Injection therapies for
Osteoarthritis in the knee

Knee joint arthritis can have a tremendously negative effect on quality of life, due to pain and loss of activity. This can greatly affect general health.

Non-surgical arthritis treatment comprises weight management, exercises to strengthen muscles and regain joint movement, cross training, medication and sometimes splinting.

For the patient with knee pain who is not responding to other therapies, an injection therapy may be clinically useful.

Knee injections are generally considered safe and reliable. Depending on your condition there are four different therapies which we offer.

Corticosteroid injection

Corticosteroids are naturally occurring compounds which are strong anti-inflammatories.

Doctors use them to decrease excessive inflammation in the body when this excessive inflammation causes problems.

We can get bigger doses into a joint by injection when compared with taking the medication by mouth in tablet form.


Corticosteroids usually improve symptoms after 5-10 days, although sometimes it takes a bit longer.

Like many injections, there may be a flare of pain for a few days. The best treatment for this is to rest the injection site from anything more than activities of daily life for 5 days, and take simple pain relievers like paracetamol and/or ibuprofen.

Some people develop temporary facial flushing/red cheeks which passes after a few days.

If the injection leaks out into the tissues it can cause changes in skin colour and texture. Although these usually resolve they can be permanent. We suggest staying relatively inactive in the first 24 hours after injection.

Infection occurs very rarely but it can occur despite following all the medically correct guidelines. If this is suspected the joint needs to be washed out and treated with antibiotics.

There can be damage to soft tissue structures and to avoid this we generally do injections using ultrasound guidance.


In summary:

Take it easy after a joint or soft tissue injection. In the first day elevate the injected part, take paracetamol or Ibuprofen (as tolerated) if needed. If you develop a fever, shivers or illness with joint redness see a doctor for a check the same day.

Slowly resume normal activity according to your doctor’s recommendations, usually after 5-7 days.

It is usually perfectly fine to drive after an injection. We suggest waiting around 30 minutes, but have a backup plan in case you don’t feel confident/well to drive.

Visco supplementation

This is a group of injectable medications which mimic healthy joint fluid which is thick (viscous). Joint fluid transports an array of chemicals to the cartilage and synovial cells which line the joint cavity.

It is sold as “Durolane”, “Synvisc” and “Osteoartz” in New Zealand. It can provide short-term (4-12 week) relief from painful knee symptoms. As such it may be used for short-term relief such as prior to an active holiday in a patient with mild knee osteoarthritis.

The cost is borne by the patient as it is generally not covered by ACC or Health Insurance.

Platelet Rich Plasma (PRP)

Our blood consists of red and white blood cells, platelets and serum. Serum contains a multitude of different biologically active chemicals (cytokines). These can be both anti-inflammatory and pro-inflammatory.

PRP is obtained by centrifuging about 10mL whole blood and using the cell-free component as a joint injection. This concentrates the cytokines and has the effect of reducing pain and inflammation in affected joints. There can be a short-lived flare of pain over 2-5 days which can be managed with paracetamol and ice and activity reduction.

We ask patients to avoid anti-inflammatory (e.g. Voltaren, ibuprofen) for a week prior to this injection.

The pain reducing effects are variable but usually last 3-5 months.