Tendonitis
Tendonitis (also tenonitis or tendinitis) is an inflammation of a tendon. For example, patellar tendonitis (jumper's knee) is an inflammation of the patellar tendon, which connects the tibia to the patella.
Chronic overuse of tendons leads to microscopic tears within the collagen matrix, which gradually weakens the tissue. Swelling in a region of microdamage or partial tear can be detected visually or by palpation. Increased water content and disorganised collagen matrix in tendon lesions may be detected by ultrasonography or magnetic resonance imaging.
Due to their highly specialised ultrastructure and slow collagen turnover, tendons and ligaments are very slow to heal if injured, and rarely regain their original strength. Partial tears heal by the rapid production of disorganised type-III collagen, which is inferior in strength to normal tendon. Recurrence of injury in the damaged region of tendon is common.
Treatment of tendon injuries is largely palliative. Non-steroidal anti-inflammatory drugs combined with rest and gradual return to exercise is a common therapy. Return to function may be accelerated by the injection of stem cells. Completely ruptured tendons may be sutured together with or without grafted material.
Achilles tendonitis is a common injury, particularly in sports that involve lunging and jumping.
