metararsal stress fracture (march fracture)

Etiology

• rheumatoid arthritis predisposes
• osteoporosis predisposes

Epidemiology

• athletes, performers & others participating in high-impact activities
• common site of stress fracture

Pathology

• most common on 2nd & 3rd metatarsal bones as these are relatively fixed in the foot & sustain the greatest impact
• 5th metatarsal less common

Clinical manifestations

• initially, dull pain only with exercise
• may progress to pain at rest
• pain starts diffusely, then localizes to site of fracture

Laboratory

• consider rule/out rheumatoid athritis
  • erythrocyte sedimentation rate & serum CRP
  • rheumatoid factor

Radiology

• X-ray of foot
  • radiographs may be negative early in the process
  • stress-fracture changes may not be evident on plain films until 3 months after the onset of symptoms
  • up to 50% of stress fractures are never observed on plain films
• MRI is the imaging modality of choice
  • same sensitivity & better specificity than bone scan
• bone scan
  • technetium-99 (99m Tc) diphosphonate 3-phase bone scanning formerly the imaging modality of choice
  • nearly 100% sensitive for diagnosis of stress fractures; specificity is considerably lower
  • bone scans can demonstrate stress fractures within 24-72 hours from the onset of symptoms
• ultrasound

Differential diagnosis

• Morton neuroma
• metatarsalgia
• turf toe

Management

• rest from offending activity
• immobilization with orthopedic cast
• surgery rarely required
• orthopedic consult for 5th metatarsal fractures or for 2nd or 3rd metatarsal fractures that do not heal after 6 weeks

More general terms

• stress fracture (fatigue fracture)

Additional terms

• metatarsal bone