You are probably referring to the use of hyaluronic acid injections for the treatment of joint osteoarthritis. Hyaluronic acid is a substance naturally found in the body in small quantities. It seems to have a role in the multiplication of normal, healthy cartilage cells. Used as an injection into the joint, it is designed to rebuild the protective joint cartilage.
Fifteen years ago, the Food and Drug Administration (FDA) approved the use of an injection of hyaluronic acid for knee arthritis. This approval was based on enough studies that showed it was safe and effective for this type of use. It has been used ever since for the effective relief of (knee) arthritis pain in some carefully selected patients.
Surgeons are starting to look at the possible use of this same injection for ankle arthritis. As you have discovered, it has not yet been approved for this type of use by the FDA. Even so, studies are starting to trickle in. So far, it looks like the procedure is well tolerated by patients with very few side effects or complications. But the question arises: does it work any better than a placebo treatment?
Surgeons from the Newton-Wellesley Hospital in Massachusetts set up a study to find out. They injected one group of patients with ankle arthritis using the hyaluronic acid. A second (control) group received the placebo injection of saline solution.
Patients were carefully selected for this study with limited inclusion criteria. Adults 18 years or older who had been formally diagnosed with ankle arthritis were included. They had to be willing to stop taking all pain meds during the study. Anyone who was pregnant, diabetic, or had circulation problems was not allowed to participate. Other exclusion criteria included the use of anticoagulant medication (prevents blood clotting) and the presence of sciatica, skin rash, plantar fasciitis, or ankle sprains.
Although the treatment with hyaluronic acid for joint osteoarthritis is usually three to five injections, patients in this study were only given a single injection (of either solution). Six and again 12 weeks after the injection, they were re-evaluated. Pain, motion, and function were the main before and after measures used to assess results.
They found that patients in both groups got much better by the end of 12 weeks. But there wasn’t a significant difference between the groups to suggest one treatment was superior to the other. The equal results did show that at least for one injection, hyaluronic acid isn’t any better than a placebo treatment.
The fact that everyone improved by the end of the study could demonstrate the natural process of healing, the effect of just inserting a needle through the skin, or it could have some other unknown meaning. The power of the placebo effect (patients expect to get better so they do) must be taken into consideration.
Until there is enough evidence that hyaluronic acid is an effective treatment for ankle arthritis, it is unlikely that the use of hyaluronic acid injections for the treatment of ankle osteoarthritis will be approved any time soon.
Further studies are needed with a series of injections to see if one just isn’t enough to have an effect. It will be necessary to try different hyaluronic products commercially available and compare results. It’s possible that some formulations of the product work better than others. Different dosages need to be evaluated as well.