DEAR DOCTOR K: I have osteoarthritis. Can you tell me what is happening in my joints that causes my painful symptoms?
DEAR READER: The short answer is that osteoarthritis causes deterioration of cartilage in the joints. But I suspect you’d like a more detailed response.
There are many different kinds of arthritis, but osteoarthritis is the most common. It causes pain, swelling and stiffness in the joints that worsens over time. The condition most often affects joints found in the shoulders, wrists, fingers, hips and knees. These joints are designed for a variety of movements that make possible all manner of activity, from playing tennis to playing the piano.
Joints, like machines with moving parts, are vulnerable to friction. If a machine’s moving parts come in contact with one another, friction will scratch the surfaces and cause pitting, distortion and eventually breakage. Two strategies can prevent such friction: applying a lubricant, or inserting a cushion. Human joints are protected in both ways.
As cartilage degenerates, patches of exposed bone appear. Over time, the space between bones narrows. The surfaces of the bones change shape, leading to friction and joint damage.
The bones try to repair themselves, but the renovation attempts are uneven. As a result, bony overgrowths form along the margins of the damaged joints. These little pieces of overgrown bone can get chipped off of the bone. Then they become like gravel in the joint, making it hurt worse.