A joint injection is the delivery of a medication or substance directly into the joint bursa, which is a lubricating sac situated between tendons and bones. Joint injections are performed in an office setting, using a local anesthetic.
A joint is a region between bones, and this structure provides support and assists with movement. Joints in the body are often inflamed due to a certain condition or damaged. Regardless of the cause, a joint can become stiff and painful. The goal of an injection is to preserve the integrity of the joint while eliminating the discomfort.
Corticosteroids are synthetic drugs that are similar in chemical makeup to cortisol, which is the hormone produced naturally from the adrenal glands. Corticosteroids are not like the testosterone “steroids” used by athletes and body builders. Rather, corticosteroids decrease inflammation and reduce the immune system activity. Two commonly used corticosteroids are triamcinolone and methylprednisolone.
The most commonly injected joint is the knee. Other joints that are injected include the shoulder, elbow, wrist, base of the thumb, hand, hip, and ankle. Ultrasound guidance is often used to inject small joints, such as the wrist and hand. Areas of tendonitis and bursitis can also be injected for conditions such as trigger finger, carpal tunnel syndrome, trochanteric bursitis, and plantar fasciitis.
Joint injections are used to treat conditions such as:
Inflammatory joint diseases
Patients with bleeding problems or those taking anticoagulants (blood-thinning agents) are not candidates for joint injections. This is because of the risk for bleeding at the injection site and into the joint. In addition, patients with poorly controlled diabetes, active infection, or a serious heart condition should not have a joint injection.
Before the joint is injected, your detailed medical history is taken, and a thorough physical examination is conducted. Imaging, scans and laboratory tests are done. You would sign a consent form after a nurse has explained the benefits and complications, if any, of the procedure to you.
The doctor uses an antiseptic to cleanse the injection site, and may numb the area with a local anesthetic. Sometimes, fluoroscopic guidance is used for correct needle placement. Once the needle is in place, the doctor may aspirate and remove some of the joint fluid for testing. The medication is instilled into the joint, and the puncture site is covered with a Band-aid.
Certain conditions cause a buildup of joint fluid. Removal of joint fluid is done for examination and laboratory analysis. The lab checks cell counts, performs a crystal analysis, and does a culture if infection is suspected. These diagnostic tests give the doctor information needed to treat the condition.
A joint injection is a fairly simple procedure, but there are a few risks involved. While rare, complications include:
Rupture of a tendon
Not all patients develop side effects to corticosteroids. However, the side effects include weight gain, irritability, trouble sleeping, fluid retention, and mood swings.
A recent large review of studies showed that corticosteroid joint injections were more effective than placebo for pain relief. For treating tendonitis and bursitis, steroid injections have an 83% success rate, based on many studies.