What are the Causes of Fracture of Knee Cap?The knee cap can be fractured due to - A direct blow, such as a collision with dashboard in a motor vehicle accident. A fall on a flexed knee or forceful quadriceps contraction, such as with stumbling or falling. Chronic stress to the knee. Pathologic conditions or chronic infections can lead to fractures. Published on Nov 12, 2014Last Updated on Nov 12, 2014