Past incidence and future demand for knee arthroplasty in Sweden - A report from the Swedish Knee Arthroplasty Register regarding the effect of past and future population changes on the number of arthroplasties performed

By combining data front the Swedish Knee Arthroplasty Register and Swedish census registers we have calculated the past age-specific incidence of prim ary knee arthroplasties and predicted the demand. During the last 20 years, osteoarthrosis has accounted for the largest incr ease in number of knee arthroplasties while operations for rheumatoid arthr itis remained constant. The mean yearly number of operations between the pe riods 1976-1980 and 1996-1997 increased more than five-fold, while only 6% of that increase could be explained by changes in the age-profile of the po pulation. Most operations were performed on persons of 65 years and older w ho also had the largest increase in incidence. By using the incidences for 1996 and 1997 and taking into account the expected future changes in the ag e profile of the Swedish population, we estimate that, in the absence of an effective preventive treatment, the number of knee arthroplasties will inc rease by at least one third until 2030.