A medical device for treating hip joint osteoarthritis in a human patient by providing at least one artificial hip joint surface. The medical device comprises a prosthetic part or a bone plug adapted to be placed in a hole in the pelvic bone and a supporting member connected to said prosthetic part or bone plug, wherein the 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. Wherein the medical device comprises an artificial caput femur surface or artificial acetabulum surface, and wherein a largest cross-sectional distance of said artificial caput femur or acetabulum surface is smaller than said hole, such that said artificial caput femur surface can pass through said hole.
