The 4 Stages of Osteoarthritis

Here’s how this degenerative joint disease progresses, from minor to moderate to maybe needing joint replacement surgery.

by Amy Marturana Winderl Health Writer

If you’re living with osteoarthritis (OA), you’re in good company. The degenerative joint disease known as “wear and tear” arthritis affects more than 32.5 million American adults. That’s nearly 10 percent of the entire U.S. population.

OA develops when cartilage—the elastic tissue that preserves the space between bones in joints. Unlike bone, cartilage can’t naturally regenerate in the body so once it’s gone, it’s gone for good. When enough cartilage wears away in a joint, the bones can start to rub against each other, resulting in pain, inflammation, stiffness, and swelling—hallmark symptoms of OA.

What Causes OA

There’s not one universal cause of OA—genetics, an injury, and the regular wear and tear that happens to everyone’s joints over time, to some extent, can all play a role. But there are certain things that increase a person’s risk, says Dee Dee Wu, M.D., assistant attending physician at Hospital for Special Surgery in New York City.

“Age is the strongest predictor,” Dr. Wu says. “Simply put, the chance of developing OA goes up as you get older.”

Other things that increase your risk: trauma to a joint (even if it happened decades ago), genetics, and gender. OA tends to run in families, though experts don’t know of a specific gene that’s responsible, Dr. Wu says. And women are more likely than men to both develop OA and end up with more severe cases, she adds. A joint deformity, like bow-leggedness, also ups the risk of developing OA since it can put excess stress on certain parts of the joint, says Julius Kunle Oni, M.D., medical director of orthopedics at Johns Hopkins Bayview in Baltimore.

Lifestyle factors can also contribute to risk, primarily being overweight. “When you’re carrying around extra weight, you put excessive forces on the joint,” Dr. Oni explains. When weight-bearing joints like the knees and hips have to handle a lot of force over time, the cartilage is likely to break down quicker.

How OA Progresses

Once cartilage starts to deteriorate, there’s no hitting the brakes and reversing what’s been done. It will continue to break down, and inflammation and discomfort will continue to increase over time. But how quickly things go from 0 to 100 is hard to predict, Dr. Oni says.

“For some people, there’s a fast progression,” he says. “We may see very mild arthritis, and then in two years, it’s advanced.” For others, there’s a long period of no significant symptoms or progression, and then eventually things advance. “That could take years and maybe even decades,” Dr. Oni says.

But just because you can’t predict exactly how fast the disease will progress or stop it altogether doesn’t mean you’re powerless. There are things you can do to reduce your symptoms and prevent OA from getting worse, Dr. Oni says. Two such examples: Lose weight if you’re overweight and swap any high-impact exercise you do, like running or jumping, with low-impact activities that reduce strain on your knees and hips, Dr. Oni suggests. Biking or swimming are both good options.

It’s also a good idea to work on improving mobility in the affected joint and building strength in the surrounding muscles. The former will help relieve pain and stiffness, and the latter will give the joint some extra support, Dr. Oni says. Your best bet is to work with a physical therapist (usually covered by insurance but be sure to check with your provider). Visit to find a PT who specializes in orthopedics. Or talk to your doctor about adding these hip-strengthening moves or these knee exercises for OA to your routine.

The 4 Stages of OA

OA is categorized into four stages, with one being the mildest and four being the most severe. Doctors use X-rays to determine which stage a patient is in, says Kirk A. Campbell, M.D., orthopedic surgeon at NYU Langone Health in New York City. “In a normal X-ray, there’s a good amount of space between bones in a joint. As [cartilage] wears away and arthritis gets worse, the joint space decreases,” he explains. “When it’s severe, bones end up touching each other.”

