What is thumb arthritis?
Thumb arthritis is most common in the thumb carpometacarpal joint, between the base of the thumb metacarpal and a wrist bone (the trapezium). Thumb arthritis is sometimes referred to as basal joint arthritis. Due to the stresses with everyday activities, basal joint arthritis is very common.
The thumb is the single most important digit in the hand, accounting for 40% of hand function. The thumb basal joint is subjected to a tremendous amount of force with pinching and grasping activities.
Symptoms of Thumb Arthritis
Initial symptoms of thumb arthritis include pain and swelling around the wrist and the base of the thumb as well as progressive weakness. Patients find that it becomes increasingly difficult to twist open jars or even turn a doorknob. In severe cases, even holding a pen or utensil can be very painful. The base of the thumb may look enlarged and out of place. Stiffness and decreased motion of the thumb can be minimal or significant, depending on the severity of disease.
Causes of Thumb Arthritis and Risk Factors
Basal joint arthritis of the thumb is more common in females over the age of 40. The exact cause of thumb arthritis is unknown, but researchers have postulated that it’s a combination of factors including joint ligament laxity, deformed joints, prior fracture or injury to the thumb, and repetitive load to the joint.
In the normal joint, cartilage covers the ends of bones to allow for smooth glide with movement of the thumb and act as a shock absorber. The thumb basal joint is a specialized joint that is saddle-shaped and allows for significant amount of motion for everyday activities involving pinching and grasping.
With progressive wear and tear (degenerative arthritis or osteoarthritis), the cartilage becomes thinner and there is direct contact between the bony surfaces (bone-on-bone).
In advanced stages, bone spurs, or osteophytes, can form in the joint, causing the thumb metacarpal to slide out of the saddle. Hyperextension instability can also occur in the adjacent joint (metacarpophalangeal joint).
Treatment of Thumb Arthritis
Initial Treatment
A number of conservative measures are helpful to decrease pain and maintain function of the thumb.
Heat and Ice
Heat can be helpful in loosening joints and relaxing stiff muscles. As the thumb joint is often stiff in the morning, you could try morning showers or soaking the hand in warm water first thing in the morning. Ice is generally effective for flare-ups or swelling at the end of the day, especially after overdoing activities.
Activity modification
A number of simple changes at home can be helpful.
- Changing door knobs to latches
- Using bigger grip pens for writing
- Using utensils and garden tools with bigger handles
- Using bottle and jar openers
Over the counter medications
Tylenol and nonsteroidal anti-inflammatory drugs (NSAIDs) may be taken for pain relief. NSAIDs have the added benefit of decreasing inflammation and swelling. In an acute flare-up, it can be helpful to take scheduled doses of NSAIDs for 5-7 days. NSAIDs include ibuprofen (Motrin, Advil), naproxen (Aleve), and several others that are prescription strength. NSAIDs should always be taken with food. Long-term usage in high doses can lead to serious side effects including gastric ulcers, gastrointestinal bleeding, and kidney damage.
Splints and Braces
There are a number of different braces and splints that support the thumb, which places the joint in a resting position and provides significant pain relief. The braces can be soft and made of neoprene or rigid with plastic frames. Depending on your work and needs, the braces can be worn as a resting splint at night or used with activities. Your doctor or hand therapist can tell you about the different options and help you decide which one is best for you. Many patients benefit from having the hand therapist make a custom thermoplast (plastic) thumb splint which provides better fit and support.
Cortisone injections
If a trial of bracing, activity modification, and use of NSAIDs is no longer effective and the pain becomes disabling, your doctor may recommend a cortisone injection. Injection of a long-acting corticosteroid into the thumb basilar joint may provide pain relief for a few months. However, the relief is temporary and the arthritis in the joint will continue to progress.
Surgery
If conservative management is no longer effective and you have persistent severe pain and weakness, there are a number of surgical options that would provide pain relief and improved function. Consult with your hand surgeon to discuss the best surgical options for you. Surgical treatment options for thumb arthritis may include:
Thumb osteotomy
Your surgeon can cut the thumb metacarpal and reposition the bone to take pressure off the joint. Correction of the deformity and change in contact in early stages of thumb arthritis provides pain relief by off-loading the joint.
Thumb arthrodesis (fusion)
In this procedure, your surgeon removes the diseased cartilage and fuses the bones in the affected joint. This provides stability and decreases pain. Although you may have improved strength with grip and lifting using the thumb without pain, you do lose flexibility.
Thumb arthroplasty (joint replacement)
Although there are plastic and joint replacements in the thumb, most surgeons prefer to reconstruct the thumb basal joint with the adjacent soft tissue (tendon). In this procedure, all or part of the bone in the arthritic joint is removed, followed by tendon arthroplasty. The surgeon uses your tendon to reconstruct the thumb ligament to restore stability (suspensionplasty) and use remnants of the tendon as a pillow or cushion (interposition) for the joint.
Recovery after surgery
In all 3 surgical procedures, you will be in a thumb splint or brace for the first 6 weeks. Following the 6 weeks of immobilization, you will be working with a hand therapist on range of motion and flexibility of the thumb. At the 3-month time point, most patients have little or no pain. Strengthening exercises are initiated at this time, both with hand therapy and in a home exercise program. Most patients regain their strength and return to normal activities at the 6-month time point.
