The knee joint is comprised of three bones: the femur (thigh bone), the patella (knee cap), and the tibia (shin bone). It can be divided into the medial compartment, the side of your knee that is closest to the center of your body; the lateral compartment, the side of your knee to the outside of your body; and the patellofemoral compartment, which is the area behind the knee cap.
The end of each of these bones is covered with a layer of smooth, glossy, elastic tissue known as articular cartilage. Cartilage protects the bones while allowing the joint to glide smoothly. It also acts as a shock absorber. Cartilage has no nerve or blood supply. If damaged or injured, it will not easily heal or repair itself.
Ligaments of the knee link the bones, while muscles and tendons aid in strength, stability, and movement. Ligaments include the anterior cruciate ligment, commonly called the ACL, the posterior cruciate ligament (the PCL), the medial collateral ligament and the lateral collateral ligament. The health and stability of your ligaments can be important determining factors in whether one surgical option is better for you than another.
Atop the tibia are two crescent-shaped pieces of cartilage called menisci. These inner and outer pads act as weight distributors when we walk, stand and move about. Their specialized shape also helps to keep the knee stable and conforms to the profile of the femur.