Calcific periarthritis of the finger verified by X-ray diffraction of apatite.

The authors describe a 24-year-old woman presenting with swelling and pain of several finger joints. Roentgenograms showed periarticular, calcific deposits at all locations of swelling. One such deposit revealed the presence of hydroxyapatite crystals on X-ray diffraction. After two injections of corticosteroids in and around one deposit its size and density diminished rapidly, whereas the uninjected corresponding site of the other hand showed no initial improvement; after two years no difference was discernible. Under systemic and topic NSAIDs, pain and swelling improved similarly in all joints. In conclusion, periarthritis of the fingers associated with radiopaque deposits responded favourably to NSAID therapy, while local corticosteroid injections showed no additional benefit.