A medical device for treating osteoarthritis of the hip joint in a human patient by offering at least one artificial hip joint surface, the hip joint comprising an acetabulum (11), which is part of the iliac bone (9 ), and a head of the femur (5), which is part of the femoral bone (7), and having a partially spherical shape having a maximum diameter, wherein said medical device comprises: - a prosthetic piece (98) or a plug bone (31) adapted to be placed in a hole (18) in the iliac bone, such that a concave inner surface of the prosthetic piece or bone plug faces the head of the femur, and - a support member (95； 99) connected to said prosthetic piece or bone plug, wherein - said prosthetic piece or bone plug is adapted to be inserted into said hole from the abdominal side of the acetabulum and oriented, during insertion, such that the surface Concave inner icie face the head of the femur, and - said support member is adapted to connect with the iliac bone and transfer a load of the prosthetic piece or bone plug to the iliac bone, once implanted, where at least: - the medical device comprises a head surface of the femur (45), and where a maximum cross-sectional distance of said head surface of the artificial femur is smaller than said hole, such that the head surface of the femur can pass to through said hole, and - the medical device comprises an artificial acetabulum surface (65), and wherein a maximum cross-sectional distance of said artificial acetabulum surface is smaller than said hole, such that the acetabulum surface can pass through said hole.Un dispositivo médico para tratar la artrosis de la articulación de la cadera en un paciente humano al ofrecer al menos una superficie de articulación de la cadera artificial, comprendiendo la articulación de la cadera un acetábulo (11), que es parte del hueso ilíaco (9), y una cabeza del fémur (5), que es parte del hueso femoral (7), y presentando una forma parcialmente esférica que tiene un diámetro máximo, en donde
