If the surgery is performed without any issues, you can start normal knee flexion and extension exercises about three days after the surgery. Then, about a week later, you can begin walking with the aid of crutches. At six weeks post-surgery, you should return to the hospital for a follow-up. If there is continuous callus formation along the fracture line, you can walk normally. However, you need to be cautious at this time, as the fracture healing is not very solid, and it is best to avoid vigorous activities. Activities like running and jumping should be postponed until about three months later. Therefore, for patellar comminuted fractures, you can generally walk normally between six to twelve weeks after the surgery.