Michael Huang, MD
When it comes to musculoskeletal injections, there are more choices than ever before. Cortisone (corticosteroid) injections are probably the most commonly performed and, most likely, what comes to mind when someone mentions an injection. But even within this category of “cortisone” there are multiple types. Then there are the viscosupplement (aka rooster comb) injections. And beyond those, there are biologic injections that can be administered. So, let’s dig in and see what these injections are all about.
Let us begin with cortisone or corticosteroid injections. These are all steroid injections. As we have discussed in prior blog posts, there are a lot of myths and facts. But basically, if you have a really inflamed joint, there probably isn’t a better choice than an injection of cortisone. If the knee is swollen, hot, and painful, an injection of cortisone can help in a matter of a day. There are many versions of cortisone: Depo-Medrol (Methylprednisolone), Kenalog (triamcinolone acetonide), Celestone (Betamethasone) to name a few. Any and all of these can be effective. I have some patients that respond better to one than another, so if you do not have the response you want, next time try another. More information can be found in our prior blog here.
Viscosupplementation describes a group of injections that are designed to lubricate the joint. If you look at all of brands available, they all contain hyaluronic acid (HA). The difference between brands is the way they package these HA molecule and the number of times it is delivered to the joint. Some brand names include: Synvisc, Hyalgan, GelOne, Euflexxa, Monovisc, Orthovisc. Different brands are made by different companies and some carry multiple lines. For instance, Synvisc is a series of three injections placed one week apart in the same joint. Synvisc One is a single injection. These injections can be helpful to the knee and some patients respond wonderfully to them, but they will still only be temporarily effective as the HA does breakdown over time. Most insurance companies will approve these once every 6 months. It is interesting to note that these injections are only approved for usage in the knee joint in the USA while in other countries, they can be injected into almost any joint. Another important thing to note is that some insurance companies have stopped authorizing these injections altogether. At the time of this blog, Blue Cross and Kaiser, have stopped paying for these injections for their patient members.
I have many patients ask or undergo Prolotherapy, so let’s discuss that next. I do not perform this type of injection and did not encounter this for many years. The definition of prolotherapy is “any substance that promotes growth of normal cells, tissues, or organs”. After searching and searching, I am still not certain exactly what is injected. Some of these injections are dextrose (sugar) which is supposed to cause growth factor production. I cannot find any good scientific articles that suggest this happens in a joint. Sometimes, prolotherapy injections include dextrose in combination with phenol. Recall from your chemistry class that phenol is a compound that is acidic and often included in household cleaners. At any rate, I also cannot find any convincing data that suggests that phenol related joint injections are helpful. These injections are also being performed for soft tissue disease (tendon and ligament damage). Mayo clinic has withheld judgement of these injections as they have not had any rigorous placebo controlled studies. If you are considering these type of injections, please find out exactly what is being injected and why.
Biologic injections are a category that include cellular or growth factor injections. This category is very broad and deserves its own blog. But briefly, a patient could have an injection of platelet rich plasma (a concentrated injection of their own platelets) in an area of damage. Some patients are getting injections of amniotic fluid which is supposedly chock-full of growth factors. Other patients are getting “stem cells” which may come from their bodies or could be obtained from another source (typically umbilical cord). At any rate, we have put some information out there on these injections and you can find that here. These category of injections are all investigational and very difficult to discuss scientifically because there are so many types of injections and hard core data is lacking thus far. So, stay tuned an check back in. We will update you as this evolves.