A medical device for treating hip joint osteoarthritis by providing at least one hip joint surface for a human patient is provided, wherein said medical device has a largest diameter or a largest cross-sectional distance, and an opening, and wherein said largest diameter or cross sectional distance is adapted to be changed during an operation. Furthermore, a method of treating a hip joint of a human patient by providing said the medical device is provided. The hip joint comprising a caput femur and an acetabulum, the method comprises the steps of: cutting the skin of the patient, dissecting an area of the pelvic bone on the opposite side from the acetabulum, creating a hole in said dissected area, said hole passing through said pelvic bone and into the hip joint of the patient, and providing said medical device to the hip joint, through said hole in the pelvic bone of the patient.