Osteoarthritis of the Knee: Hyaluronic Acid Injections

Peter Salgo, MD: Let’s go through some of the nonsurgical treatments, first. At the end of the day, everything converges on surgery when everything else fails. That is my sense of this. When I was in medical school, we had hyaluronic acid (HA). You would inject those things. How do they work? Are they safe? Are they efficacious? What’s the deal here? Who uses it?

Richard Iorio, MD: HA is safe. Although, with the old preparations, there’s a 20% pseudoseptic reaction to the molecules. The newer molecules are safer. There are less reactions to them.

Peter Salgo, MD: Septic, meaning infections?

Richard Iorio, MD: Pseudoseptic means that it looks like sepsis but it isn’t. They have an inflammatory reaction to the injection. Usually, for injections, maybe they weren’t done in the proper place.

Paul Lachiewicz, MD: I think we’ve all used them. I think there’s a lot of controversy on the use of hyaluronic acid. I don’t think we know the absolute mechanism of action, which makes a lot of people uncomfortable. You know how penicillin works. We don’t know how this works. Rich, you mentioned safety. I can tell you that I didn’t have a reaction until about 9 months ago. And, in the same week, I had 2 patients with the modern HA have this pseudoseptic reaction. One had to come in and see my partner. Another patient went to the emergency room.

Richard Iorio, MD: It’s a painful 3 days, when that happens.

Paul Lachiewicz, MD: There was a meta-analysis in the Annals of Internal Medicine. It says that 4% of patients who get HA injection can have a complication.

Peter Salgo, MD: And 4% is high.

Paul Lachiewicz, MD: Well, that’s what I’m saying. So, it’s not 0. There’s always a risk benefit ratio in everything.

Andrew Spitzer, MD: It’s important to understand what we’re trying to achieve with hyaluronic acid. In the osteoarthritic case and the aging knee, the quality of hyaluronic acid, which is really the business end of synovial fluid, is diminished in quantity and quality. And so, the concept is to give back a more normal environment to the joint by supplementing the interior of the joint with hyaluronic acid. I think there are differentiating features between the products, but the bottom line is that’s the concept. It was initially a mechanical concept, to shock, absorb, and lubricate, which we thought was a major role of hyaluronic acid.

There’s also information out there, and good data that suggest that there may be some protective effects of the cartilage, and decreased biomarker load, and in serum and urine relative to breakdown products of type 2 cartilage. There’s even a preliminary study that suggests an increase in proteoglycan content, as a result of this. But, at the end of the day, there is certainly some data to suggest a decrease in inflammation. These products can be helpful in terms of reducing pain and improving function in patients.

As Paul suggested, there is controversy about their use. However, in most of our hands, those patients who really don’t want knee replacement or can’t have it yet are candidates for hyaluronic acid, because there’s very few other tools in our toolbox when patients get to that point.

Paul Lachiewicz, MD: Yes, I think that’s key. If a patient has end-stage cardiac disease, they’re smoking, and you don’t want to do surgery on that patient, there may be a role in treating osteoarthritic patients…

Richard Iorio, MD: I only use hyaluronic acid when all else fails and they don’t want surgery.

Peter Salgo, MD: So, it’s not a first-line drug?

Richard Iorio, MD: Absolutely not.

Paul Lachiewicz, MD: No.

Andrew Spitzer, MD: I’ll push back a little bit. If you wait until the end of the game, the likelihood of efficacy is going to be less. There’s certainly studies that suggest that efficacy is greater earlier on in the disease. So, if you wait until you really need a Hail Mary, hyaluronic acid may not provide that.

Richard Iorio, MD: Earlier on in the disease, most people get better no matter what you do. That could be a selection bias issue. This is an opinion, not fact. I think there are patient populations, within the arthritic population, that respond to HA. We just don’t know who they are.

Paul Lachiewicz, MD: Yes. I want to echo what Rich said. That goes into this use of steroids. I think there’s a wet arthritis, a wet osteoarthritis, and a dry osteoarthritis. In my hands, steroids work in those patients with an inflammatory, wet arthritis, with an infusion. I personally don’t use a lot of steroids in patients with this dry arthritis. There’s some good data in our Journal of the American Academy of Orthopedic Surgeons, from October. A prospective study looked at 100 patients with steroids. They found that the best results were in thin patients with a BMI [body mass index] of less than 30, and those with stage 1 and 2 arthritis.

Peter Salgo, MD: That’s steroids?

Paul Lachiewicz, MD: That’s steroids.

Peter Salgo, MD: Before we get off HA, let me ask 1 last question. Again, I’m going to put a button on this. Is HA something a primary care physician can do?

Richard Iorio, MD: Yes.

Andrew Spitzer, MD: Absolutely.

Paul Lachiewicz, MD: I think they can. Personally, in my neighborhood of the US, I don’t see the internist being comfortable with doing that.

Andrew Spitzer, MD: I think it goes back to something you said before. If you identify a primary care physician who’s interested in this, or a nurse practitioner, or a physician’s assistant that’s designated, aspiration and injection techniques are skills. If you practice those skills and you’re good at them, then you can do them. But, if it’s just an occasional thing, hyaluronic acid needs to get to where you what it to be. Steroids are kind of sprayed across the room. If they get in the right zip code, they’re more helpful. But, injections of hyaluronic acid, and steroids, as well, really need to get into that intra-articular space.

Richard Iorio, MD: If you place hyaluronic acid in the synovial fluid, or in the fat pad, that patient is going to be miserable.

Paul Lachiewicz, MD: Or, if you inject the steroids subcutaneously, people are not happy with that either. So, you’ve got to get into the joint. The question is, some of these HA mills (in my neighborhood) claim that they’re doing it under ultrasound.

Richard Iorio, MD: We do a lot of our injections. Our rheumatologists use ultrasound. It greatly increases the accuracy. Obviously, it’s always easier to make an injection in a joint that has an infusion. Take the fluid out with a needle, and do the injection, right?

Peter Salgo, MD: Let me see if I understand what you’re saying. It’s a crazy concept. If you want to do this, do it right? Practice?

Paul Lachiewicz, MD: Yes, can you believe that? Practice.

Peter Salgo, MD: Can you learn how to do that? If you do it wrong, that’s bad. But, if they are willing to put in the time and effort to get the skills, OK.

Paul Lachiewicz, MD: I think they should be able to do it.

Transcript edited for clarity.