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, the convex surface having a center point adapted to be placed, when implanted, on the collum and caput center axis, and - an elongated portion, adapted to be connected to a prosthetic spherical portion of said artificial convex caput femur and to be fixated inside of a bowl shaped acetabulum as part of the pelvic bone of the human patient, wherein said artificial convex caput femur is adapted to have its spherical portion to be placed in contact with the inner surface of an prosthetic replacement for acetabulum to be movable in multiple directions replicating the natural ball and socket joint of the hip, wherein said artificial convex caput femur is further, when implanted, adapted to: a. be fixated to at least the bowl shaped acetabulum of the pelvic bone of the human patient through said elongated portion fixation to the pelvic bone, and b. be in movable connection with the comprised prosthetic acetabulum surface fixated to the femoral bone of the patient, comprising at least one extending portion adapted to clasp said prosthetic spherical portion, wherein c. said elongated portion comprises a restricting portion adapted to restrict the motion range of the artificial acetabulum in relation to said artificial convex caput femur, characterized in that d. a larger portion of said restricting portion is placed, when implanted, dorsal to a vertical acetabulum plane (PX'Y') coinciding with the collum and caput center axis, to enable an advantageous motion range in relation to said artificial acetabulum. - an artificial caput femur, comprising a convex surface towards the centre of the hip joint, the convex surface having a center point adapted to be placed, when implanted, on the collum and caput center axis, and - an elongated portion, adapted to be connected to a prosthetic spherical portion of said artificial convex caput femur and to be fixated inside of a bowl shaped acetabulum as part of the pelvic bone of the human patient, wherein said artificial convex caput femur is adapted to have its spherical portion to be placed in contact with the inner surface of an prosthetic replacement for acetabulum to be movable in multiple directions replicating the natural ball and socket joint of the hip, wherein said artificial convex caput femur is further, when implanted, adapted to: a. be fixated to at least the bowl shaped acetabulum of the pelvic bone of the human patient through said elongated portion fixation to the pelvic bone, and b. be in movable connection with the comprised prosthetic acetabulum surface fixated to the femoral bone of the patient, comprising at least one extending portion adapted to clasp said prosthetic spherical portion, wherein c. said elongated portion comprises a restricting portion adapted to restrict the motion range of the artificial acetabulum in relation to said artificial convex caput femur, characterized in that d. a larger portion of said restricting portion is placed, when implanted, dorsal to a vertical acetabulum plane (PX'Y') coinciding with the collum and caput center axis, to enable an advantageous motion range in relation to said artificial acetabulum. a. be fixated to at least the bowl shaped acetabulum of the pelvic bone of the human patient through said elongated portion fixation to the pelvic bone, and b. be in movable connection with the comprised prosthetic acetabulum surface fixated to the femoral bone of the patient, comprising at least one extending portion adapted to clasp said prosthetic spherical portion, wherein c. said elongated portion comprises a restricting portion adapted to restrict the motion range of the artificial acetabulum in relation to said artificial convex caput femur, characterized in that d. a larger portion of said restricting portion is placed, when implanted, dorsal to a vertical acetabulum plane (PX'Y') coinciding with the collum and caput center axis, to enable an advantageous motion range in relation to said artificial acetabulum.