Causes / typical injury mechanism: The metatarsals are common fracture sites. These injuries can occur in isolation or in conjunction with other injuries to the foot. The majority of metatarsal fractures are caused by a direct force, such as an item being dropped on the foot, a crush injury, a fall from height, or a motor vehicle accident, any of which can cause fracture at any point along the bone. Alternatively, metatarsal fractures can also be the result of lower energy injuries such as torque being applied to a fixed planted foot, or plantarflexion and inversion creating an oblique or avulsion fracture. Finally, repetitive overuse or an abrupt increase in activity can lead to stress fractures of the metatarsals.

Classic history and presentation: Presentation and history can differ depending on the mechanism of injury. Generally, those with an acute fracture will complain of focal pain and tenderness, swelling, and difficulty with weight-bearing. A careful history may elicit an acute event such as a direct trauma, fall, twisting on a fixed planted foot, or inversion of the ankle on a plantarflexed foot. In the setting of a stress fracture, history may elicit chronic overloading or an abrupt increase in activity. These fractures can be more insidious in nature with symptoms evolving from only minor pain and tenderness to progressively worsening swelling, point tenderness, and moderate to severe pain with weight-bearing.

Prevalence: Metatarsal fractures make up 5%-6% of all fractures and account for about 35% of all foot fractures in adults and 61% of all foot fractures in children. Typically, in adults, metatarsal fractures are more common in females and occur most often in patients aged 20-50 years. In children, these fractures are more common in males, with an average age of 8.6 years.

Pathophysiology: The type and location of the fracture can often be associated with a certain mechanism of injury. Many fractures of the metatarsal shafts are the result of a direct blow, a fall from height, excessive axial loading, or torque being applied to a fixed planted foot. Proximal fractures of the 1st through 4th metatarsal can have the same mechanism of injury as metatarsal shaft fractures or can be the result of falling forward over a plantarflexed foot, which can cause a Lisfranc fracture dislocation. Special consideration should be given to proximal fractures of the 5th metatarsal as these are separated into 3 categories with distinct etiologies:

• Tuberosity or avulsion fractures of the styloid of the 5th metatarsal are caused by a sudden inversion of the ankle with plantarflexion of the foot.
• Fractures of the metaphyseal-diaphyseal junction of the 5th metatarsal, with a similar mechanism of injury as tuberosity fractures.
• Stress fractures of the proximal diaphysis of the 5th metatarsal are caused by chronic overloading, classically in younger athletes involved in activities with repetitive jumping or pivoting.

Grade / classification system: Classification for the majority of metatarsal fractures is descriptive of anatomic location: base, shaft, neck, or head. Classification is particularly useful for 5th metatarsal fractures, for which the Lawrence and Botte classification is commonly utilized:

• Zone 1 – the tuberosity (avulsion fracture)
• Zone 2 – metaphyseal-diaphyseal region (Jones fracture)
• Zone 3 – proximal diaphyseal region (stress fracture)