Incidence of rheumatoid arthritis-related ankle replacement and ankle arthrodesis: A Finnish nationwide register-based study from 1997–2010

BACKGROUND AND PURPOSE: For 20 years, medical treatment of rheumatoid arthritis (RA) has been improving and the incidence of joint surgery has decreased. We investigated the rates of primary ankle joint arthrodesis and total ankle arthroplasty in patients with RA in Finland between 1997 and 2010 to establish whether trends have changed during that period. METHODS: The annual figures for primary ankle joint arthrodeses and total ankle replacements performed in patients with RA were obtained from nationwide population-based registries. Incidences were calculated per population of 10(5) and they are reported in 2-year periods. RESULTS: During the study period, 593 primary ankle joint arthrodeses and 318 total ankle arthroplasties were performed in patients with RA. The incidence of ankle joint arthrodesis reached its highest value (2.4/10(5)) in 1997–1998 and it was lowest in 2001–2002 (1.1/10(5)). After 2002, the incidence increased slightly but did not reach the level in 1997–1998, even though total ankle replacements almost ended in Finland during the period 2009–2010. From 1997, total ankle replacements increased until 2003–2004 (incidence 1.5/10(5)) and then gradually decreased. In 2009–2010, the incidence of total ankle replacements was only 0.4/10(5). INTERPRETATION: During the observation period 1997–2010, while total ankle replacements generally became more common in patients with RA, the incidence of primary ankle joint arthrodesis decreased and did not increase in the period 2009-2010, even though total ankle replacement surgery almost ended in Finland. No change in the incidence of these operations, when pooled together, was observed from 1997 to 2010.