How is a sprained ankle diagnosed?
Your doctor will diagnose your sprained ankle by performing a careful examination of your foot and ankle. This physical exam may be painful.
- Palpate. Your doctor will gently press around the ankle to determine which ligaments are injured.
- Range of motion. He or she may also move your ankle in different directions; however, a stiff, swollen ankle usually will not move much.
If there is no broken bone, your doctor may be able to tell the severity of your ankle sprain based upon the amount of swelling, pain, and bruising.
What tests can be used to diagnose a sprained ankle?
- X-rays. X-rays provide images of dense structures, such as bone. Your doctor may order x-rays to rule out a broken bone in your ankle or foot. A broken bone can cause similar symptoms of pain and swelling as a sprain.
- Stress x-rays. In addition to x-rays, your doctor may also order stress x-rays. These scans are taken while the ankle is being pushed in different directions. Stress x-rays help to show whether the ankle is moving abnormally because of injured ligaments.
- Magnetic resonance imaging (MRI) scan. Your doctor may order an MRI if he or she suspects a very severe injury to the ligaments, damage to the cartilage or bone of the joint surface, a small bone chip, or another problem. The MRI may not be ordered until after the period of swelling and bruising resolves.
- Ultrasound. This imaging scan allows your doctor to observe the ligament directly while he or she moves your ankle. This helps your doctor to determine how much stability the ligament provides.
What are the different types of ankle sprains?
After your sprained ankle is diagnosed, your doctor will determine the grade of your sprain to help develop a treatment plan. Sprains are graded based on how much damage has occurred to the ligaments.
Grade 1 Sprain (Mild)
- Slight stretching and microscopic tearing of the ligament fibers
- Mild tenderness and swelling around the ankle
Grade 2 Sprain (Moderate)
- Partial tearing of the ligament
- Moderate tenderness and swelling around the ankle
- If the doctor moves the ankle in certain ways, there is an abnormal looseness of the ankle joint
Grade 3 Sprain (Severe)
- Complete tear of the ligament
- Significant pain and swelling around the ankle
- If the doctor pulls or pushes on the ankle joint in certain movements, it feels very unstable