What Is Osteoarthritis: Stages of Knee Osteoarthritis

What Is Osteoarthritis

Osteoarthritis is a disease involving inflammation of the bone and joint cartilage. A healthy joint consists of two bones, each with its own layer of articular cartilage, which is a type of connective tissue that allows the two bones to glide against each other essentially without friction.

Osteoarthritis Articular cartilage

The knee joint is made up of the femur-tibia patella along with a synovial membrane which contains synovial fluid. Synovial fluid acts as a lubricant in the knee joint. The end of the femur is covered in articular cartilage which moves against the articular cartilage of the tibia.

Synovial joints

The synovium is composed of loose connective tissue, blood vessels, lymphatic vessels and on the surface- Type A cells that clear cellular debris and, Type B cells that produce components of the synovial fluid which helps lubricate the two articular surfaces.

In a healthy knee, the articular cartilage is smooth without the shirring and the bone is smooth. The synovial fluid is viscous aiding in lubrication.

One of the main issues in osteoarthritis is the progressive loss of this articular cartilage, which means there’s not much separating the two bones anymore, which adds a significant amount of friction between them, which then generates inflammation, and triggers pain through the nerve endings in this joint space.

Maintaining healthy articular cartilage is the “Chondrocytes” job a specialized cell responsible for maintaining everything cartilage related. The chondrocytes produce and are embedded within a strong gel or extracellular matrix which contains type 2 collagen, a protein that provides structural support, as well as proteoglycans which are aggregates of protein and sugar molecules like hyaluronic acid, chondroitin sulfate, and keratan sulfate.

All of these extracellular components give the cartilage elasticity and high tensile strength, which help weight-bearing joints distribute weight such that the underlying bone absorbs the shock and weight, and these are joints like the knees, the hips, and the lower lumbar spine.

Chondrocytes are important for the articular cartilage. in healthy people, chondrocytes maintain a delicate balance between breaking down old cartilage called catabolic activity and producing new cartilage called anabolic activity.

The use of both decorative enzymes and synthetic enzymes. When something causes an increased expression of decorative enzymes, then the balance tips toward a net loss of cartilage via loss of proteoglycans and collagen.

The risk factor for osteoarthritis seems to be age and often the cartilage degrades over long periods of time which makes it really hard to pinpoint.

Osteoarthritis is really common and nearly everyone knows someone that suffers from it. People with osteoarthritis often feel stiffness in the morning, which usually lasts less than an hour but comes back at the end of the day.

This is an important difference between rheumatoid arthritis, an inflammatory disease that also affects the joints. With rheumatoid arthritis, morning stiffness usually lasts longer than an hour. The pain in osteoarthritis is usually a sharp ache or burning sensation which also gets worse with prolonged activity, but usually, the joints don’t swell whereas rheumatoid arthritis typically involves painful swelling.

Stages of Knee Osteoarthritis:

Osteoarthritis is the most common form of arthritis and affects millions of individuals. It is classified as mild-moderate to severe.  It affects many parts of the body including the knee.

Stages of Osteoarthritis

With mild knee osteoarthritis, you will begin to have discomfort in the knee joint, though the joint space appears normal the cartilage matrix has begun to break down from a combination of wear and tear and increase production of degrading enzymes.

Healthy knee

These small and smooth dense growths of bone are part of the body’s natural response to the loss of cartilage progression of the disease may be slow at this stage by increased exercise and weight loss with moderate neo changes in the joint are much more evident.

Osteoarthritis often affects the subchondral bone located just underneath the cartilage. Subchondral bone provides hydration, and oxygen, to the cartilage as subchondral bone flattens and tries to repair itself.

Cytokines and Proteins are released into the synovial fluid osteophytes may increase in number and size making the bone rougher all these factors combine to make the joint pain more severe and long-lasting.


Management or treatment of osteoarthritis can involve non-pharmacological approaches like losing weight, or moderate exercise, as well as physical therapy. This can be especially important for large weight-bearing joints like the hips and the knees. Pharmacological treatments focus on reducing pain and inflammation.

If neither of these approaches is successful, though sometimes patients might benefit from injections of hyaluronic acid into the joint or they might need surgery to replace the affected joint.  The Treatment for severe is typically surgery by receiving a partial or total knee replacement.

If you are suffering from knee Osteoarthritis speak to your physician to discuss treatment options.