Quadriceps tendon rupture

The knee extension device consists of the quadriceps femoris, patella, and patellar tendon. When the peak of the sudden contractile force of the quadriceps muscle exceeds the mechanical load limit of a weak part of the knee extension device, it will cause the knee extension device to break, including the fracture of the patella. The rupture of the knee extension device can be an incomplete rupture, that is, the micro tearing of part of the collagen fibers, which reduces the tension and length of the knee extension device. Direct cutting injuries can also cause ruptures of the quadriceps or plantar tendons.