THE SWEDISH KNEE ARTHROPLASTY REGISTER - A NATIONWIDE STUDY OF 30,003KNEES 1976-1992

1976 through 1992, 30,003 primary knee arthroplasties and their revisi ons have been recorded in a nation-wide Swedish study. We report on th e structure of the register, demographic data and survivorship. We fou nd that operations for osteoarthrosis (OA) counted for the increase in number of arthroplasties in contrast to rheumatoid arthritis (RA), wh ere the number had slightly declined. For primary operations, the tota l knee prostheses have practically eliminated other types in RA and ar e steadily gaining popularity in OA at the expense of the unicompartme ntal prostheses. Total knee replacements showed gradually improving su rvival even in unchanged designs while the unicompartmental prostheses don't, partly because of newly introduced inferior designs. We also f ound that failed unicompartmental prostheses were best replaced with a tricompartmental prosthesis and that a total revision was to be prefe rred when a tricompartmental tibial component failed. The risk of the most devastating complications, e.g., infection, leading to extraction of the prosthesis or arthrodesis has decreased considerably also in t he last years.