A medical device for implantation in a hip joint of a human patient is provided. The natural hip joint having a ball shaped caput femur 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 caput femur has a centrally placed longitudinal extension, extending through the center of the caput and collum femur, aligned with the collum femur, defined as the caput and collum femur center axis. The medical device comprising； an artificial acetabulum, comprising a concave surface towards the centre of the hip joint. The artificial concave acetabulum is adapted to, when implanted, be fixated to the femoral bone of the human patient, and be in movable connection with an artificial caput femur fixated to the pelvic bone of the patient.
