 The operation is performed after the usual principles with rear access to the hip joint, removal of rod ends and the insertion of an uncemented socket. After preparing the femoral neck and top of thigh to the insertion of the short femur prosthesis and make selection using tantalumkugler for RSA analysis. When the prosthesis is inserted carried out sample-space theorem and using a 36 mm Co-Cr-ball, which is currently the departments practices. After surgery the patient allowed partial load the first 6 weeks. There is an ongoing clinical and radiographic controls and registration of unforeseen events arising from the use of the product. 