How to lower or eliminate your risk of knee arthritis, according to a new study

Chances are you know someone who has had a total knee replacement. The surgery is fairly common, with about 790,000 of these procedures done annually in the United States. Most people undergo a knee replacement due to osteoarthritis in the joint, which can cause pain, swelling and less knee mobility. In fact, knee osteoarthritis is considered to have a high rate of morbidity and disability. Those most at risk of developing this painful condition include older adults, women, those who are overweight, and people who have participated in certain sports, such as soccer, tennis and long-distance running. Your genes and previous knee injuries can also play a role. But new research has found you may be able to slow the progression of knee osteoarthritis or possibly eliminate its development by strengthening your leg muscles. After performing a meta-analysis on data obtained from 5,003 patients, researchers found no link between a person’s total physical activity and an increased risk for knee osteoarthritis. Researchers then divided the patients into two groups — those who engaged in non-weight-bearing activities and those who engaged in weight-bearing sports. Here, the team discovered people engaged in weight-bearing recreational physical activity were at an increased risk for developing knee osteoarthritis if they had low levels of lower-limb muscle mass. Since larger muscle mass can protect and cushion the knee from mechanical forces inside the knee joint, the researchers expected those with stronger muscles would fare better than those with weaker ones. This finding is an exciting discovery. ‘We’ve always had this idea that muscle mass matters and helps protect joints,’ said one expert. While the study’s findings are important, there is still more to learn. For example, scientists know weight is the biggest risk factor for developing knee osteoarthritis. ‘We are not completely sure,’ said one researcher. ‘(A high) BMI is a major risk factor in developing knee osteoarthritis. If it’s so dominant, maybe the rest of the association is not the same.’ Another large study is trying to determine whether physicians can personalize their advice for patients based on a patient’s muscle mass, weight, and joint movement. Despite these uncertainties, the study offers some valuable takeaways. ‘Before engaging in a lot of weight-bearing activity, do some training in the gym to strengthen your leg muscles,’ said one researcher. And if you’re going to take up a weight-bearing activity such as running, start slowly. Miller said she counsels her patients to have a healthy body weight and keep exercising. ‘And if you learn you have osteoarthritis, don’t stop your activities,’ she said. ‘People who are sedentary have lower joint health and muscle mass and are at big risk for developing symptomatic osteoarthritis.’ So take a walk, do some wall sits, or sit in a chair and stand up 10 times without using your arms to push yourself up. Just keep moving. ‘Our rule for osteoarthritis patients is that if you have mild discomfort with an activity, but it goes away quickly, that’s fine,’ said one expert. ‘But if an activity gives you higher pain and it’s not better the next day, it may be too much for your joint right now.’