[The Physician and Sportsmedicine]

Detecting and Treating Common Fractures of the Foot and Ankle: Part 2: The Midfoot and Forefoot

David B. Thordarson, MD

THE PHYSICIAN AND SPORTSMEDICINE - VOL 24 - NO. 10 - OCTOBER 96

This is the second of two articles on fractures of the foot and ankle. The first article, on ankle and hindfoot fractures, appeared in the September issue.

In Brief: Midfoot and forefoot fractures commonly seen in a primary care practice include navicular and metatarsal stress fracture, tarsometatarsal fracture-dislocation, and acute fracture of the metatarsals, sesamoid, great toe, or lesser toes. A careful history to determine the mechanism of injury and a methodical physical exam to detect sites of tenderness are essential. X-rays are usually required, but stress fractures may warrant bone scans. Compared with ankle and hindfoot fractures, sports-related midfoot and forefoot fractures are more often treated conservatively with casting or wooden shoes. Tarsometatarsal disruption and Jones fractures are more likely to require surgery.

When a person sustains a foot or ankle fracture, his or her ability to perform virtually any athletic activity is immediately impaired. Several types of sports-related ankle and foot fractures occur in the midfoot and forefoot. These injuries are often acute, but stress fractures, which are frequently due to improper technique, commonly occur in this region as well. Exact diagnosis based on physical exam findings and diagnostic images will determine treatment, whether conservative or surgical.

Navicular Stress Fracture

Traumatic fractures of the navicular require high energy and are thus uncommon in sports. The navicular, however, is one of the more common locations of stress fractures in the foot and ankle (figure 1). These fractures are frequently due to the repetitive trauma of running, and patients will typically describe chronic activity-related pain localized to the region of the navicular along the midmedial arch.

[FIGURE 1]

Radiographs are often negative, but in patients who have persistent tenderness in the navicular region, a technetium bone scan will reveal increased activity at the site of the fracture. Computed tomography or tomograms can then help to definitively diagnose the fracture.

Patients who sustain a navicular stress fracture should wear a short leg nonwalking cast for 6 to 8 weeks. An alternative is a short leg brace for the same period of non-weight-bearing to allow for mobilization. A highly competitive athlete, however, may not comply with the period of non-weight-bearing if placed in a removable brace. If immobilization does not lead to healing, these patients can be treated surgically.

Lisfranc (Tarsometatarsal) Fracture-Dislocation

A Lisfranc injury (figure 2), which involves disruption of the tarsometatarsal joint with or without associated fracture, can be a source of prolonged disability for an athlete. Most Lisfranc injuries involve the first three metatarsals, but the intercuneiform or naviculocuneiform joints may also be affected.

[FIGURE 2]

Although typically a high-energy injury, a Lisfranc fracture-dislocation can occur during athletic activities. The typical mechanisms of injury include twisting of the forefoot, axial load on the forefoot, and a crush injury (1). A twisting injury can occur, for example, when a person falls from a horse and gets a foot caught in a stirrup, or when a person is thrown from a sailboard while his or her feet are secured in the straps. A classic sports-related Lisfranc injury occurs when a football player falls onto the heel of another player's plantar-flexed foot, causing an axial load along the metatarsals.

A high index of suspicion is necessary to diagnose this injury. The patient will report severe midfoot pain, and examination will reveal moderate-to-severe swelling along the midfoot region with variable flattening of the arch or abduction of the forefoot. Severe tenderness will be present along the midfoot. Passive plantar flexion and dorsiflexion of the toes should be assessed to rule out a compartment syndrome of the foot.

Radiographic evaluation includes anteroposterior (AP), lateral, and oblique views of the foot. A normal AP or oblique radiograph should reveal that the medial and lateral aspects of the first three metatarsals align with the medial and lateral aspects of the cuneiforms with which they articulate, and the medial aspect of the fourth metatarsal aligns with the medial aspect of the cuboid on the oblique view. Any alteration of these normal relationships demonstrates the site or sites of displacement. Other radiographic signs include diastasis or a fleck fracture between the base of the first and second metatarsals on an AP radiograph or dorsal displacement of the metatarsals on lateral view.

A nondisplaced Lisfranc injury can be treated conservatively in a short leg nonwalking cast for 6 weeks followed by 6 weeks in a short leg walking cast. Most of these injuries, however, will have some degree of displacement and require open reduction and internal fixation.

Metatarsal Fractures

With the exception of stress fractures and injuries of the fifth metatarsal, metatarsal fractures typically result from a direct blow to the foot. Fractures are generally classified according to their anatomic location as neck, shaft, or base fractures, and AP and lateral radiographs are generally sufficient for assessment.

Acute fracture. A single, traumatic fracture of a metatarsal is usually minimally displaced because of the restraining forces of the intermetatarsal ligaments. Patients describe pain with weight bearing. On examination, they will have swelling and tenderness localized to the fracture site. These fractures can generally be treated conservatively in a cast or wooden shoe for 6 weeks with weight bearing as tolerated until the patient's pain and tenderness subside.

Stress fracture. Metatarsal stress fractures generally involve a single metatarsal, usually the second or third (figure 3). They typically result from training errors such as too rapid an increase in mileage in a runner. Patients will report activity-related pain that gradually increases. They will generally have tenderness over the fracture site with minimal edema. Poor shoes can also contribute. These fractures can be treated with a stiff-soled shoe or wooden shoe, and the patient should cross-train in low-impact activities such as swimming or stationary cycling until tenderness resolves.

