Osteoarthritis at the base of the thumb, affecting the carpometacarpal (CMC) or basal joint, is a common condition that can significantly impair hand function. This joint, located near the wrist, is responsible for the thumb’s wide range of motion, allowing for pinching and gripping actions. As the protective cartilage within the CMC joint degenerates, the bones rub against each other, causing pain, swelling, and a progressive loss of pinch and grip strength. Treatment follows a tiered approach, starting with non-invasive, conservative strategies and advancing to clinical interventions or surgical reconstruction only when initial methods fail.
Conservative Management and Joint Protection
Managing thumb arthritis begins with self-administered strategies focused on reducing mechanical stress and easing discomfort. Activity modification is a fundamental first step, involving changes to how the hand is used during daily tasks. Simple adjustments, such as using adaptive tools like jar openers or pens with wider grips, help minimize the strong pinch and grip forces that aggravate the CMC joint.
Applying temperature provides symptomatic relief; ice is typically used for acute flare-ups to reduce inflammation, and heat is applied to ease stiffness and muscle tension. The use of orthoses, or splints, is a primary conservative treatment. These devices stabilize the CMC joint, limiting painful movements and providing rest, which is helpful when worn during activities or at night.
Custom-made splints are often preferred over prefabricated options due to better fit and compliance, offering targeted support that restricts movement at the thumb’s base. Alongside splinting, gentle, specialized exercises are important for maintaining hand function without causing irritation. Range-of-motion exercises aim to prevent stiffness, while specific strengthening exercises help stabilize the joint by improving the strength of surrounding muscles.
Clinical Non-Surgical Treatments
When initial home-based care proves insufficient, a healthcare provider may prescribe clinical non-surgical treatments to manage pain and inflammation. Over-the-counter (OTC) and prescription Nonsteroidal Anti-Inflammatory Drugs (NSAIDs) are commonly used. Topical NSAIDs, such as diclofenac gel, are often preferred as a first-line pharmacological option. They are applied directly over the joint, providing localized relief with fewer systemic side effects than oral medications.
If pain persists, a corticosteroid injection directly into the CMC joint is a common next step. This procedure delivers a potent anti-inflammatory medication that can significantly reduce pain and swelling, often providing relief lasting several months. However, these injections are limited in frequency due to the potential for damage to the joint cartilage and surrounding soft tissues with repeated use.
Hyaluronic acid injections, known as viscosupplementation, are sometimes utilized, though they are less established for the small CMC joint than for larger joints like the knee. This substance is intended to improve joint lubrication and shock absorption. Occupational and physical therapy are also an important component of clinical treatment, offering customized hand therapy programs. Therapists provide joint protection education and work to improve strength and function through targeted exercises, helping patients use their thumb in a more stable, less painful position.
Surgical Reconstruction Options
Surgery is typically reserved for individuals with advanced CMC arthritis who experience persistent pain and loss of function despite extensive non-surgical treatment. The goal of surgical intervention is to eliminate the painful friction caused by bone-on-bone contact and restore stability to the thumb. The most common surgical approach is a trapeziectomy, which involves removing the trapezium bone at the base of the thumb.
Following the trapeziectomy, the resulting space is often stabilized through ligament reconstruction and tendon interposition (LRTI). This technique uses a portion of a local tendon to create a cushion or sling, preventing the thumb metacarpal bone from collapsing into the wrist bones. An alternative approach is joint fusion, or arthrodesis, which permanently joins the bones of the CMC joint to eliminate motion and pain.
While fusion provides excellent stability and improved pinch strength, it results in the loss of all mobility at the fused joint. In some cases, a surgeon may consider total joint replacement, or arthroplasty, where the damaged joint surfaces are replaced with an artificial implant. This option is less frequently performed than trapeziectomy with reconstruction, as the long-term durability and failure rates of specialized thumb implants can vary.