Sarah Andrus Gaines
ANKLE INJURIES
PATHOPHYSIOLOGY
Ankle joint injuries are due to abnormal movement of the talus within the mortise and the resultant stress on the malleoli and ligaments.
Injuries resulting in disruption of both sides of the joint (malleoli fracture plus ruptured ligament, fracture of both malleoli, or disruption of both ligaments) are unstable.
ANKLE SPRAINS
CLINICAL FEATURES
Sprains result from abnormal motion of the talus within the mortise, leading to stretching or disruption of the ligaments.
Typically, the patient is able to bear weight immediately after the injury, with subsequent increase in pain and swelling as the patient continues to ambulate.
Physical examination reveals tenderness and swelling over the involved ligament with a corresponding lack of tenderness over the bony prominences of the ankle.
The lateral ankle is injured more frequently, with the anterior talofibular ligament being the most commonly injured ligament.
Isolated sprain of the medial deltoid ligament is rare, and an associated fibular fracture (Maisonneuve fracture) or syndesmotic ligament injury may be present.
Joint stability, either on physical examination or radiographically, is the primary determinant of a treatment plan for a sprain.
DIAGNOSIS AND DIFFERENTIAL
To exclude other injuries, evaluation of the injured ankle begins with examination of the joints above and below the injury.
Palpate the Achilles tendon for tenderness or a defect, and perform the Thompson test (squeezing the calf while observing for resultant plantar flexion).
Palpate the proximal fibula for tenderness resulting from a Maisonneuve fracture or fibulotibialis ligament tear.
Squeeze the fibula toward the tibia to evaluate for syndesmotic ligament injury.
Palpate the calcaneus, tarsals, and the base of the fifth metatarsal to evaluate for foot fractures causing ankle pain that may not readily be apparent on standard ankle radiograph.
Palpate the posterior aspects of the medial and lateral malleoli from 6 cm proximally to the distal tips. If tenderness is isolated to the posterior aspect of the lateral malleolus, then a peroneal tendon subluxation may be present.
The Ottawa Ankle Rules are simple guidelines that have been extensively validated in numerous clinical trials (Fig. 177-1). When applied properly, they can help the emergency physician identify a subset of patients who can be safely treated without undergoing radiographic studies.
Any asymmetry in the gap between the talar dome and the malleoli on the talus radiographic view suggests joint instability.
FIG. 177-1. Ottawa Ankle Rules for ankle and midfoot injuries. Ankle radiographs are required only if there is any pain in the malleolar zone or midfoot zone along with bony tenderness in any of these four locations or the inability to bear weight both immediately and in the ED.
EMERGENCY DEPARTMENT CARE AND DISPOSITION
Treatment for the patient with a stable joint and able to bear weight is analgesics, protection, rest, ice, compression, and elevation (PRICE) for 48 to 72 hours; motion and strength exercises within 48 to 72 hours; and 1-week follow-up if the pain persists. An elastic bandage or ankle brace can be used.
For patients who have a stable joint and are unable to bear weight, treatment consists of an ankle brace and a 1-week follow-up for repeat examination. Some injuries may require orthopedic consultations and operative repair.
Patients with unstable joints require a posterior splint and referral to an orthopedist for definitive care.
ANKLE FRACTURES
Ankle fractures are classified as unimalleolar, bimalleolar, and trimalleolar. Bi-and trimalleolar fractures require open reduction-internal fixation (ORIF).
ED care includes posterior splinting, elevation, ice application, and initiating orthopedic consultation.
Unimalleolar fractures are usually treated with non-weight posterior splinting and orthopedic follow-up. Minimally displaced, small (<3 mm) avulsion fractures of the fibula are treated like ankle sprains.
Open fractures require wet sterile dressing coverage, splinting, and administration of tetanus toxoid, as necessary, and a first-generation cephalosporin (eg, cefazolin) and immediate orthopedic consultation.
If gross contamination is noted, then add tetanus immunoglobulin and an aminoglycoside to the treat ment regimen.
ANKLE DISLOCATIONS
Posterior dislocations are the most common and occur with a backward force on the plantarflexed foot, usually resulting in rupture of the tibiofibular ligaments or a lateral malleolus fracture.
If vascular compromise is present, indicated by absent pulses, a dusky foot, or skin tenting, immediate reduction by the emergency physician is warranted.
Reduction is performed by grasping the heel and foot and applying downward traction with analgesia and sedation as indicated.
Follow successful reduction by performing splinting, post-reduction neurovascular examination, radiographic evaluation, and immediate orthopedic consultation in the ED.
FOOT INJURIES
PATHOPHYSIOLOGY
The foot is divided into the hindfoot, midfoot, and forefoot. The Chopart joint separates the hind- and midfoot and the Lisfranc joint separates the mid- and forefoot. Foot injuries most commonly result from direct or twisting forces, with twisting-type mechanisms resulting in more minor avulsion-type injuries.
The first metatarsal bears twice the weight of any other metatarsal, necessitating a more conservative approach to fracture management.
The base of the second metatarsal is an important component of the Lisfranc complex and any sign of injury warrants caution.
Major fractures of the talus and subtalar dislocations are at risk for avascular necrosis because of the tenuous blood supply of the foot.
HINDFOOT INJURIES
Small avulsion fractures of the talus are treated with posterior splinting and orthopedic follow-up.
Major fractures of the talar neck and body and subtalar dislocations require immediate orthopedic consultation.
Calcaneal injuries require a large force and associated injuries are common. Compression fractures of the calcaneus require the measurement of the 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). An angle <25 degrees increases the likelihood of a fracture. Treatment consists of posterior splinting, elevation, analgesics, and orthopedic consultation.
MIDFOOT INJURIES
Pain with torsion of the midfoot is suspicious for a Lisfranc injury as are injuries about the tarsometa-tarsal joint.
Lisfranc joint injuries are often associated with a fracture, especially at the base of the second metatarsal.
On radiograph, a gap >1 mm between the bases of the first and second metatarsals is considered unstable.
Lisfranc joint injuries require CT and orthopedic consultation.
Isolated navicular, cuboid, and cuneiform injuries are rare and treated conservatively.
FOREFOOT INJURIES
Treat nondisplaced metatarsal shaft fractures with a posterior splint or orthopedic shoe, with the exception of keeping fractures of the first metatarsal non-weightbearing.
Fractures with at least 3-4 mm displacement require surgical reduction.
Treat pseudo-Jones avulsion fractures with a walking cast.
Treat the true Jones fracture (metaphyseal-diaphyseal junction fracture) with a non-weightbearing cast and orthopedic follow-up for potential surgery.
Treat nondisplaced phalangeal fractures with buddy taping and a stiff-soled cast shoe.
Treat displaced phalangeal fractures and dislocations with digital block, reduction by manual traction, and buddy taping.
CRUSH INJURY AND COMPARTMENT SYNDROME
A crushed foot that becomes tensely swollen and is associated with complaints of pain out of proportion to physical examination findings suggests the possibility of compartment syndrome.
Typically, pain is not relieved by elevation of the foot and is increased with passive dorsiflexion of the great toe.
Distal neurovascular examination may yield normal results.
Diagnosis is made by measurement of intracompart-mental pressure.
For further reading in Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 7th ed., see Chapter 273, “Ankle Injuries,” by Daniel A. Handel and Sarah Andrus Gaines, and Chapter 274, “Foot Injuries,” by Sarah Andrus Gaines, Daniel A. Handel, and Peter N. Ramsey.