Statistical analysis plan (SAP): Risk of revision for different types of cup fixation in elderly patients with primary hip osteoarthritis. A study of XXX,XXX primary total hip arthroplasties from the Nordic Arthroplasty Register Association (NARA)

Uncemented fixation of THA components are increasingly used. Although cemented femoral component fixation in total hip arthroplasty has shown better results in older patients, less is known about the cup side. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This study did not receive any funding ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Since the study relies solely on data from national registries, consent from patients and approval from the ethics committee are not needed. Following national data protection regulations, the project appears on the regional research listing. Data will be handled confidentially and only the study authors will have access. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors