Cortisone Shot In The Knee – What To Expect
With any type of machine, the longer you use it, the more stress and strain is placed on its moving parts. This holds true with our bodies as we age. A common feature of aging is osteoarthritis. Osteoarthritis affects our joints and is seen as a “wear and tear” condition that is simply a function of our joints being used repetitively for a long period of time. We feel osteoarthritis most keenly in our weight-bearing joints. Knees in particular can be very painful. There are many different types of treatments for knee pain related to osteoarthritis or other conditions. A common procedure after rest, ice, and non-steroidal anti-inflammatory drugs (NSAIDs) is to get a cortisone shot in the knee. If you are considering a knee joint injection, here’s what to expect.
What is a cortisone shot in the knee?
A cortisone shot in the knee is a minimally-invasive procedure that involves injecting a corticosteroid into the knee. Corticosteroids help to suppress the immune response that is triggering inflammation. This inflammation is caused by the rubbing of bone on bone in the knee joint. Rubbing occurs in the joints as cartilage naturally wears thin over time.
A cortisone shot is just one type of knee joint injection. Others may include hyaluronic acid (HA) or platelet rich plasma (PRP). HA injections are generally aimed at restoring lubrication in the knee joint. PRP works to use the patient’s own red blood cells to repair damage. A cortisone shot in the knee focuses on relieving pain and inflammation specifically.
Conditions treated with a cortisone shot in the knee
Osteoarthritis is the most common source of knee pain, but there are other conditions that can affect this complex joint. Four bones make up the structure of the knee: the patella, fibula, tibia, and femur. Cartilage and ligaments connect all of these bones and keep them stable.
The posterior and anterior cruciate ligaments (the PCL and ACL) connect at the center of the knee joint and help stabilize the knee through rotation. The lateral and medial ligaments also help stabilize and support the joint, while the medical meniscus cartilage provides cushioning.
Damage, injury, or deterioration in any part of this joint can cause knee pain. In addition to pain caused by osteoarthritis, some of the most common pain conditions treated with a cortisone shot in the knee include:
- Cartilage tear
Each of these conditions causes inflammation, pain, and limited mobility.
Before any treatments occur, a pain management specialist will take a complete medical history. A thorough physical examination that includes range-of-motion tests will be conducted.
In some cases, the doctor may request imaging such as X-ray or MRI to confirm a diagnosis. A cortisone shot in the knee may not be the first treatment offered if the pain is mild and can be managed in other ways.
If a cortisone shot in the knee is recommended, the knee will be thoroughly cleaned and sterilized. A local anesthetic is used most often, but patients may request mild sedation if that is more comfortable.
The pain management specialist uses fluoroscopy (live X-ray) to guide a very thin needle into the joint space of the knee. Proper placement of the injection is important for both patient safety and pain relief. Once located, a corticosteroid is injected into this space.
The entire procedure takes between 15 and 30 minutes. In many cases, pain relief is dramatic and occurs within 24 to 48 hours. Patients need only take minimal time off (usually just the day of the procedure).
Effects from knee cortisone shots
A cortisone shot in the knee is most effective for the first shot, with its pain-relieving effects diminishing slightly with each shot after. The effects of a shot can last from four to six weeks. Results can be improved if other lifestyle and supportive changes are made to manage knee pain.
Cortisone shots will not be injected directly into a tendon. If the pain management specialist believes that an inflamed tendon is the cause of pain, they may choose to place the injection near the tendon instead.
Potential side effects
Although a cortisone shot in the knee is minimally-invasive and non-surgical, there is a slight risk of side effects. Side effects are rare and generally mild. Short-term, less serious side effects can include:
- Swelling, pain, or bruising at the site of the injection
- Allergic reaction
- Face flushing
- Synovium inflammation
- Temporary increase in blood sugar
Over time and with more injections, side effects can become more prevalent and serious. Tendons and cartilage may become weaker. Other long-term side effects of cortisone shots in the knee are:
- Easy weight gain and puffiness
- Easy bruising
- Thinning skin
- High blood pressure
- Increased risk of osteoporosis
- Bone damage (avascular necrosis or osteonecrosis)
Is a cortisone shot in the knee effective?
A meta-analysis of high-quality studies in the UK found that a cortisone shot in the knee was effective for relieving inflammation and pain in both the short and long term. The analysis also found that although there is concern for cartilage damage due to the corticosteroids, most cases of damage were due to the underlying disease, not the cortisone shot in the knee.
Another study compared the results of knee injections versus placebo groups and found clinical and statistical evidence that cortisone shots in the knee offered more pain relief at one week than placebo.
Finally, a meta-analysis in 2015 looked at all types of treatments for knee pain and found that a cortisone shot in the knee was the most effective. This meta-analysis included 137 studies with over 33,000 study participants total. The focus was on short-term pain relief, with the reviewers noting that long-term data is not robust enough to include.
In all of the research above, researchers are careful to note that a cortisone shot in the knee may address the symptoms of pain and inflammation in the short-term but underlying causes must be addressed for proper treatment. A knee joint injection may allow pain patients to begin other treatments, such as physical therapy, so that a holistic pain management plan can be implemented.
As with all potential treatments, talking to your doctor is the first step. Have you ever had a cortisone shot in the knee? Was it effective for your knee pain?