An ankle sprain is an injury to one or more of the ligaments of the ankle. There are many ligaments in the ankle, but the most common sprain involves the ligaments of the lateral or outer side of the ankle. These are the anterior talofibular and calcaneofibular ligaments. A ligament is a strong fibrous band that connects bone to bone. It is an important stabilizer of the ankle joint. An ankle sprain occurs secondary to trauma such as falling, twisting or landing in an awkward position often times during sporting activities. Ankle sprains can cause pain, swelling, tenderness, bruising, stiffness and difficulty or inability to walk or bear weight on the injured ankle.
As noted above, ligaments connect bones of bone and most injuries occur in the middle or mid-substance of the ligament. As a result, the x-rays will be negative for a fracture (which is the medical and preferred term for a “break”). X-rays may show an avulsion or chip fracture. Avulsion fractures are injuries to the insertion of the ligament onto the bone and are treated the same as mid-substance injuries.
Functional rehabilitation is the treatment of choice for ankle sprains. Initial treatment includes immobilization in a brace that will allow the patient early weight-bearing. During the first few days, the patient may have difficulty placing weight on the injured ankle and may require crutches. Casting is not recommended. The next phase of treatment includes physical therapy which is recommended to regain range of motion, strength and balance. Mild ankle sprains may take a few weeks to heal, but more severe sprains may take up to 2 to 3 months to heal. The grading of an ankle sprain does not have any practical influence on the initial treatment. This includes complete ruptures or tears.
A MRI is indicated to rule out associated injuries. The most common associated injuries include peroneal tendon tears or osteochondral injuries. A MRI is recommended when a patient fails to improve with functional rehabilitation or there is a concerning find on the initial physical examination by the physician. A rupture or complete tear of the ligament seen on MRI is not an indication for surgery.
The vast majority of ankle sprains improve with functional rehabilitation and are able to return to full activity including sports. When a patient does not improve, surgical intervention can be considered. The patient may complain of recurrent instability or impingement.