There’s new hope for arthritic knees, according to a report released last fall by the American College of Rheumatology. The osteoporosis drug strontium ranelate, available in Europe but not yet approved by the U.S. Food and Drug Administration, successfully reduced the structural progression of knee osteoarthritis and may represent the first disease-modifying drug for this condition, according to Belgian researchers. In a three-year study, patients with mild-to-moderate knee osteoarthritis retained more open and more mobile joints if they took the drug. The treatment reduced the narrowing of their joints—caused by bone spurs and cysts—more than 40 percent and promises to significantly reduce the need for surgery, the researchers said. One caveat: Patients with a history of deep vein clots should not take strontium ranelate. Knee osteoarthritis affects over half of people 60 and older, many studies indicate.