Back Pain Doctor

Viscosupplementation (Hyaluronic Acid Injection)

Written by , Musculoskeletal GP, RACGP Fellow, Diploma in Musculoskeletal Medicine (FSEM UK).

Viscosupplementation is an injection of hyaluronic acid gel into an arthritic joint, given here under ultrasound guidance. It is widely used and the evidence for it is contested, so I offer it selectively and only for problems inside a joint.
Patient's knee supported on a bolster beside an ultrasound monitor
A knee supported on a treatment plinth beside an ultrasound monitor.

What it can help with

  • Osteoarthritis of a joint where first-line care has been tried properly
  • Situations where cortisone is unsuitable, or has already been used repeatedly
  • People who want a non-steroid injection option before considering a surgical opinion

Suitability depends on your individual diagnosis and is assessed at consultation.

Viscosupplementation means injecting a hyaluronic acid gel into an arthritic joint. It is a commonly offered joint injection, and an argued-about one. I offer it, under ultrasound guidance, for a narrow group of people, and I would rather explain why it is narrow than have it sold as more than it is.

Inside the joint only

Hyaluronic acid is meant to act on joint fluid, so it is only considered where the problem is inside a joint. Osteoarthritis is the usual reason. A ligament sprain, a tendon problem or pain from the tissues around a joint is a different problem, and an injection into the joint does not address it. An ankle sprain is a good example: ankle osteoarthritis is a joint problem and the injection can be discussed, but a sprained ankle ligament is not.

What the trials show

The best evidence is at the knee, and it is not flattering. A 2022 review in the BMJ pooled 169 randomised trials. In the 24 large trials that compared hyaluronic acid with a placebo injection, the average extra pain relief was about 2 mm on a 100 mm scale, far smaller than the difference a patient can feel, and serious adverse events were more common in the hyaluronic acid groups (Pereira, BMJ 2022). The RACGP guideline makes a conditional recommendation against it for knee osteoarthritis and a strong recommendation against it at the hip (RACGP 2018).

Elsewhere the trials are smaller. At the ankle, two reviews published in 2026 looked at the same handful of trials and reached different conclusions, one finding no difference from control injections (Tham, Foot Ankle Spec 2026) and the other a more favourable reading (Bertwistle, Foot Ankle Spec 2026).

None of that makes it worthless for everybody. Some people get useful relief, and an injection that avoids steroid has a place when cortisone has already been used several times. It does mean the decision should be made with the size of the likely benefit in view.

Where it fits

It sits in the fourth stage of the treatment pathway, after diagnosis, education and a proper strengthening program, and alongside rather than instead of them. Each condition guide reviews it separately. It can be discussed for:

knee osteoarthritis · patellofemoral arthritis · ankle osteoarthritis · shoulder osteoarthritis · thumb base osteoarthritis · rheumatoid arthritis of the foot and ankle

It is not offered at the hip, and it is not offered for tendon, ligament or nerve problems anywhere.

The alternatives

For most arthritic joints the alternatives are progressive strengthening and weight management first, then a cortisone injection or PRP depending on the joint and what has already been tried. At the knee, PRP has a stronger placebo-controlled evidence base than hyaluronic acid. A surgical opinion is the right step when the joint is no longer manageable with any of these.

No referral is required to book, and a Medicare rebate applies to the consultation.

How it works

Hyaluronic acid is a normal component of joint fluid and gives it its slippery, shock-absorbing quality. In an arthritic joint the concentration and quality of that fluid fall. The idea behind viscosupplementation is to top it up with a gel placed directly into the joint.

That is the rationale. Whether the injected gel does more than a placebo injection is the question the trials have been asking for thirty years, and the answer is less clear than the rationale suggests.

What the evidence shows

The largest analysis is a 2022 BMJ review of 169 randomised trials and more than 21,000 people with knee osteoarthritis. In the 24 large placebo-controlled trials (8,997 people) the average pain reduction over a placebo injection was about 2 mm on a 100 mm scale, well below the smallest difference patients notice, and serious adverse events were more common after the hyaluronic acid than after placebo (relative risk 1.49). The authors concluded that the findings do not support broad use. The RACGP guideline for knee and hip osteoarthritis (2018, currently being updated) makes a conditional recommendation against it at the knee and a strong recommendation against it at the hip. At the ankle, two 2026 reviews of a small number of trials disagree: one found no difference from control injections, the other read the same small literature more favourably. I do not think that makes it useless for everyone. It makes it a treatment for selected people, with modest expectations set before anything is injected.

Sources: Viscosupplementation for knee osteoarthritis: systematic review and meta-analysis (Pereira, BMJ 2022) , RACGP Guideline for the management of knee and hip osteoarthritis: intra-articular injections (2018) , Intra-articular hyaluronic acid for ankle osteoarthritis: meta-analysis of randomised trials (Tham, Foot Ankle Spec 2026) , Injectable treatments for ankle osteoarthritis: systematic review (Bertwistle, Foot Ankle Spec 2026)

What to expect

The decision comes first. We go through the diagnosis, what you have already tried, what the trials show and what it will cost, and I will tell you if I do not think it is worth doing for your joint. If we go ahead, the injection is given in rooms under ultrasound guidance so the gel is seen arriving in the joint. Depending on the product it is a single injection or a short series. A sore, swollen joint for a day or two afterwards is common. A hot, very swollen joint or a fever is not, and needs to be reported the same day. The strengthening and loading work continues alongside, because that is the part of osteoarthritis care with the strongest evidence. The consultation is billed under the time-based GP attendance items and attracts a Medicare rebate. The hyaluronic acid product itself is charged separately, and the cost is confirmed with you beforehand.

Conditions reviewed for this treatment

The evidence for a treatment can be different for every diagnosis. The conditions below reach a discussable level in our diagnosis-specific review. This is not a recommendation for you; suitability still depends on your diagnosis, what has already been tried, and the benefits, risks, costs and alternatives.

Frequently asked questions

Do you offer viscosupplementation?
Yes, selectively. It is considered for osteoarthritis inside a joint after first-line care has been tried properly, and particularly where cortisone is unsuitable or has already been used a number of times. It is not offered for sprains, tendon problems or pain coming from outside the joint.
Does it work?
On average, not much better than a placebo injection. The largest review found an average difference of about 2 mm on a 100 mm pain scale at the knee, which most people would not notice. Some people do report useful relief, and part of that is the effect of having an injection at all. That is why I set modest expectations before we start.
Is it safe?
Most reactions are a sore or swollen joint for a day or two. The 2022 BMJ review did find serious adverse events were more common than after placebo, which is one reason it is not offered routinely. Infection after any joint injection is rare but serious, so a hot, very swollen or increasingly painful joint, or a fever, should be reported the same day.
Is it better than cortisone?
They do different things. Cortisone usually works faster and is cheaper, but repeated injections into a joint have been associated with cartilage loss. Hyaluronic acid avoids the steroid, which is the main reason it is considered when cortisone has already been used repeatedly or is unsuitable.
Which joints is it used for?
Mainly the knee. At the ankle, shoulder and base of the thumb the trials are fewer, and each condition guide sets out what they show. The RACGP recommends against it at the hip, and I follow that.
Is it covered by Medicare?
The consultation is billed under the time-based GP attendance items and attracts a Medicare rebate. There is no separate Medicare rebate for the hyaluronic acid product, which is charged separately. Appointments are not bulk billed, and the full cost is confirmed with you before anything is injected.

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