Normal Anatomy of the Knee Joint
The knee is made up of four bones. The femur or thighbone is the bone connecting the hip to the knee. The tibia or shinbone connects the knee to the ankle. The patella (kneecap) is the small bone in front of the knee and rides on the knee joint as the knee bends. The fibula is a shorter and thinner bone running parallel to the tibia on its outside. The joint acts like a hinge but with some rotation.
A fracture is a condition in which there is break in the continuity of the bone. In younger individuals, these fractures are caused from high energy injuries, such as in a motor vehicle accident. In older people the most common cause is a fall breaking weak and fragile bone.
A Meniscal tear is the commonest knee injury in athletes, especially those involved in contact sports. A suddenly bend or twist with your knee can cause the meniscus to tear. This is a traumatic meniscus tear. Elderly people are more prone to degenerative meniscal tears as the menicus becomes less flexible with age.
The knee can be divided into three compartments: patellofemoral, medial and lateral compartment. The patellofemoral compartment is the compartment in the front of the knee between the knee cap and thigh bone. The medial compartment is the area on the inside portion of the knee, and the lateral compartment is the area on the outside portion of the knee joint.
Anterior Cruciate Ligament (ACL) Tears
The anterior cruciate ligament, or ACL, is one of the major ligaments of the knee that is located in the middle of the knee and runs from the femur (thigh bone) to the tibia (shin bone). It prevents the tibia from sliding out in front of the femur. Together with posterior cruciate ligament (PCL) it provides rotational stability to the knee.
Osteonecrosis of the knee
Osteonecrosis is a condition in which death of a section of bone occurs because of lack of blood supply to it. It is one of the most common causes of knee pain in older women. Women over the age of 60 years of age are commonly affected, three times more often than men.