Sprained Ankle

A sprained ankle is a very common injury. Approximately 25,000 people experience it each day. A sprained ankle can happen to athletes and non-athletes, children and adults. It can happen when you take part in sports and physical fitness activities. It can also happen when you simply step on an uneven surface,or step down at an angle.

The ligaments of the ankle hold the ankle bones and joint in position. They protect the ankle joint from abnormal movements-especially twisting, turning, and rolling of the foot.

A ligament is an elastic structure. Ligaments usually stretch within their limits, and then go back to their normal positions. When a ligament is forced to stretch beyond its normal range, a sprain occurs. A severe sprain causes actual tearing of the elastic fibers.

How It Happens

Ankle sprains happen when the foot twists, rolls or turns beyond its normal motions. A great force is transmitted upon landing. You can sprain your ankle if the foot is planted unevenly on a surface, beyond the normal force of stepping. This causes the ligaments to stretch beyond their normal range in an abnormal position.

Mechanism of Injury

If there is a severe in-turning or out-turning of the foot relative to the ankle, the forces cause the ligaments to stretch beyond their normal length. If the force is too strong, the ligaments can tear. You may lose your balance when your foot is placed unevenly on the ground. You may fall and be unable to stand on that foot. When excessive force is applied to the ankle's soft tissue structures, you may even hear a "pop". Pain and swelling result.

The amount of force determines the grade of the sprain. A mild sprain is a Grade 1. A moderate sprain is a Grade 2. A severe strain is a Grade 3 (see Table below).

• Grade 1 sprain:
  Slight stretching and some damage to the fibers (fibrils) of the ligament.

• Grade 2 sprain:
  Partial tearing of the ligament. If the ankle joint is examined and moved in certain ways, abnormal looseness (laxity) of the ankle joint occurs.

• Grade 3 sprain:
  Complete tear of the ligament. If the examiner pulls or pushes on the ankle joint in certain movements, gross instability occurs.

Diagnosis

See your doctor to diagnose a sprained ankle. He or she may order X-rays to make sure you don't have a broken bone in the ankle or foot. A broken bone can have similar symptoms of pain and swelling.

The injured ligament may feel tender. If there is no broken bone, the doctor may be able to tell you the grade of your ankle sprain based upon the amount of swelling, pain and bruising.

The physical exam may be painful. The doctor may need to move your ankle in various ways to see which ligament has been hurt or torn.

If there is a complete tear of the ligaments, the ankle may become unstable after the initial injury phase passes. If this occurs, it is possible that the injury may also cause damage to the ankle joint surface itself.

The doctor may order an MRI (magnetic resonance imaging) scan if he or she suspects a very severe injury to the ligaments, injury to the joint surface, a small bone chip or other problem. The MRI can make sure the diagnosis is correct. The MRI may be ordered after the period of swelling and bruising resolves.

Symptoms

The amount of pain depends on the amount of stretching and tearing of the ligament. Instability occurs when there has been complete tearing of the ligament or a complete dislocation of the ankle joint.

Is It Acute or Chronic?

If you have sprained your ankle in the past, you may continue to sprain it if the ligaments did not have time to completely heal. If the sprain happens frequently and pain continues for more than four weeks to six weeks, you may have a chronic ankle sprain. Activities that tend to make an already sprained ankle worse include stepping on uneven surfaces, cutting actions and sports that require rolling or twisting of the foot, such as trail running, basketball, tennis, football and soccer.

Possible complications of ankle sprains and treatment include abnormal proprioception. There may be imbalance and muscle weakness that causes a re-injury. If this happens over and over again, a chronic situation may persist with instability, a sense of the ankle giving way (gross laxity) and chronic pain. This can also happen if you return to work, sports or other activities without letting the ankle heal and become rehabilitated.

Contact Parkland's Foot and Ankle specialists to receive comprehensive evaluation and management for foot and ankle problems.