After the cast is removed from the patella fracture, it is completely proven that functional rehabilitation exercises can be carried out, and this is the best period of exercise at this moment. The fracture itself is protected by a long period of external fixation in a cast, and the function of the whole joint has basically disappeared. Functional rehabilitation exercises such as straightening and bending of the joint should be performed as soon as possible after the cast is removed, and the longer the time, the worse the effect of functional rehabilitation exercises. When exercising, it is important to note that the angle of the knee joint should be increased from the previous day’s angle every day, so that the exercise effect can be gradual. Otherwise, the range of motion of the joint does not increase every day, and the atrophy of the surrounding muscles will further aggravate the effect of the rehabilitation exercise.