Tenosynovitis (tendon sheath inflammation)

A sheath called the synovium surrounds frequently used areas of tendons like a protective cover. If a tendon sheath becomes inflamed, this is referred to as tenosynovitis or tendovaginitis.

Tendons connect bones and muscles with each other. They transfer muscle strength, allow the body to move, and provide stability. Some areas of tendons – such as those that cover protruding bones – are protected by a sheath made of connective tissue (known as the synovium). These sheaths are filled with a fluid that allows the tendons to move easily with minimal friction.

The tendon sheath can become inflamed and swollen if it is subjected to excessive strain. In some cases, the tendon itself also becomes inflamed and swollen. Inflammation of the tendon sheath can be very painful and can restrict mobility significantly.

Tenosynovitis occurs most frequently in the hands, arms, and feet.

Tenosynovitis is typically indicated by pain, in particular during movement. The inflamed area may also become swollen and tender. As the inflammation progresses, it may also cause pain even when the affected area is at rest, e.g., when lying in bed at night.

An inflammation can occasionally cause the tendon sheath tissue to stick together, making movement less smooth than normal. Patients may then experience rubbing, grating, or grinding sensations.

In the wrists and fingers in particular, a tendon sheath inflammation can cause a narrowing of the tendon, which restricts movement. In the fingers, it can cause the condition known as “trigger finger”. When this occurs, it is difficult to straighten fingers out again after bending them.

In addition, tenosynovitis can irritate nerves close to the inflammation, causing a loss of sensation in the area, for example.

Inflammation of the tendon sheath is usually caused by unfamiliar or repeated movement that places excessive strain on the tendons and tendon sheaths.

For example, running or walking long distances without training in advance can trigger tenosynovitis in the feet and lower legs. Wearing new or unsuitable footwear can also place excessive strain on the tendon sheaths.

Some occupations and hobbies increase the risk of developing tenosynovitis. For example, long hours spent working at a computer or playing a musical instrument can place excessive strain on the fingers, wrists, and forearms. Tendon sheath inflammation in the wrist is often caused by repeatedly stretching the thumb outwards and away from the fingers. This can occur, for example, in people who spend a lot of time typing on their smartphones, or often lift and carry an infant.

Some diseases, such as rheumatoid arthritis, gout, and diabetes also increase the risk of developing tenosynovitis. Tendon sheath inflammations are also frequent in women who are pregnant or breastfeeding.

Tenosynovitis is a common condition, in particular in the hands and wrists. In general, women are more likely than men to develop tenosynovitis. Around 2% to 3% of people will develop “trigger finger” at some point in their lives.

In most cases, tenosynovitis resolves within a few weeks, provided that movement is reduced in the affected area.

A doctor can normally detect tenosynovitis by means of a brief examination. After talking to the patient, the doctor will look at and feel the painful area. He/she will also check to see which movements trigger or increase the pain.

In most cases, no further tests are required. However, if the doctor suspects that another disease could be causing the symptoms, additional measures can be taken, such as blood tests, x-rays, or other imaging techniques, such as an ultrasound scan. The main purpose of running blood tests is to determine whether the inflammation is due to a bacterial infection.

Surgical intervention is not normally required to treat tenosynovitis. More conservative treatments are used at first. The most important of these is to rest the affected area. Once the symptoms have resolved, the patient should continue to avoid placing excessive strain on the affected tendon to prevent the inflammation recurring.

If the inflammation was caused by a work-related activity, it may be useful to make modifications to the workplace and, for example, replace a regular computer mouse with an ergonomic version. Advice on making changes at work is available from experts in the fields of occupational therapy and occupational medicine.

If these treatments don’t prove effective, the affected area may be injected with local anesthetics and cortisone to relieve the symptoms. In some cases, surgery may be considered. The procedure involves removing or cutting the affected tissue to allow the tendon to move freely again.

You can find more detailed information, for example about treatment options for tenosynovitis, at gesundheitsinformation.de.