Specialty emergency medicine ICD-9-CM 825.25, 825.35 | ICD-10 S92.3 eMedicine radio/850 | |
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A Jones fracture is a fracture in the meta-diaphyseal junction of the fifth metatarsal of the foot. The proximal end of the metatarsal, where the Jones fracture occurs, is near the midportion of the foot, on the fifth ray (of which the 5th toe belongs). Those who sustain a Jones fracture have pain over this area, swelling, and difficulty walking. The fracture was first described by orthopedic surgeon Sir Robert Jones who sustained this injury himself (while dancing) and reported it in the Annals of Surgery in 1902.
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Diagnosis
A patient with a Jones fracture may not realize that a fracture has occurred. Diagnosis includes the palpation of an intact peroneus brevis tendon, and demonstration of local tenderness distal to the tuberosity of the fifth metatarsal, and localized over the diaphysis of the proximal metatarsal. Bony crepitus is unusual.
This injury should be differentiated from the developmental apophysis (5th metatarsal tuberosity) commonly and normally occurring at this site in adolescents. Differentiation is possible by characteristics such as absence of sclerosis of the fractured edges (in acute cases) and orientation of the lucent line: transverse (at 90 degrees) to the metatarsal axis for the fracture (due to avulsion pull by the peroneus brevis muscle inserting at the proximal tip) - and parallel to the metatarsal axis in the case of the apophysis. Diagnostic x-rays include anteroposterior, oblique, and lateral views and should be made with the foot in full flexion.
Treatment
A legitimate concern in any fracture is whether the fracture will heal quickly and without complication. Failure of the fractured ends to unite is called non-union and its frequency varies with the fracture site, some fracture sites being notorious for non-union. An example of such would be a scaphoid (navicular) fracture of the wrist. Such a complication also involves fractures of the proximal end of the fifth metatarsal, such as the Jones fracture. This has been the subject of interest, and initially led to the description of three zones at the proximal end of the fifth metatarsal.
Zones I and III have been associated with relatively guaranteed union and this union has taken place with only limited restriction of activity combined with early immobilization. On the other hand, zone II has been associated with either delayed or non-union and, consequently, it has been generally agreed that fractures in this area should be considered for some form of internal immobilization, such as internal screw fixation.
These zones can be identified anatomically and on x-ray adding to the clinical usefulness of this classification. It should be emphasized that surgical intervention is not, by itself, a guarantee of cure and has its own complication rate. Other reviews of the literature have concluded that conservative, non-operative, treatment is an acceptable option for the non-athlete.
If non-surgical management is pursued, a cast, splint or walking boot for four to eight weeks may be used. Three-fourths of fractures so treated will unite.
Prognosis
For several reasons, a Jones fracture may not unite. The diaphyseal bone (zone II), where the fracture occurs, is an area of potentially poor blood supply, existing in a watershed area between two blood supplies. This may compromise healing. In addition, there are various tendons, including the peroneus brevis and fibularis tertius, and two small muscles attached to the bone. These may pull the fracture apart and prevent healing.
Other proximal fifth metatarsal fractures
Other proximal fifth metatarsal fractures exist, although they are not as severe as a Jones fracture. If the fracture enters the intermetatarsal joint, it is a Jones fracture. If, however, it enters the tarsometatarsal joint, then it is an avulsion fracture caused by pull from the peroneus brevis. An avulsion fracture is sometimes called a Pseudo-Jones fracture or a Dancer's fracture.