The basal joint of the thumb (also called the CMC or Carpal-MetaCarpal joint) is located at the base of the thumb, adjacent to the wrist. It is a very mobile joint that allows a significant amount of motion to help position the thumb. Many types of arthritis can affect this joint, with degenerative arthritis being most common. Degenerative arthritis of the thumb CMC joint is many times more common in women than in men. This arthritis may also occur as the result of an injury.
Pain is usually the most prominent symptom. The pain may be sharp (with activity) or aching in nature. It is located at the base of the thumb, but can radiate in several directions. It is often noticed with grasping activities or simple turning tasks such as opening a lid or buttoning clothing. Patients often relate that they drop objects that they are holding or picking up. Limited motion of the thumb can occur, and may affect the ability to open the palm as well as limit the movement in other thumb joints. Swelling and bony deformity of the joint may be visible. Catching and clicking may be felt and even heard.
- Splints, which immobilize the wrist and thumb, are often useful. These splints should be worn on a part-time basis. Times to wear the splint would generally be during heavy activities that cause the thumb pain, or during periods when the thumb pain is already flared. The splint is meant to immobilize the thumb and enforce rest for the inflamed joint.
- Anti-inflammatory medications.
These should also be used on an as-needed basis. There are many different medications available, and all are generally felt to be equally effective. Medicines like advil, motrin, and ibuprofen are simple and usually well tolerated. They should be taken with food, and preferably only when needed. A common starting dose is two 200 mg tablets 3 times a day. The most common side effect is stomach irritation, even leading to ulcers. Some prescription anti-inflammatory medications are more expensive, but may be better tolerated by the stomach, and may need to be taken only once or twice a day. Patients on blood thinners cannot use these medications.
- Ice. The application of ice may reduce inflammation and pain. Ice is generally most effective when applied right after work or activity causes thumb pain.
- Moist Heat. This modality may take the form of hot water bottles, heated moist towels, warm soaks, or even hot tubs. It is generally most effective when applied hours after work or activity, or even before exercise.
- Cortisone Injections.Cortisone will not cure or change the arthritis, but may help reduce painful flare-ups not being controlled by the above measures. It provides temporary relief. Up to three injections can be given.
- Supervised Therapy. Therapists may be able to provide techniques and aids to allow activities so that less stress is applied to the thumb. They can also apply cortisone through ultrasound, which is less painful than a cortisone injection.
- Nutritional Supplements. Many patients are trying non-prescription supplements such as glucosamine and chondroitin sulfate, which may provide some anti-inflammatory effect.
When symptoms and limitations become persistently frustrating, and are not adequately reduced by non-surgical measures, surgery may be necessary.
- The most common form of surgery is to remove one of the bones that form the thumb CMC joint, and replace it with soft tissue from an adjacent tendon. The bone that is removed is called the trapezium. Adjacent tendon tissue is used to rebuild a ligament for the joint, and then fill the joint space with soft tissue. This eliminates the arthritis, and is usually very effective in eliminating the pain. This surgery is very common, and has proven to be excellent at relieving pain. Therapy is required, and gradual recovery of strength is experienced over a long period. This surgery should be long lasting and not need to be redone with age.
- If this surgery is selected, you are admitted to the hospital on the day of surgery, and stay one night in the hospital after the surgery. A bulky dressing is applied and worn for 7 to 10 days. A pin is placed across the joint to immobilize it for 4 weeks. After the first week, the bulky dressing is removed and a fiberglass cast is applied. The cast and pin are removed after 4 weeks. Therapy is started after the first 4 weeks, and a plastic splint is worn during the first 6 weeks of therapy, but gradually less during the last 3 weeks.
- A variation of this surgery is to remove the bone and pin the joint for 5 weeks. No tendon tissue is harvested or used. This operation is called a Hematoma Distraction Arthroplasty and requires less surgery time and no overnight hospitalization. The postoperative cast and therapy requirements are the same. The results of these surgeries seem to be equal over time.
- Another surgical option is to fuse the arthritic joint. This replaces the joint with bone, so that motion is lost. It does provide a strong thumb, with elimination of the arthritic pain. Surgery is done as above, with a bulky dressing for one week, cast for the next 3 weeks, and a splint for the subsequent 4 weeks. A bone graft may be needed. This surgery is more commonly performed in manual workers who are more interested in strength than motion.