Before You Get That Shot in Your Knee, Be Aware of What’s in the Needle!
If you’ve been following our series on knee pain, you already know that pills aren’t the slam-dunk they’re made out to be. Opioids barely outperform placebo for knee osteoarthritis pain. Due to their side effects, current guidelines don’t recommend them at all.
So what about injections? They’re often pitched as the next step once pills and physical therapy stop working. There are a handful of options — corticosteroids, hyaluronic acid, platelet-rich plasma (PRP), and stem cells.
Some are marketed with big promises about “repairing” or “regenerating” the joint.
Injection options and what the studies show
Corticosteroids are the old reliable, but “a steroid shot” in your joints isn’t as benign as you might think. They’re anti-inflammatory but recommended only for short-term relief during a bad flare. A 2024 systematic review found a benefit only in the first few weeks, fading out by around six weeks.
There’s a serious downside to their long-term use. A 2025 study found that just one corticosteroid injection led to significant structural damage in the knee, particularly the cartilage. Another trial found repeating injections every three months for two years didn’t beat placebo on pain —and caused more cartilage loss.
Corticosteroids may calm inflammation, but they also interfere with cartilage’s repair process, weakening it over time and speeding up osteoarthritis.
Hyaluronic acid ”gel” shots are supposed to add lubrication to the joint. A larger review found the benefit is small, likely not meaningful, and comes with a higher risk of serious side effects than placebo. Current guidelines don’t recommend these for knee osteoarthritis at all.
PRP spins down your own blood to concentrate platelets, then they’re re-injected. It runs $500–$1,500 per session — $1,000–$4,500 for a full course — and you’re paying every bit yourself, since Medicare and major insurers call it experimental and deny it outright. The evidence is mixed. Some studies find benefit, others find little to none. Clinics aren’t standardized enough to know what you’re actually getting. There's no good evidence it regrows cartilage.
Stem cellscost the most and have the least proof. Most people pay $5,000–$12,000 per protocol, sometimes up to $25,000 — entirely out of pocket, since no orthopedic stem cell therapy is FDA-approved, so insurers won’t touch it. A Cochrane review found only small, low-quality evidence of benefit, and a 2023 trial of 480 patients found stem cells performed no better than corticosteroids, which cost a fraction of the price.
Nothing shows these injections repair cartilage or slow osteoarthritis progression.
Why is the evidence such a mess? Many of these studies are small or lower-quality, and the placebo effect is unusually strong with injections. Trials without a placebo component can make the treatments look better than they are. PRP and stem cells have the added problem of no standard recipe, making it hard to compare results across studies.
What does the evidence support?
exercise (especially the kind that improves your strength and alignment)
weight loss, if that’s relevant to you
short-term use of over-the-counter anti-inflammatories.
These approaches have the strongest evidence, the fewest downsides, and none of the sticker shock!
If you’re considering an injection, remember that we don’t completely understand the mechanism behind some of them, part of what you feel afterward could be placebo, and every injection carries a small infection risk.
Human error and infection risks are factors worth considering.
I’ll never forget the time I went with my mom to see a doctor for her knee pain. He gave her steroid shots in her knees—he stuck the needle in one knee, pushed the plunger, then injected that now-contaminated needle into her other knee. I was horrified.
Before paying out of pocket for the injection approach, consider whether your money and time would be better spent on exercise and weight management.
Those benefits will extend far beyond your knee!
