Essential Insights On Treating Fifth Metatarsal Fractures

Author(s): 
By Nicholas Romansky, DPM, and Todd Becker, DPM

Sorting Through The Different Classifications Of Jones Fractures
The classic metaphyseal-diaphyseal fracture, also known as a Jones fracture, is 1.5 cm to 3 cm distal to the tuberosity. Typically, this fracture can either be stress-induced or acute. The anatomic site of the cortical shaft to the proximal metaphyseal expansion creates an area predisposed to load failure.This fracture is typically an incomplete fracture with a wider gap on the lateral cortex. If weightbearing continues, one will see widening of the lateral cortex on a radiographic series.
Many classification systems have attempted to simplify fractures to the fifth metatarsal metaphyseal-diaphyseal junction. Delee classified these fractures based on fracture pattern and acuity.3 Type I fractures are defined as acute fractures and heal well with conservative means. Type II fractures are defined as stress fractures of the proximal diaphysis and have a high propensity for nonunion that necessitate surgical intervention. Vertical or medial lateral forces cause these first two types. Type III fractures involve acute fractures of the tuberosity and will be discussed in detail below.
Torg developed a classification system for proximal diaphyseal stress fractures based on radiographic findings.4 Stage I is an acute fracture with periosteal reaction, a planar-based fracture line and no medullary sclerosis. Stage II shows a similar process but medullary sclerosis and widening of the fracture line are similar to what one would see in delayed unions. Stage III shows complete obliteration of the medullary canal consistent with non-unions.
In 1902, Sir Robert Jones described a transverse diaphyseal fracture that occurred approximately 1.5 to 3.0 cm distal to the tuberosity of the fifth metatarsal.5 Since that time, two different subsets have been termed Jones fractures.
The first, defined by Stewart, occurs at the metaphyseal-diaphyseal junction and does not extend into the metatarsocuboid joint.6 This acute type of injury tends to occur with plantarflexion and adduction of the forefoot, most commonly as a result of landing on the outside of the foot. The second subset applies to proximal diaphyseal stress (aka acute on chronic) fractures. The prevailing thinking is that these fractures are the result of repetitive high bending stresses with an increase in activity. This injury is quite common in athletes who participate in such activities as running and soccer. According to Yu, et. al., these injuries are relatively refractory to conservative treatment and yield less than acceptable outcomes.7
Treatment for these fractures varies from six to eight weeks of non-weightbearing immobilization to primary surgical repair. For a Type I fracture with no displacement or comminution, the treatment of choice is cast immobilization for six to eight weeks. However, even with non-weightbearing immobilization, many of theses fractures will go on to nonunion after 10 or 12 weeks with rates as high as 28 percent being reported in the literature.

Type II fractures also tend not to heal and many go on to non-union after the eight to 12 weeks of cast immobilization. Kavanaugh and Delee advocated percutaneous insertion of a cannulated screw, which one would place longitudinally down the intramedullary canal, as the primary treatment of choice for active patients with Type I fractures and all Type II fractures.3,8 They noted that active patients tend to have a much faster recovery from this surgery and can begin earlier weightbearing (usually within days) with cross-training.

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