Symptoms and Anatomy:
Pain and arthritis at the base of the thumb is an unfortunately common problem. The thumb attaches to the wrist at the cmc (carpometacarpal) joint. This joint has a tendency to wear out because of all the gripping and pinching required by the thumb. Women are more often affected than men and problems can begin in the 40’s though usually not until the 60’s. Fortunately, treatment does not correlate with xrays and most people can get relief of their symptoms without surgery.
People usually first notice pain at the base of the thumb near the wrist with activities such as opening jars, buttoning, gripping a steering wheel, shaking hands or even turning a door knob. Often they notice a ‘bump’ at the base of the thumb. This bump actually represents the metacarpal slightly coming out of joint which is part of the arthritis.
Arthritis means the cartilage lining of the joint is thin and in some areas completely worn away. This is similar to brake pads where the lining has worn away and leaves metal on metal. Once the cartilage has worn away, this leaves bone-on-bone which is painful.
There are two types of treatment that are usually effective at reducing pain: a special splint or a cortisone injection. The splint is custom made by a hand therapist. This splint leaves the wrist and thumb tip free and allows almost normal use of the hand. The current recommended use of the splint is one month full time (day and night), one month part time (most of the day) and one month for specific activities. Treatment is considered successful when at the completion of three months of wear, leaving the splint off does not lead to return of the pain. The injection is more of the “quick fix”. Often, 2 or 3 days of moderate discomfort follow the injection. If the injection gives great relief and last for at least several months, it may be repeated one or two more times.
One or the other of the above conservative treatments are usually tried before recommending surgery. Surgery consists of removing the arthritic joint. Some surgeons use a tendon from the wrist to reconstruct a ligament (called LRTI). I have not found that additional part of the surgery to be helpful. Surgery is done with the arm numb and the person sedated or asleep. Surgery is done as an outpatient. A splint or cast is worn for five weeks after surgery. The thumb is quite achy at first, then gradually regains strength and mobility. Therapy is available but usually not required. It typically takes about 4 months until the thumb is “working” again. The strength will continue to improve for about 18 months after the surgery.