A rotationplasty is surgical procedure that provides an excellent cancer treatment option for patients with tumors in or near the knee joint, such as sarcoma. This specialized cancer treatment is best applied in children who are still growing. During this procedure, the surgeon removes the affected portion of bone, along with the knee joint. The major artery, vein, and nerve leading to the foot are saved. The lower portion of the leg is rotated 180 degrees counter clockwise and then attached to the upper portion of the leg. The ankle is now on the same plane as the former knee, with the foot and toes pointing backward and the heel facing forward. Because of the rotation, the ankle bends in the same direction as the knee. The surgeon will take into account the age of the child and their growth potential. Initially, the surgically-modified knee center will be lower than the unaffected knee. As the child grows and bones lengthen, the knee centers will match. In three to six months, after the bones have healed, the patient can be fitted for a prosthesis. The patient’s foot fits inside the socket of the prosthesis and the ankle functions as the knee joint. In time, the patient will develop greater control, function and mobility. Most patients are able to walk unassisted and return to their regular activities, including playing sports.