Arthritis affecting the thumb most commonly involves the carpometacarpal (CMC) joint, located at the base where the thumb meets the wrist. This condition develops when the smooth, protective cartilage covering the ends of the bones wears away, leading to friction between the trapezium bone and the first metacarpal bone. This degeneration causes inflammation, pain, and a progressive reduction in the ability to move the thumb effectively. The CMC joint is particularly susceptible to this wear-and-tear because it is highly mobile, allowing for the wide range of motion necessary for pinching and gripping.
Recognizing the Symptoms of Thumb Arthritis
The first and most persistent sign of CMC joint arthritis is often a deep, aching pain felt directly at the base of the thumb. This discomfort typically worsens with activities that involve grasping, pinching, or twisting motions, such as turning a key or opening a jar. Tenderness can be localized by simply pressing on the joint, and many individuals notice that their thumb feels weak when trying to hold objects firmly.
As the condition progresses, mechanical changes become more apparent, sometimes manifesting as stiffness or swelling over the area. A characteristic symptom is a grating or grinding sensation, known as crepitus, which can be felt or heard when the thumb is moved. This sensation is caused by the rough, exposed bone surfaces rubbing against each other. These symptoms collectively indicate joint instability and degeneration.
First-Line Non-Surgical Treatments
Initial management strategies focus on reducing inflammation, alleviating pain, and modifying activities to protect the affected joint. Changing how everyday tasks are performed, such as using larger handles or avoiding forceful pinching, can significantly decrease the stress placed on the CMC joint. This modification helps to interrupt the cycle of irritation and inflammation that drives the pain.
Pharmacological options often begin with over-the-counter non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen or naproxen, taken orally to reduce both pain and swelling throughout the body. For more localized relief, topical NSAID gels containing diclofenac can be applied directly over the painful joint, offering targeted anti-inflammatory benefits with potentially fewer systemic side effects. These medications work by inhibiting enzymes involved in the body’s inflammatory response.
A cornerstone of non-surgical treatment involves external support and immobilization using specialized orthotics or splints. A thumb spica splint or a specific CMC restriction orthosis stabilizes the joint and limits the destructive movement of the first metacarpal bone. Wearing the splint primarily during activities or at night provides substantial pain relief by holding the joint in a position of rest and proper alignment.
Physical or occupational therapy is frequently employed to address muscle imbalances around the hand and wrist. Therapists focus on exercises designed to strengthen the muscles that stabilize the thumb, particularly the first dorsal interosseous and the thenar muscles. Strengthening these muscle groups provides dynamic support to the CMC joint, improving its function without increasing damaging forces. This approach aims to maximize the functional use of the hand.
Advanced and Interventional Procedures
When conservative measures fail to provide adequate pain relief, healthcare providers consider interventional procedures, primarily joint injections. Corticosteroid injections are the most common advanced treatment, involving the delivery of a potent anti-inflammatory medication directly into the CMC joint space. This procedure typically includes a mix of a corticosteroid (such as triamcinolone or methylprednisolone) and a local anesthetic to immediately numb the area.
The goal of the corticosteroid is to rapidly suppress the inflammation within the joint capsule, which is a major source of pain. While the pain relief can be profound, it is generally temporary, lasting anywhere from a few weeks to several months before the symptoms recur. Due to potential side effects, including local tissue atrophy and possible cartilage damage, these injections are usually limited to three or four per year per joint.
Other injectable therapies are sometimes utilized, though they are considered less conventional for CMC arthritis. Viscosupplementation involves injecting hyaluronic acid into the joint to improve lubrication, mimicking healthy cartilage. Platelet-rich plasma (PRP) injections utilize a concentration of the patient’s own growth factors to potentially promote a healing environment. However, the long-term efficacy and insurance coverage for hyaluronic acid and PRP are variable compared to established corticosteroid treatments.
Surgical Solutions
Surgery becomes an option when non-surgical treatments have failed to control pain and the arthritis significantly limits a person’s ability to perform daily functions. The decision to proceed with a surgical intervention is typically reserved for advanced stages of the disease where the joint is severely damaged. The primary goal of surgery is to eliminate the painful bone-on-bone contact that occurs during movement.
The most common surgical procedure for CMC arthritis is trapeziectomy, which involves removing the trapezium bone entirely. This removal creates a space that prevents the metacarpal bone from rubbing against the wrist bones. Often, the surgeon follows the trapeziectomy with a ligament reconstruction tendon interposition (LRTI), where a tendon is harvested and used to stabilize the thumb base and fill the void.
Another surgical method is arthrodesis, or joint fusion, which locks the first metacarpal bone to the trapezium using plates, screws, or wires. This procedure eliminates all motion at the CMC joint, thereby eradicating the pain caused by movement. While fusion results in a permanent loss of motion, it provides maximum joint stability and strength, making it a preferred choice for younger individuals or those whose occupations require heavy gripping and pinching forces.