An osteotomy is done to change the angle of the femur (thigh bone) as the top of the bone rests in the hip socket. When an osteotomy is converted to a hip replacement, the doctor evaluates what must be done.
Sometimes more corrective surgery is needed before the joint can be replaced with an implant. The surgeon will try and leave the plate and screws in place. Removing them causes more bleeding and adds time to the operation. Extra bleeding may keep the new cement for the new implant from hardening. Loosening of the implant can occur.
Be sure and ask your doctor about his or decision about removal of the plate and screws in your case.