The knee is one of the joints that bear several times more of the body’s weight while standing, walking, and going up the stairs. The knee joints are a very complex part of the body, like a precision machine, that enables complicated movements while supporting body weight. In these joints, bones are not directly adjoined but cartilage covers the joints to allow smoother movement. This joint cartilage acts as a cushion, being more soft and flexible than bones.
- Bones: Made of calcium and collagen. Is hard and not flexible. Has good blood circulation and heals quickly.
- Cartilage: Made of proteoglycan and collagen. Is soft and flexible. Does not have good blood circulation and does not heal quickly.
Osteoarthritis is a disease where cartilage wears away and causes pain. It damages the cartilage but not the bones.
The synovial fluid, that fills the joint cavity covering the joint, sends nutrients to the joint cartilage. When the joint moves, the pressure change that occurs in this area causes the sponge to absorb water. Then once squeezed out, nutrients are taken in and unnecessary substances are emitted in order for new water to be absorbed. If there is no movement, the nutrients will not reach the joints, possibly causing the joint to go bad.