Undoubtedly, ultrasound-guided injections play a crucial role in musculoskeletal (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, including knee arthritis, are examples where ultrasound-guided injections are more effective.
There are four main types of ultrasound-guided injections based on the drugs injected.
Ultrasound-guided injections: Cortisone
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 medication that reduces inflammation and swelling in tendons and joints. Ultrasound ensures that the cortisone is injected into the right area. Additionally, the accuracy of ultrasound-guided injections enhances the drug’s effect and reduces side effects. Generally, cortisone injection benefits typically begin after about one week and can last up to three months. Before having a cortisone shot, it is essential to understand the actions and side effects of cortisone. Additionally, it is necessary to know how long it takes for a cortisone shot to take effect.
In general, cortisone injections are helpful for the following conditions:
- arthritis, including hip or knee osteoarthritis
- shoulder tendonitis
- frozen shoulder
- hand and wrist conditions such as trigger finger, De Quervain’s tenosynovitis, carpal tunnel syndrome, and thumb arthritis
- Greater trochanteric syndrome
- ITB syndrome
- foot and ankle conditions such as plantar fasciitis, Morton’s neuroma, big toe arthritis, and chronic ankle sprains
Ultrasound-guided Injections: Hyaluronic Acid
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 inflammation associated with arthritis.
Overall, there are several notable benefits to using Hyaluronic acid. One of the advantages of using Hyaluronic acid is its safer profile, which is superior to that of cortisone. Additionally, the effect of hyaluronic acid lasts significantly longer than that of cortisone, typically lasting up to 400 days. Finally, ultrasound should always be used to ensure the drug is placed in the joint. The 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 more beneficial effect on arthritis. Examples of high-molecular-weight hyaluronic acid include Durolane.
Occasionally, doctors use hyaluronic acid to treat specific types of tendonitis. For example, a specific type of Achilles tendinitis, known as 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
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 essential cells that regulate blood 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 results in a lower level of pain and enhanced tissue healing. However, there is no evidence that PRP regenerates tissue. Therefore, although these injections are referred to as ‘regenerative therapy injections,’ they do not directly address or heal tendon or joint pathology.
What is the evidence for PRP?
Evidence for the effectiveness of PRP exists only for a few common conditions:
- There are now 23 randomised controlled trials showing that PRP is better than other injections (such as cortisone or hyaluronic acid) for improving pain in knee osteoarthritis. PRP has shown better results than hyaluronic acid for knee osteoarthritis.
- PRP is more effective than cortisone for tennis elbow in some studies.
- In PLANTAR FASCIITIS, PRP is better than cortisone in 9 studies. PRP is better than cortisone and safer than surgery in patients with severe plantar fasciitis.
- One study shows that PRP is more effective than cortisone for hip tendinitis.
However, Platelet-rich plasma is ineffective for other joints and tendons, such as the ankle joint or Achilles tendon. Finally, there is no evidence 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 addresses the frequently asked questions about PRP and knee arthritis.
Ultrasound-guided injections: Arthrosamid
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 knee joint’s synovium, 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 4 years. In addition, compared to hyaluronic acid, it works better in younger and slimmer patients.
As Arthrosamid is non-degradable, your doctor must administer this injection with ultrasound guidance to ensure it reaches the joint.
