While women can do virtually anything men do, when it comes to the musculoskeletal disease, females continue to lag behind. Not only are women more likely to have autoimmune forms of arthritis such as rheumatoid arthritis, musculoskeletal pain syndromes such as fibromyalgia, and the brittle-bone disease osteoporosis, they are also more likely to have the most common and often debilitating musculoskeletal disease of all – osteoarthritis.

According the Centers for Disease Control and Prevention, the prevalence of knee, hip, hand and foot OA is higher in women than in men. Furthermore, women who have OA tend to suffer more than men. In a 2011 study published in the Biology of Sex Differences, researchers at the University of Iowa in Iowa City found that women with OA had significantly worse pain and more impaired function than men.

Why Women?

It’s not clear why women are more likely to be affected or more severely affected than men, but scientists believe many factors are involved.  Suspected factors include hormones; anatomic differences in women, such as weaker quadriceps muscles, which provide less support for women’s knees; differences in the joint structure, including the size and density of the bones and thickness of articular cartilage; and differences in gait patterns that may put different stresses on women’s versus men’s knees.

To better understand some of the factors that make women’s joints different from men’s, Mayo Clinic orthopaedic surgeon Mary O'Connor, MD, and her colleagues are going directly to the joints for answers.  In a study supported by the Society for Women’s Health Research, the researchers are studying tissue from Dr. O’Connor’s patients who underwent knee replacement surgery.  “My patients were gracious enough to agree to donate the fluid and tissue which we normally discard during the surgery -- bone chips, joint tissue and fluid – and my scientific partners are studying these tissues to understand if there are sex- based differences,” she says.  “In other words, are their different receptors in these tissues in women compared to men?”

At this point in the study, the group is doing lab tests. They hope to report their findings by as early as mid-2014, but Dr. O’Connor is excited that very early data suggests that they will see some differences. “This will open the path to exploring whether treatments to prevent the development of OA or to modify the progression of the disease should be sex based,” says O’Connor.

Treatment Options and Offers

Already, gender is affecting the treatments women are offered – or choose – but not necessarily in a positive way. Studies have shown that women are more likely to use complementary and alternative therapies (including mind-body treatments) alone or along with conventional treatments than men, but are less likely to choose – or even be offered – joint replacement surgery.

In a 2008 study published in the Canadian Medical Association Journal, Cornelia (Cory) Borkhoff, PhD, of the Women's College Research Institute and University of Toronto trained two people – a man and a woman – for appointments with various doctors in Canada for knee pain evaluations. Borkhoff found that orthopedic surgeons in Canada were nine times more likely to recommend knee replacement surgery to the male patient, even though both had the same level of pain, functional limitations and x-ray changes.