A medical device for implantation in a hip joint of a human patient, 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 center of the hip joint and a bowl shaped acetabulum as part of the pelvic bone with a concave hip joint surface towards the center of the hip joint. The medical device comprising； an artificial caput femur, comprising a convex surface towards the center of the hip joint. The artificial convex caput femur is adapted to, when implanted: be fixated to the pelvic bone of the human patient, and be in movable connection with an artificial acetabulum surface fixated to the femoral bone of the patient, thereby forming a ball and socket joint. The medical device further comprises a fixation element comprising a fixation surface adapted to be in contact with the surface of the acetabulum and adapted to fixate the artificial convex caput femur to at least the acetabulum of the pelvic bone.
