Essential Insights On Treating Fifth Metatarsal Fractures

By Nicholas Romansky, DPM, and Todd Becker, DPM
This type of fracture tends to require open reduction and internal fixation, which one may accomplish with crossed K-wires or 2.0 lag screws. Other types of fractures that can occur along the metatarsal neck include flexural transverse fractures and buckling impaction fractures. Most have acceptable alignment and heal well with four to six weeks of cast immobilization. Shaft fractures. Fractures along the shaft of the metatarsal tend to be the result of direct violence or impact. Comminuted fractures are the most common result and one may occasionally see a concurrent open wound and a segmental defect. Alternatively, indirect forces, such as a twisting fall, will result in a spiral fracture of the metatarsal shaft. In either case, in the absence of considerable displacement, both types of fractures tend to heal quite well with conservative non-weightbearing care. When ORIF is required, a one-third tubular plate with 2.7 or 3.5 screws is the recommended fixation for comminuted, displaced diaphyseal fractures. One may use bone graft as an adjunct if a severe defect is present after fixation is in place. For spiral shaft fractures with significant displacement, the surgical options include IM nail, lag screw with neutralization plate or cerclage wire. Another surgical option for shaft fractures in patients with open injuries or osteopenia is external fixation via a mini rail system. 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.

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