A medical device for treating hip joint osteoarthritis in a human patient by providing at least one artificial hip joint surface, the hip joint comprising an acetabulum, being a part of the pelvic bone, and a caput femur being a part of the femoral bone, and having a partly spherical form having a largest diameter, wherein said medical device comprises: - a prosthetic part or a bone plug adapted to be placed in a hole in the pelvic bone such that a concave interior surface of the prosthetic part or the bone plug is facing in a direction towards the caput femur, and - a supporting member (95; 99) connected to said prosthetic part or bone plug, wherein - said prosthetic part or the bone plug is adapted to be inserted into said hole from the abdominal side of the acetabulum and oriented, during the insertion, such that the concave interior surface is facing in the direction towards the caput femur, and - said supporting member is adapted to connect to the pelvic bone and transfer a load from the prosthetic part or bone plug to the pelvic bone, when implanted, wherein at least one of: o the medical device comprises an artificial caput femur surface, and wherein a largest cross-sectional distance of said artificial caput femur surface is smaller than said hole, such that said artificial caput femur surface can pass through said hole, and ∘ the medical device comprises an artificial acetabulum surface, and wherein a largest cross-sectional distance of said artificial acetabulum surface is smaller than said hole, such that said artificial acetabulum surface can pass through said hole. - a prosthetic part or a bone plug adapted to be placed in a hole in the pelvic bone such that a concave interior surface of the prosthetic part or the bone plug is facing in a direction towards the caput femur, and - a supporting member (95; 99) connected to said prosthetic part or bone plug, wherein - said prosthetic part or the bone plug is adapted to be inserted into said hole from the abdominal side of the acetabulum and oriented, during the insertion, such that the concave interior surface is facing in the direction towards the caput femur, and - said supporting member is adapted to connect to the pelvic bone and transfer a load from the prosthetic part or bone plug to the pelvic bone, when implanted, wherein at least one of: o the medical device comprises an artificial caput femur surface, and wherein a largest cross-sectional distance of said artificial caput femur surface is smaller than said hole, such that said artificial caput femur surface can pass through said hole, and ∘ the medical device comprises an artificial acetabulum surface, and wherein a largest cross-sectional distance of said artificial acetabulum surface is smaller than said hole, such that said artificial acetabulum surface can pass through said hole. o the medical device comprises an artificial caput femur surface, and wherein a largest cross-sectional distance of said artificial caput femur surface is smaller than said hole, such that said artificial caput femur surface can pass through said hole, and ∘ the medical device comprises an artificial acetabulum surface, and wherein a largest cross-sectional distance of said artificial acetabulum surface is smaller than said hole, such that said artificial acetabulum surface can pass through said hole.