Urban-rural differences in total hip replacements: the next stage

Background The aim of this study was to explore the differences in the inci dence of primary elective total hip replacements between urban and rural co mmunities and different age and sex groups in Northern Ireland, and to use this information to develop an equitable method for the allocation of surgi cal capacity among groups of general practices, in a system where referrals are matched to the contracted capacity. Methods A retrospective review was performed of all cases of primary electi ve total hip replacement between 1 April 1994 and 31 March 1997. Incidence rates were calculated using direct standardization. Age, sex, and urban and rural specific rates for Northern Ireland were calculated and applied to e ach general practice population giving that practice's annual expected numb er of total hip replacements. Results A total of 4147 cases were analysed. The age and sex standardized i ncidence of primary elective total hip replacement for the total population was 87.6 per 100000. The incidence was significantly greater in rural popu lations (101.3 per 100000), than in urban ones (77.6 per 100000), p < 0.001 . The overall standardized ratio of males to females was 1:1 although it wa s 1:1.2 in urban and 1:0.9 in rural populations. Using a 3 year commissioni ng cycle, commissioning for a population of 130000 allows a 10 per cent mar gin of error in the numbers of procedures required. Conclusions A system of calculating the expected need for a total hip repla cements was developed based on the demography and rurality of individual ge neral practices. This system allowed a method of commissioning to be instit uted that could significantly reduce in-patient waiting lists for this proc edure.