Carol* was recently telling me about her knees.
Over the past couple of years, her knees had become "achy."
They weren't constantly uncomfortable, but they were noticeably painful when she knelt down or squatted to the floor, or when she descended stairs.
When she woke up in the mornings, her knees felt okay, and walking her dogs wasn't a problem.
After her doctor took X-rays, she was offered gel injections.
Carol shared all of this with me during a 20-minute Zoom meeting.
(This is a Strategy Session. It's an opportunity to determine if we're a good fit to work together.)
So in addition to asking me whether she was a good candidate to work with me via online coaching sessions, Carol also asked, "Will gel injections help my knees?"
While it sounds like a simple question, the answer isn't straightforward.
Here's some background information:
Inside your knees, you have fluid that reduces friction allowing smooth knee movement.
This fluid also provides cushion when you're walking, hiking, playing pickleball, gardening, jogging, skiing, etc.
One of the reasons this fluid works so well is due to an ingredient called hyaluronic acid (HA).
But when someone has knee osteoarthritis (OA), there is less HA in the fluid.
The fluid is thinner, so it doesn't work as well.
Over 30 years ago, researchers began studying the effects of injections to thicken fluid as a treatment for OA. (source)
If you have knee OA, you can find a physician who will insert HA deep inside your knees during an office visit.
These treatments are commonly called gel injections.
(My colleague Doug Kelsey, PT, PhD, has a great article about gel injections. Read it here.)
Are gel injections effective?
While gel injections have been around for awhile, the question about how effective they are persists.
Last year, research was published based on studying 5,025 people from 38 randomized control trials^. They all had knee OA and were, on average, 60 years old.
^This type of research is the gold standard for understanding treatment effectiveness.(source)
After reviewing all of the data, the researchers concluded that gel injections are "safe and effective except for minor side effects such as local pain and swelling lasting for a few days. Severe allergic reactions are extremely rare. They provide adequate pain relief and functional improvement for up to six months irrespective of a number of injections and type of preparations used." (source)
Do gel injections work for everyone with knee OA?
One important thing to note about this research is that it did not include people with severe knee OA.
Note: Knee OA is given a grade on a scale of 1 (very mild) to 4 (severe).
The above research only studied people with mild to moderate knee OA-- grades 1, 2, and 3, but not grade 4.
However, a few months ago in the journal Cartilage, a study was published that did include people with severe knee OA.
Fifty-one people (33 of whom were female) who had grade 1, 2, 3, & 4 knee OA received a single gel injection.
Effectiveness of this injection was determined by the number of weeks each person experienced benefits.
Benefits for those with relatively mild knee OA (grade 1 - 2) was roughly 14 weeks longer than it was for more severe knee OA (grade 3 - 4).
But even those with more severe knee OA experienced benefits for an average of almost 50 weeks. (source)
How long do gel injections work?
Regardless of the quality of the studies, research can not predict how long a gel injection will last for a particular person.
In the study published in Cartilage, the benefits were as short as 13 weeks and as long as 155 weeks. (source)
And there were even a few exceptions to this range.
So it is possible to get a gel injection, and not feel any benefits whatsoever.
This leads researchers to conclude that gel injections have "a limited role in the treatment of knee osteoarthritis." (source)
Is there a way to make gel injections more effective?
Dr. Kelsey and I both believe there's a reason that gel injections have a "limited role" in treating knee OA.
The fluid inside your knees is influenced by exercises and movements.
But the research cited above-- and the research on this topic, in general-- doesn't consider this.
So if you, or someone you know, is considering gel injections...
Getting a gel injection requires a very short doctor's visit.
And under most circumstances, you can receive additional injections every six months.
The right types of exercises and movements for your knees requires more time and commitment.
But we've found that they increase the success of gel injections.
So we developed a guide:
