A medical device for implantation in a hip joint of a patient, the natural hip joint having a ball shaped caput femur integrated with a collum femur having a collum and caput center axis, extending longitudinal along the collum and caput femur, in the center thereof, as the proximal part of the femoral bone with a convex hip joint surface towards the centre of the hip joint and a bowl shaped acetabulum as part of the pelvic bone with a concave hip joint surface towards the centre of the hip joint, the medical device comprising； an artificial caput femur comprising a convex surface towards the centre of the hip joint, an elongated portion adapted to be connected to a prosthetic spherical portion of said artificial convex caput femur and fixated to the pelvic bone of the human patient.
