Nov.16, 2005 -- Higher doses of a popular osteoporosis drug may stave off joint destruction and the need for joint replacement surgery among people with painful knee osteoarthritis, according to a new study.
The research was presented at the annual meeting of the American College of Rheumatology in San Diego.
Most osteoarthritis drugs treat only pain. Attempts to find a drug that actually modifies the disease process have not been all that successful. A disease-modifying osteoarthritic drug is considered to be the Holy Grail by many rheumatologists.
Wear and Tear
Osteoarthritis, a wear-and-tear condition of joints, affects more than 21 million Americans. It affects not just cartilage (the smooth lining that covers the ends of bones where they meet to form the joint) but also eats away at the bone underneath the cartilage. Osteoarthritis most notably affects the knee and hip joints.
Actonel, a bisphosphonate drug used for osteoporosis, inhibits the cells responsible for the natural breakdown of bone. The researchers say that it may stave off bone loss in the bone located beneath the cartilage in the knee. As a result, the drug may also prevent joint destruction and the subsequent need for joint replacement surgery.
In the two-year study, people with osteoarthritis who already had a significant loss of cartilage in their knee who took 15 milligrams of Actonel per day halted bone loss underneath their knee cartilage. People in the study who took a 50-milligram-per-week dose actually put bone back on the joint, the study showed.
Preventing Joint Destruction
"If you compare the joint to the roof of a house, the tiles are the cartilage and the rafters supporting the cartilage are trabecular bone," explains researcher Christopher Buckland-Wright, MD, a professor of radiological anatomy at King's College London University. "You try to keep the roof by keeping the tiles, but ultimately the rafters will crumble and only by supporting the rafters can you maintain the roof."
Put another way, Actonel supports the rafters.
People in the study received either a dummy pill, 5 milligrams per day of Actonel, 15 milligrams per day of Actonel, or 50 milligrams once a week of Actonel. Each group comprised 300 patients.
"Higher doses of [Actonel] in postmenopausal women may delay joint destruction and the need for joint replacement surgery in patients with severe knee OA," he says.
While participants in the high-dose groups were protected against bone loss, there were no such effects among participants taking dummy pill or lower doses, the study showed.
"You save the bone, you save the cartilage," says Eric Matteson, MD, a professor of medicine at the Mayo Clinic in Rochester, Minn. "If the new findings hold up, it's a cool thing. The results look very promising."
The Importance of Weight Loss
While the new study appears promising, "the most important thing for knee osteoarthritis patients is to lose weight," stresses Elizabeth Karlson, MD, an assistant professor of medicine at Brigham and Women's Hospital in Boston.
"Weight reduction or maintaining a normal body mass index improves pain, improves function, and delays the need for joint replacement surgery," she tells WebMD.
Studies have shown thatcan reduce pain, relieve stiffness, and improve daily functioning for patients with mild to moderate knee osteoarthritis -- in some cases more effectively than drugs.