The knee joint is the largest joint in our body. Knee joint, which appears like a simple hinge joint, is one of the most complex joint.
It consists of the femur (thigh bone), tibia (shin bone) and patella (knee cap). It connects the thigh bone (femur) with the shin bone (tibia).
The bony surfaces within the joint are covered with articular cartilage, a smooth shiny white cushion and it is the damage to this surface, which causes arthritis. Knee joint is a synovial joint as it is lined by synovium membrane. The synovium membrane produces synovial fluid, which lubricates and nourishes the joint. Around the knee joint is soft tissue covering known as joint capsule and surrounding this are large ligaments, tendons and muscles. The joint capsule holds the bones in place and prevents dislocation.
A normal knee functions due to the bones being held in place by the joint capsule and allowed to move smoothly and freely due to the articular cartilage and synovial fluid.
As the knee joint bears enormous weight and pressure loads and provides us with flexibility in our movements, it is also vulnerable.
To give some examples of the loads placed on our knees:
- Our knees support 1.5 times our body weight when we walk
- Our knees support 3-4 times our body weight when climbing stairs
- Our knees support approx. 8 times our body weight when squatting