|Achilles tendon (one of many tendons in the human body)|
|Classification and external resources|
Tendinitis (also tendonitis), meaning inflammation of a tendon, is a type of tendinopathy often confused with the more common tendinosis, which has similar symptoms but requires different treatment. (The suffix -itis denotes diseases characterized by inflammation.) The term tendinitis is generally reserved for tendon injuries that involve larger-scale acute injuries accompanied by inflammation. Tendinitis is typically referred to in combination with the body part involved, such as Achilles tendinitis (affecting the Achilles tendon), or patellar tendinitis (jumper's knee, affecting the patellar tendon).
Symptoms can vary from aches or pains and local joint stiffness, to a burning that surrounds the whole joint around the inflamed tendon. In some cases, swelling occurs along with heat and redness, and there may be visible knots surrounding the joint. With this condition, the pain is usually worse during and after activity, and the tendon and joint area can become stiff the following day as muscles tighten from the movement of the tendon. Many patients report stressful situations in their life in correlation with the beginnings of pain which may contribute to the symptoms.
Treatment of tendon injuries is largely conservative. Use of non-steroidal anti-inflammatory drugs (NSAIDs), rest, and gradual return to exercise is a common therapy. Resting assists in the prevention of further damage to the tendon. Ice, compression and elevation are also frequently recommended. Physical therapy, occupational therapy, orthotics or braces may also be useful. Initial recovery is typically within 2 to 3 days and full recovery is within 3 to 6 months. Tendinosis occurs as the acute phase of healing has ended (6-8 weeks) but has left the area insufficiently healed. Treatment of tendinitis helps reduce some of the risks of developing tendinosis, which takes longer to heal.
Steroid injections have not been shown to have long term benefits but have been shown to be more effective than NSAIDs in the short term.
In chronic tendinitis or tendonosis laser therapy has been found to be better than conservative treatment at reducing pain; however, no other outcomes were assessed. Both prolotherapy and PRP injections are being used more frequently with good clinical short and long term outcomes in tendonosis - research has been only slightly positive for these treatment modalities due to the poor design of many of the completed studies.
In horses, tendinitis is called a bowed tendon from the appearance of the affected tendon after it heals without treatment. Mesenchymal stem cells, derived from a horse's bone marrow or fat, are currently being used for tendon repair in horses.