When you hear the word "arthritis," you probably think of an elderly person with joint pain. But osteoarthritis can actually appear in people as young as their 20s. "People come into [my] office and they have a kind of vague idea of what arthritis in general means," says Douglas Unis, MD, associate professor of orthopaedics at New York City's Icahn School of Medicine at Mount Sinai. 

So, here's a quick overview: Osteoarthritis is a degenerative condition that occurs when the cartilage that cushions and protects your joints wears away. It occurs gradually, and gets worse over time. Osteoarthritis is the most common form of arthritis, affecting about 30 million U.S. adults. The disorder most commonly affects the hands, knees, hips, and spine. 

Knowing the facts about osteoarthritis could save your joints, no matter your age. Here's what young people should know about symptoms, possible risk factors, and the best treatment options (and which ones to skip).

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Symptoms are somewhat different in young people

In younger people, osteoarthritis typically affects load-bearing joints—the knees, hips, and ankles—because they are most likely to be affected by athletic injuries and obesity (more on this later), says Dr. Unis. Although symptoms of osteoarthritis can vary depending on the joint affected, he suggests keeping an eye out for mechanical symptoms such catching, locking, and grinding, particularly in the knees. Another red flag: persistent, worsening joint pain that doesn't improve after rest or anti-inflammatory drugs.

A less common symptom in younger people is joint deformities. "These occur over time, with more advanced arthritis," Dr. Unis explains. "But some people will get worsening knock-knees or bow-legged deformities as the arthritis gets worse."

You have control over some of your risk factors

You have a greater chance of developing osteoarthritis if it runs in your family. "If you're a young person and you start having persistent knee pain—and both your grandparents and parents had joint replacements—you might want to go see an orthopedist, because you're probably going to have early arthritis," Dr. Unis says. 

Maintaining a healthy weight is one of the best ways to prevent osteoarthritis. "[Obesity] is the biggest modifiable risk," says Dr. Unis. Extra pounds increase pressure on your joints and can cause cartilage to wear down more quickly than it otherwise might have. The knees and ankles are especially susceptible to obesity-related osteoarthritis because they support so much of your body weight, Dr. Unis adds. "For knee [arthritis], we're seeing it younger and younger and younger in people in their early 30s and even late 20s," he says. "And the ankle is super sensitive to a patient's overall weight because it's a very small joint but it's bearing the entire weight of the body."

The last risk factor for early-onset osteoarthritis is a frustrating one: being active and athletic. A 2014 paper published in the journal Clinical Medicine Insights: Arthritis and Musculoskeletal Disorders notes that athletes are more susceptible to joint injuries than the average person, putting them at risk for arthritis. Athletes also simply use their joints more, accelerating wear and tear on cartilage. 

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Hip osteoarthritis can appear particularly early

Some people are born with hip dysplasia, an abnormal formation of the hip socket that puts them at risk for hip osteoarthritis. "Because the hip socket isn't as deep as it should be, it's kind of like driving a car where the tires are out of alignment: it just wears out faster," Dr. Unis explains. People with hip osteoarthritis may start developing symptoms in their late 20s or early 30s.

You have plenty of treatment options

There's no cure for osteoarthritis, but there are many proven ways to manage pain. "You definitely want to try conservative management first," says Dr. Unis. This includes weight loss, physical therapy, acupuncture, and over-the-counter or prescription anti-inflammatories. 

If these strategies don't help, Dr. Unis says that cortisone injections may help, but that younger patients should be wary about how often they get them. "Over time, there's a build-up of residue in the joint that accumulates and can cause abrasive wear to the remaining cartilage," he explains. "It's not an ideal situation for younger patients to get lots and lots of cortisone shots, but it's fine to do occasionally."

For advanced osteoarthritis, patients may want to talk to their doctor about getting a joint replacement. This may help improve quality of life for people with hip osteoarthritis in particular: "The threshold to do a hip replacement is much younger than knee replacement for most surgeons," Dr. Unis says. "A hip replacement feels pretty natural."

However, not every treatment you hear about is worth doing. Dr. Unis warns against gel shots ("They do not work," he says) and platelet-rich plasma ("It's not covered by insurance, and there's not a lot of evidence that it really does anything"). He adds that the jury is still out on stem cell injections: "It's a new therapy, but the evidence has just not been established yet."

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You may need to change the way you exercise 

Listen to your body. High-impact workouts like plyometrics and running may inflame arthritic joints and worsen your symptoms. For knee arthritis in particular, you should avoid "loaded flexion" strength exercises (think: squats, lunges, and leg presses), says Dr. Unis. "They put a ton of stress on the front of the knee." 

That doesn't mean you should stop working out altogether. "Exercise is critical for maintaining arthritic joints," says Dr. Unis, because it strengthens muscles around the affected joint, broadens your range of motion, and helps you control your weight. And high-intensity exercise is not out of the question for people with arthritis; you can still rev your heart rate and stoke your metabolism with low-impact workouts like swimming, cycling, TRX, and circuit training.