The knee includes two crescent-shaped cartilage structures referred to as menisci, which act as shock absorbers and facilitate sleek movement on the joint. Tears within the meniscus or cartilage can develop from sudden twists, deep squats, or degenerative variations with time.  The recovery system for the PCL injury may differ https://www.theorthopaedicandpainpractice.com/what-happens-if-i-injure-my-posterior-cruciate-ligament/