Risk factors and mechanisms of fifth metatarsal stress fracture

Fractures of the proximal fifth metatarsal are troublesome to treat and often carry the risk of nonunion, delayed union, and recurrent fracture. For this reason, researchers have classified fractures of the proximal fifth metatarsal on the basis of which of the three fracture zones is involved and have verified that the healing process, mechanism of injury, and recommended treatment differ among the fracture types. Two studies have identified varus hindfoot as a risk factor for fifth metatarsal stress fracture. The pathogenetic mechanism of this injury is repetitive loading stress on the fifth metatarsal.