What Is Knee Osteoarthritis?

Written by Marijke Vroomen Durning, RN
Medically Reviewed by Jabeen Begum, MD on June 17, 2025
11 min read

Age is a major risk factor for osteoarthritis (OA) of the knee, but young people can get it, too. For some people, it may be hereditary. For others, osteoarthritis of the knee can result from injury, infection, or being overweight. Here are answers to your questions about knee osteoarthritis, including how it’s treated and what you can do at home to ease the pain.

Osteoarthritis is degenerative, meaning thatthe natural cushioning between the joints — called cartilage — wears away. It’s often called wear-and-tear arthritis.

“The cushioning over the bones in the joint wears down, just like a tire would wear down on a car after so many miles,” explains Joseph Ciotola, MD, an orthopedic surgeon at Mercy Medical Center in Baltimore, Maryland. “There’s also a genetic component to osteoarthritis. Some people are prone to it.” 

When the cartilage wears down, the joint bones rub more closely against one another due to reduced cushioning that normally acts as a shock absorber. The rubbing causes pain, swelling, and stiffness. Knee osteoarthritis can make it harder to walk and may also cause bone spurs.

Knee osteoarthritis can be primary or secondary. Primary knee OA means the cartilage has worn down due to wear and tear. Secondary knee OA happens when there’s a specific cause, such as trauma, bone deformation, or certain diseases.

Osteoarthritis is the most common type of arthritis. While it can occur in young people, the chance of getting osteoarthritis rises after age 45. About 33 million people in the U.S. have osteoarthritis, with the knee being one of the most commonly affected areas. Women are more likely to have osteoarthritis than men.

Since osteoarthritis is usually caused by wear and tear, its most common cause is age. But several things can increase the risk of having significant arthritis at an earlier age.

Age. As you get older, your cells don’t repair themselves as quickly, so the cartilage wears down. According to Ciotola, doctors used to believe that almost everyone would develop OA at some point, but they’ve learned that’s not true. “We have definitely seen people well into their 90s who still have beautiful-looking joints. Osteoarthritis is common, but it’s not inevitable.”

Weight. Weight increases pressure on all your weight-bearing joints, especially your knees. Every pound of weight gained adds about 4 pounds of extra pressure on the knees.

Heredity. OA can run in families. “There are people who have collagen vascular diseases [connective tissue disease] and are hypermobile, like with Ehlers-Danlos,” Ciotola says. “Those patients get arthritis faster than others.” Inherited abnormalities in the shape of the bones surrounding the knee joint can also be a cause.

Gender. Women aged 50 and older are more likely than men to get osteoarthritis of the knee.

Repetitive stress injuries. People who often repeat the same tasks, whether due to work or favorite activities, put constant pressure on their joints. So, if you do a lot of kneeling, squatting, or lifting heavy weights, you could be at risk of developing osteoarthritis of the knee.

Athletics. Athletes involved in sports that put a lot of pressure on the knees, such as long-distance running, may be at higher risk for osteoarthritis of the knee. But it depends on how often they participate and other risk factors, such as having previous knee injuries. Athletes who were born female may be at higher risk as well. It’s important to note that regular moderate exercise strengthens the muscles around the joints and can cut the risk of osteoarthritis. In fact, weak muscles around the knee can also lead to osteoarthritis.

Secondary knee osteoarthritis

You can develop osteoarthritis without the usual wear-and-tear cause as well. Possible causes include:

Symptoms of knee osteoarthritis often come on gradually. You might start noticing them off and on, and then they start to worsen. These are the most common early knee osteoarthritis symptoms:

  • Pain that worsens when you’re active but eases with rest
  • Pain that worsens if you need to bend your knee over and over, like when going up stairs

Over time, you might experience:

  • A feeling like your knee won’t support you as you stand or walk (may feel wobbly)
  • Swelling
  • Stiffness in the knee, especially in the morning or when you have been sitting for a while
  • Less mobility of the knee, making it hard to get in and out of chairs or cars, use the stairs, or walk
  • A feeling like your knee is locking up, getting stuck, and won’t move how you want it to move
  • A creaking, crackly sound when you move your knee

Diagnosing knee osteoarthritis begins with a physical exam by your doctor. They may examine:

  • How your knee looks. Is it swollen or discolored?
  • Where the pain is. When you point to where it hurts, is the location a specific place or more all over the knee?
  • Signs of injury
  • When you move your knee, how well can you move it?
  • When they touch your knee, does it feel loose or unstable?
  • How you walk. When you walk, how does your step look?

