PATIENT GUIDE
Knee injections explained.
Steroid, viscosupplement, platelet-rich plasma (PRP) and hydrogel injections have different evidence, aims and limitations. This guide helps you prepare for an informed discussion.
What an injection can—and cannot—do.
A knee injection may be considered to reduce symptoms and support movement or rehabilitation. It does not reverse established arthritis, regrow cartilage or guarantee that surgery will be avoided. The most suitable option depends on the diagnosis, severity of symptoms, examination findings, imaging, previous treatment and your wider health.
THE IMPORTANT DISTINCTION
Symptom relief is different from curing arthritis.
Some injections may provide a period of symptom relief for selected patients. A temporary improvement does not mean that the underlying arthritis has been cured.
OPTION 01
Corticosteroid injection
A corticosteroid injection is intended to reduce inflammation and pain. NICE advises that it may be considered when other medicines are ineffective or unsuitable, or to help someone participate in therapeutic exercise. NICE describes the expected benefit as short term, typically around 2 to 10 weeks.
Possible disadvantages include a temporary flare in pain, changes in blood glucose, bleeding, skin or fatty-tissue changes and, rarely, infection. Repeated injections require careful consideration.
OPTION 02
Viscosupplement injection
Viscosupplementation places a hyaluronic-acid preparation into the knee joint. It is sometimes described as a lubricant injection. NICE recommends that intra-articular hyaluronan should not be offered for osteoarthritis because the evidence has not shown consistent benefit across the wider patient population. It is also not a cure for arthritis.
Why might it still be discussed privately?
Some carefully selected patients seek this treatment through self-pay or private insurance and may experience temporary symptomatic relief, sometimes for several months after a single injection. Response is variable and cannot be predicted or guaranteed. The NICE recommendation, uncertainty in the evidence, cost, alternatives and your individual circumstances should all be discussed before deciding.
OPTION 03
Platelet-rich plasma (PRP)
PRP is prepared from a sample of your own blood and contains a concentrated mixture of platelets. It is offered by some private providers for knee symptoms. Preparation methods and treatment protocols vary, and the evidence is still developing. PRP should not be presented as a way to regrow cartilage or cure osteoarthritis.
If PRP is being considered, useful questions include what diagnosis is being treated, what preparation is used, how many injections are proposed, the total cost and what outcome would count as a worthwhile response.
OPTION 04
Arthrosamid® hydrogel
Arthrosamid is a non-biodegradable hydrogel injected into the knee joint for symptomatic osteoarthritis. NICE considered the technology for possible guidance but did not select it because the evidence was insufficient for a health technology evaluation. That is different from a NICE recommendation supporting routine use.
It may be available privately following assessment and informed consent. Discussion should include the available evidence, uncertainties, potential risks, cost and established alternatives.
Questions to ask at your assessment.
What is causing my symptoms?Confirming the diagnosis matters before choosing an injection.
What benefit is realistic?Ask about likely duration, uncertainty and what happens if it does not help.
What are the alternatives?Exercise, weight management, medicines, activity changes and surgery may also be relevant.
Sources and review information
Written for patient education and reviewed by Mr Muhammad Umar, Consultant Trauma & Orthopaedic Surgeon. Last reviewed September 2026. Sources: NICE NG226: Osteoarthritis in over 16s, NICE topic information: Arthrosamid, and NHS osteoarthritis treatment guidance.
PERSONALISED ADVICE
Discuss the options for your knee.
An assessment can clarify the likely cause of your symptoms and whether an injection, rehabilitation or another treatment is appropriate.