Have you ever thought about how much you use your thumb? Thumb arthritis—which can cause severe pain, stiffness, swelling, and limited range of motion—poses problems in a great number of common activities; for example, holding a pen, opening a door, twisting a jar lid, or snapping your fingers. From an anatomical point of view, the joint that connects the trapezium to the first metacarpal bone is called the thumb carpometacarpal (CMC) joint. The CMC joint swivels, pivots, pinches, and gives you the ability to grasp things in your hand. Because the incongruent contours of the metacarpal and trapezium joint surfaces provide no skeletal stability, however, the CMC joint is the most common site for disabling arthritis in the hand. Physicians believe that thumb CMC joint arthritis is the result of chronic stress to this unique joint.
Osteoarthritis, also called degenerative or “wear-and-tear” joint disease, is a noninflammatory type of arthritis that occurs when the cartilage begins to wear away. As the global population ages, more people—especially women—will face increasing difficulty with daily tasks due to painful thumb arthritis and will look to the medical profession for help. significantly higher among elderly women. Although severe thumb arthritis might require reconstructive surgery, physicians tend to recommend conservative treatment, such as a combination of medication and splints and/or braces; this is because some studies successfully proved that the majority of patients who were treated by wearing a splint along with taking non-steroid anti-inflammatory medication no longer required surgical intervention after one year of treatment. Other short-term clinical research findings also showed that patients given splints/braces experienced decreased pain and stiffness and improvement in daily activities, supported by increased hand grip strength. Additionally, in the UK, for example, the National Collaborating Centre for Chronic Conditions and the evidence-based European League Against Rheumatism (EULAR) recommends splints and/or braces as a primary treatment for thumb CMC osteoarthritis.
Because arthritis is a progressive, degenerative disease, the condition often worsens over time. Following conservative care, the next phase in treatment is a steroid solution injected directly into the joint; however, this cannot be repeated indefinitely. If pain persists, patients now face two options: CMC arthrodesis or CMC arthroplasty. CMC arthrodesis, however, has fallen out of favor because it involves fusing the bones of the joint together, thereby limiting finger movement. It is generally reserved for severe or post-traumatic rheumatoid arthritis. On the other hand, CMC arthroplasty, which removes part of the joint and reconstructs it with an implant made of silicone, has demonstrated initial promising results in terms of an increase in grip and pinch strength, improved range of motion, and decreased pain. However, long-term clinical studies have yielded negative results, such as high incidences of subluxation (i.e. partial dislocation), silicone wear, prosthetic fracture, and bony erosion. Furthermore, orthopedic surgeons in the US, for example, are skeptical about performing CMC arthroplasty due to the legal challenges faced by the now-defunct Swedish company Artimplant due to problems with its Artelon CMC spacer. Specifically, there were numerous complaints and injury cases involving Artelon thumb spacers, with 50 instances reported to the FDA through the time of Artimplant's bankruptcy declaration in August 2013. Additionally, the American Journal of Hand Surgery cited examples of failed Artelon CMC spacer implants and claimed that they were associated with a foreign body reaction, which caused persistent pain. As a result, physician confidence in CMC arthroplasty procedures has been undermined globally.
The future of patients with thumb CMC osteoarthritis is a little unclear; more in-depth clinical studies will thus be conducted to test the safety, efficacy, and cost-effectiveness of the remaining CMC arthroplasty implants on the market in order to combat existing negative publicity and to provide patients with more options for treating their thumbs.
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