Ankle Instability & Sprains

An ankle sprain results when the ligaments that provide stability to the ankle joint are stretched or torn. Most commonly, these injuries occur while playing sports, walking on uneven surfaces or with traumatic falls. The injury can range from mild to severe, depending on the extent of damage to the ligaments.


There are three ligaments on the outside of the ankle that make up the lateral ligament complex,

  • The anterior talofibular ligament (ATFL)
  • The calcaneofibular ligament (CFL)
  • The posterior talofibular ligament (PTFL),

The deltoid ligament, a thick ligament which supports the entire medial, or inner, side of the ankle. The anterior inferior tibiofibular ligament (AITFL) connects the tibia to the fibula, while the posterior inferior tibiofibular ligament (PITFL) tranverse the back of the tibia and fibula. The interosseous ligament runs the entire length of the tibia and fibula from the knee to the ankle joint.

The majority of ankle sprains involve the lateral ligaments and range from sprains to tears of this lateral complex. If there is a complete tear of a ligaments, the ankle may become unstable and can result in damage to the bones and cartilage of the ankle joint over time.

Signs and Symptoms

A sprained ankle is painful, and may also involve swelling, ecchymosis and feelings of instability with weight bearing/walking.

Physical Examination and Work-up

On exam, there is often tenderness to palpation in the area of injury. Range of motion of the ankle may be restricted due to the swelling. Laxity of the joint can be tested with a hands-on examination.


X-rays are performed to rule out a fracture or avulsion injury of the ankle joint. Stress X-rays may be performed, which involve the physician placing the ankle joint in a position which would demonstrate a diagnostic abnormality. MRI may be ordered to assess damage to cartilage and to assess the integrity of the ligaments and surrounding soft tissue.

Grades of Ankle Sprains

  • Grade 1 Sprain (Mild): sprain and microscopic tearing of the ligament fibers
  • Grade 2 Sprain (Moderate): partial tearing of the ligament
  • Grade 3 Sprain (Severe): Complete tear of the ligament

Management of Ankle Sprains & Instability

The majority of ankle sprains are managed without surgery. Initial management includes rest, elevation, immobilization/protection of the joint and anti-inflammatories. Physical therapy is incorporated to aid the return to full, desired activities. Physical therapy focuses on restoration of motion, reduction in pain, advancement of activities and return of proprioception/balance.

If non-operative management fails, surgery may be indicated. Both arthroscopic and open options exist depending on the extent of injury. Arthroscopy is performed to remove any loose bodies of bone or cartilage, or to repair/fix cartilage injuries to the ankle joint. Ligament reconstruction addresses the instability issues due to the damaged ligament by replacing it. A period of post-operative immobilization follows, along with a guided course of physical therapy.

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