Knee cancer surgery. Artwork showing a late stage in the surgical treatment of a knee cancer using a Modular Universal Tumour And Revision System (MUTARS) interim prosthesis. The cancer was at the base of the femur (thigh bone) at upper left, and has now been removed and replaced with a femoral implant. Here, the internal muscle, bone and fat layers are shown, along with the blood vessels (red and blue) and nerves (yellow). The femoral implant forms part of a replacement knee joint, hinging with a tibial implant (upper right), and an artificial patellar underside. The overlying muscle layers are being sutured back in place.