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What's Likely to Be Causing Your Knee Pain

How to identify the culprit — and which drugs, injections and habits will bring you the most relief

spinner image A woman clutching her knee suffering from pain in her knee
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Oh, my aching knees! If that's your daily refrain, whether you're walking the dog, climbing stairs or just sleeping, you're not alone.

For many, the culprit behind that nagging soreness is osteoarthritis, which affects an estimated 31 million Americans — quite often, in this particular joint — according to the Arthritis Association.

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But there are other common causes of knee pain, stemming from the fact that knees are our largest, most complex joints. “Knee joints allow you to stand up straight, walk stairs and get up and down from sitting,” says Daniel Saris, an orthopedic surgeon at the Mayo Clinic and professor of orthopedic surgery at the Mayo Medical School. “But they are also the most difficult joint because they're not stable. Hip joints and ankles are both pretty stable by themselves, but the knee is just three bones trying to be good friends, and they need muscles and ligaments for stability."

Knee pain is not to be taken lightly. A Japanese study, published last year in the Journal of the American Geriatrics Society, found a link between the onset of knee pain in people 65 or older and depression. And a recent study from the University of North Carolina School of Medicine Thurston Arthritis Research Center and Harvard's Brigham and Women's Hospital found that knee pain in men and women over age 45 correlated with higher rates of death.

So how do you know if your knee pain is bad enough to see an orthopedist? “If your knee hurts or is swollen or is affecting your function in some way, we want to address it,” says Michelle Wolcott, an orthopedic surgeon at the University of Colorado School of Medicine who treats several university and professional sports teams.

During a standard knee exam, explains Michael Fredericson, M.D., director of Physical Medicine and Rehabilitation Sports Medicine at Stanford University, your doctor will ask about the particulars of your discomfort and do a physical exam, checking alignment (are the knees knocked or bowed?) and scanning for any issues with internal ligaments and cartilage. Your physician will also order an X-ray and possibly an MRI of your knees.

For those worried that a knee pain diagnosis will inevitably lead to knee replacement surgery, take heart: Many knee problems respond well to noninvasive treatments that allow you to either avoid surgery or at least delay it.


If you are over 50 and have knee pain, it is likely due to one of the following issues:

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This condition, which frequently comes on gradually and worsens with age, involves deterioration of the knee cartilage and adjacent bone. “This is the number one issue in terms of knees,” Fredericson says. “It might be related to an injury that occurred when a patient was younger, but often it just occurs from aging itself.” Osteoarthritis symptoms vary widely and can even come and go, but include pain, swelling, stiffness and difficulty moving. Biomechanics can be a factor, too. “We'll frequently see knee problems occur within families,” Wolcott observes. “Someone in their 50s will come in and say, ‘My dad had knee replacements, my mom had knee problems, and I'm shaped like them.’ It could be that they are knock-kneed. It could be that they have loose kneecaps. It's just anatomy.”

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Meniscal tear or deterioration

The menisci, two rubbery pieces of cartilage inside the knee, serve as shock absorbers between the thighbone and the shinbone. Partial or total meniscal tears, which often result when the knee is twisted, can range from small, innocuous tears that the patient doesn't even feel to traumatic tears, say, from skiing or tennis, that cause sudden, severe pain. “Often people who have osteoarthritis also have meniscal tears,” Fredericson says. “It's all part of the same process.” At one time, patients routinely underwent surgery to repair or remove the torn meniscus. Today that is not considered the optimal solution. Symptoms include pain (particularly when the knee is straightened), swelling, occasional “clicking” or “locking” of the knee joint (caused by loose pieces of the meniscus), and difficulty squatting or getting up from a chair. “In patients past age 40 or 50, the kinds of meniscal tears we see are usually degenerative, not something that developed overnight, and the patient did something to aggravate it,” Fredericson says.


The obesity epidemic among Americans has led to a commensurate strain on our knees. Almost 40 percent of Americans are obese, meaning their BMI is 30 or higher, according to the Centers for Disease Control and Prevention. “The more you weigh, the harder it is on your knees,” Saris notes. “Every extra pound on your body means 5 to 7 extra pounds on your knees."

Tendinitis or bursitis

These conditions can occur at any age, including in patients over 50. Tendinitis is inflammation of one or more of the tendons that surround the knee and that get less flexible as we age. This condition often results from sports activities, when the tendon stretches and becomes inflamed. Symptoms include pain above or below the kneecap, which typically gets worse with movement and eases with rest. Bursitis is inflammation of the bursae, the fluid-filled sacs that cushion the knee. Symptoms can vary, but often the affected area will be swollen and feel warm and tender to the touch.

Rheumatoid arthritis

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This autoimmune disease results in the patient's immune system attacking the knee's synovial lining (which provides fluid to lubricate the joint), ultimately leading to cartilage damage. “It would be unusual to have rheumatoid arthritis isolated just in the knees,” says Nancy Carteron, a rheumatologist and associate clinical professor at the University of California San Francisco Medical School. “Usually, it would appear first in the hands and feet.” The symptoms include pain, stiffness, swelling and redness, especially after sleep. The condition is treated with steroids and disease-modifying antirheumatic drugs (DMARDs).

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Once your doctor has done an examination and pinpointed the culprit, treatment for most of the causes above will involve a multipronged approach. “There's a step-by-step process that includes pain medication, weight reduction, physical exercise and sometimes the use of a brace, a cold pack or a neoprene sleeve,” Saris says. If those don't work, there are a variety of injections into the knee that can provide relief and also correct the root problem. And if no remedy alleviates the daily discomfort, knee replacement surgery may be suggested.


Effective for anything that is painful and involves swelling (from osteoarthritis to tendinitis), anti-inflammatories include oral over-the-counter pain medications like aspirin and ibuprofen. Fredericson also recommends that patients take natural anti-inflammatory supplements, such as fish oil and turmeric, and switch to an anti-inflammatory diet, like the Mediterranean. “The most important thing is to get a lot of fresh fruits and vegetables and to avoid any saturated fat, any processed foods and, particularly, any processed sugar,” he says.


There are several that are commonly used. Corticosteroid injections “have been shown to be effective for about 40 percent of patients with osteoarthritis of the knee,” Saris says. “They usually work best with patients who have pain and swelling, because they quiet down the inflammatory response.” A second type of injection for osteoarthritis, called viscosupplementation, lubricates the knee with hyaluronic acid, a substance that occurs naturally in the knee, which is also manufactured as a synthetic gel to provide a protective coating to joint surfaces. Getting such an injection “tells the knee it's better, so it doesn't swell as often,” Saris explains.


“If you look at all the research on osteoarthritis of the knee, one thing that jumps out is the importance of exercise,” Fredericson observes, noting that the benefits extend beyond weight loss. Often, orthopedic practices include physical therapists who can help patients find exercises that alleviate their knee pain, no matter the cause. Fredericson recommends focusing on exercises that strengthen the quadriceps (on the fronts of the thighs) and the glutes (the muscles in your behind, which help control the movement of your hips). “Lean muscle mass can absorb stress; fat can't,” Wolcott explains. “So if you have muscle support around your knee, that stress is going to be absorbed somewhere besides in the joint itself.” And exercise doesn't have to hurt. A 2018 study from the Shirley Ryan AbilityLab and Northwestern Medicine found that, among golfers, walking the course, instead of riding in a cart, was not linked to increased pain, cartilage breakdown or inflammation. Bottom line: “We need our joints to move well, and we need to move a lot to keep our joints well,” Saris says.

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