Strontium ranelate has been proven effective as a treatment for osteoporosis. Now, it appears that the compound also is helpful for some knee osteoarthritis sufferers.

Medscape.com reported that researchers spent three years tracking the progress of 1,371 people diagnosed with Grade 2 or Grade 3 knee osteoarthritis. The patients received daily treatments of strontium ranelate. Many of them experienced reduced narrowing of joint space, less pain and better health. There was evidence of enhanced bone strength and cartilage growth. Researchers cautioned, however, that the benefits were “moderate” in most cases.

Patients involved in the double-blind, randomized, placebo-controlled study (called SEKOIA) began with joint space widths between 2.5 and 5 millimeters. Strontium ranelate treatments, at daily doses of 1 or 2 grams, were “associated with a significant reduction in progression of radiographic joint space width,” the researchers wrote. The therapy also reportedly had a positive effect on “overall health associated with knee osteoarthritis.”

Though allergic reactions and thrombosis sometimes result from strontium treatments, the study found little difference in such outcomes between the patients who received the therapy and those in the control group.

Knee Osteoarthritis is the most common form of arthritis and a leading cause of disability. Early treatment typically involves physical therapy and nonsteroidal anti-inflammatory drugs. Joint replacement and surgery are options in more advanced cases. The SEKIOA study offers hope that strontium ranelate might provide the first disease-modifying therapy for knee osteoarthritis.

Further research is necessary before authorities endorse widespread use of the compound. While the study detected bone and cartilage improvements, strontium ranelate is not known to reduce pain in muscles and tendons around the joints. That means the substance may not benefit some patients, including those in advanced stages of the disease. Strontium ranelate seems to have the greatest effect when it is administered before a joint sustains substantial damage.