Knee Osteoarthritis

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.