Knee osteoarthritis develops as the cartilage that cushions the bones in the joint gradually breaks down. Healthy cartilage allows the knee to move smoothly while helping protect the bones. As this protective layer becomes thinner, pain and other problems can develop and may become more severe over time.

"Osteoarthritis can cause knee pain and stiffness, which can negatively impact a person's activity level, risk of falling, mood and general quality of life," said Dr. Abby Cheng, an orthopedic surgeon at Washington University School of Medicine in St. Louis who also specializes in physiatry, the nonsurgical treatment and rehabilitation of conditions such as arthritis.

Knee Osteoarthritis Can Affect More Than Mobility

The effects of osteoarthritis can extend well beyond pain in the joint. Difficulty moving can result in missed work and lost income. It can also discourage people from being physically active, which may increase their risk of chronic conditions including heart disease, cancer and diabetes.

Osteoarthritis is also extremely common. More than 30 million adults in the U.S. have some form of the condition, and the knee is the joint most frequently affected. Although osteoarthritis is often associated with older age, roughly half of cases occur among people who are still of working age.

"Having weak leg muscles and being overweight or obese increases a person's risk for knee osteoarthritis," Cheng said. "Women, older adults, people with a prior knee injury and those with a family history of osteoarthritis are also more likely to have the condition."

Lifestyle Changes Can Help Ease Knee Pain

People who already have osteoarthritis have several options for managing pain and mobility problems. Healthy habits, along with medical treatments when needed, may also help slow the condition from getting worse.

"Eating more plants and less processed or sugary food reduces inflammation in the body, which can reduce pain from osteoarthritis in all joints," Cheng said. "Other common treatments for knee osteoarthritis include strengthening the thigh muscles, using knee braces, taking anti-inflammatory medications, getting cortisone and other injections, and sometimes having knee replacement surgery."

Health care providers can work with patients to develop individualized strategies for managing osteoarthritis. They can also connect people with programs and other resources that can make it easier to begin healthy changes and maintain them over time.

Small improvements can have a surprisingly large effect. Cheng noted that for a person who is overweight, losing 10 pounds can reduce the stress placed on the knees by 40 pounds with every step. That reduction in pressure can significantly ease joint pain.

Exercise and Healthy Weight May Lower Risk

Many of the strategies used to manage osteoarthritis may also help reduce the chances of developing it.

Regular physical activity is one of them. Despite the common belief that running damages the knees, running can be part of an active lifestyle aimed at lowering osteoarthritis risk. Maintaining a healthy weight can also reduce strain on the joints.

Diet matters as well. A healthy eating pattern rich in whole grains, fruits and vegetables, while limiting processed and refined foods, can support overall health and may help protect against osteoarthritis.

Family History Does Not Determine Your Future

Osteoarthritis differs from diseases such as cancer and heart disease, but its effects on health, well-being and quality of life can still be substantial. Millions of people live with the condition, yet there are practical steps individuals can take to reduce their own risk and potentially help protect the health of their families.

"Some people think that because a parent or grandparent had osteoarthritis, they will develop it too," Cheng said. "And while it's true that osteoarthritis can run in families, it doesn't mean there's nothing a person can do to successfully lower their risk of developing it."

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