Rare Proximal Diaphyseal Stress Fractures of the Fifth Metatarsal Associated With Metatarsus Adductus

Before the report of English surgeon Robert Jones, who sustained a fracture to his fifth metatarsal while dancing around a tent pole, metatarsal fractures were thought to be the result of direct trauma to the foot. The mechanism of metatarsal fractures, in particular, those involving the fifth metatarsal, is now well understood. Patients with an adducted alignment of their forefoot can overload the fifth metatarsal base, putting them at an increased risk of fractures of this bone. Studies have reported that 2 distinct types of proximal diaphyseal or junctional fractures of the fifth metatarsal occur: the acute proximal diaphyseal or transverse proximal diaphyseal fracture and the proximal diaphyseal stress fracture. The radiographic characteristics associated with proximal diaphyseal stress fractures of the fifth metatarsal can vary by the chronicity; however, the findings typically entail a radiolucent fracture line with surrounding reactive sclerosis. In addition, a reduced medullary canal width can be appreciated. In the present retrospective analysis of patients with stress-related trauma to the fifth metatarsal base with an adducted forefoot, 2012 foot trauma cases were reviewed at 3 separate institutions. Of the 2012 cases, 22 (1.11%) met the outlined criteria of stress fractures of the fifth metatarsal base and underlying metatarsus adductus.