Knee injections are usually considered when a patient has been undergoing physical therapy for several weeks or months for a given condition, with insufficient results. The goal of an injection is to relieve the patient of his or her pain.
Knee injections: which technique for which condition?
At CMI Clinics, we perform three types of injections: cortisone injection, viscosupplementation (or hyaluronic acid injection), and Platelet Rich Plasma (PRP) injection.
If you suffer from persistent knee pain, talk to your doctor. He or she will present you with the different options and guide you to the most appropriate one for your symptoms.
Cortisone injection
What is it?
With its anti-inflammatory properties, cortisone is used to quickly relieve pain associated with knee joint inflammation. It is similar to the natural hormone that is produced by our adrenal glands.
Cortisone can help avoid or stop the use of anti-inflammatory pain medication.
Please note that cortisone injection should not be seen as a maintenance treatment, to be used regularly when symptoms reappear. Instead, it must be considered as a way out of an inflammatory crisis.
Osteoarthritis, tendinitis or bursitis: when can a cortisone injection be used?
Cortisone injections can be considered in the case of knee tendinitis, knee bursitis or knee inflammation.
For tendinitis or bursitis, an injection could be used if traditional and conservative treatment fails to relieve the patient’s pain.
Osteoarthritis of the knee is a progressive degradation of the cartilage that can be associated with inflammation. Cortisone injections are effective in reducing the pain caused by an inflammatory crisis.
How is a knee injection performed?
A cortisone injection is performed by a doctor. After disinfecting the area to be treated, the doctor injects the product with a needle into the painful area. This procedure does not require anesthesia
How much rest is needed after the injection?
Although rest is not required for a corticosteroid injection, it is recommended to avoid straining the joint in the following hours.
How long does it take for the effects to appear?
Relief generally begins to be felt one or two days after the injection. However, it can take longer.
Are there any side effects?
There may be a slight increase in blood sugar levels within two weeks of the injection.
In some cases, the injection into the subcutaneous tissues may cause skin atrophy, i.e. thinning of the skin. This complication is usually reversible.
How much does an injection cost?
The injection technique is covered by the RAMQ. The cortisone is provided free of charge by CMI Cliniques.
Hyaluronic acid injection (viscosupplementation)
What is it?
Hyaluronic acid injection, also called viscosupplementation, is the injection of a natural substance already present in our body. This viscous and elastic substance is a component of the synovial fluid, which surrounds the joints and cartilage.
The synovial fluid protects the joints, but also acts as a lubricant to facilitate sliding and avoid friction.
Hyaluronic acid injections are used to improve the quality of the synovial fluid, nourish the cartilage, improve the knee’s functional capacities, and slow down the degeneration process.
Hyaluronic acid injections act more slowly but have a longer lasting effect than cortisone injections.
When is it used?
Viscosupplementation is used in cases of moderate and painful osteoarthritis, when medication is not effective; or in certain cases of severe osteoarthritis, when the cartilage degrades too quickly and surgery is impossible.
Viscosupplementation is intended to slow down cartilage degradation, which is caused, among other things, by a depletion of the hyaluronic acid contained in the synovial fluid in cases of osteoarthritis.
In some cases, viscosupplementation can be used for tendon or ligament damage.
How is a knee injection performed?
A viscosupplementation is performed in the same way as a cortisone injection. After local disinfection of the skin, the doctor will use a needle to introduce the hyaluronic acid into the injection site, making sure it is in the joint.
However, to treat periarticular injuries, the doctor will inject the hyaluronic acid around the injured tendon or ligament.
How much rest is needed after the injection?
We recommend a 48-hour rest period after the injection.
How long does it take for the effects to appear?
The effects generally appear after a few weeks, and rarely after a few days, as with a cortisone injection.
However, pain relief lasts longer. The effects can last up to a year, after which it is recommended to repeat the treatment in cases of osteoarthritis.
If hyaluronic acid injection is used for pain related to ligament or tendon injuries, one to two repetitions should be sufficient.
Are there any side effects?
Hyaluronic acid injection can cause slight local pain and swelling. If this occurs, applying ice should help relieve the patient.
In very rare cases, a patient may develop fever and redness. If this is the case, it is important to consult a doctor to rule out infection.
How much does an injection cost?
The injection technique is covered by the RAMQ. The patient will have to pay for the product. For this procedure, hyaluronic acid will cost between $150 and $450, depending on the quantity.
The product is generally reimbursed by the CNESST, SAAQ and most private insurance plans.
PRP (Platelet Rich Plasma) injections
What is it?
It may sound surprising, but platelet-rich plasma injection consists of taking a sample of your own blood, centrifuging it, keeping the concentrated platelet layer, and then injecting it into the affected joint.
What is it used for?
Platelet-rich plasma can be effective in many cases, whether they involve joints, muscles or tendons.
In the knee, PRP injections can be used to treat gonarthrosis (osteoarthritis), or to reduce pain related to meniscus injuries or patellar tendinitis.
It is important to note that this option should be discussed with your physician to see if it is appropriate for your condition and symptoms.
How is a knee injection performed?
As mentioned above, the PRP injection has several steps. First, the doctor takes your blood and puts it through a centrifuge for 20 minutes to extract the layer with the highest platelet count.
After disinfecting the joint and the area where the PRP will be injected, the doctor will insert the needle to inject the product.
What rest do I need after an injection?
After a PRP injection in the knee, the patient must avoid all physical activity for two weeks. After this rest period, they can gradually return to their physical activities, depending on their tolerance.
How long does it take for the effects to appear?
The effects may take from a few days to a few weeks to appear. Four months after the injection, the doctor will be able to determine if a second treatment is needed.
Are there any side effects?
Since the platelet-rich plasma comes from your own blood, there is almost no risk of allergic reactions or rejection.
How much does an injection cost?
The injection technique is not covered by the RAMQ. The price of the product, in this case PRP, varies between $500 and $700, depending on the injection site. The product is generally not covered by insurance.
Is a knee injection painful?
Regardless of the type of injection (PRP, cortisone or viscosupplementation), it is generally not painful. In fact, they do not require anesthesia.
If you have persistent knee pain related to osteoarthritis or another condition, make an appointment with a healthcare professional to discuss the different injection options.