What actually causes knee arthritis, and who is most at risk?

More than wear and tear

Osteoarthritis was once described as simple wear and tear, but it is better understood as a disease of the whole joint. The cartilage thins, the bone underneath thickens and forms spurs, the lining of the joint becomes irritated, and the surrounding muscles weaken. The process is usually slow and runs over many years.

The main risk factors

• Age: cartilage becomes less able to repair itself, so arthritis is more common after 50
• Body weight: extra weight increases the load through the knee and adds low-grade inflammation
• Genetics: arthritis often runs in families, especially in the hands and knees
• Sex: women develop knee arthritis more often, particularly after menopause
• Alignment: bow legs load the inner knee and knock knees load the outer knee
• Previous injury: ACL tears, meniscus tears, fractures into the joint and meniscus removal raise the risk
• Work and sport: years of heavy lifting, kneeling and squatting, or high-impact sport on an injured knee

Other types of arthritis to rule out

Not every arthritic knee is osteoarthritis. Rheumatoid arthritis, gout, pseudogout and infection can also damage the joint and need different treatment. Clues include several joints affected at once, sudden hot swelling, fever, or stiffness that lasts well over an hour every morning. These need prompt medical assessment.

Why the cause matters for treatment

Understanding why your knee wore out shapes the plan. A bow-legged knee with inner-side arthritis may suit realignment or a partial replacement, a knee damaged by an old injury may need stability addressed, and weight-related load responds to weight management. At Aman Hospital in Doha, Dr. Gelber examines the knee and its alignment and reviews standing X-rays before recommending anything.