Carpometacarpal (CMC) osteoarthritis (OA), also known as trapeziometacarpal osteoarthritis or osteoarthritis at the base of the thumb, is a reparitive joint disease affecting the first carpometacarpal joint (CMC1). This joint is formed by the trapezium bone of the wrist and the first metacarpal bone of the thumb. Because of its relative instability, this joint is a frequent site for osteoarthritis. Carpometacarpal osteoarthritis (CMC OA) of the thumb occurs when the cushioning cartilage of the joint surfaces wears away, resulting in damage of the joint.
The main complaint of patients is pain. Pain at the base of the thumb occurs when moving the thumb and might eventually persist at rest. Other symptoms include stiffness, swelling and loss of strength of the thumb. Treatment options include conservative and surgical therapies.
Thumb arthritis commonly occurs with aging. Previous trauma or injury to the thumb joint also can cause thumb arthritis.
In a normal thumb joint, cartilage covers the ends of the bones — acting as a cushion and allowing the bones to glide smoothly against each other. With thumb arthritis, the cartilage that covers the ends of the bones deteriorates, and its smooth surface roughens. The bones then rub against each other, resulting in friction and joint damage.
The damage to the joint might result in growth of new bone along the sides of the existing bone (bone spurs), which can produce noticeable lumps on your thumb joint.
Factors that can increase your risk of thumb arthritis include:
- Female sex.
- Age above 40 years.
- Certain hereditary conditions, such as joint ligament laxity and malformed joints.
- Injuries to your thumb joint, such as fractures and sprains.
- Diseases that change the normal structure and function of cartilage, such as rheumatoid arthritis. Although osteoarthritis is the most common cause of thumb arthritis, rheumatoid arthritis can also affect the CMC joint, usually to a lesser extent than other joints of the hand.
- Activities and jobs that put high stress on the thumb joint.
- Pain with activities that involve gripping or pinching, such as turning a key, opening a door, or snapping your fingers
- Swelling and tenderness at the base of the thumb
- An aching discomfort after prolonged use
- Loss of strength in gripping or pinching activities
- An enlarged, “out-of-joint” appearance
- Development of a bony prominence or bump over the joint
- Limited motion
During a physical exam, your doctor will ask about your symptoms and look for noticeable swelling or lumps on your joints.
Your doctor might hold your joint while moving your thumb, with pressure, against your wrist bone. If this movement produces a grinding sound, or causes pain or a gritty feeling, the cartilage has likely worn down, and the bones are rubbing against each other.
Imaging techniques, usually X-rays, can reveal signs of thumb arthritis, including:
- Bone spurs
- Worn-down cartilage
- Loss of joint space
Arthritis is different in each individual. There are a variety of treatments that may work for your particular symptoms.
Initial treatment options involve:
- application of ice
- steroid injections
If these methods do not relieve pain and improve function, the joint may need to be reconstructed with surgery.
As with any form of arthritis, it is important to talk to your doctor before treating your condition, especially before taking any medications.
Exercise for your thumbs
Your doctor or a physical therapist may recommend hand exercises. You can do these exercises to improve range of motion and improve your arthritis symptoms.
Simple exercises can include a thumb stretch, in which you attempt to touch the tip of your thumb to just under your pinky finger.
Another stretch, called IP, uses flexion. It requires you to hold your thumb stable with your other hand and attempt to bend just the upper part of the thumb. And an additional exercise is to simply touch the tips of each of your fingers to the tip of your thumb.
You should only do these exercises after consulting with your doctor or physical therapist. And be sure to get instructions to make sure you’re doing the movements correctly.
Medications for thumb arthritis
Medications used for pain include over-the-counter (OTC) medications, prescription medications, and injectable medications.
OTC medications that can help with pain include acetaminophen (Tylenol), nonsteroidal anti-inflammatory drugs (NSAIDs), and supplements.
There are supplements with some evidence of efficacy. These include glucosamine and chondroitin, which are available as pills and powders. Additionally, capsaicin skin creams applied to the thumb may help relieve pain.
Prescription medications for arthritis include COX-2 inhibitors like celecoxib (Celebrex) and meloxicam (Mobic). Tramadol (Ultram, Conzip) may also be prescribed. These medications may cause side effects at high doses, such as ringing in your ears, cardiovascular problems, liver and kidney damage, and gastrointestinal bleeding. You may need to have certain blood tests while taking these medications.
