Forget everything you know about osteoarthritis (OA). It isn’t just a curse of old age, brought on by joints that have simply worn out. It’s a complex disease with several subtypes, each with risk factors, biomechanical processes and potential for treatment and perhaps even prevention.

Research has led to a better understanding of distinct OA subtypes – called phenotypes – with efforts aimed at earlier diagnosis and better therapies for individual phenotypes. This new thinking was highlighted last year by the brightest minds in the field from North America and Europe during the Arthritis Foundation’s Segal North American Osteoarthritis Workshop (SNOW).

Genetics and OA

Even before you take your first breath, you might be on the path to developing arthritis, thanks in part to your body’s blueprint. So far, three genes linked to a higher risk of developing OA have been identified. Scientists are looking for others. But genetic susceptibility to OA is complex, with each individual gene that plays a role contributing only a modest amount to the susceptibility, according to John Loughlin, PhD, professor of musculoskeletal research at Newcastle University Musculoskeletal Research Group in England.

In other words, there is no one smoking gun. “There are no major impact genes for OA. Each of us is walking around with many genes predisposing us to many diseases,” says Loughlin, who is also secretary general of the Osteoarthritis Research Society International, an organization of scientists and health care professionals focused on OA prevention, treatment and education.

Currently, no interventions exist for genetic abnormalities related to OA. “The hope is that, as we identity more OA susceptibility genes, we’ll be able to develop new treatments,” Loughlin says. “It’s also hoped that we may at some point offer people risk prediction based on their genetic profile.”

Post Traumatic OA

Did you take one too many twists or tumbles on the soccer field or sprain a knee while skiing down a slope? Sport mishaps, a car accident or a bad fall can land you on the path to post-traumatic arthritis, which develops after a bad jolt to a joint.

The numbers are not reassuring. Researchers have determined that 10 to 20 years after traumatic injury to the knee – such as an ACL or meniscus tear – about 50 percent of patients will develop OA. 

Cumulatively, “12 percent of end-stage OA [with little or no cartilage left, severe joint pain and loss of function] in the hip, knee and ankle is due to injury,” notes Joseph Buckwalter, MD, professor and head of orthopaedics and rehabilitation at the University of Iowa Hospital in Iowa City. In terms of physical impairment, he adds, “The disability is equal to end-stage heart and kidney disease.”