Relief for Base of Thumb Pain
Do you feel a sharp pain at the base of your thumb when you turn a key, open a jar, or pinch a zipper? You might be experiencing arthritis of the thumb basal joint (CMC joint). It is one of the most common hand conditions we treat at California Pacific Orthopaedics in San Francisco. Our specialists are here to help you stop the pain and regain your grip.
Overview: What is Thumb CMC Arthritis?
The thumb is the most important digit on your hand. It separates us from most other animals because it allows us to pinch and grasp objects. This movement happens at a specialized joint near your wrist called the Carpometacarpal (CMC) joint, often called the basal joint.
The CMC joint is shaped like a saddle. This shape gives your thumb incredible flexibility—it can pivot, swivel, and pinch. However, this flexibility comes at a cost. Because the joint moves so much, it is prone to wearing out.
Osteoarthritis (wear-and-tear arthritis) occurs when the smooth cushion of cartilage that covers the ends of the bones wears away. In the thumb, this happens between the metacarpal bone of the thumb and a small wrist bone called the trapezium.
When the cartilage is gone, these two bones rub against each other—bone on bone. This friction causes inflammation, pain, and eventually damage to the joint structure.
Common Symptoms
Thumb arthritis often starts slowly. You might notice an ache after a day of gardening or typing. Over time, the pain becomes more frequent.
Key signs of CMC arthritis include:
- Pain with Pinching: A sharp, stabbing pain at the base of the thumb when you use a “pinch” grip (like turning a key or pulling up a zipper).
- Deep Aching: A dull, constant ache deep in the fleshy part of the thumb near the wrist.
- Weakness: You might drop things or find you simply cannot open jars anymore.
- Deformity: As the condition gets worse, the base of the thumb may look swollen or “squared off.” You might develop a bony bump.
- Limited Motion: Your thumb may feel stiff, making it hard to pull it away from your palm.
Causes and Risk Factors
Why does this happen? For most people, it is simply a matter of time and anatomy.
The “Saddle” Problem
Because the CMC joint is shaped like a saddle, it relies on strong ligaments to stay in place. If these ligaments become loose over time, the bones slide around too much with every movement. This sliding wears down the cartilage faster, leading to arthritis.
Who is Most at Risk?
- Age: It is most common in people over age 40.
- Gender: Women are 10 to 20 times more likely to develop this condition than men. This is likely due to looser ligaments and hormonal factors.
- Genetics: If your mother or grandmother had “knobby thumbs” or thumb pain, you are more likely to have it too.
- Previous Injury: A past fracture or severe sprain of the thumb can disrupt the joint surface and lead to arthritis years later.
- Job History: Jobs that require high-force pinching or repetitive gripping (like assembly work or dentistry) can stress the joint over time.
Diagnosis: How We Find the Problem
At California Pacific Orthopaedics, diagnosing thumb arthritis is usually straightforward. We combine a physical exam with imaging to see exactly what is going on inside your hand.
Physical Exam
Your doctor will ask about your symptoms and examine your hand. They may perform a specific test called the “Grind Test.” During this test, the doctor gently applies pressure to your thumb and rotates it. If this reproduces your pain or causes a gritty feeling (crepitus), it is a strong sign of arthritis.
X-Rays
X-rays are the gold standard for diagnosing CMC arthritis. They allow us to see:
- Joint Space: In a healthy thumb, there is a gap between the bones where the cartilage sits. In an arthritic thumb, the bones are touching.
- Bone Spurs: We look for osteophytes (bone spurs) that form as the body tries to stabilize the worn-out joint.
- Alignment: We check to see if the bones have shifted out of place (subluxation).
Non-Surgical Treatment Options
The good news is that many patients can manage their symptoms without surgery. We always explore these options first.
- Splinting: A soft or rigid brace (called a thumb spica splint) supports the joint and gives the ligaments a rest. Many patients find relief just by wearing this at night.
- Hand Therapy: A certified hand therapist can teach you how to use your hand differently to protect the joint (joint protection techniques) and strengthen the muscles that stabilize the thumb.
- Medication: Over-the-counter anti-inflammatories (like ibuprofen) or topical gels (like Voltaren) can help reduce pain.
- Cortisone Injections: If splints aren’t enough, a steroid injection directly into the joint can provide powerful relief. This reduces inflammation and can “calm down” the arthritis for several months.
Surgical Treatment Options
If you have tried splinting and injections but your pain still limits your daily life, surgery may be the best path forward. San Francisco is home to some of the nation’s best hand surgeons, and our team at Cal Pac Ortho uses the most advanced techniques.
Ligament Reconstruction and Tendon Interposition (LRTI)
This is the “gold standard” surgery for thumb arthritis and has been used successfully for decades.
- The Procedure: The surgeon removes the arthritic bone (the trapezium). This immediately eliminates the bone-on-bone grinding.
- The Cushion: To fill the empty space, the surgeon takes a small portion of a tendon from your forearm. They roll it up like a standard anchovy or a ball of yarn and place it in the gap to act as a soft cushion.
- The Result: This provides a new, pain-free “joint” that allows you to keep your motion.
Suspensionplasty (TightRope®)
This is a newer variation of the surgery.
- The Procedure: Like LRTI, the arthritic bone is removed.
- The Suspension: Instead of using a large piece of tendon to fill the gap, the surgeon uses a specialized suture (heavy thread) or a small button implant to “suspend” the thumb metacarpal bone. This prevents it from collapsing into the space where the removed bone used to be.
- The Benefit: Recovery can sometimes be slightly faster because less tendon is harvested.
Thumb CMC Fusion
In this procedure, the two bones are permanently joined together.
- The Result: The pain is gone because the joint no longer moves. However, you lose the ability to perform certain motions. This is typically reserved for heavy laborers who need strength more than flexibility.
What to Expect: Recovery
Recovery from thumb surgery is a process, but the long-term results are excellent.
- Immediately After: You will go home the same day with a bulky dressing or cast. Your hand will be numb for several hours.
- First 2 Weeks: You must keep the hand elevated and dry. You won’t be able to use the thumb.
- 2 to 6 Weeks: You will transition to a cast or a removable splint.
- Therapy: Around 4 to 6 weeks, you will start working with a hand therapist. They will help you regain motion.
- Full Recovery: Most patients return to light activities by 8 weeks. Full grip strength usually returns around 3 to 6 months. While it takes time, most patients are thrilled to be pain-free for the first time in years.
Why Choose California Pacific Orthopaedics?
Thumb arthritis can make you feel helpless, robbing you of the ability to do simple things like writing a note or opening a door. You need a specialist who understands the intricate mechanics of the hand.
- Fellowship-Trained Experts Our hand surgeons have undergone rigorous fellowship training specifically in the treatment of the hand and upper extremity. We perform hundreds of thumb procedures every year for patients across the Bay Area.
- A Focus on Function We don’t just treat X-rays; we treat people. Whether you are a musician who needs dexterity or a construction worker who needs power, we tailor our treatment plan to your specific goals.
- San Francisco Convenience Located centrally in San Francisco, we offer comprehensive care—from diagnosis and X-rays to injections and surgery—all within our network.
Get Your Grip Back
Don’t let thumb pain dictate your life. Contact us today to schedule a consultation with one of our San Francisco hand specialists. Let’s see if we can help you live pain-free.
