What is the treatment for an avulsion fracture at the base of the fifth metatarsal?

Treatment of Fifth Metatarsal Avulsion Fractures

For avulsion fractures at the base of the fifth metatarsal, treat non-displaced or minimally displaced fractures (<2mm) with functional immobilization using a walking boot or soft dressing, allowing early weight-bearing; surgical fixation is indicated for fractures displaced >2mm or involving >30% of the cubometatarsal joint. 1, 2, 3

Initial Assessment and Imaging

• Obtain standard radiographs with anteroposterior, lateral, and mortise views that include the base of the fifth metatarsal 1
• Weight-bearing radiographs provide critical information about fracture stability when the patient can tolerate them 1
• Assess displacement carefully—the 2mm threshold is the key decision point for surgical versus conservative management 2, 3

Treatment Algorithm Based on Displacement

Non-Displaced or Minimally Displaced Fractures (<2mm)

Conservative functional treatment is the preferred approach for these fractures:

• Use a walking boot (pneumatic or orthopedic) or soft Jones dressing rather than a rigid cast 4, 5
• Allow immediate or early weight-bearing as tolerated (typically within 9 days) 5
• Patients treated with soft dressings return to full activity faster (average 33 days) compared to rigid casts (46 days) 4
• Continue immobilization for approximately 4-6 weeks until clinical and radiographic healing is evident 6, 5

Important caveat: Conservative management carries a 35.5% risk of asymptomatic nonunion, though patients remain symptom-free at one year 3. This is clinically acceptable for most patients with minimal displacement.

Displaced Fractures (>2mm) or >30% Joint Involvement

Surgical fixation is strongly recommended:

• Surgical management eliminates the risk of nonunion (0% versus 35.5% with conservative treatment) 3
• Options include open reduction with internal fixation or closed reduction with percutaneous fixation 3
• Surgery ensures timely return to preinjury activity levels 3
• Surgical treatment is particularly important for active patients or those requiring predictable healing 2

Rehabilitation Protocol

• Begin progressive weight-bearing as tolerated after the initial immobilization period 1
• Introduce early physical training and muscle strengthening followed by balance training 7
• Avoid prolonged immobilization beyond 6 weeks to prevent stiffness and muscle atrophy 7

Follow-Up Care

• Perform radiographic assessment at 5-6 weeks to evaluate healing and determine when to discontinue immobilization 6
• Final clinical check at 12 weeks to ensure complete recovery 6
• Average radiographic healing occurs by 44-65 days for conservatively managed fractures 4

Special Patient Populations

Diabetic patients with neuropathy require heightened vigilance:

• Ensure proper fitting of orthotic devices to prevent pressure sores 1
• Implement careful offloading strategies to prevent ulceration at the fracture site 1
• Monitor closely for signs of skin breakdown or infection 1

Common Pitfalls to Avoid

• Do not manipulate the ankle prior to obtaining radiographs unless there is neurovascular compromise or critical skin injury 1
• Do not use rigid casts when functional bracing is available—soft dressings and walking boots provide superior outcomes with faster recovery 4, 5
• Do not underestimate displacement—fractures appearing "minimally displaced" on initial films may warrant surgical treatment if >2mm 3