Achilles tendinitis is a common condition that occurs when the large tendon that runs down the back of your lower leg becomes irritated and inflamed.
The Achilles tendon is the largest tendon in the body. It connects your calf muscles to your heel bone and is used when you walk, run, climb stairs, jump, and stand on your tip toes. Although the Achilles tendon can withstand great stresses from running and jumping, it is also prone to tendinitis, a condition associated with overuse and degeneration.
Achilles tendinitis pain can occur within the tendon itself or at the point where it attaches to the heel bone, called the Achilles tendon insertion.
Simply defined, tendinitis is inflammation of a tendon. Inflammation is the body's natural response to injury or disease, and often causes swelling, pain, or irritation.
There are two types of Achilles tendinitis, based upon which part of the tendon is inflamed.
Noninsertional Achilles tendinitis
Noninsertional Achilles Tendinitis
In noninsertional Achilles tendinitis, fibers in the middle portion of the tendon have begun to break down with tiny tears (degenerate), swell, and thicken.
Tendinitis of the middle portion of the tendon more commonly affects younger, active people.
Insertional Achilles Tendinitis
Insertional Achilles tendinitis
Insertional Achilles tendinitis involves the lower portion of the heel, where the tendon attaches (inserts) to the heel bone.
In both noninsertional and insertional Achilles tendinitis, damaged tendon fibers may also calcify (harden). Bone spurs (extra bone growth) often form with insertional Achilles tendinitis.
Tendinitis that affects the insertion of the tendon can occur at any time, even in patients who are not active. More often than not, however, it comes from years of overuse (long distance runners, sprinters).
Achilles tendinitis is typically not related to a specific injury. The problem results from repetitive stress to the tendon. This often happens when we push our bodies to do too much, too soon, but other factors can make it more likely to develop tendinitis, including:
- Sudden increase in the amount or intensity of exercise activity—for example, increasing the distance you run every day by a few miles without giving your body a chance to adjust to the new distance
- Tight calf muscles—Having tight calf muscles and suddenly starting an aggressive exercise program can put extra stress on the Achilles tendon
- Bone spur—Extra bone growth where the Achilles tendon attaches to the heel bone can rub against the tendon and cause pain
A bone spur that has developed where the tendon attaches to the heel bone.
Common symptoms of Achilles tendinitis include:
- Pain and stiffness along the Achilles tendon in the morning
- Pain along the tendon or back of the heel that worsens with activity
- Severe pain the day after exercising
- Thickening of the tendon
- Bone spur (insertional tendinitis)
- Swelling that is present all the time and gets worse throughout the day with activity
If you have experienced a sudden "pop" in the back of your calf or heel, you may have ruptured (torn) your Achilles tendon. See your doctor immediately if you think you may have torn your tendon.
After you describe your symptoms and discuss your concerns, the doctor will examine your foot and ankle. The doctor will look for these signs:
- Swelling along the Achilles tendon or at the back of your heel
- Thickening or enlargement of the Achilles tendon
- Bony spurs at the lower part of the tendon at the back of your heel (insertional tendinitis)
- The point of maximum tenderness
- Pain in the middle of the tendon, (noninsertional tendinitis)
- Pain at the back of your heel at the lower part of the tendon (insertional tendinitis)
- Limited range of motion in your ankle—specifically, a decreased ability to flex your foot
Warm Up, Cool Down and Be Flexible
Your doctor may order imaging tests to make sure your symptoms are caused by Achilles tendinitis.
X-ray tests provide clear images of bones. X-rays can show whether the lower part of the Achilles tendon has calcified, or become hardened. This calcification indicates insertional Achilles tendinitis. In cases of severe noninsertional Achilles tendinitis, there can be calcification in the middle portion of the tendon, as well.
Magnetic Resonance Imaging (MRI)
Although magnetic resonance imaging (MRI) is not necessary to diagnose Achilles tendinitis, it is important for planning surgery. An MRI scan can show how severe the damage is in the tendon. If surgery is needed, your doctor will select the procedure based on the amount of tendon damage.