Comparison of the Efficacy of Two High-Molecular-Weight Hyaluronic Acid Products for Patients With Knee Osteoarthritis.

In Japan, hyaluronic acid (HA) is often used to treat patients with relatively mild knee osteoarthritis (OA). The use of HA in and the physique and lifestyle of the Japanese population differ from those of other populations. Therefore, clinical reports of HA from around the world must be interpreted with caution for application in Japan. We compared the clinical efficacy of two HA products, with average molecular weights of 900,000 (HA90) and 1.9 million (HA190), for Japanese patients with knee OA. There were 49 patients and 54 knees (27 patients received both HA90 and HA190 injections). We used a disease-specific/patient standing-type knee OA function evaluation scale that was developed earlier and later improved considering the uniqueness of the Japanese lifestyle. The assigned HA product was injected into the joints of patients with knee OA with Kellgren-Lawrence classification system grades I to III once a week, for 5 consecutive weeks. Effects were subjectively self-evaluated using the Japanese Knee Osteoarthritis Measure (JKOM) and a visual analog scale. The average age of the patients was 65.4 years (range, 42-88 years). Both HA products alleviated walking pain and improved JKOM scores, and symptoms continued to improve with continued injections for 6 months. The continued administration of HA90 improved general activity more than that of HA190. In contrast, HA190 improved initial pain more, but its continued administration did not contribute to improving general activity. These results suggest that it may be effective to use different HA products depending on the symptoms and conditions of patients with knee OA. [. 2022;45(1):13-18.].