What is hyaluronic acid?
Hyaluronic acid is used to treat osteoarthritis, a condition that affects the joints. It may be used to treat osteoarthritis of the knee. It is not used as a treatment for rheumatoid arthritis.
In a normal joint a layer of cartilage or gristle covers the ends of the bones. Cartilage helps the joint move smoothly and cushions the ends of the bones. In osteoarthritis cartilage breaks down and becomes thin. This leaves the ends of the bones unprotected and the joint loses its ability to move smoothly.
Hyaluronic acid is found naturally in joints and other parts of the body. In the joint it is found in the cartilage and the synovial fluid that lubricate the joints to keep them working smoothly.
In people with osteoarthritis the hyaluronic acid gets thinner and it is no longer able to protect the joint. Hyaluronic acid injections into affected joints may be offered to people with osteoarthritis of the knee if other treatments have not worked or are unsuitable.
Emerging evidence indicates that the effect of hyaluronic acid could be smaller than previously reported.
What benefit can you expect from your treatment?
A 2022 review of the clinical trials of hyaluronic acid demonstrated that hyaluronic acid injections may lead to a small reduction in knee osteoarthritis pain. However, this reduction in pain was not considered clinically important. There was also evidence that injection of hyaluronic acid is associated with an increased risk of serious adverse effects.
How is hyaluronic acid given?
Your doctor will inject the hyaluronic acid directly into the knee joint. Local anaesthetic is sometimes used before the injection. Injections may be given once a week for three weeks or a single injection depending on the product/brand that your doctor recommends.
Can other medicines be taken with hyaluronic acid?
Hyaluronic acid may be used with other arthritis medicines including:
- steroid medicines such as prednisolone or cortisone injections into the joint
- anti-inflammatory medicines (NSAIDs) such as naproxen (Naprosyn) or ibuprofen (Brufen, Nurofen)
- simple pain relieving medicines such as paracetamol.
There are separate information sheets for the medicines mentioned above.
Are there any side effects?
Most side effects of hyaluronic acid are limited to the site of injection, some may be serious. Tell your doctor if you are concerned about possible side effects.
Most common possible side effects:
Local side effects may include:
- redness and tenderness at the site of the injection
- increased stiffness, swelling or warmth (inflammation) lasting 24 to 48 hours following the injection.
These local reactions may be treated by resting and applying ice to the injected area or by simple pain relievers.
Less common or rare possible side effects:
- Allergy including rashes, hives, itching, flushing and swelling of the face, tongue or throat, chest tightness and shortness of breath. If you experience any of these symptoms, contact your doctor straight away.
- Less commonly a joint may become severely inflamed after injection. This may be due to acute arthritis from crystals in the joint. Very rarely an infection in the joint may develop after the injection. If the pain and swelling in the joint that was injected increases a great deal or the joint becomes red and hot contact your doctor quickly.
- Other side effects that have been observed include headache, muscle pain, nausea, sore throat and flu-like symptoms.
What other precautions are necessary?
After the injection
It is recommended that strenuous activity (e.g., high impact sport such as jogging or tennis) or prolonged weight-bearing activities are avoided for about 48 hours after the injection.
Hyaluronic acid injections will not be given if you have an infection in your joint or a skin disease or infection around the area where the injection will be given.
- Hyaluronic acid injections will not be given if you have circulatory problems in your legs.
- Tell your doctor if you have significant swelling or blood clots in your legs.
- Hyaluronic acid injections will not be given if you have had a prior allergic reaction to hyaluronan-based products.
- Tell your doctor if you are allergic to products from birds such as feathers, eggs and poultry.
Use with other medicines
- You should tell all your doctors about all medicines you are taking or plan to take especially blood-thinning drugs such as warfarin. This includes over the counter, herbal or naturopathic medicines.
- You should also mention your treatment when you see other health professionals.
Use in pregnancy and breastfeeding
- Hyaluronic acid has not been tested in pregnant women or women who are breastfeeding.
- It is important to tell your doctor if you are or intend to become pregnant or if you are breastfeeding.
Important things to remember:
- You should tell your doctor if pain and swelling in the joint increases following the injection.
- You should tell your doctor if your joint becomes red and hot following the injection.
For more information see the Hyaluronic acid – printable information sheet.This Information Sheet has been prepared using materials obtained from various sources which have been reviewed by the Australian Rheumatology Association (ARA). It contains general information only and does not contain a complete or definitive statement of all possible uses, actions, precautions, side effects or interactions of the medicines referenced. This information is not intended as medical advice for individual conditions nor for making an individual assessment of the risks and benefits of taking a particular medicine. Decisions regarding the assessment and treatment of patients are the sole responsibility of the treating medical professional, exercising their own clinical judgment and taking into account all of the circumstances and the medical history of the individual patient. ARA has used all reasonable endeavours to ensure the information on which this Information Sheet is based is accurate and up to date. However, the ARA accepts no responsibility or liability for the accuracy, currency, reliability and/or completeness of the information contained in this Information Sheet. To the maximum extent permitted by law, the ARA expressly disclaims any liability for any injury, loss, harm or damage arising from or in connection with use of and reliance on the information contained in this Information Sheet. This information sheet is copyright and may be reproduced in its entirety but may not be altered without prior written permission from the ARA. Page updated October 2023
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