Knee Injections for Osteoarthritis: Comparing the Options
8 min read · By Dr. Arvin Yarollahi
Several types of injection are used in the management of knee osteoarthritis. They work by different mechanisms, have different evidence bases, and suit different situations. There is no single option that is right for everyone, and the choice depends on the individual case.
This article is educational. It describes the main types of knee injection, what studies have reported about each, and the situations in which each may be considered. Whether any of them is suitable for you is determined in consultation, following assessment of your knee pain and osteoarthritis.
Corticosteroid injections
Corticosteroid injections deliver an anti-inflammatory steroid directly into the knee joint. They act by reducing inflammation in the joint lining, which may ease pain and swelling during a flare.
Usually a single injection is given. Trials generally show benefit in the first weeks, which tends to diminish by around six months. Because of concerns about the effect of repeated steroid exposure on joint tissue, repeated use is approached cautiously and spaced out.
Corticosteroid may be considered for short-term relief of a painful, inflamed flare, for example to allow a patient to engage with physiotherapy.
Hyaluronic acid injections
Hyaluronic acid injections, also called viscosupplementation, introduce a gel similar to a component of natural joint fluid. The aim is to improve lubrication and shock absorption within the knee.
Depending on the product, a course may be a single injection or between three and five injections given a week apart, and courses may be repeated. The evidence is mixed: some studies have reported modest improvements in pain, while others have found little difference from placebo, and guidance from different clinical bodies varies.
Hyaluronic acid may be considered for some patients with mild to moderate knee osteoarthritis, depending on the guidance followed and the individual case.
PRP (platelet-rich plasma)
PRP is prepared from a small sample of the patient's own blood, which is processed to concentrate the platelets and their growth factors before being injected into the knee. Because it is autologous, there is no foreign material involved. You can read more about our PRP therapy protocol.
PRP is often given as one to three injections, and may be repeated. Studies have reported effects lasting up to around 12 months in some patients. The evidence base is strongest in mild to moderate osteoarthritis, while results in advanced disease are less consistent. Preparation methods vary between clinics, which makes studies harder to compare.
PRP may be considered for patients with mild to moderate knee osteoarthritis who prefer an option derived from their own blood. Results vary between individuals.
Arthrosamid®
Arthrosamid®, a non-biodegradable injectable polyacrylamide hydrogel, is a CE-marked medical device used in the management of symptomatic knee osteoarthritis. It is administered as a clinical procedure performed by a doctor following medical assessment. More detail is available on our Arthrosamid® knee injection page.
The hydrogel is reported to integrate into the synovial tissue lining the joint, where it is thought to support the cushioning of the knee. It is given as a single intra-articular injection, and studies have reported follow-up out to five years.
It has limitations that should be weighed carefully. Arthrosamid® is permanent and cannot be removed once injected. A proportion of patients do not respond, and long-term data, while extending to several years, remain more limited than for older options. It is used in the knee only.
Arthrosamid® may be considered for adults with symptomatic knee osteoarthritis following medical assessment, where other measures have not provided enough relief.
Comparison at a glance
| Treatment | What it is | Number of injections | Duration reported in studies | Typically considered for |
|---|---|---|---|---|
| Corticosteroid | Anti-inflammatory steroid injection | Usually one; repeated use approached cautiously | Benefit in the first weeks, generally diminishing by six months | Short-term relief of a painful flare |
| Hyaluronic acid | Viscosupplementation with a lubricating gel | One to five, depending on the product; may be repeated | Evidence is mixed; reported duration varies | Mild to moderate osteoarthritis, where guidance supports it |
| PRP (platelet-rich plasma) | Concentrate prepared from the patient's own blood | Often one to three; may be repeated | Studies have reported effects up to 12 months in some patients | Mild to moderate osteoarthritis |
| Arthrosamid® | Non-biodegradable injectable polyacrylamide hydrogel | Single injection | Studies have reported follow-up out to five years | Symptomatic knee osteoarthritis after medical assessment |
Durations are those reported in studies and vary widely between individuals. They are not a prediction of what any one patient will experience.
What determines which option is appropriate
The choice between these injections depends on several factors: the severity of the osteoarthritis, the treatments already tried and how well they worked, imaging findings, the patient's goals and activity levels, and an individual medical assessment. Two patients with similar symptoms may be advised differently.
Risks and contraindications
All intra-articular injections carry common risks, including temporary pain and swelling at the injection site and, rarely, infection. Each option also has its own contraindications, such as active infection in or around the knee, and specific considerations that are reviewed before any treatment is offered.
Deciding on the right approach
Rather than choosing an injection in advance, the most useful step is a consultation in which your history, imaging and goals can be reviewed together. That is where suitability for any of these options is determined.
Dr. Arvin Yarollahi · NICA 40505
This content is informative. Results may vary between patients and treatment requires prior medical assessment.
Ready to find out if you are a candidate for treatment? Book a free video consultation with Dr. Arvin Yarollahi.
Medically reviewed by Dr. Arvin Yarollahi, Orthopaedic and Sports Medicine Specialist. Last reviewed .
Dr. Arvin Yarollahi
Founder & Medical Director, CellOrtho
Specialist in orthopaedics, sports medicine and regenerative medicine. Licensed in Sweden, the UK and Spain.
