Treatment of 5th Metatarsal Base Fracture
For non-displaced 5th metatarsal base (tuberosity avulsion) fractures, treat with a CAM-walker boot or hard-soled shoe with immediate weight-bearing as tolerated, transitioning to normal activities within 2-4 weeks. 1, 2
Initial Assessment and Imaging
- Obtain three standard radiographic views (anteroposterior, lateral, and mortise) to confirm the diagnosis and assess displacement 1
- Apply Ottawa ankle rules: imaging is required if there is point tenderness at the base of the 5th metatarsal or inability to bear weight for four steps 1
- Check immediately for vascular compromise (blue, purple, or pale foot) requiring emergent intervention 1
- Assess for open wounds requiring clean dressing coverage 1
Treatment Based on Fracture Type and Displacement
Zone 1 (Tuberosity Avulsion) Fractures - Non-displaced or <2mm displacement:
- Initial treatment: Apply compressive dressing acutely, then transition to CAM-walker boot or hard-soled shoe 2, 3
- Weight-bearing: Allow immediate weight-bearing as tolerated 1, 3
- Duration: 2 weeks in boot, then transition to rigid-sole shoe for additional 2-3 weeks 2, 3
- Healing time: Average 7-9 weeks for complete radiographic healing 3
- Return to activity: Average 8-10 weeks 3
Critical pitfall: Soft (Jones) dressing allows faster return to activity (33 days) compared to rigid short leg cast (46 days) for avulsion fractures 4
Zone 1 Fractures - Displaced >2mm or >30% cubometatarsal joint involvement:
- Surgical fixation is indicated with K-wires, plate, or screw fixation 5
Zone 2 (Jones Fracture - Metaphyseal-diaphyseal junction):
- High-risk for nonunion requiring prolonged immobilization 5, 2
- Non-operative treatment: Short leg non-weight-bearing cast for 6-8 weeks minimum, potentially extending to 10-12 weeks 2
- Surgical treatment: Consider intramedullary screw fixation for active patients or Torg type II-III fractures 5
Mid-shaft Fractures:
- Non-displaced or minimally displaced: Posterior splint initially with non-weight-bearing, then short leg walking cast/boot for 4-6 weeks 2
- Displaced >3-4mm or angulated >10 degrees: Surgical fixation with percutaneous K-wires, plate, or screw 5
Pain Management
- Start with scheduled acetaminophen unless contraindicated 1
- Add opioids cautiously if needed, particularly if renal function unknown 1
- Avoid NSAIDs if renal dysfunction suspected 1
- Early fracture stabilization through proper immobilization provides the most effective analgesia 1, 6
Rehabilitation Protocol
- Introduce early physical training and muscle strengthening once initial healing begins 1
- Progress to long-term balance training and fall prevention 1
- Avoid prolonged immobilization beyond 6 weeks as this causes stiffness and muscle atrophy 1, 6
Follow-up and Monitoring
- Regular radiographic assessment to ensure proper healing and alignment 1
- Monitor for signs of nonunion, particularly in Jones fractures 5, 2
- Address smoking cessation preoperatively if surgery planned, as smoking increases nonunion risk 6
Special Considerations
- For diabetic patients with neuropathy, ensure proper offloading to prevent complications 1
- CT imaging may be beneficial to evaluate true extent of osseous injury and guide surgical planning for unstable fractures 1
- Do not apply compression wraps too tightly as this compromises circulation 1
- Do not place ice directly on skin if using cryotherapy 1