Corticosteroid injections to the thumb joint may help relieve swelling and pain. These can only be done two or three times a year. The relief these injections provide is temporary but can be significant. Be careful to avoid excess physical activity while on a steroid medication otherwise you risk damaging the joints.
Your doctor or physical therapist may recommend a splint for your thumb, especially at night. A thumb splint may look like a half glove with reinforcing material inside. Wearing this splint can help decrease pain, encourage the correct position for your thumb, and rest the joint.
This type of splint is sometimes called a “long opponens” or “thumb spica” splint. Splinting is often done continuously for three to four weeks. Then, the splint is worn some of the time, either at night or during certain daily activities that may strain the joint.
If exercise, medications, and splinting do not sufficiently reduce pain and restore range of motion and strength, surgery may be required. Possible surgeries for thumb arthritis include:
Trapeziectomy: One of your wrist bones involved in the thumb joint is removed.
Osteotomy: The bones in your joint are moved and aligned correctly. They may be trimmed to remove excess growth.
Joint fusion: The bones in the joint are fused. This improves stability and reduces pain. However, there is no longer flexibility in the joint, and you will no longer be able to perform certain tasks.
Joint replacement: The joint is replaced with tendon grafts.
A lot has been written about osteoarthritis prevention. It boils down to modifying risk factors for the disease by adjusting certain aspects of your lifestyle.
There are 6 basic recommendations for osteoarthritis prevention. Think about each one and ask yourself if you are doing what you should be doing.
1 – Maintain Your Ideal Body Weight
It has been estimated that the force of 3 to 6 times a person’s body weight is exerted across the knee while walking. In other words, being 10 pounds overweight increases the force on the knee by 30 to 60 pounds with each step taken while walking.
The force across the hip is, at most, 3 times body weight. Losing weight reduces stress on your joints.
2 – Exercise Regularly and Participate in Regular Physical Activity
For optimal joint health, it’s recommended that people perform 30 minutes of moderately strenuous exercise at least 5 days a week.
It’s an established fact that regular exercise has health benefits. Lower levels of exercise can also be beneficial, according to study results. It’s better to get some exercise as opposed to no exercise.
3 – Protect Your Joints
There are several joint protection principles, which if followed, will help to conserve energy and preserve joint function. The advice is quite simple, but you must be mindful of proper movements and recognize body signals (e.g., pain). Good posture and proper body mechanics are important because protecting your joints is a factor in osteoarthritis prevention.
4 – Avoid Repetitive Stress on the Joints
Signs of repetitive stress include too many uninterrupted repetitions of an activity or motion, unnatural or awkward motions, overexertion, incorrect posture, and muscle fatigue. These symptoms usually are associated with your occupation. Try to find solutions at your workplace and avoid prolonged periods of repetitive stress.
5 – Listen to Your Pain
This recommendation seems so obvious, yet people don’t always do it. Learning to view pain as a signal that you are overdoing it and that it’s time to rest requires conscious effort. Balancing rest and activity is optimal for healthy joints. It’s part of self-management to learn not to overuse your joints and to learn not to push past your limits. Consider that the pain is like a stop sign.
6 – Avoid Injury to Joints
Previous joint injury is recognized as a common cause of osteoarthritis. In joints burdened by improper alignment due to injury, articular cartilage wears away and osteoarthritis can begin to develop.
Avoid injury if at all possible — and if you do injure a joint, seek treatment immediately.
To ease pain and improve joint mobility, try to:
- Modify hand tools. Consider purchasing adaptive equipment — such as jar openers, key turners and large zipper pulls — designed for people with limited hand strength. Replace traditional door handles, which you must grasp with your thumb, with levers.
- Apply cold. Icing the joint for five to 15 minutes several times a day can help relieve swelling and pain.
While there is no cure for arthritis in your thumb, there are various simple treatments that can help relieve symptoms for many people. Talk to your doctor or physical therapist about which treatments might work best for you.
Severe arthritis, particularly if it affects your hands or arms, can make it difficult for you to do daily tasks. Arthritis of weight-bearing joints can keep you from walking comfortably or sitting up straight. In some cases, joints may become twisted and deformed.