What is hyaluronic acid?
Hyaluronic acid (brand names Synvisc, Osteoartz) is used to treat osteoarthritis, a condition that affects the joints. It is most commonly 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. Injections of artificial hyaluronic acid into affected joints may improve the protection.
Hyaluronic acid injections are usually offered to people with osteoarthritis of the knee if other treatments have not worked or are unsuitable.
What benefit can you expect from your treatment?
Hyaluronic acid injections help reduce the pain caused by osteoarthritis. Some patients find relief from symptoms within a few days. Full benefits usually are reached 3-5 weeks after the treatment.
The treatment may provide pain relief for up to 6 months. Response varies and the injections do not help everyone. If successful the injections can be repeated after 6 months.
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 particular product 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?
Side effects from hyaluronic acid injections are not common. Most are limited to the site of injection and do not last long. Tell your doctor if you are concerned about possible side effects.
Most common possible side effects:
Local side affects may include:
- redness and tenderness at the site of the injection
- increased stiffness, swelling or warmth inflammation (flare) 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 your doctor (including your general practitioner, rheumatologist and others) 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.
- More detailed information is available at https://rheumatology.org.au/gps/documents/ARAPregnancyPrescribingGuidanceupdateApr19.pdf
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.
The information in this sheet has been obtained from various sources and has been reviewed by the Australian Rheumatology Association. It is intended as an educational aid and does not cover all possible uses, actions, precautions, side effects, or interactions of the medicines mentioned. This information is not intended as medical advice for individual problems nor for making an individual assessment of the risks and benefits of taking a particular medicine. It can be reproduced in its entirety but cannot be altered without permission from the ARA. The NHMRC publication: How to present the evidence for consumers: preparation of consumer publications (2000) was used as a guide in developing this publication.
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