Fig. 4.

a An anteroposterior (AP) radiograph of the left knee shows a joint-preserving tumor resection and custom expandable prosthetic reconstruction in an 8-year-old boy. b An AP radiograph of the left knee taken 6 years after surgery shows continuous growth of the remaining distal femur epiphysis. More conservative resection and accurate reconstruction may be performed with the CATS technique, because less soft tissue dissection is required to define the intended resection planes intraoperatively and the blood supply to the remaining epiphysis is preserved