CMC arthroplasty is a surgical procedure designed to alleviate pain and restore function in the thumb joint damaged by advanced arthritis. The condition, known as basal joint or carpometacarpal (CMC) arthritis, occurs when the smooth cartilage covering the ends of the bones at the thumb’s base wears away. This deterioration causes bone-on-bone friction, resulting in significant pain, stiffness, and a reduced ability to grip or pinch objects. When non-surgical treatments no longer provide relief, surgery becomes the most effective option.
Understanding the CMC Arthroplasty Procedure
The actual time spent performing CMC arthroplasty surgery is notably short compared to the total time a patient spends at the surgical center. The procedure typically takes between 45 and 90 minutes to complete once the patient is prepped in the operating room. This timeframe can vary based on the specific technique utilized by the surgeon and the unique anatomy of the patient’s hand.
The most common method is the Ligament Reconstruction and Tendon Interposition (LRTI) arthroplasty, which involves the removal of the trapezial bone. The trapezium is one of the small wrist bones that forms the arthritic joint at the base of the thumb. Removing this bone creates a space, eliminating the source of bone-on-bone pain.
After the trapezial bone is excised, the surgeon stabilizes the joint and fills the void to prevent the thumb metacarpal from collapsing into the wrist. This is often achieved using a portion of a nearby tendon, such as the flexor carpi radialis (FCR). The tendon is anchored to reconstruct the ligament and rolled into a soft cushion, sometimes called an “anchovy,” which is placed into the empty space. This reconstructed area provides a stable, pain-free base for the thumb.
Preparation Before Surgery
Preparing for CMC arthroplasty begins well before the scheduled operation date with necessary medical clearances. Patients may need to undergo blood tests or an EKG to ensure they are healthy enough for the procedure and anesthesia. The surgical team will also review all medications, vitamins, and supplements the patient is currently taking.
Patients must stop taking certain medications, particularly nonsteroidal anti-inflammatory drugs (NSAIDs) and blood thinners, at least seven days before surgery to minimize the risk of excessive bleeding. Patients are also instructed to fast (no food or drink) for at least eight hours prior to the procedure to prevent complications related to anesthesia.
Logistical arrangements are required, as the procedure is performed on an outpatient basis. Patients must arrange for a responsible adult to drive them home after the surgery and to stay with them for the first 24 hours. Planning for managing daily tasks post-surgery, especially if the dominant hand is operated on, is important for a successful recovery.
Immediate Postoperative Care and Timeline
Once the surgical reconstruction is complete and the incisions are closed, the patient is transferred to a recovery area for close monitoring. Nurses observe for any adverse reactions to the anesthesia and manage initial pain. A regional nerve block, administered near the collarbone or armpit, often provides profound pain relief that can last for several hours after the procedure.
The thumb and wrist are immobilized immediately with a bulky dressing and a plaster splint or cast to protect the surgical site and the new joint reconstruction. This initial immobilization period is essential for soft tissues to begin healing and typically lasts for 10 to 14 days until the first follow-up appointment. During this time, the hand should be kept elevated above the heart as much as possible to control swelling and reduce pain.
At the first follow-up, the sutures are removed, and the bulky dressing is replaced with a custom-fitted, rigid or semi-rigid thumb spica splint. This lighter, protective splint is worn continuously for a further period, often ranging from two to six weeks, depending on the surgeon’s protocol. While the thumb remains protected, the patient is encouraged to begin gentle exercises for the non-immobilized fingers, elbow, and shoulder to prevent stiffness in the rest of the arm.
Long-Term Rehabilitation and Expected Results
The transition from the initial protective phase to active long-term rehabilitation typically begins around six weeks post-surgery. At this stage, the patient often starts formal hand therapy sessions with a certified hand therapist to regain motion and strength. The initial focus of therapy involves gentle active and passive range-of-motion exercises for the thumb, carefully progressing from simple movements to more complex opposition.
Regaining maximum strength is a gradual process that involves specific exercises using therapeutic putty and resistance bands to rebuild pinch and grip strength. Light activities of daily living are usually permitted around the six to eight-week mark, but heavy gripping, lifting, or demanding physical work is restricted until the twelve-week milestone. The tendon material used in the arthroplasty continues to mature and strengthen over time, providing a solid cushion for the joint.
While significant pain relief is often experienced within the first few months, the full recovery of strength and functional improvement can take between six months and a full year. Patients should anticipate continued progress in their ability to perform demanding tasks well after the initial six-month period. The ultimate goal is to provide lasting pain relief and improve the ability to use the thumb for grasping and pinching activities.