Fig. 1From: Sex differences in risk and heritability estimates on primary knee osteoarthritis leading to total knee arthroplasty: a nationwide population based follow up study in Danish twinsFlowchart of the participating twins. CPR Danish Personal Registration Number, DKR Danish Knee Arthroplasty Register, DTR Danish Twin Register, OA Osteoarthritis, TKA Total Knee ArthroplastyBack to article page