Thumb CMC Arthritis

What is thumb CMC arthritis?

Thumb CMC arthritis is degeneration of the thumb metacarpal, which articulates with the trapezium, known as the carpometacarpal joint (CMC joint).

What are the causes of thumb CMC arthritis?

There are three primary reasons for developing thumb CMC arthritis: genetics (family history), trauma (such as a car accident or sports injury), and repetitive overuse (heavy labor job or occupations such as hairdresser). All patients have all three components, but the percent contribution varies by patient.

What are the symptoms of thumb CMC arthritis?

Patients present with pain at the thumb CMC joint. The pain occurs with activities such as pinching a key, turning a door knob, and opening a jar. There is often swelling, deformity, and tenderness at the base of the thumb.

How is thumb CMC arthritis diagnosed?

On physical exam, the physician is often able to reproduce the pain, and radiographs help confirm the diagnosis. There are four grades of thumb CMC arthritis on X-ray. Eaton Grade 1 and 2 show mild changes with small bone spurs. Eaton Grade 3 has larger bone spurs, greater than 2mm, and significant joint space loss. Eaton Grade 4 includes the STT joint and is the most severe grade.

X-ray of Eaton Grade 3 thumb CMC arthritis

Conservative treatment of thumb CMC arthritis

Conservative treatment consists of rest, avoiding painful activities, splinting, anti-inflammatories, and injections. Low-profile braces, such as a meta grip splint, can help control pain. Through measures such as these, CMC arthritis can often be managed for months to years. Injections consist of corticosteroids and platelet-rich plasma. Corticosteroid injections can provide near-immediate pain relief, and 1-3 injections can be utilized over 1-2 years. Unfortunately, they cannot be used long-term as they cause additional joint and soft tissue degeneration. Platelet-rich plasma is a newer treatment option where a patient’s blood is placed in a centrifuge, and the platelets are filtered out. Platelet-derived growth Factor( PDGF) is isolated and injected into the joint. This growth factor is similar to a stem cell and can facilitate cartilage healing in the joint. The cartilage can take several months to heal, and multiple injections may be needed, but this is an exciting natural way to treat CMC arthritis.

Surgical treatment of thumb CMC arthritis

There are three basic surgical options for thumb CMC arthritis: thumb denervation procedure, thumb CMC Arthroplasty, and thumb CMC fusion.

Thumb denervation procedure

The thumb denervation procedure is a newer option for treating thumb CMC arthritis. Anatomic dissections have isolated some deep nerves that provide the pain fibers to the thumb CMC joint. By severing, excising, and cauterizing these nerves, the pain associated with CMC arthritis can be alleviated. The surgery involves an incision over the thumb CMC joint. The specific nerves isolated are the thenar branches of the median nerve, the articular branches of the palmar cutaneous nerves, the articular branches of the radial sensory nerve, and the articular branches of the radial sensory nerve. These nerves are isolated, excised, and cauterized through delicate and meticulous dissection. All of this is accomplished without disturbing the CMC joint. The major advantage of this procedure is the recovery is very fast. Since it is only a soft tissue procedure, recovery is the time it takes the incision to heal, usually several weeks. Since only articular branches are excised, patients do not lose sensation; they just get pain relief. Not everyone is a candidate for this procedure, which will be considered and discussed during your visit.

Thumb CMC arthroplasty / suspensionplasty

The most traditional surgical procedure for thumb CMC arthritis is called a CMC arthroplasty. The basics of this procedure have been performed for over 50 years, but recent improvements have resulted in more function, strength, and faster return to use than traditional procedures. The fundamentals of CMC arthroplasty involve removing the arthritic trapezium. Tendons within the surgical field, the FCR and APL tendons, are then used internally to “suspend” the thumb with a very strong suture configured as a “hammock” or “sling.” It’s important to know that these tendons are not removed as in the original “anchovy” procedure, allowing for a faster and less painful recovery. In addition, an “internal brace” is used to connect the thumb metacarpal to the index metacarpal, providing even more suspension and fixation. One advantage of this procedure is that motion is allowed soon after surgery with a removal splint and full use of the fingers but not the thumb.

Thumb CMC fusion

Thumb CMC fusion is another procedure used for thumb CMC arthritis. In thumb CMC fusion, the trapezium is not removed but “fused” to the thumb metacarpal. This is typically done with a metal plate and bone graft. Both surgical procedures provide for a strong thumb, but CMC fusion may allow for more strength and may be used in patients who need more strength for things like heavy labor jobs. CMC fusion, in theory, makes the thumb a little stiffer, but in practicality, patients have an excellent function.

X-ray of Eaton Grade 3 thumb CMC Arthritis with subluxation of the joint

X-ray of thumb CMC fusion in the patient above

Dr. Sachar will discuss which of the three surgical procedures is best for you based on many factors, including your exam, X-rays, and personal preference.

Rehabilitation after thumb CMC surgery

The thumb denervation procedure has minimal therapy requirements. After surgery, the patient is placed in a splint for 5-7 days. Motion is started at the first postoperative visit, and once the wound is healed, the patient can build toward normal activities. Most patients are doing most things within 3 weeks. Full activity is allowed as soon as the activity can be tolerated.

In thumb, CMC Arthroplasty and CMC fusion, a similar splint, are used for the first 5-7 days. At the first postoperative visit, patients are placed in a removable splint that covers the thumb and wrist but allows full finger motion. The CMC joint is not moved much for the first month, but all other joints are moved, and basic daily activities are allowed. After one month, patients are switched to a hand-based splint, and CMC motion is started. At 2 months, patients start building strength, and the split is used only for protection. At 3 months, patients are allowed to begin sports activities as tolerated. It is important to know that it takes approximately 9 months to build full strength, and activities like golf, skiing, and mountain biking may take 4-6 months to resume, varying by patient. Our goal is to get patients back to all activities as soon as possible, and therapy is geared towards resuming normal activities.