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

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.

High rate of osteolytic lesions in medium-term followup after the AES total ankle replacement.

BACKGROUND: Some previous studies have shown a high percentage of early-onset and rapidly progressing osteolysis associated with total ankle arthroplasty (TAA) by the Ankle Evolutive System (AES). The purpose of our study was to analyze medium-term results at our institution. MATERIALS AND METHODS: Altogether 38 TAAs using AES prostheses were carried out between 2003 and 2007. Diagnoses were rheumatoid arthritis (71%), post-traumatic and idiopathic osteoarthritis (29%). The mean age was 54 years, followup 28 months. Tibial and talar components had hydroxyapatite coating on metal (Co-Cr) components (HA-coated). Since 2005 the design was changed and components were porous coated with titanium and hydroxyapatite (dual-coated). RESULTS: Two-year survival was 79% (95% CI: 56 to 98). At followup 34 (89%) primary tibial and talar components were preserved. In 19 (50%) TAAs osteolysis (more than or equal to 2 mm) occurred in the periprosthetic bone area and in nine (24%) comprised large "cyst-like osteolysis''. In HA-coated prostheses radiolucent lines (less than or equal to 2 mm) or osteolysis (more than or equal to 2 mm) were detected in 11 (100%) cases and in dual-coated prostheses in 19 (74%) (p = 0.08). On the other hand there was more large "cyst-like osteolysis'' around the dual-coated prosthesis and lesions were larger (p = 0.017). In rheumatoid arthritis osteolysis was detected in 14 (52%) and large "cyst-like osteolysis'' in seven (26%) prostheses and in the group of traumatic and idiopathic osteoarthritis in six (55%) and two (18%), respectively. CONCLUSION: This study showed a high frequency of osteolysis in medium-term followup after the AES ankle replacement. The outcome was not sufficiently beneficial and we have discontinued use of this prosthesis.