The knee is a critical joint in our existence. An unstable joint at best, this articulation handles all of our body weight while allowing propulsive muscles to extend it and thus drive us forward.

The knee is held together by one pair of extra articular ligaments (collateral or tibial and fibular) and one pair of intra-articular ligaments (anterior and posterior cruciates). In addition, there is a set of articular discs interposed between the condyles of the femur and tibia that help to absorb shock and stabilize this tenuous joint.

The knee's stability relies partly on muscles surrounding it, the hamstrings and the quadriceps and the aforementioned ligaments.