The different causes of tendon pain include tendinitis, tendinosis, partial tendon rupture, and a full tendon rupture. Tendinitis is inflammation of the tendon — i.e., the tissue connecting muscle to bone — and often causes a dull, aching pain that gets worse over a period of time. Tendinosis, which is damage to the tendon but without inflammation, can also cause long term tendon pain. Tendon ruptures, both partial and full, are usually the result of excess force through the tendon, and can cause immediate pain.
Tendinitis is probably the most common cause of tendon pain. It can occur in any tendon, but is particularly common in the Achilles and patella tendons. Tendon pain that is caused by tendinitis is often a dull ache, and is aggravated with exercise. Tendinitis can also cause pain to the area surrounding a joint, and there may be visible swelling.
Tendinosis is a chronic injury to the tendon, and can result in longterm tendon pain. It is usually caused by degradation of the tendon tissue. Aside from tendon pain, tendinosis can also increase the chance of a tendon rupture. Tendinosis is often confused with tendinitis, as the symptoms are similar, but the conditions require different treatments.
A partial rupture is a less common cause of tendon pain. The pain is sometimes delayed until the surrounding muscles and tissue have cooled down after exercise. Depending on the tendon involved, the symptoms may be mild, and conservative treatment can sometimes be enough for the tendon to heal. If left untreated, however, scar tissue may form in the tendon which can lead to chronic pain. In some cases, surgery may be required to heal the rupture.
Full rupture of a tendon can be extremely painful. Although surgery is not always required, it is often recommended if the person is to regain full function. For example, if the patella tendon — the tendon which connects the patella, or the kneecap, with the shin — becomes ruptured, then surgery is almost always required. Since this tendon is fundamental to the knee's ability to function, anything less than surgery is unlikely to help the patient properly use that joint.
Tendon pain is usually the result of either repetitive strain or a large force. Repetitive strain can lead to tendinitis, which is common among runners and people who spend a lot of time at a computer. If left untreated or ignored, this can become chronic tendinosis over time. Partial and full tendon ruptures, among young people, can often be caused by athletic activities. There are, however, a number of diseases and conditions that can make a rupture more likely for older people.