This study examined radiographically the prevalence of arthritis mutilans hand deformities in an inception cohort of 68 rheumatoid arthritis (RA) patients. Hand deformities of 103 RF-positive RA patients were evaluated after 8 years, 83 patients after 15 years and 68 patients 20 years after entry. The grade of destruction in the hand joints was assessed by the Larsen method and Larsen scores of 0-50 were determined for both PIP (+IP) and MCP joints. At the end point, 3 patients had Larsen scores > or =40 for both PIP and MCP joints. These three patients had severe resorption in most of the finger joints, but did not demonstrate classical opera-glass hand. The prevalence of mutilans-like hand deformities with RA was 3/68 (4.4%) in a prospective 20-year study.