What is the appropriate initial management for a 13-year-old male with an avulsion fracture of the base of the fifth metatarsal?

Treatment of Avulsion Fracture at Base of Fifth Metatarsal in a 13-Year-Old Male

For a 13-year-old male with an avulsion fracture at the base of the fifth metatarsal, treat with immediate immobilization in a walking boot or cast shoe, allow weight-bearing as tolerated, and avoid routine follow-up radiographs before 6-8 weeks since they rarely change management. 1

Initial Assessment and Imaging

• Confirm the diagnosis with standard three-view foot radiographs (anteroposterior, lateral, and oblique) 2
• Apply Ottawa foot rules, which are validated for children >5 years with approximately 99% sensitivity for detecting fifth metatarsal fractures 1
• Assess for displacement: surgical referral is indicated only if the fracture is displaced >2mm or involves >30% of the cubometatarsal joint surface 3, 4, 5
• Check for vascular compromise (pale, blue, or purple foot) requiring emergent intervention 2
• Examine for open wounds requiring clean dressing coverage 2

Pain Management

• Provide scheduled acetaminophen (paracetamol) as first-line analgesia unless contraindicated 2
• Add opioids cautiously if needed, particularly if renal function is unknown 2
• Avoid NSAIDs if renal dysfunction is suspected 2
• Early immobilization provides superior pain relief compared to medications alone 2

Immobilization Strategy

For non-displaced or minimally displaced avulsion fractures (the vast majority in pediatric patients), use a soft dressing or walking boot rather than a rigid cast. 6 This approach is supported by research showing patients treated with soft (Jones) dressings return to activity in an average of 33 days versus 46 days with short leg casts, with excellent modified foot scores of 92 versus 86 respectively 6.

• Immobilize in a walking boot or cast shoe for 4-6 weeks 3
• Allow immediate weight-bearing as tolerated—progressive weight-bearing does not compromise healing and may improve outcomes 2
• Avoid compression wraps that are too tight, as they can compromise circulation 2

Follow-Up and Monitoring

Routine follow-up radiographs before 6-8 weeks do not alter clinical management and are unnecessary in most pediatric patients. 1 This is a critical point that distinguishes pediatric from adult management.

• Discharge patients based on clinical signs of healing rather than radiographic union 1
• Only 29% of fifth metatarsal fractures demonstrate radiographic union at final clinic visit, yet patients can be safely discharged clinically 1
• Radiographic displacement on follow-up is rare (approximately 1%) and rarely requires change from conservative management 1

Surgical Indications (Rare in Avulsion Fractures)

Arrange orthopedic consultation within 24-48 hours if: 2, 4, 5

• Displacement >2mm

• 30% involvement of the cubometatarsal joint surface

• Comminuted fracture
• Delayed union after conservative treatment

Common Pitfalls to Avoid

• Do not obtain repeat radiographs at 2-4 weeks—they provide no clinical benefit and expose the child to unnecessary radiation 1
• Do not use rigid short leg casts—soft dressings or walking boots allow faster return to activity with equivalent healing 6
• Do not restrict weight-bearing unnecessarily—immediate weight-bearing as tolerated is safe and may improve outcomes 2
• Do not confuse avulsion fractures (Zone 1) with Jones fractures (Zone 2) or proximal diaphyseal stress fractures (Zone 3), which carry significantly higher risk of delayed union and non-union 1, 5

Expected Timeline

• Protected weight-bearing in boot/cast shoe: 4-6 weeks 3
• Return to full activity: average 33 days with soft dressing 6
• Clinical healing typically precedes radiographic union 1