Quite common there is an involvement of the enthesis, meaning the insertion of tendons, ligaments and capsules into the bone. These inflammatory changes are referred to as enthesitis (Francois RJ, Braun J, Khan MA). Any enthesis may be concerned, but most frequently an enthesitis of the Achilles tendon is found. Enthesitis causes pain, swelling and thickening as well as loss of function, it can occur all of a sudden, but is found quite often as a chronic inflammation, which can finally lead to rupture of the tendon. Arthritis of the adjacent joint has also been described, enthesitis is.
