Trends in hip and knee joint replacement: socioeconomic inequalities and projections of need.

OBJECTIVES To examine trends in primary and revision joint (hip and knee) replacement in England between 1991 and 2000. METHODS Analysis of hospital episodes statistics between 1 April 1991 and 30 March 2001 for total hip replacement (THR) and total knee replacement (TKR). Descriptive statistics and regression modelling were used to summarise patients' demographic and clinical characteristics and to explore variations in joint surgery rates by age, sex, and deprivation. RESULTS Between 1991 and 2000, the incidence of primary THR increased by 18%, while the incidence of revision THR more than doubled. The incidence of primary TKR doubled, with revision TKR increasing by 300%. Over the 10 year period, the proportion of THR episodes that involved revision operations rose from 8% to 20%. Substantial variations in operation rates by socioeconomic status were seen, with the most deprived fifth of the population experiencing significantly lower rates. Projections estimate that primary THR numbers could rise by up to 22% by the year 2010, with primary TKR numbers rising by up to 63%. CONCLUSIONS Provision of joint replacement surgery in English NHS hospitals has increased substantially over the past decade. Revision operations in particular have increased markedly. The growth in primary operations has mostly occurred among those aged 60 years and over; rates among young people have changed very little. There is a significant deprivation based gradient in rates. If current trends continue there would be almost 47 000 primary hip and 54 000 primary knee operations annually by 2010.