X-rays can also pick up bone spurs, or osteophytes, which can form as OA progresses and bones begin to rub against each other. “The body doesn’t know how to make cartilage, but it knows how to make new bone,” Dr. Oni explains. “So it makes new bone in response to loss of cartilage in the affected area.” These bone formations can add to the pain and discomfort of OA. The more advanced your OA is, the more likely you are to have more and bigger bone spurs, Dr. Campbell says.

“In general, people feel fewer symptoms in minor to mild stages and have more good days than bad days,” Dr. Oni says. “In moderate to severe stages, people start to have more bad days than good days.”

More specifically, here’s what happens in each stage:

Stage 1: Minor

The first stage of OA is the least severe, Dr. Oni says. It’s typically considered minor arthritis. “At this point, there’s minor wear and tear in the joint, but typically people feel little to no pain and can keep doing all the things they want to do.”

Your doctor may suggest modifying activities to be lower impact or weight loss if you’re overweight, Dr. Oni says. Both of these things can help slow down the progression of OA.

Stage 2: Mild

Stage 2 is considered mild arthritis. “This is when X-rays start to actually show some findings, like bone spurs,” Dr. Oni says. At this stage, you may experience intermittent flares of pain, swelling, and stiffness in the affected joint, especially after doing high-impact activity or being sedentary for an extended period of time, Dr. Campbell says. “But after using non-steroidal anti-inflammatories (NSAIDs), icing, and maybe physical therapy, it usually calms down,” he says. The best treatment plan for you—at any stage—will be determined by you and your doctor.

Stage 3: Moderate

At this point, “The cartilage is really starting to erode now, and we’re starting to see significant narrowing of the joint,” Dr. Oni says. Bone spurs and increased joint inflammation are also common characteristics of moderate OA.

“You may have pain and stiffness after prolonged walking or even just going up and down the stairs,” Dr. Campbell says. Swelling at the end of the day is common. The knee in particular may feel weak and buckle at times.

Appropriate treatments for moderate OA include over-the-counter anti-inflammatory medications (NSAIDs), icing, physical therapy, and/or injections—either corticosteroids or viscosupplementation—to reduce pain and inflammation, Dr. Campbell says . “These treatments are not going to cure arthritis, but they can provide good symptomatic relief.”

Stage 4: Severe

This is the most severe stage of arthritis—a “bone-on-bone” situation. “The cartilage is almost completely gone, and there’s a cascade of events that cause significant pain, stiffness, and swelling,” Dr. Oni says. You may need assistive devices, like a cane, and deformities may even start to happen, like worsening of bow-leggedness or knock knee, depending on which area of the joints are affected.

Severe arthritis may be successfully managed with NSAIDs, injections, and physical therapy, but if these nonsurgical treatment options don’t cut it, it may be an appropriate time to consider surgery, Dr. Oni says. Surgery may mean a partial joint replacement to a total joint replacement, depending on your specific situation. Of course, surgery comes with risks, so you’ll want to discuss this option at length with your doctor.

An Important Reminder

It’s important to note that symptoms may not always correlate with what you see on an X-ray or the specific stage of OA you’re in—the experience of OA can be wildly different for everyone, Dr. Oni says. “Some people can have moderate or severe OA and have minimal symptoms, while others can have minor OA and will have severe symptoms.” Because of this, your doctor will recommend treatment based on more than just your X-ray and stage.

“Clinical history is more important than X-ray, because a lot of people have damage on an X-ray but are asymptomatic,” Dr. Wu says. Translation: The goal of OA treatment is to allow you to function normally without pain, so the way you feel and how much OA is impacting your daily life is more important than simply what the X-ray shows.

Amy Marturana Winderl
Meet Our Writer
Amy Marturana Winderl

Amy is a freelance journalist and certified personal trainer. She covers a wide range of health topics, including fitness, health conditions, mental health, sexual and reproductive health, nutrition, and more. Her work has appeared on SELF, Bicycling, Health, and other publications. When she's not busy writing or editing, you can find her hiking, cooking, running, or lounging on the couch watching the latest true crime show on Netflix.