For some people, a little. On average the evidence is MIXED. People do feel better after gel injections, but much of that relief also happens after a salt water (placebo) injection.
Guideline groups don’t agree.
US orthopedic surgeons don’t recommend gel shots for routine use. US rheumatologists, in their latest guidance, advise against them, and so does national guidance in England. An international arthritis research society supports them for some people, such as those who can’t safely take anti-inflammatory tablets.
If they help you, relief usually takes a few WEEKS to build and can last several months. They don’t regrow cartilage.
What a gel injection is
- Hyaluronic acid: a natural part of the fluid inside your knee. It makes the fluid slippery and helps it cushion the joint. In arthritis, this fluid tends to be thinner
- The shot: a gel version is injected into the knee joint. Depending on the product, you’ll have one shot or a course of up to five, spread over a few weeks. Doctors call this viscosupplementation
- The idea: topping up the joint’s natural lubricant to ease pain and stiffness
- What it can’t do: it doesn’t reverse arthritis or rebuild worn cartilage
What the research shows
- Salt water works too: in trials, people given a salt water injection often improve a lot. The gel adds only a small amount on top of that, on average. Some large reviews judged that extra benefit too small to matter to most people
- Some people respond better: a few people get clear relief, and many notice little. There’s no reliable way to tell in advance who will respond
- Milder arthritis: it may work best in early arthritis, though that isn’t proven
- Slower than a steroid shot: a cortisone shot usually works within days. Gel takes weeks to build. See cortisone shot in the knee
- Safety: pain, warmth and mild swelling in the knee for a day or two are common. Serious problems, such as infection, are rare
The AAOS OrthoInfo page on viscosupplementation puts it plainly: some patients report pain relief, but recent research hasn’t shown a significant reduction in pain or better function overall.
A gel shot won’t give you a new knee. At best, it buys you a calmer one for a few months.
How long gel injections last
- Weeks to kick in: don’t judge it in the first week. If it’s going to help, you’ll usually notice over several weeks
- Several months if it works: how long it lasts varies a lot from person to person
- Repeat courses: if a course clearly helped, it can be repeated. In the US, Medicare typically won’t pay for a repeat until at least 6 months after the last course
- If the first course did nothing: another round is unlikely to be worth it, and insurers usually won’t cover it
Cost and insurance
- In the US: Medicare and many insurers may cover gel shots for knee arthritis, but usually only after you’ve tried about 3 months of other treatment, such as exercise, physical therapy, weight management and painkillers, and a steroid shot hasn’t helped or isn’t suitable for you
- In the UK: national guidance says not to offer them, so they’re rarely available on the NHS
- Paying yourself: prices vary between clinics and products. Ask for the total for the whole course before you start
What has stronger evidence
- Strengthening exercise: recommended for everyone with knee arthritis, at every stage. Strong thigh and hip muscles take load off the joint
- Weight loss, if needed: less weight means less load on the knee with every step
- A steroid shot for a flare: better supported by guidelines than gel for short-term relief, though not as a regular schedule
If you haven’t had a proper go at a strengthening program yet, start there. See knee arthritis. If you’re weighing up other injections, see PRP injection for the knee.
Questions to ask before a gel injection
- How bad is my arthritis? Results may be better in milder knees
- How many shots, and what’s the total cost? Check with your insurer before you book
- What should I expect, and by when? Agree how you’ll judge whether it worked
- Will it affect surgery plans? If a knee replacement is on the horizon, ask how an injection fits with the timing. See when is it time for a knee replacement
- What should I do alongside it? Any good plan still includes exercise
Call your doctor today if
- The knee gets hotter, redder and more swollen after the first couple of days instead of settling
- You have a fever or chills, or feel unwell
- The pain is severe and you can’t put weight on the leg
- Your calf becomes swollen, warm or painful
Get it checked if
- Soreness after the shot lasts more than a few days
- You’ve finished a course and noticed no change after a couple of months
- You’re being offered repeat courses even though the last one didn’t help
- The knee locks, catches or gives way
A gel shot might ease your knee for a season, but strong muscles carry it for years.