An intra-articular injection is a type of shot that's placed directly into a joint to relieve pain. Corticosteroids (steroids), local anesthetics, hyaluronic acid, and Botox are the most common substances injected into joints for this treatment.
Your healthcare provider might discuss a joint injection with you if your pain has not improved with conservative treatments, such as pain relievers, oral anti-inflammatory drugs, and physical therapy.
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Types of Intra-Articular Injections
Besides treating pain, joint injections can have different purposes. They may be used to deliver chemotherapy drugs like Doxil (doxorubicin) directly into a joint affected by cancer.
They may also be an effective means of eradicating a fungal infection in joints (also known as fungal arthritis).
When used for alleviating pain, different intra-articular therapies work in different ways. These pain relievers include:
Corticosteroids
Corticosteroids work to decrease local inflammation by inhibiting the production of inflammatory cells that are naturally produced in response to an acute injury or chronic condition. Intra-articular treatments are most commonly used to treat osteoarthritis, acute gout, and rheumatoid arthritis of the knee.
Intra-articular injection of corticosteroids for osteoarthritis of the hip and knee has earned a strong recommendation from the American College of Rheumatology, and a conditional recommendation for osteoarthritis of the hand. Long-term use of corticosteroids has been thought to progressively damage the joints, but this is controversial.
Corticosteroid shots are typically administered no less than three months apart. The duration of relief can vary based on the type of steroid used.
Hyaluronic Acid
Hyaluronic acid is a naturally occurring substance found in synovial fluids that lubricate the joints. With osteoarthritis, this substance can rapidly break down and lead to a worsening of the condition. Intra-articular injections have been used to increase lubrication, reduce pain, and improve the range of motion in a joint.
However, clinical studies have been mixed on how effective these shots really are. The American College of Rheumatology now strongly recommends against injections of hyaluronic acid in hip osteoarthritis and conditionally recommends against their use in hands and knees affected by osteoarthritis.
Hyaluronic acid injections are generally administered as a series of shots scheduled over three to five weeks. They are mainly used to buy time before knee replacement surgery in people who are unable to tolerate steroids and have not found relief from oral medications.
Local Anesthetics
Local anesthetics are sometimes delivered by intra-articular injections as a form of pain relief following arthroscopic surgery. But it is a practice that has come under scrutiny as evidence suggests that it may degrade chondrocytes (the only cells found in cartilage) in the joint.
Botulinum Toxin
Botox (botulinum neurotoxin A) injections may offer safe and effective pain relief in painful knee osteoarthritis, but more study is needed. Currently, the American College of Rheumatology conditionally recommends against Botox injections for osteoarthritis of the hip and knee.
Botox treatment effects can last as long as 12 weeks in some people and as short as four weeks in others.
Platelet-Rich Plasma
Platelet-rich plasma (PRP) is derived from whole blood and contains platelets (a type of blood cell that is essential for clotting) and the liquid portion of blood known as plasma.
Although intra-articular injections of PRP have been shown to reduce pain and improve physical function for some people, their effectiveness in osteoarthritis is controversial. The American College of Rheumatology strongly recommends against the use of PRP in knee and hip osteoarthritis.
The effectiveness of PRP is controversial, though there is some evidence that injections can help reduce pain and improve function. Treatment benefits have been reported to last anywhere from six to nine months.
Side Effects
The two main side effects associated with intra-articular injections are infections and local site reactions. Other side effects can occur in relation to the specific drugs or substances injected.
Corticosteroid Injections
Short-term complications of intra-articular corticosteroid injections are rare and include septic arthritis, injection site pain, skin pigmentation, and atrophy. Corticosteroid injects were found to have minimal systemic effects.
Hyaluronic Acid
Side effects of intra-articular hyaluronic acid injections include muscle pain and stiffness, difficulty moving, joint pain, and swelling or redness in the joint. Other less serious side effects include bleeding, blistering, discoloration of the skin, itching, numbness, tingling, and tenderness.
Local Anesthetics
In addition to injection site reactions, intra-articular injections of local anesthetics, such as lidocaine, bupivacaine, and ropivacaine, have the potential to damage cartilage, according to research, and should be used with caution.
Botox
Intra-articular Botox injections have very few side effects. Injection site reactions are the most common side effect and may include redness or bruising. Allergic reactions to botox, though rare, are possible and can include anaphylaxis.
Platelet-Rich Plasma
Side effects of intra-articular injections of PRP are mild and include temporary joint pain and stiffness, injection site pain, bruising, itching, and tingling sensations in the joint. Side effects typically resolve within 48 hours.
A Word From Verywell
Intra-articular injections help to relieve joint pain and stiffness by delivering medication directly to the joint, helping to minimize systemic side effects. Intra-articular injects can be an important part of your treatment plan, However, they should not be the sole means of treatment for osteoarthritis or other joint disorders. The effects of many of these drugs tend to wane over time, and the long-term impact, particularly of corticosteroids, on the joints themselves is controversial.
Frequently Asked Questions
Where is an intra-articular injection given?
Intra-articular injections are given directly into the joint. Intra-articular injections are most commonly used to treat osteoarthritis in the hip or knee, but they can also be given in other joints, including shoulders, wrists, ankles, hands, and fingers.
Are intra-articular injections painful?
Intra-articular injections can be painful. In some cases, your healthcare provider may numb the area with a local anesthetic prior to performing the injection. Pain from an intra-articular injection occurs during the procedure and may linger for a few hours after treatment.
