If your thumb hurts every time you open a jar or turn a key, you are not alone. Many people live with thumb arthritis at the base of the thumb. This kind of arthritis is called rhizarthrosis or trapeziometacarpal arthritis. It happens where your thumb bone meets your wrist.
When medicine and splints no longer help, doctors sometimes suggest surgery. One option is a special thumb prosthesis. A prosthesis is a medical device that replaces a damaged joint. But does it really work for the long term? A new study looked at nearly 200 patients who got a thumb prosthesis called the MAIA. The researchers wanted to see how well it worked over many years.
Here are three important things from this study:
- The thumb prosthesis lasted well in most patients over 12 years.
- Pain scores went down to very low levels after surgery.
- Most people who had problems needed help only in the first three years.
Key Findings at a Glance
- 88% of MAIA thumb prostheses were still working after 12 years
- Patients reported very low pain levels (only 1 out of 10 on average)
- Only 9% of patients had major complications like dislocation or loosening
- Most dislocations happened in the first 3 years and were often related to how the prosthesis was placed
- The study followed 191 patients from 2001 to 2016
In This Article
What Did This Study Look At?
Researchers looked at 191 patients who received the MAIA trapeziometacarpal prosthesis. This is a thumb joint replacement made in France. The surgery happened between 2001 and 2016 at one medical center. The doctors wanted to see how these prostheses held up over time.
The study followed patients for up to 140 months. That is almost 12 years. Some patients stayed in the study for a shorter time. The shortest follow up was only 17 days. This happened when someone had a problem very early.
You may be wondering why this matters. Long term studies like this tell us if a treatment really works over many years, not just a few months.
How Long Did the Prostheses Last?
According to this study, 88% of the prostheses were still working at the final follow up. That means that out of every 100 patients, 88 still had their original prosthesis in place and working well after many years.
This survival rate is an important measure. It tells us how many devices stayed in the body without needing to be removed or replaced. A survival rate of 88% over 12 years is considered good in joint replacement surgery.
Here is where it gets interesting. The researchers did not just count how many prostheses stayed in place. They also looked at how well patients felt and how the joint worked.
Did Patients Get Pain Relief?
Research shows that patients had very low pain after surgery. The median pain score was only 1 out of 10. Median means the middle number when you line up all the scores from lowest to highest. A pain score uses numbers from 0 to 10. Zero means no pain at all. Ten means the worst pain you can imagine.
A score of 1 out of 10 is almost no pain. This is a big improvement for people who had severe thumb pain before surgery.
The study also measured how well patients could use their hands. They used a test called the Quick Disabilities of the Arm, Shoulder and Hand score. This is shortened to QuickDASH. The median QuickDASH score was 20.
A score of 20 means patients still had some mild difficulty with certain tasks. But it also means they could do most things without much trouble.
What Complications Happened?
No surgery is perfect. This study found that 9% of patients had major complications. Major complications are serious problems that need extra treatment or another surgery.
The study found two main types of major complications:
- 5% of patients had dislocations
- 4% of patients had loosening of the prosthesis
All of the patients who had a dislocation needed another surgery to fix the problem. This is called revision surgery. Revision means going back in to repair or replace something.
Let us look closer at what caused these problems.
When Did Most Problems Occur?
According to this study, the risk of dislocation was highest during the first 3 years after surgery. After that, dislocations became much less common.
The researchers found that most dislocations happened because the trapezium implant was not placed in the perfect position during surgery. The trapezium is the small wrist bone. The implant has to fit into this bone at just the right angle. If it is even slightly off, the prosthesis can pop out of place.
This finding is important for surgeons. It tells them that getting the position exactly right during surgery can prevent problems later.
| Complication Type | Percentage of Patients | What Happens |
|---|---|---|
| Dislocation | 5% | Prosthesis moves out of place |
| Loosening | 4% | Prosthesis does not stay firmly attached |
| Total Major Complications | 9% | Any serious problem needing more treatment |
What Does the Evidence Level Mean?
This study is labeled as Level IV evidence. Evidence levels tell us how strong the research is. Level I is the strongest. Level IV means this is what doctors call a case series. The researchers looked back at patients who already had surgery. They did not compare the prosthesis to other treatments in a controlled way.
This does not mean the study is bad. It gives us valuable information about how the prosthesis works in the real world over many years. But it means we should be careful about making broad conclusions.
Frequently Asked Questions
How long do thumb prostheses usually last?
According to this study, 88% of MAIA thumb prostheses were still working after 12 years. This means most patients kept their prosthesis for a long time without needing it replaced.
Will I still have pain after getting a thumb prosthesis?
Research shows that most patients have very little pain after this surgery. The average pain score was only 1 out of 10, which is very low. Most people feel much better than before surgery.
What are the chances something will go wrong?
Studies indicate that 9% of patients had major complications. This means 91 out of 100 patients did not have serious problems. The most common issue was dislocation, which happened in 5% of patients. Most problems happened in the first 3 years after surgery.
Can I use my hand normally after this surgery?
Most patients can use their hands well after recovery. The average QuickDASH score was 20, which means mild difficulty with some tasks but good overall hand function. You should be able to do most everyday activities.
What Does This Mean for You?
If you have severe thumb arthritis that does not get better with medicine or splints, a thumb prosthesis might be an option for you. This study shows that the MAIA prosthesis can work well for many years.
Most patients in this study had much less pain after surgery. They could use their hands better. And most of the prostheses stayed in place and kept working for over a decade.
Of course, every surgery has risks. About 9 out of 100 patients had serious complications. But the other 91 patients did well. Your doctor can help you decide if this surgery is right for your situation.
The first three years after surgery seem to be the most important. That is when problems are most likely to happen. Good surgical technique matters a lot. Make sure you choose a surgeon who has experience with this type of surgery.
About This Site
We simplify medical science so you can understand your thumb pain and rhizarthrosis better. Every article on this site is based only on published scientific research. We read the medical journals so you do not have to. We explain what the studies really say in words that make sense. Feel free to explore more articles to learn about your condition and your treatment options.
Disclaimer
This article is for information only. It is not medical advice. It does not replace talking to your doctor. Every person is different. Your doctor knows your health history and can give you advice that fits your specific situation. Always talk to a healthcare professional before making decisions about surgery or treatment.
Scientific Source
Study Citation: Chiche, L.; Chammas, P. E.; Vial D’Allais, P.; Lazerges, C.; Coulet, B.; Chammas, M. (2023). Long-term survival analysis of 191 MAIA(R) prostheses for trapeziometacarpal arthritis. Journal of Hand Surgery (European Volume).
Read the full study: https://doi.org/10.1177/17531934221136442
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