Undoubtedly, ultrasound-guided injections play an essential role in MSK treatment. First and foremost, injections provide pain relief. With less discomfort, people can begin and progress with exercise. However, it is essential to note that injections don’t cure most MSK disorders. In other words, it should not be the only form of treatment: it must be combined with exercise therapy.

In general, evidence suggests that using ultrasound improves the accuracy and effectiveness of injection therapy.   Shoulder disorders, such as shoulder tendonitis or frozen shoulder, and knee disorders, such as knee arthritis, are good examples where ultrasound-guided injections are shown to be more effective.

There are four main types of ultrasound-guided injections based on the drugs injected.

Ultrasound-guided injections: Cortisone 

cortisone shot

Generally, cortisone is the most common type of injection. It works well in both arthritis and tendonitis. When injected, cortisone is a potent anti-inflammatory drug that will reduce inflammation and swelling in tendons and joints.   Ultrasound ensures that the cortisone is injected into the right area. In addition, accuracy of ultrasound-guided injections improves the drug’s effect and reduces side effects. In general, cortisone injection benefits begin after about one week and can last up to 3 months. Before having a cortisone shot, it is essential to understand the actions and side effects of cortisone. Also, you need to know how long it takes for a cortisone shot to work.

In general, cortisone injections are helpful for the following conditions:

Ultrasound-guided injections: Hyaluronic acid

natural gel injection

Next, we use hyaluronic acid injections for arthritis treatment.   Common locations include the knee, hip, elbow, shoulder, ankle, foot, and hand. Essentially, hyaluronic acid is a clear, gooey substance produced naturally by our bodies. Specifically, we find it in the skin, eyes, and connective tissues. It acts as a lubricant to reduce pain and swelling in arthritis.

On the whole, there are a few notable benefits to using Hyaluronic acid.   One of the advantages of using Hyaluronic acid is the safety profile, which is much better than cortisone. In addition, the effect of hyaluronic acid is much longer than cortisone, usually up to 430 days. Finally, ultrasound should always be used to ensure the drug is placed in the joint. This accuracy of ultrasound-guided injections reduces potential side effects, such as a joint flare.

Not all hyaluronic acids on the market are the same. Recent evidence suggests that high molecular weight hyaluronic acid has a better effect on arthritis. Examples of high molecular weight hyaluronic acid include Durolane.

Occasionally, doctors use hyaluronic acid for specific tendonitis. For example, a particular type of Achilles tendinitis called plantaris-associated Achilles tendonitis responds well to a hyaluronic acid injection. In these cases, hyaluronic acid is injected between the two tendons allowing the person to return to running or sports.

Ultrasound-guided injections: Platelet-rich plasma

Platelet-rich plasma injections - alternative to cortisone injection in shoulder

One of the newest types of injection is regenerative injection therapy or PRP.  As the name implies, we use the patient’s blood to treat a condition.  Firstly, we take a blood sample.  Similar to a normal blood test, we draw blood from a vein in the elbow.  Next, we place the blood in a centrifuge.  Gradually, the cells separate into two components: serum and cells.  This serum contains platelets. Platelets contain a high number of growth factors. Finally, we remove the serum and platelets from the red cells and inject them into a joint or tendon.  Once again, we use ultrasound to improve accuracy.

How does platelet-rich plasma work?   

Platelets are important cells that control clotting. Also, they contain a high concentration of growth factors. These growth factors control inflammation and healing. Injecting platelet-rich plasma into a joint or tendon leads to the release of growth factors improving the local tendon or joint environment. Ultimately, this leads to a lower level of pain and tissue healing. However, there is no evidence that PRP regenerates tissue. So, although these injections are called ‘regenerative therapy injections,’ they do not heal tendon or joint pathology.

What is the evidence for PRP?

Evidence for the effectiveness of PRP exists only for a few common conditions:

However, Platelet-rich plasma is ineffective for other joints and tendons, such as the hip joint, ankle joint, Achilles tendon, or shoulder tendon. Finally, no evidence exists that platelet-rich plasma regenerates new cartilage or tendon tissue. So, perhaps, we shouldn’t call these treatments regenerative injeciton therapy.

Dr Masci co-authored a study summarising the effectiveness of injections in tendonitis, including PRP.

This blog answers the common questions asked about PRP and knee arthritis.

Ultrasound-guided injections: Arthrosamid 

Arthrosamid injection

Arthrosamid is a unique hydrogel of water molecules attached to a polyacrylamide backbone. The injectable is non-degradable, meaning the body does not break it down.

It works by coating the lining of the synovium of the knee joint, reducing inflammation, and providing lubrication.

The drug is only licensed for use in knee arthritis.

Recent studies show improvement in pain scores lasting for up to 2 years. In addition, compared to hyaluronic acid, it works better in younger and slimmer patients.

As Arthrosamid is non-degradable, your doctor must do this injection with ultrasound guidance to ensure it gets into the joint.