Description

The most common cause of ankle injury comprising a significant proportion of sports injuries:

• Types of ankle sprains: lateral, medial, and syndesmotic (or high ankle sprain)
  • Lateral ankle sprains are the most common, accounting for up to 89% of all ankle sprains (1):
    • In lateral ankle sprains, the anterior talofibular ligament (ATFL) is most likely to be injured.
    • The calcaneofibular ligament (CFL) is the second most likely ligament to be injured.
    • The posterior talofibular ligament (PTFL) is the least likely to be injured.
  • Medial ankle sprains (5–10%) result from an injury to the deltoid ligament.
  • Syndesmotic (“high ankle sprain”) injuries account for 5–10% of ankle sprains.
    • The syndesmosis between the distal tibia and distal fibula bones consists of the anterior, posterior, and transverse tibiofibular ligaments; the interosseous ligament; and interosseous membrane.
• Ankle sprains are classified according to the degree of ligamentous disruption:
  • Grade I: mild stretching of a ligament with possible microscopic tears
  • Grade II: incomplete tear of a ligament
  • Grade III: complete ligament tear

Geriatric Considerations
Increased risk of fracture in patients with preexisting bone weakness (osteoporosis/osteopenia)

Pediatric Considerations

• Increased risk of physeal injuries instead of ligament sprain because ligaments have greater tensile strength than physes
• Inversion ankle injuries in children may have a concomitant fibular physeal injury (Salter-Harris type I or higher fracture).
• Consider tarsal coalition with recurrent ankle sprains.

Epidemiology

Incidence

• Ankle sprains are more common in childhood and adolescents, particularly in active individuals (2).
• 1/2 of all ankle sprains are sports related; highest incidence in indoor/court sports (basketball, volleyball, tennis), followed by football and soccer (3)
• Most common sports injury
• More common in males age <30 years and females >30 years old

Prevalence

• 25% of sports injuries in the United States
• 75% of all ankle injuries are sprains.

Etiology and Pathophysiology

• Lateral ankle sprains result from an inversion force with the ankle in plantar flexion.
• Medial ankle sprains are due to forced eversion while the foot is in dorsiflexion.
• Syndesmotic sprains result from eversion stress/extreme dorsiflexion along with internal rotation of tibia.

Risk Factors

• The greatest risk factor is a prior history of an ankle sprain (3–34% recurrence rate).
• Postural instability, gait alterations
• Joint laxity and decreased proprioception are not risk factors.

General Prevention

• Improve overall physical conditioning:
  • Training in agility and flexibility
  • Single-leg balancing
  • Proprioceptive training
• Taping and bracing may help prevent primary injury in selected sports (i.e., volleyball, basketball, football) or reinjury (4). Taping and bracing do not reduce sprain severity.
• Weight loss may help in overweight patients (4)[A].

Commonly Associated Conditions

• Contusions
• Fractures
  • Fibular head fracture/dislocation (Maisonneuve)
  • Fracture of the base of the 5th metatarsal
  • Distal fibula physeal fracture (includes Salter-Harris fractures in pediatric patients; most common type of pediatric ankle fracture)