Thumb CMC Arthritis

Three things drive thumb CMC arthritis, and most patients have some of each:

• Genetics. A family history of hand arthritis is the strongest predictor.
• Injury. A fall, a car accident or a sports injury that damages the joint or its ligaments can start the wear years earlier than it would otherwise begin.
• Repetitive use. Heavy-labor jobs and occupations that pinch and grip all day, such as hairdressing, load the joint thousands of times a day.

Women are affected more often than men, and it becomes more common after age 40.

The main symptom is pain at the base of the thumb with everyday pinching and turning: turning a key, opening a jar, turning a doorknob, writing or texting. Many patients also notice:

• swelling and tenderness at the base of the thumb
• a bump or a change in the shape of the thumb base as the joint slips out of position
• loss of pinch strength and dropping objects
• stiffness, and pain that is worse after use

Dr. Sachar can usually reproduce the pain on a physical exam by pressing on the joint and grinding it gently. X-rays confirm the diagnosis and show how far the arthritis has progressed. Thumb CMC arthritis is graded on X-ray using the Eaton scale:

• Grades 1 and 2 show mild changes with small bone spurs.
• Grade 3 shows larger bone spurs, narrowing of the joint space and often slippage of the joint.
• Grade 4 means the arthritis has spread to the neighboring joint between the trapezium and the scaphoid.

The grade helps guide treatment, but symptoms matter more than the X-ray. Some patients with advanced X-ray changes have little pain, and some with early changes have a lot.

Treatment starts conservatively, and many patients manage thumb CMC arthritis for years without surgery:

• Rest and activity changes. Avoiding the pinching and twisting activities that hurt.
• Splinting. A low-profile brace, such as a metagrip splint, supports the joint and controls pain without immobilizing the whole hand.
• Anti-inflammatory medication. Over-the-counter medicines such as ibuprofen reduce swelling and pain.
• Injections. A steroid injection into the joint can calm a flare for weeks to months.

When these measures stop working and the pain interferes with daily life, surgery becomes an option.

There are three basic surgical options for thumb CMC arthritis. Dr. Sachar will talk through which fits you best based on your exam, your X-rays, how you use your hands and your own preference.

Thumb denervation

A newer, smaller procedure. Anatomic studies have identified the small nerves that carry pain signals from the CMC joint. Cutting and sealing those nerves relieves the pain while leaving the joint itself alone, so strength and motion are preserved and recovery is fast. It is a good option for patients who want relief without a joint reconstruction.

Thumb CMC arthroplasty (suspensionplasty)

The traditional operation, performed for more than 50 years and refined considerably in recent years. The worn trapezium bone is removed and the thumb metacarpal is suspended in its place using a tendon or a suture construct. Modern techniques give more strength, better function and a faster return to use than the older versions of the procedure.

Thumb CMC fusion

The trapezium is kept and fused to the thumb metacarpal with a small plate and bone graft, so the joint no longer moves. Fusion gives a strong, stable, pain-free thumb at the cost of some motion, and it is often chosen for younger, heavier-use hands.

Touch CMC prosthesis

Dr. Sachar also offers the Touch CMC prosthesis, a recently FDA-approved implant that replaces the joint, similar to a small hip replacement. With more than 120,000 cases in Europe, it has a long track record of restoring motion and pinch strength quickly. Not every thumb is a candidate; Dr. Sachar will tell you whether yours is.

Thumb denervation needs very little therapy. A splint is worn for five to seven days, motion starts at the first post-operative visit, and once the incision has healed patients build back toward normal activity over a few weeks.

Arthroplasty and fusion start with the same five-to-seven-day splint. At the first post-operative visit a removable splint that covers the thumb and wrist but leaves the fingers free replaces it. The thumb joint is protected for several weeks while it heals, then hand therapy rebuilds motion and strength. Most patients are back to light daily use within about six weeks and to full strength over three to six months, with fusion taking somewhat longer to consolidate than arthroplasty.

Whichever procedure is chosen, the goal is the same: a thumb you can pinch and grip with, without pain.

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