A chronic degenerative condition
Knee OA is a chronic degenerative condition, which means that it gradually worsens over time. In the early stages of development, people often find themselves cutting back on their activities or work because of the discomfort and pain. Advanced knee OA is usually associated with a great deal of pain, stiffness and inflammation.
Mild knee OA
In a healthy knee, you have cartilage covering the ends of the bones, which prevents them from rubbing against each other. Synovial fluid is found in the tiny space between the bones and its purpose is to lubricate and protect the joint.
As the surface of the cartilage starts to break down, very small cracks and indentations may form. At this stage, the knee might also start to show signs of varus misalignment, more commonly known as bowed or bandy legs.
Moderate knee OA
Sections of cartilage start to wear right down, reducing its flexibility and increasing the likelihood of it becoming damaged by daily activities and/or injury. The lubricating liquid (‘synovial fluid’) also starts to break down and become less effective, while cracks and pits may continue to appear in the cartilage. The leg is likely to appear even more bowed.
Severe knee OA
Bones are left unprotected as large sections of the cartilage are completely worn away, resulting in pain from the bones grating against each other as they move. Pain and further damage may also arise from small fragments of cartilage that have become detached and may be floating around the joint. Externally, the leg will often appear severely bowed in relation to the thigh.