Osteoporosis drug fights knee arthritis

Risedronate preserves underlying bone to delay collapse of the joint

A drug that treats brittle bones may also help people with worn out knees.

British researchers have found that high doses of risedronate (brand name Actonel), an osteoporosis drug called a bisphosphonate, can preserve the underlying bone in the knee joints of people with osteoarthritis, the wear-and-tear form of arthritis.

"It has been known for some time within the literature that bisphosphonates could actually do this but nobody actually had the data to show it and so we are the first group to be able to do that," says Christopher Buckland-Wright, the senior study investigator and a professor of radiological anatomy at King's College London. He says the treatment slows the collapse of the joint and could potentially delay the need for knee replacement surgery.

Buckland-Wright and his colleagues studied 100 people who had knee osteoarthritis and were taking inactive pills or several different doses of risedronate. Over the next two years, X-rays showed that study participants with more advanced arthritis who were taking the higher medication doses experienced a halt or reversal in the loss of underlying bone in their knee joints.

People with advanced arthritis on the low-dose risedronate or inactive pills did not show any benefit, and those with less advanced arthritis had a modest loss of bone regardless of treatment.

Buckland-Wright says the drug was well tolerated even at high doses, and there is no reason to believe that other bisphosphonates would not also be effective.

Dr. Eric Matteson, professor of medicine at the Mayo Clinic in Rochester, Minn., says this study marks a new approach to slowing the progress of arthritis. "We now have a very good tool for slowing down this process, other than weight loss."