Your doctor will also ask you about your medical history and note any symptoms. It’s important to mention what makes the pain worse or better and if anyone else in your family has arthritis. Your doctor may order tests, including:

  • X-rays, which can show bone and cartilage damage as well as the presence of bone spurs
  • MRI scans

MRIs are done when X-rays don’t give a clear reason for your joint pain or when the X-rays suggest that other types of joint tissue could be damaged. Your doctor might also ask for blood tests to rule out other conditions as the cause of pain, such as rheumatoid arthritis. Finally, if needed, your doctor might want to take some fluid from your knee to send for testing.

“Sometimes, it could be gout or pseudo gout,” Ciotola explains. This can cause similar joint pain and swelling. “We’d diagnose that with a knee aspiration, where we take fluid out of the knee and look for crystals in the fluid.”

The main goals for knee osteoarthritis treatment are to relieve the pain and make you more mobile. The treatment plan will typically include a mix of medical treatments and lifestyle changes:

Lifestyle and at-home treatments

There are some things you can try at home to help manage OA pain and slow down its advance, but it’s important to speak with your doctor before doing anything new, including exercise. You need to work together to ensure you don’t, by accident, cause more damage.

Weight loss. Losing even a small amount of weight, if needed, can significantly decrease knee pain from osteoarthritis.

Exercise. Strengthening the muscles around the knee makes the joint more stable and decreases pain. Swimming is a good exercise that doesn’t put pressure on your knee, but walking or biking — if not too painful — can also be helpful. “Avoid pounding on your knee,” Ciotola advises. Stretching exercises may help keep the knee joint mobile and flexible.

Pain relievers and anti-inflammatory drugs. Over-the-counter (OTC) choices such as acetaminophen, ibuprofen, or naproxen sodium can help manage your pain, but don’t take OTC medications for more than 10 days without checking with your doctor. Taking them for longer increases the chance of side effects. If OTC medications don’t help, your doctor might give you a prescription for stronger doses or other medications to help ease the pain.

Using devices such as braces. There are two types of braces: 

  • “Unloader” braces, which take the weight away from the side of the knee affected by arthritis
  • “Support” braces, which offer support for the entire knee

Alternative therapies. Some alternative therapies that may be effective include topical creams with capsaicin, acupuncture, or supplements like glucosamine and chondroitin.

Nonsurgical medical treatments

If at-home therapies don’t help, your doctor might suggest:

Physical and occupational therapy. If you are having trouble with daily activities, physical or occupational therapy may help. Physical therapists teach you ways to strengthen muscles and make your joints more flexible. Occupational therapists teach you ways or provide you with tools to do regular, daily activities, such as housework, with less pain.

Injections. “Injections are the first line of treatment,” Ciotola says. Doctors prefer noninvasive treatments because they have fewer possible complications.

Injections may include: 

Corticosteroids. Steroids are powerful anti-inflammatory drugs that can lower inflammation inside the joint.

Knee gel (hyaluronic acid) into the knee. Hyaluronic acid is a natural lubricant that’s already in your body. Injecting more gel might help lubricate your knee, reducing how the bones rub together. 

Genicular nerve block. This treatment is for temporary pain management. Your doctor would inject a combination of steroids and a local anesthetic close to specific nerves around your knee to block the pain.

Knee OA treatments under study

Researchers are continuing to look to find better injections to ease the pain caused by osteoarthritis of the knee without surgery. Here are some of the latest treatments that they’ve been studying:

Platelet-rich plasma (PRP) injections. You give a sample of your blood that is sent to a lab where it’s placed in a machine called a centrifuge. The tube spins and the force pulls out your blood’s platelets and plasma. This is collected and then injected back into your knee. This very concentrated mixture contains substances that could promote healing.

