Injections of hyaluronic acid (HA) into the knee for osteoarthritis (OA) is called viscosupplementation. This treatment is designed to restore the lubrication in the knee joint that keeps it moving freely.
There are five forms of injectable HA. The authors of this study reviewed published results of research using viscosupplementation. The goal was to see if one worked better than the others.
Of the 20 studies they found that met their criteria, five meta-analyses were available. A meta-anylsis summarizes the results of many studies combined together. The methods, differences, and outcomes for each of these five meta-analyses were presented in this article.
There was some agreement among the studies. For example, lower-molecular weight HA and higher-molecular weight forms of HA had the same results. In general, HA was effective for decreasing symptoms of knee OA such as pain, swelling, and stiffness. However, the amount of change was fairly small. There was no single product that outperformed the others.
The authors suggest more research is needed to identify which patients can benefit from HA the most. Physicians need more information to decide when the results outweigh the risks and costs in using HA for each patient.