[FIGURE 3]

Multiple fracture. Multiple fractures frequently require open reduction and internal fixation because of significant displacement. Residual displacement of a metatarsal fracture can predispose a patient to develop a callus. This is because a displaced metatarsal, whether plantar or dorsally displaced, alters the pressure pattern in the forefoot, and a callus forms in the area of increased pressure. The callus, or intractable plantar keratosis, will cause persistent pain with weight bearing and will require an orthosis or possibly even surgical correction of the underlying bony deformity.

Fifth-metatarsal fracture. The most common injury of the fifth metatarsal is an avulsion fracture at the insertion of the peroneus brevis tendon, which occurs with an inversion injury to the hindfoot (figure 4). Patients will say that they sprained their ankle, but the tenderness will be localized over the base of the fifth metatarsal. These fractures heal reliably and can be treated with a wooden shoe, tennis shoe for support, or other symptomatic treatment, provided that no displacement of the intra-articular base of the metatarsal exists.

[FIGURE 4]

A much more serious fracture of the fifth metatarsal is the Jones fracture (figure 5). This fracture occurs at the diaphyseal-metaphyseal junction of the base of the fifth metatarsal. A watershed area of the blood supply of the fifth metatarsal exists in this region, thus predisposing this area to delayed healing, nonunion, or stress fracture. Patients who sustain a Jones fracture may experience a sudden onset of pain with trivial trauma, or they may develop a gradual onset of pain in the midlateral border of the foot.

[FIGURE 5]

Traumatic or stress fractures in this area must be treated with 6 weeks in a nonwalking cast. Despite this aggressive nonoperative treatment, a significant proportion of these patients will develop a nonunion (1). Primary open reduction and internal fixation of this fracture may be preferred in competitive athletes to compress the fracture site to facilitate healing and thus minimize the period of disability.

Sesamoid Fracture

Fractures of the sesamoid bones can occur acutely as a result of direct trauma or indirectly from hyperdorsiflexion of the hallux metatarsophalangeal joint, such as in a football player. Because of their poor blood supply, the sesamoids are also prone to stress fractures.

With either an acute or a stress fracture, patients typically will have pain over the plantar aspect of the first metatarsal head and localized tenderness over the affected sesamoid. The medial sesamoid is usually involved--probably because it is located more directly beneath the first metatarsal (1). These fractures can be very recalcitrant, and patients must be warned that symptoms will frequently persist for 4 to 6 months. Radiographic evaluation includes AP and lateral views of the foot and a sesamoid x-ray--a tangential view of the plantar aspect of the first metatarsal with the toe extended.

For an acute fracture, most authors advocate a short leg walking cast for 3 to 6 weeks followed by a stiff-soled shoe with a metatarsal pad to elevate the metatarsal head until symptoms resolve. Stress fractures are more difficult to treat and require 6 to 12 weeks in a short leg walking cast. Patients must avoid all high-impact activities until tenderness subsides. Patients with pain persisting for 3 to 6 months despite adherence to the above regimen may require partial or complete surgical excision of the sesamoid. However, sesamoid excision can be complicated by hallux valgus (with a medial sesamoid excision), hallux varus (lateral sesamoid excision) or stiffness, and thus should be avoided if possible. A few authors even advocate bone grafting (1).

Great Toe Fracture

Fractures of the great toe generally result from a direct blow or an axial load. Pain and tenderness will be localized over the fracture. Nondisplaced fractures can be treated with either a walking cast with a toe plate or a wooden shoe and crutches as needed. A fracture displaced into the metatarsophalangeal or interphalangeal joint should be surgically repaired to prevent osteoarthritis. AP and lateral radiographs will demonstrate the fracture anatomy.

Lesser Toe Fracture

Lesser toe fractures (figure 6) are typically caused by an axial load or direct trauma. Even displaced fractures or intra-articular fractures are generally amenable to nonoperative treatment. These patients are able to walk despite the fracture but have problems with footwear. Again, AP and lateral x-rays will help pinpoint the fracture.

Patients are instructed to tape the injured toe to an adjacent uninjured toe (buddy taping) and to place a small piece of gauze between the toes to prevent maceration of the skin. A wooden shoe can be used until tenderness subsides to the point where the patient can begin using tennis shoes. Most fracture tenderness resolves in 3 to 4 weeks. Typically, follow-up radiographs are unnecessary since they will not influence subsequent treatment decisions.

[FIGURE 6]

Attuned to Foot Fractures

Fractures of the midfoot and forefoot are similar to those of the ankle and hindfoot in that they can often be treated nonoperatively. But each fracture has its own distinguishing characteristics and treatment options, so physicians need to be attuned to both detection and management of these injuries. Misdiagnosing a Jones fracture, for example, can have serious consequences to an active patient.

References

  1. De Lee JC: Fractures and dislocations of the foot, in Mann RA, Coughlin MJ (eds): Surgery of the Foot and Ankle, ed 6. St Louis, Mosby, 1993, pp 1465-1703

Dr Thordarson is an assistant professor of orthopedic surgery and the chief of Foot and Ankle Trauma and Reconstructive Surgery in the Department of Orthopaedic Surgery at the University of Southern California in Los Angeles. Address correspondence to David B. Thordarson, MD, 1200 N State St, GNH 3900, Los Angeles, CA 90033.


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