Knee osteoarthritis (OA), also known as degenerative joint disease, affects the knee joint due to gradual wear and tear of the articular cartilage. Let’s delve into the details:

1. Epidemiology:

   • OA is the most common joint disease worldwide, with the knee being the most commonly affected joint in the body.

2. Relevant Anatomy:

   • The knee joint consists of three bones: the femur (thigh bone), tibia (shin bone), and patella (kneecap).

   • Articular cartilage covers the ends of these bones, providing cushioning and allowing smooth movement.

3. Pathological Process:

   • Over time, the cartilage wears away, becoming frayed and rough.

   • As cartilage thins, the protective space between bones decreases.

   • Result: bone rubbing on bone, leading to painful bone spurs.

4. Stages of Knee OA (based on the Kellgren-Lawrence classification):

   • Stage 1 (Minor):

     • X-rays may not reveal damage, but early signs include osteophytes (bony growths) and slight cartilage damage.

     • No discomfort or pain at this stage.

   • Stage 2 (Mild):

     • X-rays show narrowing of the joint space and bone spurs.

     • Stiffness and joint pain, especially after rest.

     • Hardening of tissues and thin layer of bone beneath cartilage.

   • Stage 3 (Moderate):

     • Clear joint space narrowing, bone spurs, and cartilage damage.

     • Pain during daily activities, early signs of joint inflammation, and swelling.

   • Stage 4 (Severe):

     • Severe joint space narrowing, bones meet and rub together.

Remember that early diagnosis and appropriate management are crucial for minimizing pain and maintaining joint function. If you experience knee pain or stiffness, consult Dr Chinmoy Roy at Rajarhat Pain clinic Kolkata for evaluation and personalized treatment options.