If you have thumb pain at the base of your thumb that makes everyday tasks hard, you are not alone. Many people live with thumb arthritis, also called rhizarthrosis. Sometimes doctors suggest a small artificial joint to replace the damaged one. But you may wonder: does it really last? And does it work well over time?
A recent study looked at a specific thumb joint replacement called the ISIS prosthesis. Researchers followed 77 thumb implants in 66 people for more than five years. They wanted to see how well the implant worked and how long it lasted.
Here are three important things they found:
- Pain and hand function improved a lot after surgery.
- The prosthesis stayed in place and working in 94 out of 100 cases.
- Using screws to attach one part of the implant worked better than using cement.
Key Findings at a Glance
- Researchers followed 77 thumb joint replacements for an average of almost nine years.
- Pain and function improved significantly after surgery.
- The survival rate of the implant was 94%, meaning it stayed in place and working in most people.
- Screwed cups loosened less often than cemented cups.
- Only five implants needed to be removed and replaced during the study period.
What is a thumb joint replacement?
Your thumb connects to your wrist at a special joint. This joint is called the trapeziometacarpal joint, or TMC joint for short. It is the joint at the very base of your thumb where it meets your hand.
When arthritis damages this joint badly, one treatment option is to replace it with an artificial joint. This is called a prosthesis. A prosthesis is a man made part that takes the place of your natural joint.
The ISIS prosthesis has two main parts. One part fits into the trapezium bone in your wrist. The other part fits into the metacarpal bone in your thumb. These two parts work together like a ball and socket so your thumb can move.
What did this study find?
According to this study, researchers in France looked at 77 ISIS implants placed in 66 people. They checked on these patients for a very long time. The average follow up was almost nine years. That means they watched how well the implants worked for nearly a decade.
You may be wondering why this matters. Long term results tell us if a treatment truly helps over many years, not just for a few months.
Research shows that pain levels went down after surgery. Function improved too. Function means how well you can use your hand to do everyday things like gripping, pinching, and holding objects.
How well did the implant work?
The survival rate of the ISIS prosthesis was 94%. This means that in 94 out of every 100 cases, the implant stayed in place and kept working during the study period.
| Outcome | Result |
|---|---|
| Survival rate | 94% |
| Average follow up time | 107.5 months (almost 9 years) |
| Implants removed | 5 out of 77 |
This is a strong result. It tells us that most people who get this implant can expect it to last for many years.
Here is where it gets interesting. The researchers also found that pain and hand function improved significantly. Significantly means the improvement was big enough to make a real difference in daily life. It was not just a small change.
What problems happened?
No surgery is perfect. Some complications can happen. Let us look closer at what went wrong in this study.
On x rays, doctors saw that 14 cups appeared to have loosened. The cup is the part that fits into the wrist bone. When a cup loosens, it can move slightly inside the bone. This can cause pain or make the implant not work as well.
Three stems also appeared to have loosened. The stem is the part that fits into the thumb bone.
Only five implants needed to be removed and replaced. This is a small number compared to the 77 implants studied. The surgery to remove an implant is called revision surgery.
Four of the removed implants were cups that had been attached with cement. One was a stem that had loosened.
One person had a dislocation. Dislocation means the two parts of the implant came apart from each other. This is rare but it did happen once during the study.
Which type of cup worked better?
The ISIS prosthesis can be put in place in two different ways. The cup can be attached with bone cement or it can be attached with small screws.
Studies indicate that the screwed cups loosened less often than the cemented cups. The researchers found this difference was statistically significant. That means it was not just by chance.
According to this study, using a screwed cup instead of a cemented one appears to prevent loosening. It also seems to lower the need for revision surgery.
This finding is important for surgeons. It helps them choose the best way to attach the implant. It may also help more implants last longer.
Common questions
How long does a thumb joint replacement last?
According to medical evidence from this study, the ISIS prosthesis had a 94% survival rate at an average follow up of almost nine years. This means most implants stayed in place and working for that long.
Will my thumb pain go away after joint replacement?
Research shows that pain improved significantly after surgery in this study. Many people experience much less pain and better hand function after a thumb joint replacement.
What can go wrong with a thumb implant?
Studies indicate that loosening of the implant parts is the most common problem. In this study, 14 cups and 3 stems loosened on x rays. Only five implants needed to be removed. One dislocation also occurred.
Is a screwed cup better than a cemented cup?
According to this research, screwed cups loosened less often than cemented cups. Using screws appears to be a better choice for attaching the cup part of the implant.
About this site
This website helps people like you understand medical science about thumb pain and rhizarthrosis. We read published scientific articles and explain them in simple language. Everything we share comes from real research done by doctors and scientists. We never make up facts. If you want to learn more about your thumb pain and treatment options, explore more articles on this site. You are taking an important step by learning about your health.
What this means for you
If you suffer from painful thumb arthritis that does not get better with other treatments, a joint replacement may be an option. The ISIS prosthesis appears to be a reliable choice. It lasts for many years in most people. Pain and function improve after surgery.
The risk of problems is low. Only a small number of implants need to be removed. If you do need this surgery, ask your surgeon which type of cup they plan to use. Research suggests that screwed cups may work better than cemented ones.
Every person is different. Talk with your doctor about what is best for your situation. This information can help you have a good conversation with your medical team.
Disclaimer
This article is for educational purposes only. It is not medical advice. It does not replace a visit with your doctor. Always talk to a qualified healthcare provider about your symptoms and treatment options. Only a doctor who examines you can give you personal medical advice.
Research source
Fauquette, P. J.; Deken-Delannoy, V.; Chantelot, C.; Saab, M. (2023). The ISIS(R) prosthesis in 77 cases of trapeziometacarpal arthritis: outcomes and survival at a minimum follow-up of 5 years. Journal of Hand Surgery (European Volume).
https://doi.org/10.1177/17531934221123166
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