When the protective synovial membrane – or sheath – around a tendon becomes inflamed, this is tenosynovitis. The sheath is filled with fluid that assists smooth movement of the tendon as it interacts with muscle and bone. When inflamed, movement can be restricted. It can occur in many parts of the body but in athletes is particularly common in the feet and hands.
The joint near to the tendon may become visibly swelled or inflamed, and the surrounding area painful and also tender to touch. You may experience pain while attempting to move a nearby joint, and the process of moving the joint at all will be difficult. Common problem areas are wrists, ankles, hands and feet. Excessive redness or continuous pain around the tendon might suggest an accompanying infection.
The cause of the sheath's inflammation is often unknown, but in sports is regularly associated with overuse. If you have recently made a rapid increase to your training program that places greater strain on the affected tendon, this may have caused the condition. Likewise if you have been exercising with fatigued or weak muscles, or have been constantly using uneven surfaces, you are more likely to suffer from an overuse injury. Other causes include a strike to the affected area, exacerbation of a previous injury, additional muscle strain and sometimes infection, and if you suspect an infection as the cause then you should consult a doctor immediately.
A medical professional will conduct a physical exam of the tendon to assess the injury's severity. Resting the area is the most important step to take yourself, keeping the tendon(s) stationary until symptoms improve. There are ways to ensure this lack of movement such as a removable brace or bandage, and a doctor can recommend the most suitable methods. Applying heat to the affected area is a useful way to decrease the inflammation. The heat should not be extreme but rather regular soaking in a hot bath or shower, and the application of heat pads or other over the counter remedies.
Anti-inflammatory medication (e.g. ibuprofen) will often be beneficial, but you should always check with a doctor. They may sometimes prescribe vitamin supplements. Occasionally injections of corticosteroids may be necessary to diminish the inflammation, and in rare cases surgery.
When you have recovered, stretch and strengthen the surrounding muscles in order to reduce the risk of the injury returning, and also to help in the prevention of further injury from weakness or fatigue. Conditioning the muscles in this way greatly decreases the chances of overuse injuries. You should cease the practice or activity that contributed to the condition, whether this means modifying your method of warming up or even training in a different area. Always wear appropriate protective gear for sports if available, and avoid repetitive movement of vulnerable areas due to the strain this can easily cause.