What Is Osteoarthritis?

Does a knee grumble on the first stairs of the morning, then loosen up once you’re moving? That pattern — stiff at rest, easier with gentle use, achy again after a long day — is how many people first meet osteoarthritis. The video at the top of this page, titled simply "Osteoarthritis," is a good place to start before we walk through the questions people ask most often about it.

So what's actually wearing down inside the joint?

Think of cartilage as the smooth, slippery cap that covers the ends of your bones where they meet. It lets the joint glide and helps absorb load. In osteoarthritis, that cap gradually breaks down and thins over time. This site's 58-second osteoarthritis explainer puts it plainly: it describes a degenerative joint disease caused by the chronic breakdown and eventual loss of cartilage, after which the bones that meet at the joint begin to rub against each other. As the cushion fades, the bone underneath and the tissues around the joint change too, which is why the ache can feel deep and why the joint may not move as freely as it once did.

Which joints tend to complain first?

It depends on where life has loaded you. Knees and hips carry your weight, so they're common sites, as are the hands — especially the joints near the fingertips and the base of the thumb — and the spine. One joint or several can be involved, and the two sides of the body don't always match. An old injury to a joint can matter, too: a knee that took a knock years ago may develop changes earlier than its neighbour. Age is part of the picture for many people, but osteoarthritis isn't simply "wear and tear" as a slogan — it's a slow change in the whole joint, not just a worn surface.

How does it usually show up, day to day?

Pain tends to build gradually rather than arrive overnight. You might notice stiffness after sitting or first thing in the morning that eases as you get going, aching after activity, a grinding or clicking feeling when the joint bends, and days when the joint feels tender or slightly swollen. Symptoms fluctuate — a busy week on your feet can stir things up, and a quieter few days can settle them again. Because that pattern overlaps with other joint problems, a proper assessment matters: a clinician will usually ask about your history, examine the joint, and decide whether imaging or other tests would actually help.

What helps, and when does surgery enter the picture?

For most people the starting point isn't an operation. Keeping the joint moving and strengthening the muscles around it supports the joint and often eases stiffness; pacing activity — little and often rather than one exhausting effort — suits many joints better. Your own clinician or physiotherapist can tailor that advice, talk through pain relief options in general, and tell you what to watch for. Surgery is usually a later conversation, when pain and loss of function persist despite those measures. If a knee reaches that stage, our guide to what a knee replacement involves explains what that operation is and what to expect — a separate step, not an automatic destination for everyone with osteoarthritis.

MedicalVideos.com has published trusted medical videos since 2007. The site was founded by Dr. Mohamed Ibrahim, MD, PhD — physician and researcher.

Frequently Asked Questions

Is osteoarthritis the same as rheumatoid arthritis?
No. Osteoarthritis is mainly a gradual breakdown of cartilage and change in the whole joint. Rheumatoid arthritis is a different condition, driven by the immune system attacking the joint lining, and it needs its own specific treatment — which is why getting the right diagnosis matters.

Does exercise make osteoarthritis worse?
Gentle, regular movement is generally part of managing an osteoarthritic joint, not something to avoid altogether — joints that stop moving tend to stiffen. The right type and amount vary by joint and by person, so a physiotherapist's guidance is worth having, especially after a flare.

Can cartilage grow back on its own?
Cartilage has a limited ability to repair itself, and lost cartilage doesn't simply regrow to its original state. That's why most care focuses on easing symptoms, keeping the joint moving, and supporting it with the muscles around it.

When should I get an aching joint checked?
Book an appointment if pain keeps returning, the joint swells, it locks or gives way, or everyday tasks are getting harder. Seek help promptly after an injury, or if a joint becomes hot, very swollen, or you develop a fever — those signs need same-day attention.

Educational only — this article is general information about osteoarthritis, not medical advice and not a diagnosis. If a joint pain is new, severe, follows an injury, or comes with fever or marked swelling, seek medical care promptly rather than relying on general information.