Emergent Care / Stabilization:

• Assess the patient for additional injuries (including lateral ankle and midfoot ligamentous and bone structures) and provide pain control.
• Order x-rays to evaluate for fractures and joint abnormalities.
• Evaluate the skin for open injuries that may require intravenous (IV) antibiotics and urgent debridement.
• Determine if surgery is warranted and treat accordingly based on fracture type.

Diagnosis Overview:
Causes / typical injury mechanism: A proximal fifth metatarsal fracture can be the result of an acute injury or repeated microtraumas over the course of weeks to months. Proximal fifth metatarsal fractures are divided into 3 categories with distinct etiologies.

• Styloid avulsion fracture (also referred to as zone 1 or pseudo-Jones fracture): Occurs when the hindfoot is forced into inversion during plantarflexion. This is typically an acute injury due to a sudden, forceful pull of the peroneus brevis tendon and the plantar aponeurosis.
• Fracture of the metaphyseal-diaphyseal junction (also referred to as zone 2 or Jones fracture): This is typically an acute injury due to significant and sudden force or direct trauma under the lateral aspect of the distal fifth metatarsal. Alternatively, a stress fracture may occur in this area due to chronic overloading.
• Diaphyseal stress fracture (also referred to as zone 3 fracture): Often a result of chronic injuries of repetitive microtrauma to the lateral foot.

Distal fifth metatarsal fractures are also possible.

• Dancer's fracture: A long, spiral fracture of the distal fifth metatarsal that may extend into the proximal fifth metatarsal. This type of fracture is more commonly seen in dancers when they roll over their foot while in demi-pointe position or while landing a jump.

Classic history and presentation: Proximal fifth metatarsal fractures are divided into 3 categories with distinct etiologies and presentations.

• Styloid avulsion fracture: Presents similarly to a lateral ankle sprain, and patients may complain of a "twisted ankle." Weight-bearing may be painful. A typical history would be an athlete landing awkwardly after a jump.
• Fracture of the metaphyseal-diaphyseal junction: Typically presents as pain in the midportion of the lateral foot, with increased pain with weight-bearing. An acute injury is often seen in athletes who made a sudden change in direction or landed on the side of the foot after stumbling. A stress fracture may occur in this area due to chronic overloading as well.
• Diaphyseal stress fracture: Often a result of chronic injuries of repetitive microtrauma or stress on the lateral aspect of the foot, made worse by weight-bearing. A typical history would be an athlete, such as a basketball player, who repetitively pivots on one foot.

In all cases, physical examination may reveal point tenderness with palpation over the base of the fifth metatarsal, localized swelling, ecchymosis, and pain with resisted foot eversion.

Prevalence: Fractures of the fifth metatarsal are the most prevalent metatarsal fracture, with styloid avulsion fractures being the most common.

• Fractures peak in the third decade of life for men and the seventh decade of life for women, although with increasing female participation in sports, there has been an increase in fractures in the young female population as well.
• There is a strong correlation between the female sex and styloid avulsion fractures as well as dancer's fractures.

Risk factors:

• Exposure to high-energy trauma
• Repeated microtraumas over the course of weeks to months
• Anatomic factors including hindfoot varus, pes cavus, metatarsus adductus, or genu varum
• Improper footwear during athletics

Grade / classification system: The base of the fifth metatarsal is broken into 3 anatomical zones:

• Styloid avulsion fracture, also referred to as zone 1 fractures or pseudo-Jones fractures.
• Fracture of the metaphyseal-diaphyseal junction, also referred to as zone 2 or Jones fracture.
• Diaphyseal stress fracture, also referred to as a zone 3 fracture.

Other fractures a patient may present with include:

• A shaft fracture greater than 1.5 cm distal to the tuberosity.
• A long, spiral fracture extending into the distal metaphyseal area, referred to as a dancer's fracture.

The radiographic appearance of a proximal fifth metatarsal fracture is classified using the Torg classification system.

• Type I fractures: Early, with no intramedullary sclerosis; sharp fracture line with no widening; minimal cortical hypertrophy; minimal periosteal reaction.
• Type II fracture: Delayed, with evidence of intramedullary sclerosing; widened fracture line with the involvement of both cortices; periosteal reaction present.
• Type III fracture: Nonunion; complete obliteration of the medullary canal by sclerotic bone; wide fracture line with new periosteal bone.

Related topics: foot fracture, metatarsal bone fracture