Chapter 175. Ankle and Foot Injuries

Ligament and Tendon Injuries

Clinical Features

Tendon injuries typically result from either hyperdorsiflexion, when the peroneal tendon is injured, or sudden plantarflexion, which results in an Achilles tendon injury. Patients with an Achilles tendon rupture have severe pain and are unable to walk on their toes, run, or climb stairs. Ligamentous sprains tend to result from inversion and eversion injuries. The most common ankle sprain involves the anterior talofibular ligament. An isolated sprain of the medial deltoid ligament is rare, and an associated fibular fracture (Maisonneuve fracture) or syndesmotic ligament injury may be present. Any injury with signs of neurovascular compromise requires immediate attention.

Diagnosis and Differential

Evaluate the ankle along with the joints above and below the injury. A positive Thompson test (with the patient lying prone and knee flexed at 90°, the foot fails to plantarflex when the calf is squeezed) is diagnostic of Achilles tendon rupture. Palpate the proximal fibula for tenderness resulting from a fracture or fibulotibialis ligament tear. Squeeze the fibula toward the tibia to evaluate for syndesmotic ligament injury. If tenderness is isolated to the posterior aspect of the lateral malleolus, then a peroneal tendon subluxation may be present.

The Ottawa Ankle Rules guide clinicians in determining when imaging studies are needed for suspected ankle injuries (Fig. 175-1).

Joint stability is the primary determinant of a treatment plan for a sprain. Instability is suspected based on physical examination and radiography. The examiner may perform the anterior drawer and talar tilt tests to assess stability. If the examiner is unable to perform reliable stress testing, the injury is considered potentially unstable. Any asymmetry in the gap between the talar dome and the malleoli on the talus x-ray view suggests joint instability.

Emergency Department Care and Disposition

1. If the patient has a stable joint and is able to bear weight, then protection (with an elastic bandage or ankle brace), rest, ice, compression, and elevation (PRICE) for up to 72 hours is indicated. Prescribe analgesics, and add motion and strength exercises within 48 to 72 hours. The patient should follow-up in 1 week if the pain persists.

2. A patient with a stable joint who is unable to bear weight requires an ankle brace and orthopedic follow-up.

3. A patient with an unstable joint requires a posterior splint and referral to an orthopedist for definitive care.

4. Treatment of Achilles tendon rupture includes splinting in plantar flexion, nonweightbearing, and referral to an orthopedist for possible operative repair.

Dislocations

Posterior dislocations are the most common ankle dislocation and occur with a backward force on the plantarflexed foot, usually resulting in rupture of the tibiofibular ligaments or a lateral malleolus fracture. Reduce ankle dislocations immediately if vascular compromise (absent pulses, a dusky foot, or skin tenting) is present. Grasp the heel and foot and apply downward traction, with analgesia and sedation as needed. Following successful reduction, apply a splint, assess postreduction neurovascular status, obtain postreduction radiographs, and consult orthopedics immediately.

Fractures

Ankle fractures are classified as unimalleolar, bimalleolar, and trimalleolar. Bi- and trimalleolar fractures require open reduction and internal fixation (ORIF) by the orthopedist. ED care includes posterior splinting, elevation, ice application, and orthopedic consultation. Treat unimalleolar fractures with nonweight bearing and posterior splinting. Manage minimally displaced avulsion factures of the fibula like ankle sprains. Ankle fractures can be occult and associated with other parts of the lower extremity (Table 175-1). Patients with open fractures require wet sterile dressing, splinting, tetanus toxoid as necessary, a first generation cephalosporin (eg, cefazolin 1 gram IV), and immediate orthopedic consultation.

Clinical Features

The foot is divided into the hindfoot, midfoot, and forefoot. The Chopart joint separates the hindfoot and midfoot, and the Lisfranc joint separates the midfoot and forefoot.

Diagnosis and Differential

Pay special attention on physical examination to the base of the fifth metatarsal and the area over the base of the second metatarsal. CT is indicated for suspected Lisfranc joint injuries.

Hindfoot Injuries

Calcaneal injuries require a large force, and associated injuries are common. Measure Boehler angle (formed by the intersection of a line connecting the posterior tuberosity and apex of the posterior facet and a line from the posterior facet to the apex of the anterior facet, on the lateral radiograph view) if concerned for a calcaneal compression fracture. An angle of less than 25° is suggestive of a fracture. Treat with a posterior splint, elevation, analgesics, and orthopedic consultation. Manage small avulsion fractures of the talus with posterior splinting and orthopedic follow-up. Major fractures of the talar neck and body and subtalar dislocations require immediate orthopedic consultation.

Midfoot Injuries

Injuries around the tarsometatarsal joint and pain with torsion of the midfoot is suspicious for a Lisfranc injury. Lisfranc joint injuries are often associated with a fracture, especially at the base of the second metatarsal. On x-ray, a gap greater than 1 mm between the bases of the first and second metatarsals is considered unstable. These injuries require CT and orthopedic consultation. Isolated navicular, cuboid, and cuneiform injuries are rare and treated conservatively.

Forefoot

Treat nondisplaced metatarsal shaft fractures with a posterior splint or orthopedic shoe. Fractures with >3 to 4 mm displacement require surgical reduction. Treat pseudo Jones fractures (nondisplaced avulsion fractures of the tuberosity of the fifth metatarsal) with a walking cast. Manage true Jones fractures (metaphyseal-diaphyseal junction fracture of the fifth metatarsal) with a nonweightbearing cast and orthopedic follow-up for potential surgery. Nondisplaced phalangeal fractures require buddy taping and a stiff-sole shoe. Treat displaced fractures and dislocations with a digital block, reduction by manual traction, and buddy taping. Recommended imaging and care for foot injuries can be found in Table 175-2.