Cortisone shots are commonly used to treat joint-related problems like arthritis, tendonitis, and bursitis. Cortisone shots can provide long-term pain relief by decreasing inflammation in joint spaces and connective tissues.
Cortisone shots are generally safe, and side effects are rare. However, there are possible risks, including long-lasting skin discoloration, cartilage damage (if given too often), and tendon damage if it is injected into a tendon rather than around a tendon.
How Do Cortisone Shots Work?
Your body contains two small glands called adrenal glands that produce a hormone known as cortisol. Cortisol is released at times of stress and has many functions in the human body, including the suppression of inflammation. It is classified as a corticosteroid, meaning a steroid hormone produced by the adrenal glands.
Cortisone is the man-made version of cortisol. As a synthetic corticosteroid, it mimics the effects of cortisol and is used to treat a variety of inflammatory conditions.
Corticosteroids should not be confused with anabolic steroids that are used to build muscle.
What Conditions Can a Cortisone Shot Treat?
Cortisone shots are commonly used to treat inflammatory conditions affecting the joints or connective tissue. These include:
- Ankylosing spondylitis (an inflammatory disease of the spine)
- Autoimmune arthritis like rheumatoid arthritis and psoriatic arthritis
- Bursitis (inflammation of fluid-filled joint cushions called bursae)
- Carpal tunnel syndrome (caused by a pinched nerve in the wrist)
- Osteoarthritis ("wear-and-tear arthritis")
- Plantar fasciitis (inflammation of the thick band of tissue between the heel and toes)
- Spinal problems like spinal stenosis or herniated discs
- Tendonitis (inflammation of a tendon in the knee, elbow, or other joints)
Cortisone shots can also be used to treat inflammatory skin conditions like eczema (atopic dermatitis) or to reduce severe scars known as keloids. They are also sometimes given to prevent the development of nodules in people with sarcoidosis.
While osteoarthritis is generally non-inflammatory, the progressive deterioration of joint cartilage can trigger inflammation as bone rubs against bone and damages surrounding tissues.
How Cortisone Shots Are Given
Cortisone shots are given into or around the affected tissue. For joints, the injection is given into the joint (intra-articular injection). For tendons, then injection is given into the tendon covering around the tendon. For bursitis, the injection is given into the bursa.
The shot may involve the following steps, depending on the extent of joint inflammation:
- The skin is cleaned with an iodine or surgical soap.
- A numbing injection or topical numbing agent may be used to reduce pain.
- If the joint is filled with extra fluid, a larger needle may be inserted into the joint space to draw it out. This is known as arthrocentesis or joint aspiration.
- After cleaning the skin again, a smaller needle is inserted into the joint space to deliver a dose of cortisone.
It's common to mix cortisone with an anesthetic such as lidocaine for immediate pain relief.
How Often Can You Get a Cortisone Shot?
There is no hard-and-fast rule as to how many cortisone shots you can get. Still, there are limitations and risk you need to consider.
If a cortisone shot wears off quickly or does not help, then doing it again may be of little benefit. Repeated cortisone injections also increase the risk of side effects.
Because of this, many healthcare providers limit the number of shots to no more than three to four per year at the same site. Even so, the decision to give more or fewer shots is made on a case-by-case basis, weighing the risks and benefits.
Cortisone shots are not recommended as a first-line treatment in younger people whose joints are still growing.
How Long Does a Cortisone Shot Last?
Cortisone shots usually work within two to seven days, but in some people it may take up to 14 days to help.
The duration and level of pain relief can vary from one person to the next. Factors influencing the treatment response include the underlying condition, the joint being treated, and the severity of joint pain or injury.
With knee osteoarthritis, pain relief may last several months to up to a year for some people. But anywhere from 20% to 30% will have no treatment response.
Side Effects
Cortisone injections are generally safe, but, like any drug, there are possible side effects and risks.
Possible side effects include:
- Injection site pain, sometimes lasting up to 48 hours
- Facial flushing, most often in people assigned female at birth
- Lightening or darkening of the skin around the injection site (more common for superficial sites)
- Hardening and dimpling of the skin (more common for superficial sites)
- A temporary increase in blood sugar
- Bruising near the injection site
- Steroid flare (more severe pain in the injected joint for a few days after the injection)
Cortisone Shots and Tendon Rupture
One concern about cortisone injections is a ruptured tendon. Cortisone may temporarily weaken a tendon, and a weakened tendon is more likely to rupture during normal activities or when stressed.
Placing the cortisone in the tendon covering or around the tendon and not into the tendon lowers the risk of rupture. Cortisone injections are avoided around certain tendons due to the increased complication risk if the tendon ruptures.
Cortisone Shot Alternatives
If you cannot tolerate a cortisone shot or the treatment stops working, there may be other options to consider.
Hyaluronic Acid
Hyaluronic acid is a natural substance found in the joints that helps the joint fluid be thicker and more slippery. Hyaluronic acid can also be manufactured in the lab and be used to supplement the fluid already in a joint space. It is a treatment for osteoarthritis.
Hyaluronic acid doesn't reduce inflammation but may provide relief in people with knee osteoarthritis. The main side effect is injection site pain.
Platelet-Rich Plasma (PRP)
Platelets and plasma are two components of blood. In addition to helping blood clot, they contain growth factors that play a role in the healing process.
Injecting platelet-rich plasma (PRP) into an affected joint placed high concentrations of these growth factors into damaged joints. It is a less commonly used therapy but one may be beneficial to people with joint injuries, osteoarthritis, and tendonitis.
PRP is made with a supply of your own blood. The blood is placed in a centrifuge which separates the platelets and plasma from red and white blood cells. The PRP is then given by intra-articular injection. Because PRP comes from your own blood, side effects are rare.
Summary
Cortisone is a man-made corticosteroid that mimics the effects of cortisol. It is typically given by injection to reduce inflammation in joints or connective tissues. It is generally safe to use and can offer long-term relief from joint pain and swelling. Injection site pain is the most common side effect.
Most healthcare providers limit the number of shots to three to four per year for any single joint.