Fifth Metatarsal Fractures

Injuries to the base of the fifth metatarsal are common in athletes and are often due to an inversion force combined with the resistance of strong ligamentous structures.1 These fractures are termed avulsion fractures and usually involve the proximal 1 to 1.5 cm of the fifth metatarsal metaphysis. This area of the bone has been termed the tuberosity. These are considered type 1 fractures.2 Type 1 fractures are usually nondisplaced and are generally extra-articular.

Patients present with a history of an inversion injury, often reporting they hear a "pop." A complete physical examination of the foot and ankle should be performed to identify any other injuries. Patients with this fracture will have tenderness and ecchymosis over the lateral midfoot. Neurovascular status must be evaluated, as well as the integrity of the Lisfranc joint complex.

All patients should have weight-bearing (if at all possible) anteroposterior and lateral and non-weight-bearing oblique views of the foot. Additional ankle views should be included if there is any question of injury in the ankle area.

The vast majority of these type 1 fractures may be treated nonoperatively. In general, a firm-soled shoe and activity modification are all that is needed for the athlete. Occasionally, a more symptomatic patient may need a more supportive fracture brace. Healing is usually uneventful and can be expected in 6 to 8 weeks. Not all fractures will show complete radiographic union, but very rarely are these symptomatic. If a symptomatic nonunion occurs, simple excision is usually successful.3 In the rare case of an intra-articular fracture that is displaced more than 2 to 3 mm, fixation with small lag screws is preferred.

As opposed to the fifth metatarsal tuberosity fracture, true Jones fractures involve the metatarsal in the area 2.5 cm distal to the tuberosity at the metaphyseal-diaphyseal junction. These are termed type 2 fractures. Acute injuries involve inversion, axial load, and adduction of the forefoot. Radiographs show a lucent line at the metaphyseal-diaphyseal junction of the bone and usually minimal displacement (Fig. 71-1). The presence of sclerosis around the fracture site and the history of a prodrome of vague pain in the area indicate a Jones stress fracture (Fig. 71-2) Stress fractures almost always require operative intervention and are discussed subsequently.

Physical examination of an acute Jones fracture finds pain to palpation over the lateral midfoot and varied amounts of swelling and ecchymosis. It is important to examine the foot and ankle fully in order to identify any associated injuries to the ankle, forefoot, and especially the Lisfranc complex.

Radiographs consisting of anteroposterior, lateral, and oblique views are necessary to fully evaluate the foot. Again, weight-bearing films are preferred if the patient is able. Rarely are any other studies indicated.

Treatment of a Jones fracture is significantly different from that of an avulsion fracture. The Jones fracture occurs in what has been described as a watershed area of blood flow and is associated with a relatively high rate of nonunion.4 Symptomatic treatment, with a shoe or boot, is not acceptable. If nonoperative treatment is chosen, the patient should be immobilized in a non-weight-bearing fiberglass cast for 6 to 8 weeks (preferably 8 weeks) until radiographic union occurs and the fracture site is nontender. Because the rate of nonunion using a non-weight-bearing cast has been reported to be as high as 28%, surgical treatment is often preferred for the athletic patient.5

Surgical treatment is performed using a percutaneous technique. Under fluoroscopic guidance, a small incision is made laterally at the base of the metatarsal tuberosity and a drill or guidewire for a cannulated screw is inserted. The choice of screw size has been discussed fairly extensively, and discussion exists as to whether solid or cannulated screws should be used.5,6 Various studies have examined techniques using 4.5-, 5.5-, and 6.5-mm screws.4-9 It is the author's opinion that screw size should be based on the patient's anatomy. The canal is tapped as needed, and the appropriate length screw is inserted. Care must be taken to ensure that the screw threads cross the fracture site completely, yet the screw should not be so long as to

Figure 71-1 Acute Jones fracture radiographs. A, Anteroposterior. B, Oblique. C, Lateral.

straighten the normal curve of the bone and thus distract the fracture (Fig. 71-3). The author's preference is to use a 6.5-mm cannulated screw in most fractures with a 4.5-mm screw used in smaller bones. Initial discussion of screw fixation in athletes suggested that early weight bearing could be allowed; however, this has not been reliable.7 The athlete must be protected from weight bearing until union is fully established, generally 6 to 8 weeks (Fig. 71-4A).

Jones stress fractures are commonly identified when a relatively minor acute injury occurs preceded by a prodrome of

Figure 71-2 Jones stress fracture. A and B, Anteroposterior radiograph. Note the sclerosis proximal and distal to the fracture (arrow).
Jones Fracture Screw

Figure 71-4 Healed Jones acute and stress fractures: anteroposterior radiographs. A, Acute fracture. B, Stress fracture.

Figure 71-4 Healed Jones acute and stress fractures: anteroposterior radiographs. A, Acute fracture. B, Stress fracture.

lateral foot pain. They may occur in the classic Jones location or in the next 1 cm distal to this region. These are considered type 3 fractures. The radiographic appearance shows sclerosis in the canal at the fracture site and sometimes a lucent gap (see Fig. 71-2). Operative treatment is almost always indicated. Screw fixation as described previously, with or without onlay bone grafting has been described as successful.6 It is the author's preference to use a bone graft in the well-established nonunions. Generally, an H-shaped trough across the fracture is made and bone graft packed into and around this trough. It is important to fully drill the sclerotic canal to encourage new vascular ingrowth. Weight bearing should be delayed until union occurs and may be prolonged in severe cases (see Fig. 71-4B). The addition of electrical and/or ultrasonic stimulation may be useful.

Was this article helpful?

0 0
Cure Tennis Elbow Without Surgery

Cure Tennis Elbow Without Surgery

Everything you wanted to know about. How To Cure Tennis Elbow. Are you an athlete who suffers from tennis elbow? Contrary to popular opinion, most people who suffer from tennis elbow do not even play tennis. They get this condition, which is a torn tendon in the elbow, from the strain of using the same motions with the arm, repeatedly. If you have tennis elbow, you understand how the pain can disrupt your day.

Get My Free Ebook

Post a comment