Q: I am seeing a physiotherapist for my shoulder problem (adhesive capsulitis) and I'm doing pretty well. I was looking on the Internet and saw you can get the same injections to the shoulder as they say work for the knee. It's not a steroid injection but something else.

A: You might be thinking of hyaluronic acid, a substance that is present in the fluid structure outside, around, and between cells. It is a thick substance that is a normal part of the matrix that makes up cartilage.. It's found in the synovial fluid that lines and lubricates the joints. It is also the protective coating around each cartilage cell.

Hyaluronic acid has the ability to suck up and water needed to cushion joints from the shear stresses and compression they are subjected to. It seems to have many roles. Besides remaining elastic under high shear forces, it also makes it possible for the joint to withstand the heat that develops within the joint even with low shear stress.

Hyaluronic acid can store mechanical energy for release later when needed. It bathes the cartilage cells with fluid and keeps them nourished. It even has antiinflammatory properties to reduce joint inflammation and an ability to reduce pain -- or at least the perception of pain.

There was a recent study in Taiwan comparing the use of physiotherapy (PT) alone with PT plus hyaluronic acid. Patients were randomly placed in one of two groups: group one received the HA injections along with physiotherapy. Group two only went to physiotherapy and did NOT get the injections.

Neither one was more effective than the other in reducing pain, improving motion, or restoring function. The results were equal between the two groups. If this is the case, then the added expense of the injections may not be needed for this condition.

There were some shortcomings in this study though. So before the recommendation to drop the use of hyaluronic acid for shoulder adhesive capsulitis is made, more research is needed to settle some of the questions left unanswered in this study. For example, they did not compare patients receiving injection only to these other two groups.

Fluoroscopy or ultrasound was not used to guide the injections, so it's possible more accurate injection technique might make a difference. And different stages of adhesive capsulitis may respond differently to treatment making hyaluronic acid a time-specific treatment. And finally, long term results (six months to several years later) should be investigated.

Reference: Lin-Fen Hsieh, MD, et al. Addition of Intra-Articular Hyaluronate Injection to Physiotherapy Program Produces No Extra Benefits in Patients with Adhesive Capsulitis of the Shoulder: A Randomized Controlled Trial. In Archives of Physical Medicine and Rehabilitation. June 2012. Vol. 93. No. 6. Pp. 957-964.

The Cambridge Physiotherapy provides services for physiotherapy in Cambridge, Galt, and Preston.