ORTHOPEDICS + SPORTS MEDICINE
Thumb CMC Arthroplasty
Reconstructing the arthritic joint at the base of the thumb to restore pinch, grip, and pain-free use.
The thumb is involved in nearly every grasping and pinching motion the hand performs. When arthritis develops at its base, tasks such as turning a key, opening a jar, writing, or holding a phone can become increasingly painful. Thumb CMC arthroplasty treats the damaged joint while preserving the mobility needed for practical hand use.Surgery is not the starting point for most patients with thumb arthritis.
At Sforzo | Dillingham | Stewart Orthopedics + Sports Medicine, thumb CMC arthroplasty is considered when pain continues despite bracing, medication, activity changes, hand therapy, or injections. The surgical plan reflects the condition of the joint, the stability of the thumb, and the activities the patient hopes to resume.
Anatomy of the Thumb
The carpometacarpal, or CMC, joint is located where the first metacarpal bone of the thumb meets the trapezium, a small bone in the wrist. It is sometimes called the basal joint.
The shape of this joint allows the thumb to move across the palm, rotate, pinch, and oppose the fingers. This wide range of motion is essential to hand function, but it also places substantial force across a relatively small joint.
Healthy cartilage covers the ends of the bones and creates a smooth surface for movement. With thumb CMC arthritis, this cartilage gradually wears down. As the protective surface becomes thinner, the bones can rub against each other and cause pain, swelling, stiffness, and weakness.
How Thumb Arthritis Changes Hand Use
Thumb CMC arthritis often develops gradually. Pain may initially occur only during forceful pinching or gripping, but it can become more persistent as the joint deteriorates.
Patients may notice:
- Pain at the base of the thumb
- Difficulty opening containers or turning doorknobs
- Weakness when pinching or grasping
- Swelling or tenderness near the wrist
- A grinding sensation during thumb movement
- Reduced thumb motion
- A visible prominence or change in the shape of the joint
The severity of arthritis seen on an X-ray does not always match the intensity of the symptoms. Treatment decisions are therefore based on both the condition of the joint and the effect pain has on the patient’s daily life.
When Is Thumb CMC Arthroplasty Considered?
Initial treatment may include a brace that supports the base of the thumb, changes to painful activities, anti-inflammatory medication, topical medication, or a corticosteroid injection. Hand therapy can also introduce joint-protection strategies and exercises to maintain motion and support the thumb.
Surgery may become an option when these treatments no longer provide adequate relief and arthritis begins to limit routine activities. Thumb CMC arthroplasty is generally reserved for patients whose symptoms are significant enough to justify the recovery required after reconstruction.
An examination may include pressure and rotation through the CMC joint to determine whether the movement reproduces pain or grinding. X-rays can show cartilage loss, narrowing of the joint space, changes in bone alignment, and bone spurs. The specialist may also evaluate nearby joints and check for other hand conditions that could affect treatment.
What Happens During Thumb CMC Arthroplasty?
Thumb CMC arthroplasty removes or reshapes the painful arthritic surfaces at the base of the thumb. A common approach involves removing the trapezium, the small wrist bone that forms one side of the damaged joint. Removing this bone prevents the worn joint surfaces from continuing to rub together.
The thumb must then be supported in its new position. Depending on the technique selected, the surgeon may use a portion of a nearby tendon or another stabilizing method to suspend the thumb metacarpal and maintain the space created by the procedure.
Some reconstructions include ligament reconstruction and tendon interposition, often referred to as LRTI. In this approach, tendon tissue helps stabilize the thumb and may be placed within the space left after the trapezium is removed. Other arthroplasty techniques can accomplish similar goals without using the same type of tendon reconstruction.
There is no single operation that is appropriate for every patient. The choice of technique depends on factors such as joint damage, thumb alignment, ligament stability, bone quality, previous surgery, and the physical demands placed on the hand.
Recovery Requires Time and Protection
Thumb CMC arthroplasty involves more than healing a small incision. The reconstructed joint needs time to stabilize before it can tolerate pinching, gripping, and lifting.
A splint or cast is typically used during the early stage of recovery. This protects the surgical area and maintains the thumb in the proper position. Patients can usually move the fingers during this period, but use of the thumb is restricted.
As healing progresses, patients transition to a removable brace and begin controlled thumb movement. Light hand use returns before forceful gripping or pinching. Although timing varies by procedure and patient, recovery commonly takes several months. Grip and pinch strength may continue improving for up to a year.
Physical Therapy After Surgery
Physical therapy is an important part of recovery after thumb CMC arthroplasty. Rehabilitation is introduced according to the surgeon’s protocol so that movement improves without placing excessive stress on the reconstruction.
Therapy may address:
- Swelling and scar management
- Thumb and wrist range of motion
- Proper thumb positioning
- Gradual restoration of grip and pinch strength
- Safe methods for completing daily tasks
- Preparation for work or recreational activities
Attempting strong gripping too early can irritate healing tissues. Following the prescribed progression allows strength to return while the reconstructed thumb base becomes more stable.
When to Consult a Hand Specialist
Thumb-base pain deserves evaluation when it begins interfering with gripping, pinching, writing, cooking, or other regular activities. An assessment is also appropriate when the joint appears swollen, feels unstable, or remains painful despite the use of a brace and activity changes.
A hand specialist can distinguish CMC arthritis from tendon irritation, wrist arthritis, or other sources of pain in the same area. Identifying which structure is responsible helps determine whether continued nonsurgical treatment or reconstructive surgery should be considered.
Summary
Thumb CMC arthroplasty replaces a painful, damaged articulation with a stable reconstruction designed to maintain functional movement. Because the thumb contributes so much to overall hand use, the operation and rehabilitation must balance pain reduction, mobility, and strength.
Careful surgical planning and a gradual therapy program provide the framework for returning to the activities that depend on a comfortable, working thumb.