A small study recently reported that an oral formulation of hyaluronic acid called Hyal-Joint improved knee arthritis pain by up to 50 percent, but was still not better than a placebo. Hyaluronic acid has long been injected into arthritic areas. The novelty of the drug is that it can be taken orally, and our studies have shown that it can be absorbed, said Dr. Daniel Martinez, a researcher at the drug’s manufacturer. Hyal-Joint is available in the United States and Europe: marketed as a nutritional supplement, Bioberica has yet to prove how it works. Dr. Martinez and his colleagues studied Hyal-Joint in 70 adults with moderate to severe osteoarthritis of the knee (Kellgren-Lawrence Criteria Classification IIC Grade III) who had transverse or longitudinal synovial effusion (greater than 4 mm in the suprapatellar crypt). The team randomly assigned half of these patients to receive Hyal-Joint 80 mg daily and the other half to receive placebo for three months. They measured synovial effusion in the suprapatellar saphenous fossa using a high-frequency linear array of ultrasound. They measured pain intensity using a Huskisson visual analog scale. At the World Congress on Osteoarthritis in San Diego on Friday, the researchers said the mean synovial fluid accumulation was similar in both groups at baseline (6.85 mm in the Hyal-Joint group and 6.16 mm in the placebo group). Synovial fluid decreased to 2.72 mm in the Hyal-Joint group and 3.15 mm in the placebo group. Pain intensity was at the same level in both groups at the beginning (6.4 in the Hyal-Joint group and 6.5 in the placebo group). However, at week 9, pain was reduced by 50% from baseline in the Hyal-Joint group and by 32% in the placebo group. The difference between the placebo and Hyal-Joint groups was clinically significant but not statistically significant, Dr. Martinez said. Dr. Sharon L. Kolasinski, a rheumatologist at Penn State University who was independent of the product and the study, commented that the study may have been too small and therefore did not show statistical significance for Hyal-Joint as a superior treatment. In addition, she said, she found the study very interesting because the researchers measured actual changes in synovial fluid, not just subjective changes in pain. Further work needs to be done. Dr. Martinez said Hyal-Joint was statistically superior to 500 mg of acetaminophen in previous retrospective studies.