The cause of patellar fracture a burst of stabbing pain, mainly according to the patient’s condition to determine, there are several possibilities, respectively, fracture broken end displacement, external fixation is too tight, premature weight bearing and so on. 1. Displaced fracture: it is mostly seen in the patients who take external fixation or unfixed after the fracture without incision and internal fixation, which can lead to friction and displacement of the fracture of the patella when the patient is not careful with the activities, and the patient can feel a burst of stabbing pain. 2. External fixation is too tight: mainly seen in patients who take plaster or small splint external fixation, if the external fixation is too tight, it can affect the local blood circulation, and the patients can have a burst of pain. 3. Premature weight-bearing: mainly seen in the fracture has not completely healed, the patient on the knee joint activities or weight-bearing, will lead to the fracture of the broken end of the tingling sensation, the more serious can also lead to the fracture of the broken end of the second injury, the tingling sensation. We recommend that you go to the hospital and complete all the tests to find out the cause of the pain.