What Accounts for the Surge In Knee Arthritis?

Osteoarthritis of the knee will affect at least half of people in their lifetime, and accounts for the majority of the more than 700,000 knee replacements in the U.S. each year.

Often thought of as an older person’s affliction, in fact nearly half of adults with osteoarthritis are under age 65. Even more surprising, the rate of osteoarthritis of the knee has doubled since the middle of the 20th Century. This is according to a recent study published in the Proceedings of the National Academy of Sciences (PNAS), and your orthopedic surgeons in Jupiter, Florida, at The Medical Group of South Florida, have seen evidence to support this finding.

The interesting feature of this study, conducted at Harvard University, is that researchers didn’t just limit themselves to current sufferers. They examined skeletons from prehistoric times to the present. They found that until about the middle of the 20th Century, skeletons showed similar rates of osteoarthritis, from about 6 to 8 percent of those studied. After 1976, the prevalence jumped to 16 percent.

The question the study wasn’t able to answer is why?

Until this study, most cases of knee osteoarthritis attributed to the “wear and tear” of aging, compounded by lengthening lifespans, and to the rising prevalence of obesity among the population. Because it places extra stress on the joints and contributes to inflammation throughout the body, obesity is a recognized risk factor for osteoarthritis. But where possible, the researchers controlled for obesity, and found this couldn’t explain the spike.

Ian Wallace, a paleoanthropologist at Harvard who participated in the study, told Newsweek, “It points to this mysterious conclusion: A lot of cases of osteoarthritis, which we thought might be inevitable, may be preventable . . . and are due to unknown factors.”

“Our analyses contradict the view that the recent surge in knee osteoarthritis occurred simply because people live longer and are more commonly obese,” the study authors wrote in PNAS. “Instead, our results highlight the need to study additional, likely preventable risk factors that have become ubiquitous within the last half-century.”

Suggestions regarding possible causes include walking on hard pavement (which our ancestors didn’t do); inactivity (earlier humans were far more active than we tend to be); injury; and even wearing high-heels (at least one study supports this theory). Inflammation is also a prime suspect. Obesity contributes to inflammation, as does stress and poor diet. The rise of processed foods in the latter half of the 20th Century would seem to support this hypothesis, because such foods are known to contribute to inflammation throughout the body.

As noted above, the study authors concluded that many of the causes of arthritis may be preventable, and your orthopedic surgeons at MGSFL concur. The most important avenue to combat knee and other types of osteoarthritis is activity, the more strenuous, the better.

“If you were alive 100 years ago, you walked more, you were much more active,” Dr. Jordan Metzl, a sports medicine physician at New York’s Hospital for Special Surgery, told CBS This Morning.

To reduce or even reverse symptoms, he recommends such muscle-strengthening exercises as squats and lunges, a recommendation that has been supported by much recent research.

“We want them to be very active. When they get arthritis I get them started on exercise, strengthening,” he said.

We can help you devise strategies to minimize and even relieve the osteoarthritis pain you’re experiencing. Please contact us for concrete solutions.