Jones fracture

Clinical History

Traumatic fracture of the proximal fifth metatarsal bone.

Imaging Findings

An eleven year old girl sustained a twisting injury to her right ankle during an amateur dancing competition. She complained of pain and difficulty in weight bearing. On examination, there was bruising and tenderness around the outer aspect of the midfoot. Plain X-rays showed a fracture of the proximal fifth metatarsal base that was in keeping with a Jones fracture.

Discussion

Sir Robert Jones, an orthopaedic surgeon, first described this fracture in 1902 when he sustained this injury following a dance around the maypole in a military garden. The Jones fracture occurs at the metaphyseal-diaphyseal junction of the fifth metatarsal located within 1.5 cm distal to the tuberosity. Jones fractures occur in areas of diminished blood supply and as such are at risk of delayed union and nonunion. The mechanism of injury is repetitive weight bearing and pivoting on the involved foot. Acute fractures occur equally in both sexes, generally in non athletes, and usually in individuals older than 21. Chronic or fatigue fractures occur in individuals between 15 and 21 years of age and predominantly in male athletes. Jones fractures are classified according to radiographic criteria developed by Torg and colleagues. This classification is useful for distinguishing fractures that can be treated conservatively and those that may need operative intervention. Type I fractures have a sharp, well-delineated fracture line, minimal cortical hypertrophy and no intramedullary sclerosis. These fractures are treated with a non-weight-bearing cast for six to eight weeks. Type II fractures (delayed unions) have a fracture line that involves both cortices with the associated periosteal new bone, or a widened fracture line with adjacent radiolucency, or intramedullary sclerosis. These fractures may also be treated with a non-weight-bearing cast, but a prolonged period may be required until the union is achieved. In athletes, these fractures are usually treated operatively, either with medullary curettage and bone grafting or intramedullary screw fixation. Type III fractures (nonunions) have a wide fracture line with periosteal new bone and radiolucency, and complete obliteration of the medullary canal at the fracture site by the sclerotic bone. These fractures should be treated operatively. In general, although most fractures of the proximal portion of the fifth metatarsal respond well to appropriate management, delayed union, muscle atrophy and chronic pain may be long-term complications. An awareness of the Jones fracture will prevent it from being mistaken for the more common avulsion fracture of the base of the fifth metatarsal by the peroneus brevis tendon. Avulsion fractures, due to better local blood supply, are not subject to the same degree of risk of delayed union or nonunion. Thus, prognosis and management for the two distinct fracture types may be totally different.

Differential Diagnosis List

Final Diagnosis

Jones fracture.

URL:	https://www.eurorad.org/case/3121
DOI:	10.1594/EURORAD/CASE.3121
ISSN:	1563-4086