1. Other disease of affected hip than primary coxarthrosis at time of inclusion 1.1. Secondary osteoarthritis 1.1.1. sequelae after acetabular fracture 1.1.2. hip-near femoral fracture 1.1.3. calve perthe 1.1.4. dysplasia (severe) 1.1.5. other 1.2 Atraumatic caput necrosis