Whether knee pain has you navigating stairs like a hiker descending a mountain or simply dreading the mere thought of bending down, you're likely looking for ways to get rid of it. And if it's lingering pain you can't seem to shake, you might also wonder whether an underlying issue is at play.

"Knee osteoarthritis is a degenerative disease characterized by mechanical degradation of cartilage, the soft padding at the ends of the bones in the knee joint," says Dr. Timothy Brown, an orthopedic surgeon at Houston Methodist. "This is a natural byproduct of age and activity, but as cushioning in the knee continues to wear down, it can eventually lead to pain, stiffness and swelling."

It's a common issue, with estimates suggesting that almost half of all adults will develop osteoarthritis of the knee at some point in their lives. These chances increase with age, but the natural wear and tear of cartilage that happens over time can also be accelerated by certain factors.

How do you know if you have knee arthritis?

Overdoing it during a workout, suffering a traumatic injury — knee pain can crop up for a variety of reasons. So how do you know when the cause is osteoarthritis and not something else?

"By definition, arthritis is an inflammatory condition," explains Dr. Brown. "Knee osteoarthritis is no different. The pain felt is due to inflammation, which also leads to some other characteristic symptoms."

Knee arthritis symptoms include:

• Joint pain
• Swelling in the knee
• Knee stiffness
• Loss of range of motion in knee joint
• Deformity of the knee, curving inward (bow leg) or outward (knock knee)

If you're experiencing knee pain but there's no visible change to the knee, and you're able to extend your leg without much issue, overworn cartilage likely isn't the culprit. This type of knee pain could instead be caused by anything from patellar tendonitis to knee bursitis to something else.

But if your knee is swollen, stiff and the joint has even started to curve inward or outward, knee arthritis becomes a concern.

"Another clue that knee pain might be due to arthritis is timing," explains Dr. Brown. "If you stepped off of a curb and there's pain and swelling in the knee, we're thinking about acute damage to the meniscus or soft tissue. But if, over the last few years, it's taking less and less activity before your knee is hurting and swollen, that's more likely to be osteoarthritis."

What causes knee arthritis?

Many factors can lead to degeneration of cartilage in the knees — some of which can be modified, some of which can't.

The causes of knee arthritis include:

• Age – wear and tear of knee cartilage naturally accumulates over time
• Genetics – the structure and makeup of your cartilage, including how fast it wears down, is inherited from your parents
• Body weight and shape – the more weight you carry, the more pressure that's placed on the cartilage in the knee joint. Certain skeletal shapes can also predispose to knee arthritis.
• Daily activity level – a career that requires you to be on your feet carrying heavy loads or going up and down flights of stairs every day for many years can put extra pressure on the knee joint
• Injury – whether acute or due to overuse, injuries can accelerate the natural wear and tear of cartilage

"The cause of knee osteoarthritis tends to be multifactorial," says Dr. Brown. "Surgery can accelerate it, too. Maybe you had part of the meniscus taken out or an ACL repaired, and thirty or so years later knee arthritis develops. Age, weight, activity level, injury — a lot of things can play into it."

Managing the modifiable factors that contribute to osteoarthritis, like being overweight, can help limit your chances of experiencing knee pain in the future. Conversely, understanding the factors you can't change, such as a previous injury, helps highlight the importance of reducing the risk factors you can.

How to treat (and prevent) knee pain caused by osteoarthritis

If you're already familiar with the R.I.C.E. self-care technique, the early steps for dealing with knee pain from arthritis won't surprise you.

"Rest, ice, compression, elevation — these all help reduce swelling," says Dr. Brown. "Anti-inflammatory medications, like ibuprofen, can also help."

Consult your doctor if symptoms persist for several weeks despite these self-care measures. Dr. Brown warns that once pain from knee arthritis develops, the issue can easily snowball if corrective steps aren't taken.

"The human body is made for movement, and your joints are only healthy when they're moving," explains Dr. Brown. "Osteoarthritis can often lead to weakening of the muscles supporting the knee — quadriceps, hamstring and calf — which only makes the problem worse."

For instance, if knee pain causes you to stop being active, your muscles weaken and make it easier to load the joint in an unusual way when you do move. This can not only make the pain worse but potentially even lead to increased risk of knee injury. And that's not all. The less you move and the weaker you get, the easier it is to gain weight. Weight gain adds to the stress the knee joint faces, accelerating cartilage degradation and leading to further progression of the disease.

"When people ask me what they can do to slow osteoarthritis, I always say the most important factors are to stay in motion, keep your muscles strong and get to a healthy weight," stresses Dr. Brown.

Physical therapy is key for managing knee arthritis. A physical therapist can guide you in exercises that help keep the muscles supporting your knee strong, which can reduce pain. The therapist will also recommend any activity modifications needed to make sure you're not exacerbating the issue as you stay active.

What should you do if knee arthritis isn't going away?

If knee arthritis progresses despite physical therapy and activity modification, your doctor may recommend other ways to reduce inflammation, such as steroid injections or prescription medications. In some cases, surgical intervention may be needed to resolve pain and help you get active again.

"If you've tried other treatments but are still experiencing daily symptoms that significantly impact your quality of life, we start the conversation around knee replacement," explains Dr. Brown.

For instance, if knee pain is keeping you from getting sleep at night or causing you to change your daily routine, that's when you might consider surgery.

"Robotics have made knee replacement more personalized and accurate, which translates to less post-surgical inflammation and faster recovery than traditional techniques," adds Dr. Brown.

Knee replacement is not a trivial surgery, but debilitating knee pain isn't a trivial concern either. An orthopedic surgeon can help you understand if knee replacement is right for you.