A prosthetic implant assembly including a modified liner configured for fixation to an acetabular shell. The modified liner having a sheath and a liner. The liner is configured to be inserted into and affixed to the sheath. The sheath having an annular rim, a plurality of longitudinal ribs extending from the annular rim, and a cross-rib spaced apart from the annular rim and intersecting the plurality of longitudinal ribs. Each longitudinal rib of the plurality of longitudinal ribs is curved such that the plurality of longitudinal ribs collectively define a partially spherical surface. Additionally, the annular rim, the plurality of longitudinal ribs, and the cross-rib define a plurality of openings between the annular rim and the cross rib.

A medical device for implantation in a hip joint of a patient is provided. The medical device is adapted to be fixated to the pelvic bone of the patient. The medical device comprises an inner and an outer surface, wherein a contacting portion, of said inner surface is spherical and adapted to face the center of the hip joint when said medical device is implanted. The medical device is adapted to receive a caput femur or a prosthetic replacement therefor having a spherical portion, wherein said medical device comprises at least one extending portion, extending said contacting portion of said inner surface such that said at least one extending portion clasps said spherical portion of said caput femur, or a prosthetic replacement therefor, such that said spherical portion is restrained in said medical device. Restraining the caput femur in the medical device reduces the risk that the hip joint dislocates when in use by the patient.

A surgical instrument for operating hip joint osteoarthritis in a human patient is provided. The hip joint comprises an acetabulum, being a part of the pelvic bone, and a caput femur, being the proximal part of the femoral bone. The surgical instrument is adapted to assist in the operating of the hip joint osteoarthritis from the abdominal side of the pelvic bone of said human patient.

A surgical and a laparoscopic/arthroscopic method for operating hip osteoarthritis using an instrument that is adapted to create a through-going hole placed in the acetabulum area from the abdominal side of the pelvic bone of the human patient. The instrument comprises: a driving member, a bone contacting organ in connection with said driving member, an operating device adapted to operate said driving member. The bone contacting organ is adapted to create a hole in the acetabulum area starting from the abdominal side of the pelvic bone through repetitive or continuous movement.

A method for fixating an artificial convex caput femur surface to the pelvic bone of a patient, the method comprising the steps of: exposing the acetabulum surface, creating a hole or recess in the pelvic bone from the acetabulum side of the pelvic bone, providing the artificial convex caput femur, comprising an elongated member to the hip joint, inserting said elongated member in said hole, and performing an action on the acetabulum side of the pelvic bone such that the elongated member is structurally changed on the abdominal side of the pelvic bone or inside the pelvic bone.