The knee has two crescent-formed cartilage structures named menisci, which act as shock absorbers and aid easy movement on the joint. Tears inside the meniscus or cartilage can build from unexpected twists, deep squats, or degenerative improvements after some time.  Rest and Rehabilitation: Rest is critical inside the First stage, https://www.theorthopaedicandpainpractice.com/what-happens-if-i-injure-my-posterior-cruciate-ligament/