If you are living with painful, stiff joints due to osteoarthritis, you may have heard about a number of different therapies where the treatment is injected into the affected joint or area surrounding a tendon with a needle, usually by a primary care physician or rheumatologist in a medical office setting. “Patients are looking for things to help them feel better,” says Dr Lauren King, a Toronto rheumatologist and a PhD student in Clinical Epidemiology & Health Care Research.
“There are variable ways that people get information: the internet, talking to friends and family, discussing with it other health care providers that they've seen on their journey. So it’s really not uncommon to have some kind of conversation about injections with patients.” She adds that it’s important for people living with arthritis who are interested in learning more to ask questions of their health care providers. “Is this going to be effective? Is it going to help my symptoms in the short term, in the long term? Are there other treatments that are better? What are the risks of injections? What are the costs? All of these things need to be taken into account.”
Read on to get some more background about four different kinds of injection treatments for osteoarthritis.
Corticosteroid injections
What is it?
Also called glucocorticoids, a corticosteroid injection into the affected joint mimics the anti-inflammatory action of cortisol, a hormone made in our adrenal glands. It can be used to treat some inflammatory forms of arthritis as well as osteoarthritis, and is most often used in the knee joint.
Is it effective?
“Glucocorticoids are the ones with the best evidence base for helping a patient’s symptoms [compared to other injection treatments],” notes Dr King. The evidence suggests that the benefits are short-lived, she says, peaking at around the two-week mark, persisting for about six weeks and wearing off after about 12 weeks, although this can vary from person to person. “So while there is a small to moderate benefit, it is in the short term. The place of this treatment is as an adjunct treatment, where there may be a particular life event, maybe a flare and pain, maybe just a need to get over some short-term pain exacerbation to get on with an exercise program that’s going to have a greater effect in the long term.”
What are the risks or side effects?
Some research suggests that too many steroid injections may damage cartilage or weaken tendons and ligaments, leading to the recommendation of not exceeding four injections per year. Some patients feel “flushed,” after an injection, but usually it is not serious. Steroid injections may cause a rise in blood sugar, especially if you have diabetes, so talk about testing glucose levels with your doctor. Rarely, steroid injections cause changes to the skin at the injection site, such as the skin turning white due to a loss of pigment (more common in people with dark skin) or the skin turning purple, due to the loss of the fat layer below the skin.
For more information, visit the Corticosteroids section of the Arthritis Society's Anti-Inflammatory Medications page, as well as the Medication Reference Guide section on Steroid Injections.
Viscosupplementation (hyaluronan) injections
What is it?
This treatment refers to the injection of a clear, gel-like material called hyaluronan into the joint. It is used to treat OA, usually in the hip or knee. The goal is to lubricate the joint, reduce pain and allow for greater joint movement. It may be given as a one-time injection, or once weekly for up to five weeks.
Is it effective?
“American College of Rheumatology treatment guidelines actually recommend against the risk of supplementation in the hyaluronic acid,” says Dr King. “Because when you look at the studies for hyaluronic acid and individuals with OA, where we have the most data, when you restrict to the studies that are of the highest quality, it doesn't look like that there's an effect that is meaningful for patients.” Still, she says, this therapy may have a place in some treatment plans.
“Some clinicians choose to offer hyaluronic acid […] but it will be much, much further down in the treatment algorithm. So after exhausting core treatments, including education, physical activity, weight management, a trial of a steroid injection, then at that point, a clinician and patient may have a discussion about hyaluronic acid.” According to Osteoarthritis Research Society International recommendations, “Intra-articular hyaluronic acid (IAHA) may have beneficial effects on pain at and beyond 12 weeks of treatment and a more favorable long-term safety profile than repeated IACS (intra-articular corticosteroids).”
What are the risks or side effects?
Negative side effects can include reactions at the injection site or swelling or pain in the joint. Rarely, viscosupplementation products can cause a drop in blood counts and fever.
For more information, visit the Viscosupplementation section of the Anti-Inflammatory Medications page, or the Medication Reference Guide section on Viscosupplementation.
Platelet rich plasma (PRP) injections
What is it?
PRP is a kind of cell therapy for OA, where a sample of your own blood is drawn and processed in a centrifuge machine to separate platelets from red blood cells. The collected platelets are then injected into the joint, with the aim of stimulating regeneration and healing.
Is it effective?
“American College of Rheumatology guidelines recommend against using PRP,” says Dr King. One main concern, she says, is that there are not a lot of high-quality studies. Research questions include how should these injections be delivered? How many and how often injections are required? How does it work in the body? Which patients may see benefits? Is there a meaningful benefit in a high-quality study compared to a placebo? And if so, who should these treatments be targeted to, and when in the treatment? “We have a lot more research that's needed. And again, for that reason, this isn't a recommended treatment at this point.”
What are the risks or side effects?
Because this treatment has not been rigorously studied, it’s difficult to evaluate the potential risks or side effects. Dr King adds she is sometimes asked about a related treatment for OA: stem cell therapy, where bone marrow aspirates are processed and injected into a joint. “In 2019, Health Canada actually put a safety alert out because of concerns of unproven health claims being made towards patients. And so there is ongoing research to understand whether this is effective for patients with osteoarthritis, but at this point, [it is] not recommended. We really need a lot more research.”
To learn more, visit: Platelet rich plasma treatment
Prolotherapy injections
What is it?
This treatment is also called hypertonic dextrose injection. Dextrose is a sugar water solution, which is injected into ligaments, tendons or joints to treat OA. The idea behind the treatment is these injections promote the growth of normal cells and tissue by causing inflammation and prompting the ligament or joint to repair itself.
Is it effective?
“This [treatment] isn’t something that that we discuss within the rheumatology community all that much, because studies are very small, there's a very small number of participants and again it’s not really clear how this should be delivered. This isn’t a recommended treatment in our guidelines,” explains Dr King. Because health care providers and researchers just don’t have enough information about how to deliver prolotherapy, how it works, the costs involved and whether it results in any meaningful improvement in symptoms, it is not recommended in the international OA treatment guidelines.
What are the risks or side effects?
Because this treatment has not been rigorously studied, it’s difficult to evaluate the potential risks or side effects.
For more information, visit: Prolotherapy injections
What’s the bottom line?
Injectable treatments are an exciting area, but there is a lot more work to be done. “As a clinician, I really want to have effective treatments to offer patients and be able to individualize them to patients, take into account their preferences [and] where they are in their disease journey,” says Dr King. “But as a scientist, I take pause with the evidence for injections [aside from steroid injections] to date. We’re not there yet with the data.”
The good news, she says is that there are lots of studies ongoing worldwide to give us some better answers. “Treatment of arthritis really is a multi-pronged approach. It’s important for patients to have the knowledge and be equipped with the evidence around the injections to see where this may fit in their whole treatment plan. We know there are non-pharmacological treatments that work better to improve pain, to improve function, in the long term, with the focus on education, weight management, exercise. Injections like glucocorticoids can play a supportive adjunct role.”