Patellar tendonitis, generally known as jumper’s knee, influences the tendon connecting the kneecap into the shinbone. It's widespread among the athletes which include badminton gamers.  Torn meniscus – A meniscus tear happens when the knee is subjected to abnormal strain or twisting whilst the foot is planted on the ground. https://www.theorthopaedicandpainpractice.com/what-happens-if-i-injure-my-posterior-cruciate-ligament/