Bone fragmentation in the rheumatoid wrist: radiographic and pathologic considerations.

A peculiar pattern of bone fragmentation of the wrist was noted in 16% of 50 rheumatoid patients. This involved erosion of the navicular, distal radius and ulna, carpal fusion, demineralization, and the presence of an elongated bony spicule overlying the radiocarpal joint. Additional examples were found in rheumatoid cadavers. Pathogenesis of the alteration was not entirely clear although contributing factors included extensive pannus proliferation, osseous compression and fracture. The fate of the detached spicules, their relationship to "fistulous rheumatism", and the differential diagnosis are discussed.