Stable occurrence of knee and hip total joint replacement in Central Finland between 1986 and 2003: an indication of improved long-term outcomes of rheumatoid arthritis

Background: Total joint replacement (TJR) surgery is an important severe long-term outcome of rheumatoid arthritis, but relatively little is known about changes of its incidence in patients with rheumatoid arthritis over the past two decades. Methods: A population-based, retrospective, incidence case review was conducted to analyse the frequency of primary TJR surgery of the knee and hip in all patients, and specifically in patients with rheumatoid arthritis in Central Finland between 1986 and 2003. Patients with TJR surgery of the knee and hip were identified in hospital databases over the 18-year period. Age-standardised incidence rate ratios for the primary TJR of the knee and hip were calculated, stratified to sex and diagnosis, with 1986 as the reference value. Results: In patients without rheumatoid arthritis the age-adjusted incidence rate ratios (with 95% CI) for TJR of the knee increased 9.8-fold from 1986 to 2003 in women and men, and for TJR of the hip 1.8-fold in women and 2-fold in men. By contrast, no meaningful change was seen over this period, in age-adjusted incidence rate ratios for TJR of the knee or hip in patients with rheumatoid arthritis, ranging from 0.7 to 1.2 in 2003 compared with 1986. Conclusion: The prevalence of TJR surgery has increased 2-10-fold in patients without rheumatoid arthritis patients, associated with an ageing population, but has not increased in patients with rheumatoid arthritis between 1986 and 2003. These data are consistent with emerging evidence that long-term outcomes of rheumatoid arthritis have improved substantially, even before the availability of biological agents.