General considerations

• Fractures produced as a result of repetitive stress on bone 
• General risk factors
  • New, different or rigorous repetitive activity
  • Females
  • Increasing age
  • Caucasians
  • Low bone mineral density
  • Low calcium intake
• In the foot, these are most common in the shafts of the 2^nd (most) and 3^rd metatarsals
• Marching, stomping on ground, prolonged standing, ballet, postoperative bunionectomy increase risk

Clinical findings

• Pain usually starts more diffusely and then localizes to site of fracture
• Swelling
• Redness
• Localized tenderness

Imaging findings

• Conventional Radiography
• 15% sensitive in early fractures, increasing to 50% on follow-up
• Sclerotic band (due to trabecular compression and callus formation) usually perpendicular to cortex
• Intracortical radiolucent striations (early)
• Solid thick lamellar periosteal new bone formation
• Endosteal thickening (later)
• Follow-up radiography after 2-3 weeks of conservative therapy may reveal fracture not seen earlier
• Nuclear medicine
• “Gold standard" = almost 100% sensitive
• Abnormal uptake within 6-72 hours of injury (prior to radiographic abnormality)
• "Stress reaction" is a focus of subtly increased uptake
• Focal fusiform area of intense cortical uptake
• Abnormal uptake persists for months
• MRI
• Very sensitive modality
• Fat saturation technique most sensitive to detect increase in water content of medullary edema / hemorrhage
• Diminished marrow signal intensity on T1WI
• Increased marrow signal intensity on T2WI

Prognosis

• Usually heal without complication when involving 1^st through 4^th metatarsals

Complications

• Nonunion
• Higher (up to 50%) in 5^th metatarsal fracture