Genetic Factors Increase the Risk of Knee Pain

People whose parents have undergone total knee replacement surgery due to osteoarthritis are more than twice as likely to develop knee pain themselves, according to a recent study published in the Annals of the Rheumatic Diseases.

Australian researchers followed 186 adults who had a parent with knee replacement surgery and a control group of 186 adults whose parents had no history of knee arthritis or knee replacement surgery. Both sets of participants completed questionnaires at the beginning of the study, reporting any knee pain or history of X-rays or MRI scans. The questionnaires were repeated after two years and again after a total of 10 years.

At the two year mark, both groups were about the same, with just over half of participants reporting knee pain. However, after 10 years, knee pain was reported in 74 percent of participants whose parents had knee replacement surgery, while only 54 percent of the control group reported any knee pain.

Because knee pain can be caused by other factors such as obesity and structural abnormalities, researchers made adjustments to account for age, gender, weight, smoking history and structural problems. However, even after these adjustments were made, results showed that participants with a family history of knee arthritis were 2.2 times more likely to develop knee pain than the control group.

Lead study author, Dr. Graeme Jones of the University of Tasmania in Hobart, believes that these results strongly indicate that genetic factors play a major role in the development of osteoarthritis-related knee pain. "It was abundantly clear that genes were a strong contributor to risk of osteoarthritis but there had been limited success in finding these genes," Jones said. "Thus, a better way may be to look at mechanisms by which genes lead to arthritis and the best way of doing this was to study the adult children of people who have had knee replacements for osteoarthritis."

Jones adds that genetics can contribute to arthritis in a number of ways. "I suppose there are many mechanisms by which genes lead to arthritis - some we can help, some we can’t," says Jones. "Offspring have more pain, weigh more, are more susceptible to the effects of smoking, have weaker muscles, more splits in the cartilage and menisci and greater cartilage loss over time."

While it’s impossible to control family history of osteoarthritis, high-risk individuals can help lower their chances of developing knee pain by controlling their weight, staying physically active, avoiding injury, and not smoking. Jones also suggests medications, such as glucosamine, as a possibility for high-risk individuals (Source: Reuters).