Your knee is the largest joint in your body and one of the most complicated and vulnerable.
The knee connects the two longest mechanical levers in the human body: the thigh and lower leg. As a result, substantial forces are acting on and around this joint. Large thigh muscles provide the knee with strength and mobility. The ligaments or connectors surrounding the knee provide the main stability.
Unlike the hip joint, which is partially protected by the bony structures of the pelvis, the knee joint is not shielded by any other parts of the skeleton. Additionally, the knee joint bears the weight of the upper body, and absorbs the shock carried upward through the feet when walking or running.