

For Displaced Fragments (>2mm displacement):

• Closed reduction should be attempted first 1
• If reduction is achieved but unstable, percutaneous pinning is suitable for fixation 1
• For fragments with joint involvement or multiple fragments, open reduction and internal fixation may be required 1

Monitoring and Follow-up

• Radiographic evaluation should be performed at 3 weeks and at the end of immobilization (6 weeks) to ensure proper healing 5
• Active range of motion exercises should be initiated during the recovery period to prevent stiffness, which is one of the most functionally disabling complications 5
• Return to prior activity levels typically occurs between 8-10 weeks 3

Special Considerations

• Proximal 2nd metatarsal stress fractures have different risk factors compared to non-proximal fractures, including Achilles contracture, differences in first-to-second metatarsal length, and low bone mass 6
• For avulsion injuries at the base of metatarsals, consider the involvement of ligamentous structures that may need protection during healing 1
• Avoid overtightening any splint or immobilization device as this can compromise circulation 7

Potential Complications

• Delayed union or nonunion may occur, particularly if weight bearing is resumed too early 1
• Stiffness is a common complication that can be difficult to treat after healing, highlighting the importance of early motion exercises while maintaining fracture stability 5
• Transfer lesions may develop due to altered weight bearing patterns during healing 2

High-Risk Features Requiring Special Attention

• The proximal second metatarsal is considered a high-risk location for stress fractures 2
• Open fractures, signs of poor perfusion (blue, purple, or pale appearance), or significant soft tissue injury may require more aggressive management 7
• Patients with multiple stress fractures or low bone mass may require longer healing times and additional workup 6