DOS 2020

184 · DOS Abstracts Has the Use of Fixation Techniques in THA Changed in This Decade? The Uncemented Paradox Revisited Kristine Bunyoz, Erik Malchau, Henrik Malchau, Anders Troelsen Department of orthopaedics, Hvidovre Hospital; Department of orthopaedics, Sahlgrenska University Hospital Background: Despite studies favoring cemented fixation for patients > 75 years, a trend toward increased use of uncemented fixation has been described using arthroplasty registry data from 2006 to 2010. Updated data are needed to investigate contemporary trends in the usage of uncemented fixation, espe- cially in patients > 75 years. Purpose / Aim of Study: 1:Has percentage of primary THAs performed with uncemented fixation changed since 2010? 2:Has percentage of primary THAs performed in patients > 75 years performed with uncemented fixation changed since 2010? 3:After stratifying by age, which fixation strategy (cemented vs uncemented, hybrid vs uncemented) is associated with lowest risk of revision? Materials and Methods: National reports from hip arthroplasty registers were identified, and data were extracted if published in English/Scandinavian lan- guage, with at least 3 years of reported data from 2010- 2017. All cause rates of revisions related to fixation and secondary to age groups, were taken directly from the registers and no re- analysis was done. Risk estimates were presented as HR, rate per 100 component years or K-M estimates of revision. Findings / Results: Current use of uncemented fixation in primary THAs var- ies between 24% and 71%. Increasing use is reported in Norway, Denmark, and Sweden, whereas decreasing use is reported in England- Wales, Australia, New Zealand, and Finland. In patients > 75 years, numbers are stable in Netherlands, Sweden, New Zealand, and England-Wales, whereas an increasing trend is seen in Denmark and Australia. In Finland, the use of uncemented fixation has decreased (from 43 % to 24 %) from 2010 to 2017. Compared with uncemented fixation, risk of revision using cemented fixation was lower in patients > 75 years for all registers surveyed, except for the oldest males in the Finnish register, where no difference was found. Conclusions: Our findings should be used as feedback on current THAs per- formed, to direct surgeons to choose the right implant fixation, especially in patients > 75 years, thereby reducing revision risk and increasing the long-term survival of primary THAs. Femoral stem fixation may be the most important revision risk factor in older patients, and future studies should examine this per- spective. 163.