Pain relief – as we mentioned in this guide to painkillers for knees some time ago – is a complicated area. People get joint pain for very different reasons, and we all react slightly differently to the treatments available. There are also many different, complex-sounding brands and products on the market. It can all get quite confusing!
If you’re struggling with arthritis-related knee pain yourself, you’re probably aware that some of these treatments come in the form of “jabs” – injections that are designed to deliver pain relief directly into the knee joint, over an extended period. And many of them are widely available, either on the NHS or in private clinics and hospitals like Nuffield Health or Circle Health.
But what are the main types of knee injections, and how do they work against joint pain? Here’s a quick overview to help you understand the ins and outs of knee joint injections.
Corticosteroids
When people talk about injections for knee pain, this is usually what they have in mind. Corticosteroids – typically using a steroid called hydrocortisone – are the frontline treatment for injection-based pain relief for joints. The injection goes into the soft tissue around the affected joint, often with a local anaesthetic, where it helps to calm the body’s immune response to pain, reduce swelling and improve movement. The benefits typically last around 2-3 months, but sometimes up to a year. Pain and swelling may feel worse immediately after the injection, but this usually settles within a few days.
Read more about hydrocortisone injections (NHS)
Hyaluronic acid
Hyaluronic acid is a substance that’s already present in your body. It’s stored in the synovial fluid within your joints, where it helps to lubricate the mechanism of your knee. The idea of a hyaluronic injection is to introduce some of this chemical into the knee capsule, providing some of the lubricating qualities that get lost through arthritic joint damage. Studies suggest around 75% of patients see benefits, with effects typically lasting 6-12 months. The injections tend to work best for younger, more active patients. You can read how one of our own patients used them for his osteoarthritis in this case study.
More about hyaluronic acid injections (blog)
Platelet-rich plasma (PRP)
Plasma is the main component of blood (about 55% of the volume). As you may know if you’ve ever donated blood, it’s the part that carries our red and white blood cells, and also platelets – tiny cell fragments which help to stem bleeding. The idea behind PRP is to extract some of your own blood (drawn from your arm) and then process it within a centrifuge machine. This separates off the platelets and plasma, which are then injected back into your joint tissues to (theoretically) release growth factors, support healing and reduce inflammation. Does it work? It’s hard to say with certainty. Research has suggested it benefits some patients. But the findings have generally been mixed.
More about Platelet-rich plasma injections (Circle Health)
Hydrogel
A hydrogel is a semi-solid / semi-liquid substance that resembles living tissue, in that it’s soft, elastic and biocompatible (ie safe for the body), with a very high water content (in fact the water part is about 97% of the total). After injection into the knee, the gel blends into the protective synovial membrane in the joint. The theory is that this creates a kind of shock-absorbing cushion inside the knee, reducing the friction that occurs with arthritis damage. The main hydrogel on the market is a product called Arthrosamid, which the manufacturer describes as the “first and only approved injectable implant treatment decreasing joint stiffness, diminishing pain, improving the function of the knee, and enhancing your quality of life.” You can read about its claims here.
More about hydrogel injections (Nuffield Health)
Stem cell
Stem cell treatments have been around for some time, mostly for blood disorders and immune system problems. The concept here is to extract these cells from fat or bone marrow, where they are richest, then inject them back into another part of the body, where they may be able to stimulate the growth of new cells and tissues where they are most needed. It sounds ingenious, but the evidence for the treatment’s effectiveness isn’t particularly strong. A major 2025 study, published by the non-profit Cochrane network, reviewed 25 randomised trials of stem cell injections for knee osteoarthritis; their conclusions were mixed at best. “The evidence isn’t strong enough to determine whether there is any improvement in quality of life following a stem cell injection, whether cartilage regrows, or to estimate the risk of harm,” the reviewers explained. You can read more in the link below.
More about stem cell injections (The Conversation)
Neurotrophin inhibitors
This is a treatment that’s so new, it’s still in the trial phase – we examined it in some detail late last year (see link below). “LEVI-04” targets compounds called neurotrophins, which help grow and maintain nerve cells. Rather than blocking these compounds entirely, the drug “scavenges” excess neurotrophins present in chronically painful joints, helping to turn down the dial on arthritis pain. In the trials, patients given LEVI-04 reported a greater than 50% reduction in their pain score at 17 weeks. As we say, it’s early days – the UK-based company behind them is now developing a Phase III trial – but the initial results have been very encouraging.
More about neurotrophin inhibitors (blog)
Are you suffering from persistent knee pain? If so – whatever the cause – it’s important to have it properly investigated. You can do that here in the clinic by booking an appointment with us. We’ll make sure you’re seen, examined and treated as soon as possible.
