Cath Lab Digest

A Guide To Common Fifth Metatarsal Fractures
The site of the fracture, the fracture pattern and one’s understanding of the fifth metatarsal anatomy gives the podiatric physician an adequate amount of information related to the force producing the fracture. In regard to these fractures, there have been a number of classification systems to help clinicians better understand specific fracture patterns within a given region of the bone and their common outcomes.
Capital fractures. Fractures to the head of the fifth metatarsal generally occur from direct impact (in the vertical direction) or trauma from projectiles. Fractures due to compression may also occur but these tend to be quite stable and only involve minor displacement. When significant displacement does occur, it tends to be in a plantar and lateral direction.
One must pay careful attention with these fractures due to their intraarticular involvement and possible unwanted sequelae of arthritis and joint stiffness. These injuries may require open reduction with pinning if closed reduction fails to restore an appropriate articular surface. Another surgical option may include metatarsal head resection with conversion into an arthroplasty if one cannot reconstruct/realign the articular surface.
Cervical fractures. The most common neck fracture of the fifth metatarsal is the spiral fracture. The spiral fracture tends to be displaced medially along the shearing axis of the fracture. In most cases, these fractures are caused by a torque force mediated by bending and loading the lateral aspect of the foot (i.e. rolling over on the outer border) while the foot is in a plantarflexed and inverted position. This is known as the demi-pointe position in relation to dancing. This type of fracture tends to require open reduction and internal fixation, which one may accomplish with crossed K-wires or 2.0 lag screws.
Other types of fractures that can occur along the metatarsal neck include flexural transverse fractures and buckling impaction fractures. Most have acceptable alignment and heal well with four to six weeks of cast immobilization.

Shaft fractures. Fractures along the shaft of the metatarsal tend to be the result of direct violence or impact. Comminuted fractures are the most common result and one may occasionally see a concurrent open wound and a segmental defect. Alternatively, indirect forces, such as a twisting fall, will result in a spiral fracture of the metatarsal shaft. In either case, in the absence of considerable displacement, both types of fractures tend to heal quite well with conservative non-weightbearing care.
When ORIF is required, a one-third tubular plate with 2.7 or 3.5 screws is the recommended fixation for comminuted, displaced diaphyseal fractures. One may use bone graft as an adjunct if a severe defect is present after fixation is in place. For spiral shaft fractures with significant displacement, the surgical options include IM nail, lag screw with neutralization plate or cerclage wire. Another surgical option for shaft fractures in patients with open injuries or osteopenia is external fixation via a mini rail system.