Achilles tendinitis associated with chondrocalcinosis.

Achilles tendinitis was observed in 3 patients with idiopathic articular chondrocalcinosis. It was associated with linear radiological calcifications which in this condition are not unusual but generally asymptomatic. Crystals presumed to be calcium pyrophosphate dihydrate (CPPD) were found in the 2 cases that were biopsied. In 2 patients the acute inflammation of the tendon subsided after several days, but in the 3rd it lasted 4 1/2 months, and resulted in a cicatricial thickening of the tendon with a progressive disappearence of the calcifications. Therefore, the development of Achilles tendinitis in an elderly patient may be an inflammatory reaction to CPPD crystal deposits.