What Is Osteoarthritis?

Who is Arthur, and why is he hurting so many people? Dr. Rob gives the inside scoop on this villain.

Rob Lamberts, MD
4-minute read
Episode #54

There’s a guy out there who is a real pain. Many of my patients talk about how he messes up their lives, makes it hard to do their daily tasks, and makes them feel very old. His name is Arthur--Arthur Ritis.

So what about Aurthur? This podcast will focus the most common type of arthritis: osteoarthritis, or degenerative arthritis. The word osteoarthritis comes from the Greek “osteo” meaning bone, “arthro” meaning joint, and “itis” meaning inflammation

Arthritis is a big topic, so I’ll cover the causes, risk factors, and symptoms of osteoarthritis in this article, and next week will discuss prevention and treatment. In a future article, I’ll cover the more severe but less common inflammatory kinds of arthritis, including rheumatoid arthritis. 

What Is Osteoarthritis?

In order to discuss osteoarthritis, I first need to talk about joints and bones. A joint is the place where two or more bones come together, such as your elbow or knee. Your bones are covered with a thin smooth substance called cartilage, and the joints are filled with a lubricant called synovial fluid. The cartilage and fluid keep the bones from rubbing against each other at the joints and wearing down. But in osteoarthritis (OA), the cartilage gradually wears down, as does the lubricating ability of the synovial fluid. The joints get more narrow, and the bones in the joint space become deformed, resulting in pain and decreased movement. Sometimes, the bones at the joint enlarge and develop outcroppings commonly called “bone spurs.”

What Are the Symptoms of Osteoarthritis?

Although OA can affect almost any joint, it most often affects the hands, knees, hips, and spine. The symptoms depend on the joint affected, but generally include:

  • Pain that occurs with movement.

  • Stiffness that occurs after inactivity--particularly in the morning--which gets better with use.

  • Bony swelling, which is especially apparent on the hands, affecting the two joints closest to the ends of the fingers.

  • Pain in the bones around the joint when they are touched.

  • Decreased range of motion

Which Symptoms Are Not Osteoarthritis?

There are several things that point against a diagnosis of OA:

  • Joint pain that is not symmetric. OA usually affects both sides of the body just about the same, unless that joint suffered a significant injury earlier in life.

  • Onset at a younger age. Symptomatic OA usually happens over age 50, although it can show up earlier on x-rays.

  • Sudden onset of pain and/or swelling.

  • Warmth or redness of the joint.

What Causes Osteoarthritis?

Doctors used to believe that OA was a normal part of getting older, but that is not really true. Most people get OA as they get older, but getting older doesn’t cause OA. There are a number of things that can predispose a person to getting OA:

  • Family history

  • Obesity, which can predispose people to getting OA in the knees

  • History of a significant injury to a joint earlier in life

  • Participation in certain sports

Women are also more prone to serious arthritis than men--particularly in the hands and knees.


Please note that all content here is strictly for informational purposes only. This content does not substitute any medical advice, and does not replace any medical judgment or reasoning by your own personal health provider. Please always seek a licensed physician in your area regarding all health related questions and issues.