Joanne M. Jordan, MD, director of the Thurston Arthritis Research Center at the University of North Carolina at Chapel Hill agrees. Dr. Jordan, who has done population studies on race and osteoarthritis, says that many patients who have implants as a result of OA also have other chronic conditions. Dr. Jordan was not involved in the study.

Osteoarthritis is by far the most common reason for [joint replacement] surgeries, and frequently OA exists in conjunction with other serious illnesses like diabetes, heart disease and obesity. So when we see this many people with artificial joints, we need to be aware of the [number] of these people because of the medical care they may need in the future,” Dr. Jordan explains.

Another factor that might also burden the healthcare system is that one joint replacement can lead to another, for a couple of reasons. Hip and knee replacements can last a long time, but sometimes they wear out or another problem develops (such as loosening, dislocation or infection of the implant) and the patient needs a second surgery, called a revision. The younger the patients are when they have the first surgery and the longer they live after, means more revision procedures are likely.

In addition, Dr. Jordan says, “When you get a knee or hip replacement, your body’s whole biomechanics change, and it’s not uncommon for someone who has one joint replacement to need one on the other side or to have a knee replaced and then need a hip

These new data are important, she says. It impacts the health care system, and that’s why we need to know about it.”

These new statistics are also a wake-up call, says Dr. Jordan, a reminder that the medical community is failing to control OA and treat it adequately. “What would be ideal is if we would need these procedures less often by taking care of, preventing or even curing OA – the disease that causes joint failure in the first place,” she says.

“For the appropriate patients having significant disability and pain from OA in their knee and hip, [joint replacement surgery] is an effective intervention that can help, and we need to make sure those who need it get it,” she says. “But we also need to recognize the demand for this is going up because of an explosion of OA, due in part to obesity, inactivity and other things like joint injuries.”