Description

The most common cause of ankle injury comprising a significant proportion of injuries in the athletic and general populations:

• There are three types of ankle sprains: lateral, medial, and syndesmotic (“high ankle sprain”):
  • Lateral ankle sprains (LAS) are the most common. The anterior talofibular ligament (ATFL) is the most likely to be injured, followed by the calcaneofibular ligament (CFL) and then posterior talofibular ligament (PTFL) (1).
  • Medial ankle sprains (MAS) are the second most common and result from an injury to the deltoid ligament.
  • Syndesmotic injuries are the least common ankle sprains. These injuries result from injury to the syndesmosis between the distal tibia and distal fibula bones, consisting 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 very common in the general population and are some of the most commonly reported sport-related injuries. Nearly half of all ankle sprains occur during sports participation (1).
• The highest incidence of LAS occur in indoor/court sports (basketball, volleyball, tennis), followed by field sports such as football and soccer (1),(2).
• High ankle sprains are reported most frequently in men’s football, wrestling, and soccer (1).

Prevalence

• 11–17% of high school and collegiate sports-related injuries in the United States (2)
• Although common in the general population, ankles sprains occur more frequently with athletic participation.

Etiology and Pathophysiology

• LAS result from an inversion force with the ankle in plantar flexion.
• MAS 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

• Intrinsic risk factors
  • Limited ankle dorsiflexion range of motion
  • Reduced ankle proprioception
  • Decreased postural core strength/balance
  • Female gender
  • Low body mass index (BMI)
  • Poor strength, cardiorespiratory endurance, and/or coordination
  • Anatomical abnormalities of the knee, ankle, and/or foot
• Extrinsic risk factors
  • Type of sport played:
    • LAS: basketball, indoor volleyball, field sports and climbing
    • MAS: collegiate men’s/women’s soccer, men’s football, women’s gymnastics
    • Syndesmotic injury: football, wrestling, ice hockey
  • Higher heel height on footwear
• Prior history of ankle sprain may contribute to chronic ankle instability and increased risk for repeated ankle sprain (2).

General Prevention

• Address modifiable risk factors and improve overall physical conditioning:
  • Training in agility and flexibility
  • Single-leg balancing
  • Proprioceptive training
• Taping and/or bracing may help reduce the risk of both primary injury in selected sports (i.e., volleyball, basketball, football) or reinjury (1),(2). Taping and bracing do not reduce sprain severity.

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)