​What it is

Osteoarthritis of the knee wears down the cartilage that cushions the joint. The joint fluid also becomes thinner and less effective as a lubricant.

Hyaluronic acid is a gel-like substance that is already present in healthy joints. An intra-articular HA injection places a medical-grade form of that gel directly into the knee joint. The aim is to improve lubrication and reduce pain with walking, stairs, and daily activity — not to replace the joint.

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Who it may help

HA injections are usually considered for people with mild to moderate knee osteoarthritis who still have pain after:

• activity modification and physiotherapy

• simple pain relief

• weight management where relevant

• sometimes a steroid injection, depending on the case

They are less likely to help if the joint is already bone-on-bone or if surgery has already been advised. Whether HA is suitable is decided after an assessment — history, examination, and usually recent X-rays.

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What to expect

During
The skin is cleaned. Local anaesthetic may be used. HA is injected into the joint space. The appointment is short; the injection itself takes only a few minutes.

After

• Rest the knee the same day; avoid long walks, squats, and strenuous exercise for 24–48 hours.

• Ice if it feels sore.

• Keep the site clean and dry for a day.

• Pain relief from HA is often gradual (days to a few weeks), not immediate like some steroid injections.

• If it helps, benefit commonly lasts a few months; a further course can be discussed later.
   

Benefits and limits 

Patients usually report less pain and easier walking. 

HA does not grow cartilage back and does not delay the need for surgery in every patient. It is one option in a plan that still includes exercise, weight, and day-to-day joint care.

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Risks

Common and usually short-lived:

• ache, warmth, or swelling in the knee for a day or two

Less common:

• a stronger flare of pain and swelling

• bruising

• allergic reaction (some products are derived from avian sources — tell us about egg or bird allergies)

Rare but serious:

• joint infection

Contact the clinic the same day if the knee becomes very hot, red, or increasingly painful, or if you develop fever.

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Fees

Injection of the knee joint typically cost around $450 -$500. The HA injection cannot be claimed under CHAS or Medisave. 

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