What is the treatment for a fifth metatarsal fracture?

Treatment of Fifth Metatarsal Fractures

The treatment of fifth metatarsal fractures depends on the specific location, displacement, and type of fracture, with controlled ankle motion (CAM) walker boots being the preferred initial treatment for most non-displaced fractures due to better pressure offloading and faster bone healing compared to other conservative options.

Classification and Diagnosis

Fifth metatarsal fractures are among the most common foot fractures and are typically classified by location:

1. Zone 1: Avulsion fractures at the tuberosity/base (most common)
2. Zone 2: Jones fractures at the metaphyseal-diaphyseal junction
3. Zone 3: Proximal diaphyseal (shaft) fractures
4. Shaft fractures: Fractures of the metatarsal shaft

Diagnostic Approach

• Standard three radiographic views are essential: anteroposterior, lateral, and mortise views 1
• MRI may be considered if radiographs are negative but clinical suspicion remains high 1
• Ottawa rules can help determine the need for radiographs in acute trauma:
  • Point bone tenderness at the base of the fifth metatarsal
  • Inability to bear weight or walk 4 steps immediately after injury 2

Treatment Algorithm

1. Zone 1 (Tuberosity/Avulsion) Fractures

• Non-displaced or minimally displaced (<2mm):

  • First-line: CAM walker boot with weight-bearing as tolerated 3
  • CAM walker boots show faster bone healing (average 7.2 weeks) compared to hard-soled shoes (8.6 weeks) 3
  • CAM walker boots significantly reduce peak and contact pressures at the fifth metatarsal during walking compared to postoperative sandals 4
  • Duration: Typically 6-8 weeks until clinical and radiographic healing

• Displaced (>2mm) or involving >30% of cubometatarsal joint:

  • Surgical fixation is indicated 5
  • Options include percutaneous K-wires, screws, or plate fixation

2. Jones Fractures (Zone 2)

Treatment based on Torg classification:

• Type I (acute fracture):

  • Non-athletic patients: Non-operative treatment with non-weight-bearing in a CAM walker boot for 6-8 weeks
  • Athletic patients: Consider early surgical fixation with intramedullary screw 6

• Type II (delayed union):

  • Non-athletic patients: Trial of non-operative treatment
  • Athletic patients: Surgical fixation recommended 5

• Type III (non-union with medullary sclerosis):

  • Surgical treatment recommended regardless of activity level 5

3. Shaft Fractures

• Non-displaced or minimally displaced (<3-4mm, <10° angulation):

  • CAM walker boot for 4-6 weeks 5

• Displaced (>3-4mm or >10° angulation):

  • Surgical fixation with K-wires, plates, or screws 5

Follow-up and Rehabilitation

• Clinical and radiographic assessment at 2,6, and 12 weeks
• Progressive weight-bearing based on clinical and radiographic healing
• Return to prior activity levels typically occurs around 8-10 weeks for conservatively treated fractures 3
• For surgically treated fractures, return to sports may take 10-14 weeks

Potential Complications

• Jones fractures (Zone 2) are known for prolonged healing time and higher non-union rates 5
• Displacement during conservative treatment may necessitate surgical intervention
• Persistent pain may indicate non-union or other underlying pathology

Special Considerations

• Athletes and highly active individuals may benefit from earlier surgical intervention for Jones fractures to reduce healing time and return to sports more quickly 6
• CAM walker boots provide better pressure offloading at the fifth metatarsal base compared to postoperative sandals or athletic shoes during common gait activities 4

Early functional treatment with appropriate immobilization and gradual return to activities has shown good outcomes with high patient satisfaction (92%) and minimal complications 7.