Overview of Shoulder Joint Injection
Shoulder pain is really common, affecting about 15 out of every 1000 people each year. In fact, up to 70% people may experience shoulder pain at some point in their life. This pain can often be caused by issues related to the rotator cuff, acromioclavicular joint, and glenohumeral joint, which are all parts that make up your shoulder.
It can also be due to inflammation. If you’re suffering from a condition called adhesive capsulitis, or frozen shoulder, you sometimes might be offered a steroid injection inside your shoulder joint to help manage the pain.
Injecting the shoulder joint can be done with or without image guidance. Image guidance simply means that the doctor uses an imaging technology like a fluoroscope to guide the needle to the right spot in the shoulder. This method was first described in 1933 by a doctor named Oberholzer. Nowadays, a simplified version of this method is mostly followed, which was described by Schneider and his team.
When doctors carry out a fluoroscope-guided shoulder joint injection, they aim to:
- Minimize the patient’s discomfort.
- Ensure the patient’s safety.
- Use the proper technique to guide the needle into the right part of the shoulder, like the rotator cuff or the acromioclavicular joint.
Anatomy and Physiology of Shoulder Joint Injection
The shoulder is made up of four joints: the sternoclavicular, acromioclavicular, scapulothoracic, and glenohumeral joints. The glenohumeral joint is the part where the head of the upper-arm bone fits into the shoulder blade, like a ball and socket. This joint is surrounded by a loose capsule, and the ball of the upper-arm bone is larger than the socket. This makes the shoulder a very mobile joint, able to move freely in all directions.
However, this mobility comes with a trade-off in stability. The stability of the shoulder joint is assured by static structures (like the glenoid labrum, a ring of cartilage, and ligaments that connect bones to each other) and dynamic ones (like muscles and tendons that move the bones). For example, the rotator cuff muscles and the long-head part of the biceps tendon are dynamic structures that help to maintain the stability of the shoulder joint.
Another important joint is the acromioclavicular (AC) joint. This is where the collarbone connects to the shoulder blade. Various factors like injury, degeneration, infection, or inflammation can cause arthritis in this joint. Pain may occur when lifting the arm overhead. Doctors usually recommend physical therapy, anti-inflammatory drugs, and sometimes injections into the joint to ease the pain. If these treatments don’t work, a surgical procedure to remove a part of the collarbone might be an option.
Why do People Need Shoulder Joint Injection
Doctors often consider injecting medicine into a joint as a treatment option after trying other solutions. The first strategies usually include physical therapy and anti-inflammatory drugs (like Advil or Aleve). Main reasons for receiving a shoulder joint injection include arthritis and “frozen shoulder” (a condition where your shoulder joint becomes so stiff and painful that it’s hard to move). Injections using a special dye that shows up on X-rays, CT scans, or MRIs can also be helpful. These injections can give your doctor a clear view of your shoulder joint to help diagnose your problem. Similar reasons for a therapeutic injection into the joint where your shoulder blade and collarbone meet include arthritis and a breakdown of the end part of the collarbone following an injury.
When a Person Should Avoid Shoulder Joint Injection
There are certain conditions that make it absolutely unsafe to proceed with certain procedures. These include:
Septic arthritis, which is a severe joint infection. If you have this, it’s too risky to do the procedure.
If you have a skin infection, called cellulitis, around the area where the needle needs to be inserted, the procedure can’t be done because it could spread the infection.
Bacteremia is when there are bacteria in your blood. If you have this, it’s not safe to do the procedure because it could spread the infection further.
If you’ve recently suffered a broken bone, the procedure can’t be done because it could interfere with healing.
Lastly, if you have a history of allergic reactions (also known as anaphylaxis) to any substances that need to be injected during the procedure, it’s not safe to go ahead with it.
Equipment used for Shoulder Joint Injection
The equipment and methods used in medical procedures can change depending on the hospital or clinic, and can even be specific to each doctor. Here’s a list that summarizes the typical equipment used for certain types of joint injections.
First, let’s look at injections into the shoulder joint (Glenohumeral joint):
* A drape or towels to keep the area clean
* A fluoroscopy machine, which delivers real-time X-ray images to guide the doctor
* 1 to 3 milliliters of 1% lidocaine hydrochloride, a local anesthetic to numb the area
* A 23-gauge needle for the injection
* 2 to 4 milliliters of iodinated contrast, a type of dye to help visualize structures inside the body
* If the injection also includes treatment, 1mL of 40 mg/mL of triamcinolone and 1 mL of 0.2% ropivacaine are needed. Triamcinolone is a medication used to decrease inflammation and ropivacaine is another type of local anesthetic
* If an MRI scan of the area is needed afterwards, 10 mL of 0.5% gadolinium is used as a contrast agent to enhance the image.
Next, let’s look at injections into the shoulder where the collarbone joins (Acromioclavicular joint):
* A drape or towels to keep the area clean
* A fluoroscopy machine
* 1 to 3 milliliters of 1% lidocaine hydrochloride for local anesthesia
* A 23-gauge needle for the injection
* A mixture of 0.5 mL of triamcinolone solution (40 mg/ml) and 0.5 mL of 1% lidocaine which helps both numb the area and decrease inflammation.
Who is needed to perform Shoulder Joint Injection?
