Base of Fifth Metatarsal Fracture

Abstract

Metatarsal bone fractures account for more than half of all pediatric foot fractures and 15% of all injuries of the foot. Fortunately, the vast majority of these fractures can be treated conservatively with immobilization alone. Metatarsal fractures generally result from direct trauma such as a heavy object falling on the foot or a crush injury in a motor vehicle accident or from indirect trauma such as a twisting injury. Metatarsal neck fractures are more often caused by a torsional force applied to the foot, whereas direct compression results in shaft fractures. Open reduction with internal fixation is indicated for patients with open fractures, irreducible fractures, and those that cannot maintain reduction by casting.

Fractures of the base of the fifth metatarsal are best classified according to their anatomical location which are divided into three zones of the proximal metatarsal.

Zone I comprises the cancellous tuberosity, including the insertion of the peroneus brevis tendon and the calcaneometatarsal ligament of the plantar fascia. Zone II is the distal aspect of the tuberosity with dorsal and plantar ligamentous attachments to the fourth metatarsal. Zone III begins distal to the ligamentous attachments and extends to the mid-diaphyseal area. It is important to recognize a zone II injury, the Jones fracture, which is prone to nonunion because of the watershed area of blood supply in this region. Surgical treatment of acute Jones fractures has been advocated for active and athletic adolescents to avoid issues associated with delayed healing.