Even though they’re popular with some high-profile athletes, PRP injections still aren’t proven, and the treatment formulations can vary a lot.

Mesenchymal stem cells (MSCs). Your bone marrow makes MSCs that can grow into new tissues, including cartilage. By gathering these cells and injecting them into the knee joint, the hope is that they will give rise to new cartilage and reduce inflammation.

This treatment is still in the very early stages, and right now, there are too many differences between how the studies are done to really understand if it’s effective.

Bone marrow aspirate concentrate. This draws on the same concept as MSCs. Experts take cells from your body and use them to stimulate the healing process inside your knee.

The advantage is that bone marrow may be easier to obtain than MSCs, and it also contains other substances that help with cartilage regrowth and ease inflammation. A recent article that reviewed studies looking at this treatment didn’t find it to be very effective, and it is quite expensive.

Autologous cultured chondrocytes. This is a procedure to repair injuries that can lead to osteoarthritis. It involves collecting the cells that form cartilage from your own joints, growing the cells in a laboratory, and then injecting these cells into the knee. The treatment is promising, but not yet proven.

Water-cooled radiofrequency ablation. Another experimental procedure to treat pain, it aims to disable the nerves causing pain by heating them. “Water cooling” is a way to control the speed of warming. While it’s gotten a lot of publicity, studies so far are limited to small groups of people.

If medical treatments don’t help relieve your pain or slow down knee damage, your doctor might suggest surgery. The surgical options include

Arthroscopy. Your surgeon uses a thin tube-shaped instrument (arthroscope) inserted through one of a few small incisions (cuts) in your knee. Using special tools, your surgeon can remove damaged cartilage or loose particles, clean the bone surface, and repair other types of tissue if damage is found. Unfortunately, this isn’t proving to be a very effective treatment for knee osteoarthritis, so experts recommend it only if there are other problems with the knee too, such as a recent trauma.

Osteotomy (knee bone reshaping). An osteotomy is a procedure that aims to make the knee alignment better by changing the shape of the bones, which helps lessen pressure on the joint. This type of surgery may be recommended if you have damage mostly in one area of the knee. It might also be recommended if you have broken your knee and it has not healed well. An osteotomy is not permanent, and further surgery may be needed later on.

Arthroplasty (joint replacement surgery). This is a surgical procedure in which joints are replaced with artificial parts made from metals or plastic. The replacement could involve one side of the knee (partial) or the entire knee (total). You might have to have a repeat surgery later if your prosthetic joint wears out eventually. But with today’s modern advancements, most new joints will last over 20 years. The surgery has risks, but the results are generally very good.

Getting older doesn’t always mean you’ll have knee osteoarthritis, but it’s quite common. It’s a wear-and-tear type of arthritis that affects the joints that support you, such as your knees. There are some steps you can take to try to slow down how fast it advances, such as losing weight if you need to and exercising to strengthen the muscles around the knee. But if you’re having pain from osteoarthritis of the knee, speak with your doctor because some medical and surgical options might help.

Can osteoarthritis of the knee be cured?

No, there’s no cure for osteoarthritis of the knee, but you may be able to manage it with lifestyle changes and some types of treatments. Or, if you have a total knee replacement, this will remove the bones from rubbing against each other.

What does osteoarthritis of the knee feel like?

If you have osteoarthritis of the knee, you might feel pain that worsens with activity but eases with rest, as well as stiffness after periods of inactivity. You may also feel like your knee is not stable.

How can I stop my knee osteoarthritis from progressing?

It’s important to speak with your doctor about finding out the best way to keep your knee osteoarthritis from progressing. For some people, it might mean losing weight if they need to; for others, getting more exercise or trying physical therapy may help. Some treatments might also slow it down.

Can you recover from knee osteoarthritis?

Since osteoarthritis isn’t something that can be cured, the only way you might recover from it is if you have a knee replacement.