The medical team for your procedure will have a few key members. First, there’s the doctor who will do the injection. Then, there’s a specially trained professional, called a radiology technologist, who knows how to use a special imaging machine called a fluoroscopy machine. This machine helps the doctor see exactly where to put the injection.
If you’re receiving an injection into the shoulder joint, or ‘glenohumeral joint’ for a specific type of scan called an MR arthrogram, then two additional people may be indirectly involved. First, there’s an MRI technologist, a professional who knows how to perform MRI scans. Then there’s a radiologist, another type of doctor who specializes in interpreting medical images. They’re important because they check the images from your scan to make sure everything looks normal.
Preparing for Shoulder Joint Injection
Before any medical procedure, it’s important that the doctor explains everything to the patient clearly. This involves explaining how the procedure works, what it will feel like, checking the skin where it will be performed, discussing any past medical conditions or surgeries that could affect it, what the procedure might diagnose, and any potential risks or complications.
Before we start a certain type of X-ray procedure called a fluoroscopy, everyone in the room must wear a special protective apron, made of lead, that blocks the X-rays. The patient will lie flat on their back and their arm will be turned so that the palm is facing up. To keep the arm in the right position, a small weight might be placed in the patient’s hand. Then, the doctor will use the X-ray to take a picture with a small metal marker showing the exact spot where the procedure will take place. This helps the doctor see the path they will take with their needle. They’ll mark this spot on the skin, which will then be cleaned using a standard sterile technique to prevent any infections.
If the procedure is to look at or treat the joint where your collarbone meets your shoulder (the acromioclavicular or AC joint), the marker stick will help to pinpoint the joint capsule, and the skin over this area will be marked. Again, this spot will be cleaned using a standard sterilization method to avoid any infection.
How is Shoulder Joint Injection performed
The doctor is going to numb the skin using a local anesthetic. This local anesthetic is given in a very small amount, about 1 to 3 mL, of a medicine called 1% lidocaine hydrochloride. They are going to use a thin needle to inject the anesthetic. This needle has a separate piece called a stylet inside it.
The doctor will carefully insert the needle through the soft tissues until it reaches the upper part of the arm bone, known as the humerus. While doing this, they’ll use a special type of real-time X-ray, called a fluoroscopy, to double-check the needle’s position. This process help ensures that the needle is being inserted at a perfect right angle into the joint space to avoid any damage to the cartilage that covers the bone surface.
Once the needle is in the right position, it is slightly pulled back. The stylet is then removed from the needle. A small amount of anesthetic is injected into the joint to numb the area of the bone’s surface. The doctor then injects a substance called contrast, using the fluoroscopy to confirm the needle is in the right place and not in any surrounding fluid-filled sacs that cushion the joint, which are called bursa. The doctor can tell the needle is in the right place if they can see a small line of contrast between the socket in the shoulder blade and the humerus.
Once this is confirmed, a different needle is connected to a tube filled with a medication known as a corticosteroid (often just called a steroid). The steroid is then injected into the joint. If you’re having an MRI, a special substance called gadolinium is mixed with the steroid. The doctor will inject about 8 to 10 mL of this mixture into the shoulder joint.
The doctor might also need to give an injection into the acromioclavicular joint, which is a different joint in the shoulder. In this case, the process is repeated using a similar approach. The doctor will numb the area with lidocaine, and then insert a needle into the joint and confirm its position using fluoroscopy. After that, about a 1 mL mixture of a steroid medication called triamcinolone and more lidocaine will be injected.
Possible Complications of Shoulder Joint Injection
It’s rare, but sometimes there can be complications after a procedure. These might include:
– An increase in the pain you were already feeling
– An allergic reaction to something used during the procedure
– Damage to small blood vessels
– Septic arthropathy, which is a type of joint infection
All these potential complications are rare and usually, procedures are carried out safely and successfully. If you experience any changes or increased pain after the procedure, make sure to inform your doctor.
What Else Should I Know About Shoulder Joint Injection?
Shoulder pain is a common muscle and joint problem that affects between 7% to 26% of people at any given time. This problem can really impact a person’s quality of life. Often, this pain comes from inflammation (swelling and redness) caused by conditions like osteoarthrosis, which is related to aging and injuries. This inflammation leads to both short-term and long-term pain in the shoulder joints.
Many treatments exist for shoulder pain, including physical therapy, anti-inflammatory drugs (called NSAIDs), and steroid injections. Different studies have tried to establish whether steroid injections or NSAIDs work better. While the results vary, a couple of key reviews of these studies have found that steroid injections can be more effective than NSAIDs. These studies have also shown that steroid injections can provide short-term relief for shoulder pain.
Steroid injections, in particular, can be very helpful in treating a condition called “adhesive capsulitis,” more commonly known as “frozen shoulder.” A frozen shoulder is an issue that resolves on its own over time, but it can be incredibly painful. It occurs in three stages, each of which can last months. Steroid injections can alleviate the pain associated with a frozen shoulder, especially when administered periodically throughout the course of the condition.
When using steroid injections to treat shoulder pain, it’s important to avoid hitting certain critical parts of the shoulder, like certain tendons and the labrum (a piece of fibrocartilage attached to the rim of the shoulder socket that helps keep the ball of the joint in place). Fluoroscopic guidance, a type of medical imaging that shows a continuous X-ray image on a monitor, can help with this. It allows for better control over the needle to avoid these pivotal structures and helps prevent any possible complications from the procedure.
