If you have pain at the base of your thumb, your doctor might suggest an injection to help with the swelling and discomfort. But how do doctors make sure the medicine goes into the right spot? This study looked at whether a small handheld ultrasound device helps doctors aim better when injecting the thumb joint.
Scientists tested two methods. One group of thumb joints received injections without any imaging help. The other group received injections guided by a small wireless ultrasound machine. The results might surprise you.
Here are three important things this study found:
- Handheld ultrasound did not improve accuracy compared to injections done without imaging
- Both methods worked about the same, with around 70 to 75 percent of injections reaching the right spot
- An experienced hand surgeon performed all the injections
Key Findings at a Glance
- Research shows that handheld ultrasound guided injections were accurate 75 percent of the time
- Blind injections (without imaging) were accurate 70 percent of the time
- The study tested 18 thumb joints on fresh cadaveric hands
- There was no statistically significant difference between the two injection methods
- An experienced hand surgeon performed all procedures
In this article:
What is thumb arthritis and why do injections help?
The joint at the base of your thumb is called the trapeziometacarpal joint. That is a big word for the spot where your thumb bone meets a small bone in your wrist. When this joint wears down over time, it creates a condition called thumb arthritis or rhizarthrosis.
What is the trapeziometacarpal joint?
This is the joint at the very base of your thumb where it connects to your wrist. It lets you move your thumb in many directions so you can grip and pinch things.
You may be wondering why this matters. When this joint becomes painful, everyday tasks like opening a jar or turning a key can hurt. In the early stages, doctors can give you an injection of medicine directly into the joint. This medicine helps reduce swelling and pain.
But there is a challenge. The thumb joint is small and sits deep under the skin. Doctors need to place the needle in exactly the right spot for the medicine to work best.
How did this study work?
According to this study published in Cureus in 2023, researchers wanted to test if a small wireless ultrasound device could help doctors aim better. Ultrasound is a tool that uses sound waves to create pictures of what is inside your body. It is the same technology used to see babies before they are born.
Here is where it gets interesting. The scientists used fresh cadaveric hands for this test. That means they used hands donated to science after someone passed away. This allowed them to inject the joints and then open them up to see exactly where the dye went.
They divided 20 thumb joints into two groups:
- Group A received blind injections, which means the doctor injected without any imaging help
- Group B received injections guided by a handheld ultrasound device
The doctor injected a blue dye called methylene blue instead of medicine. After the injection, they carefully opened each joint to see if the blue color was inside.
What is a blind injection?
This is when a doctor injects based on their knowledge of anatomy and feel, without using any imaging device to guide the needle.
Two thumbs had to be removed from the study because they had already undergone a surgery called trapeziectomy. This left 18 thumb joints for the final results.
What did the researchers find?
Let us look closer at the numbers. In Group A, the doctor performed 10 blind injections. Seven out of 10 were accurate. That means 70 percent of the time, the blue dye ended up exactly where it should be.
In Group B, the doctor performed eight ultrasound guided injections. Six out of eight were accurate. That means 75 percent of the time, the dye reached the right spot.
Results table
| Injection Method | Number of Injections | Accurate Injections | Accuracy Rate |
|---|---|---|---|
| Blind (No Imaging) | 10 | 7 | 70% |
| Handheld Ultrasound | 8 | 6 | 75% |
Research shows that the difference between 70 percent and 75 percent was very small. When scientists did a special math test called a Fisher’s exact test, they found no significant difference between the two methods.
This means the handheld ultrasound device did not give the doctor a clear advantage over injecting without imaging.
Why might this be?
The study was done by an experienced hand surgeon. Someone who has done this procedure many times already knows the anatomy very well. They can feel the right landmarks and guide the needle with skill.
The handheld ultrasound machines are also newer technology. They are smaller and more portable than the big ultrasound machines you might see in a hospital. But they might not show images as clearly. The study authors suggest that future research should compare these small devices to larger traditional ultrasound machines.
What does this mean for you?
If your doctor recommends an injection for your thumb pain, this study suggests that their experience matters a lot. An experienced hand surgeon can place injections accurately even without ultrasound guidance.
You may be wondering whether you should ask for ultrasound guidance. According to this study, the handheld device did not improve accuracy. However, other types of ultrasound machines were not tested here. Your doctor can discuss what tools are available and what might work best for your situation.
The most important thing is that you are seeing a specialist who performs these injections regularly. Practice and skill make a big difference.
What Happens During the Injection?
When you receive a thumb joint injection, your doctor will clean the skin. They will feel the area to locate the joint. If they use ultrasound, they will place a small device on your skin to see the joint on a screen. Then they will insert a thin needle and inject the medicine.
The injection usually contains a steroid medicine to reduce inflammation. Inflammation is the swelling and heat that happen when your body reacts to injury or wear and tear. The medicine can help relieve pain for weeks or even months.
About This Site
Our mission is to help you understand thumb pain and rhizarthrosis by breaking down published scientific research into simple, friendly language. We only use real medical studies from trusted journals. Every article is based on actual science, not opinions or advertisements. We invite you to explore more content on our site to learn about your condition and treatment options.
What questions do people ask?
Does ultrasound make thumb injections hurt less?
This study did not measure pain during the injection. Ultrasound helps doctors see where the needle is going, but whether it reduces pain was not tested here. Your doctor can use numbing medicine to make the injection more comfortable.
How accurate do thumb injections need to be?
According to this study, even experienced surgeons miss the joint about 25 to 30 percent of the time. When the medicine does not go into the joint, it may not work as well. More research is needed to understand how accuracy affects pain relief.
Should I ask my doctor to use ultrasound?
Research shows that handheld ultrasound did not improve accuracy in this study. However, your doctor may have access to different equipment or prefer ultrasound for other reasons. It is always okay to ask your doctor what method they recommend and why.
What is a handheld ultrasound device?
A handheld ultrasound is a small wireless device that can fit in your hand. It connects to a phone or tablet to show images. These devices are newer and more portable than traditional ultrasound machines, but they may show less detail.
What is the bottom line?
This study looked at whether a small wireless ultrasound device helps doctors inject the thumb joint more accurately. The research found that handheld ultrasound did not improve accuracy compared to injections done without imaging.
An experienced hand surgeon was accurate about 70 to 75 percent of the time with both methods. This tells us that the skill and experience of your doctor matter a great deal.
The authors note that more research is needed. They suggest testing larger groups of patients and comparing handheld devices to traditional ultrasound machines.
If you are considering an injection for your thumb pain, talk openly with your doctor. Ask about their experience and what tools they use. Together, you can make the best choice for your care.
What is important to know?
This article is for educational purposes only. It is not medical advice. Always talk to your doctor or healthcare provider about your specific symptoms and treatment options. Only a qualified medical professional can diagnose your condition and recommend the right treatment for you.
What is the scientific source?
Study Citation:
Hamoudi, Ceyran; Martins, Antoine; Willaume, Thibault; Debordes, Pierre-Antoine; Liverneaux, Philippe; Facca, Sybille (2023). Accuracy of Wireless Hand-Held Guided Ultrasound Injections in the Trapeziometacarpal Joint: A Cadaveric Study. Cureus.