For anyone thinking of having Synvisc, or some other artificial lubricant that uses hyaluronic acid, injected into their decaying knee joints, there’s a new study out that will give you pause.
Apparently the shots have little effect on pain and none on function. And that’s the good news.
The bad news is the procedure may lead to cardiovascular and gastrointestinal problems.
Products such as Synvisc treat bad knees through viscosupplementation. In unhealthy or diseased joints, the synovial fluid becomes thin and watery, less capable of effectively doing its job (healthy fluid has the consistency of egg whites and both lubricates the knee joint and cushions it from impacts).
Viscosupplementation injections (approved by the FDA in 1997) are intended to artificially boost the viscosity and performance of your ailing synovial fluid. The cost can be more than $1,800 (based on 2006 prices), according to this article.
Here are some details about the study (here’s another article that’s a bit more granular about the results):
* It was a meta-analysis, which means that no new research was conducted. Rather, the conclusions and methodologies of existing studies were examined. The findings of such broad, sweeping meta-studies are typically more powerful because of their much greater reach (in this case, 89 clinicial trials and more than 12,600 participants).
* A weakness was the poor quality of many trials. Also, some studies were unpublished (thus not vigorously vetted) and funded by pharmaceutical companies. The funding point, though, makes it likely that the results overstated the efficacy of viscosupplementation, if anything.
* 18 large-scale trials with 5,094 subjects found the injections made so little difference for pain as to be “clinically irrelevant.”
Okay, now my 2 cents: As I’ve said before, my reading of message boards (which I did a lot of when I was trying to fix my own knees) led me to conclude that about half of Synvisc takers claim an improvement, while half say the shots worsened their condition or hurt a lot or did nothing -- and unfortunately, beforehand you can’t tell which group you’ll be in. And even if you get the improvement, it’s only temporary, wearing off in as little as 4 weeks, it appears.
I know a shot seems simple. I know we’re frequently conditioned, when in chronic pain, to look to a deft surgeon’s hand or the miracle of 21st century medical technology. But just be careful. Often there are no good shortcuts to fixing a hard problem.