Hip replacement surgery. Image 21 of 30. Surgical spreaders revealing the old hip socket in the pelvis, during a hip replacement operation. Bone will be removed to make room for the implantation of a new socket. This socket will then articulate with the ball of the implant placed in the femur (upper leg bone), forming the new hip joint. This surgery is usually performed in response to arthritis, the degeneration of the joints, and restores mobility to people who would otherwise be incapacitated by pain and unable to move freely. For a sequence of images showing the full surgery, see M551/340-369. For a sequence showing the operation on the pelvis, see images M551/360-366.