Regenerative & pain
Do Hyaluronic Acid Injections Help Knee Arthritis?
Hyaluronic acid injections are widely offered for knee osteoarthritis. Large placebo-controlled trials found only a small average benefit, and guidelines disagree on whether to use them.
Short answer
Usually only a little, if at all. A 2026 review of placebo-controlled trials found that hyaluronic acid injections lowered knee osteoarthritis pain by about 2 mm on a 100 mm scale at 3 months, a difference the authors call clinically irrelevant (Pisaniello et al., 2026). The AAOS 2021 guideline recommends against routine use, while some other guidelines allow it for selected patients (Pisaniello et al., 2026). Medicare coverage, where it exists, is limited to people who have tried other options first (Palmetto GBA, 2022).
What this means
Hyaluronic acid is a gel-like substance found naturally in joint fluid. Products made from it are injected into the knee to add lubrication and cushioning, which is why they are also called viscosupplements. Osteoarthritis is wear-related change in the joint, and in the knee it often shows up as pain with walking, stairs and prolonged standing. The idea behind the injection is reasonable, but trials have not shown that it delivers much more than a saline injection does.
That does not mean no one feels better after an injection. Some people report relief, and knee pain varies from week to week. The research question is whether the product itself adds benefit beyond the effect of getting any injection, and on average the answer in large trials is a small one.
Candidacy
Hyaluronic acid injections are used for symptomatic knee osteoarthritis that has not improved enough with other approaches. They are not used for other kinds of knee pain, and they are not used if there is infection or skin disease at the injection site or a known allergy to the product (Palmetto GBA, 2022). Several guidelines that allow the injection for selected patients point to people with persistent pain, or those who cannot take anti-inflammatory pills (Pisaniello et al., 2026). Candidacy is decided after an examination and imaging, not by age or X-ray grade alone.
Clinical evaluation
A physician evaluation for knee pain should cover:
- The pain source. Osteoarthritis, a meniscus problem, tendon irritation, or pain referred from the hip or back can look alike.
- Imaging. A knee X-ray showing osteoarthritis is the usual starting point, and ultrasound or MRI are added when the picture is unclear.
- What has been tried. Exercise therapy, weight management, anti-inflammatory medication and prior injections, and how each worked.
- Medical history. Blood thinners, diabetes, allergies and any prior joint infection.
- Goals. What you want to get back to, and over what time frame.
Available options
Knee osteoarthritis has several mainstream options. Exercise and physical therapy, weight loss when relevant, and oral or topical anti-inflammatory medication are usual first steps. A corticosteroid injection may give some short-term relief (American Academy of Orthopaedic Surgeons, 2021). Hyaluronic acid injections sit alongside these, with the mixed guideline picture described above. Other injectables, including platelet-rich plasma, are studied separately and have their own FDA status and evidence. Which of these fits you is discussed after an evaluation.
Benefits, limitations and risks
Common reactions are injection-site discomfort, joint aching and swelling, usually settling within a day or two (Pisaniello et al., 2026). Rarer harms include septic arthritis (joint infection), severe inflammatory reactions and severe skin reactions. In 15 large placebo-controlled trials, serious adverse events occurred in 3.7% of people given hyaluronic acid and 2.5% of those given placebo (relative risk 1.49; 95% CI 1.12 to 1.98), although 11 of the 15 trials reported no serious events related to the product, so the clinical meaning is unclear (Pisaniello et al., 2026).
The practical limit is cost and expectation. Many patients pay out of pocket, a series can involve one to several visits depending on the product, and the average benefit in trials is small.
What the evidence shows
What it establishes: A systematic review of 169 trials with 21,163 participants, summarized in Australian Prescriber, based its main analysis on 24 large placebo-controlled trials (8,702 participants). It found a pain reduction of 2.0 mm on a 100 mm scale (95% CI 0.5 to 3.8) and a function improvement of 1.2 points on the 0 to 68 WOMAC scale (95% CI 0.6 to 2.0) at 3 months, and the authors describe both as clinically irrelevant (Pisaniello et al., 2026). The AAOS 2021 summary states it is not recommended for routine use in symptomatic knee osteoarthritis (American Academy of Orthopaedic Surgeons, 2021).
What it does not establish: that no individual benefits. Averages hide variation, and the guidelines disagree: OARSI, ESCEO and VA/DoD conditionally support use in some patients, while ACR/Arthritis Foundation, AAOS and NICE advise against or recommend against routine offering (Pisaniello et al., 2026). Most trials also measured outcomes at about 3 months, so they say less about longer-term effects.
Recovery and next steps
After a knee injection, many people are advised to rest the joint for a day or two and call the office for increasing redness, warmth, fever or severe pain. If you are weighing an injection, bring your X-ray reports, a list of what you have tried, and your insurance information, and ask what outcome would count as success and when you would reassess. Individual results vary.
Frequently asked questions
Does Medicare cover hyaluronic acid injections for the knee?
It depends on your region. One Medicare contractor’s policy (Palmetto GBA) covers them for knee osteoarthritis when there is X-ray evidence, at least 3 months of other therapy has not worked, and a steroid injection has failed or is not suitable. A repeat series needs at least 6 months and prior benefit. Check the policy for your area.
Is a hyaluronic acid injection better than a cortisone injection?
The guidelines summarized here do not rank them head to head. The AAOS summary says corticosteroid injections may give short-term relief and does not recommend hyaluronic acid routinely.
Is it safe?
Most reactions are mild and short. Serious reactions such as joint infection are uncommon but reported, and a large trial pool showed slightly more serious adverse events with hyaluronic acid than with placebo.
How long does a series take?
It depends on the product. Dose and number of injections follow the FDA labeling for the specific product, and your physician can explain the schedule.
References
- Pisaniello, H. L., Goh, S., & Buchbinder, R. (2026). Intra-articular hyaluronic acid (viscosupplementation) for osteoarthritis: Is it effective? Australian Prescriber, 49, 16–21. https://australianprescriber.tg.org.au/articles/intra-articular-hyaluronic-acid-viscosupplementation-for-osteoarthritis-is-it-effective.html
- Palmetto GBA. (2022). Local coverage determination: Hyaluronic acid injections for knee osteoarthritis (L39260) (effective for services on or after August 21, 2022). Centers for Medicare & Medicaid Services. https://www.cms.gov/medicare-coverage-database/view/lcd.aspx?lcdId=39260&ver=5
- American Academy of Orthopaedic Surgeons. (2021). Knee osteoarthritis clinical guidelines (summary). Medscape. https://reference.medscape.com/viewarticle/961808
Medically reviewed by Kenny Chantasi, DO, on October 7, 2026. General education only; not a substitute for individual medical advice. Individual results vary. Treatment options are discussed after a medical evaluation. In an emergency, call 911.