Could a Small Implant Really Help Your Thumb Pain for 10 Years?

If you have painful thumb arthritis, you may have heard about different surgeries that can help. One option is a small implant called the Pi2. It is made of a special material called pyrocarbon. Pyrocarbon is a very hard and smooth material that works well inside the body.

A recent study followed 42 people for more than 10 years after they had this implant placed in their thumbs. The results show that most people were very happy with the outcome. Their pain went down and their thumb strength came back.

Here are three key things the study found:

• Almost 97% of patients were satisfied or very satisfied after 10 years.
• The implant did not need to be removed in any patient during the study.
• People returned to daily activities in about 76 days on average.

What Is Rhizarthrosis and Why Does It Hurt?

Rhizarthrosis is the medical name for arthritis at the base of the thumb. This is the joint where your thumb meets your wrist. Over time, the cushion between the bones wears down. This causes pain, stiffness, and weakness. Simple tasks like opening jars or turning keys can become very hard.

You may be wondering why this matters.

When the pain gets very bad, doctors sometimes remove a small bone called the trapezium. The trapezium is a small square bone in your wrist that your thumb rests on. Removing it creates a gap. The Pi2 implant fills that gap and keeps your thumb stable.

What Is the Pi2 Implant?

The Pi2 is a tiny implant shaped like a small button. It is made from pyrocarbon. Pyrocarbon is a material that feels smooth like your natural cartilage. Cartilage is the slippery cover on the ends of bones that helps them glide smoothly.

Here is where it gets interesting.

The implant is not screwed or glued into place. It sits freely between the bones. Your body holds it in place naturally. Doctors call this a free interposition implant. Interposition means placed between two things.

Who Was in the Study?

According to this study, researchers followed 42 people who had the Pi2 implant placed between March 2003 and April 2005. Most were women. There were 34 women and 5 men. The average age was 63 years old. Most of the people were retired.

All of them had severe thumb arthritis. The doctors used a system called the Dell classification. This system ranks arthritis from stage 1 to stage 4. Stage 4 is the most severe. Everyone in this study had stage 3 or stage 4 arthritis.

The researchers checked on these people for more than 10 years. The average follow up time was 125 months. That is about 10 and a half years.

What Happened After Surgery?

Research shows that the results were very good. Almost all patients were happy with the outcome. Specifically, 96.6% said they were satisfied or very satisfied.

Let us look closer.

Pain improved a lot. Doctors measured pain using a visual analogue scale. This is a simple tool where you point to a number between 0 and 10. Zero means no pain. Ten means the worst pain you can imagine.

Thumb movement also got much better. The study used something called the Kapandji index. This measures how well you can touch your thumb to different parts of your hand. The average score was 9.60 out of 10. That is excellent.

The study also found that the metacarpophalangeal joint did not suffer. The metacarpophalangeal joint is the big knuckle at the base of your thumb. Sometimes after thumb surgery, this joint bends backwards too much. That did not happen much in this study.

How Strong Did Thumbs Become?

Strength is very important for daily life. Studies indicate that after surgery, the average pinch strength was 5.9 kilograms. Pinch strength is how hard you can squeeze your thumb and finger together. The average grip strength was 24.2 kilograms. Grip strength is how hard you can squeeze your whole hand around something.

These numbers mean people could do most everyday tasks without trouble.

The study also measured function using two scoring systems. One is called the QuickDASH. It asks questions about daily activities. The average QuickDASH score was 19.9 out of 100. Lower scores mean better function. So 19.9 is a good score.

The other system is called the PRWE. It stands for Patient Rated Wrist Evaluation. The average PRWE score was 16.4 out of 100. Again, lower is better. This shows that patients had very little trouble with their wrists and thumbs.

Were There Any Problems?

Medical evidence shows that some patients had bone changes on x-rays. About 48.2% of patients had some bone remodeling. Remodeling means the bone changed shape slightly over time. This happened mostly in a bone called the scaphoid. The scaphoid is another small bone in your wrist near the thumb.

You may be wondering if this is dangerous.

According to this study, the bone changes did not cause any pain or problems. They were stable between 5 and 10 years. That means they did not get worse over time.

Two patients had a dislocation. Dislocation means the implant moved out of place. This happened in 4.6% of cases. But here is the good news. Neither patient needed another surgery to fix it. The researchers said these dislocations happened early in their experience. As the surgeons got better at placing the implant, dislocations stopped happening.

Research shows that no implant needed to be removed during the 10 year follow up. The implant survival rate was 100%. This is very impressive.

Why Did the Implant Work So Well?

The study authors said the Pi2 works well because it keeps the thumb at the right height. When you remove the trapezium bone, the thumb can sink down. This can cause the metacarpophalangeal joint to bend backwards too much. That joint can become painful.

The Pi2 implant acts like a spacer. It keeps the bones apart. This protects the joint from bending the wrong way.

Frequently Asked Questions

Conclusion

The Pi2 pyrocarbon implant offers real hope for people with severe thumb arthritis. This 10 year study shows that it works well and lasts a long time. Almost all patients were happy with the results. They had less pain, better movement, and good strength.

If you have thumb pain that does not get better with other treatments, this may be an option to discuss with your doctor. The surgery does require a skilled hand surgeon who knows how to place the implant correctly.

Remember that every person is different. Your doctor can help you decide if this surgery is right for you.

Disclaimer

This article is for informational purposes only. It is not medical advice. Always talk to your doctor or a qualified healthcare provider before making any decisions about your health or treatment. Only a medical professional can diagnose your condition and recommend the best treatment for you.

Article Source

Agout, Charles; Bellemère, Philippe; Ardouin, Ludovic (2016). A 10-Year Prospective Outcome Study of Pi2 Pyrocarbon Arthroplasty for the Treatment of Thumb Metacarpal Joint Osteoarthritis. Hand.

https://doi.org/10.1177/1558944716660555d