Fifth metatarsal fracture

• Most common fracture at base of 5th metatarsal
• Sx often mild, patients usually present with sprained ankle complaint
• Occurs due to forced inversion foot/ankle while in plantar flexion

• Second most common fracture at base of 5th metatarsal
• Abrupt onset of lateral foot pain, with no prior history of pain at that site, suggests acute injury and helps distinguish from stress injury
• Occurs due to sudden change in direction with heel off the ground
• Edema & ecchymosis usually present, may not be able to bear weight

• Occurs through repetitive microtrauma, usually in younger athletes
• Important to identify given propensity for delayed union and nonunion
• Usually present with history of months of pain, which is more intense during exercise or weight-bearing
  • always ask about persistent pain prior to acute event to help distinguish worsening stress fracture from acute fracture

• Talus fracture
• Calcaneus fracture

• Lisfranc injury
• Navicular fracture
• Cuboid fracture
• Cuneiform fracture

• Fifth metatarsal fracture
• Non-fifth metatarsal fracture
• Toe fracture

• Plain radiographs are usually adequate

5th Metatarsal fracture types

Fractures of the fifth metatarsal base. Frontal radiograph (A) demonstrates fifth metatarsal base fractures based on location. Frontal radiograph (B) in a 24-year-old runner following inversion injury demonstrates an avulsion fracture of the fifth metatarsal base. Oblique radiograph (C) in an 11-year-old boy demonstrates an unfused fifth metatarsal base apophysis, a common fracture mimic.

Jones fracture. Transverse fracture 2 cm from the base of the fifth metatarsal

• Must distinguish Jones fracture from diaphyseal stress freacture:
  • Acute fracture will have narrow fracture line that appears sharp, normal thin cortex adjacent to fracture, and normal intramedullary canal
  • Stress fracture will demonstrate cortical thickening near fracture line, older stress fracture will demonstrate widened fracture line and intramedullary sclerosis

• Acute pain management
• Open fractures require immediate IV antibiotics and urgent surgical washout
• Neurovascular compromise from fracture requires emergent reduction and/or orthopedic intervention
• Consider risk for compartment syndrome

Proximal to the more diaphyseal Jones fracture

• Refer to ortho if > 3mm displacement
• Nondisplaced fracture usually require only symptomatic treatment, RICE
• Walking boot (casting rarely necessary) and weight-bearing as tolerated, follow up in 1 week

• Posterior Ankle Splint, strict NWB, RICE, ortho follow up in 3-5 days
• 50% of Jones fracture treated conservatively may result in nonunion or re-fracture
• Conservative treatment failure usually due to poor vascular supply of bone and premature return to weight-bearing

• Strict NWB short-leg cast, RICE
• Ortho referral for all stress fractures

• Posterior Ankle Splint, NWB, RICE, ortho/podiatry follow up in 3-5 days
• Dorsal or Plantar displacement >10% or 3-4mm may require reduction in ED or at referral clinic while lateral/medial displacement usually heal well without reduction