Thumb Arthritis
The Basics
-
Basilar Thumb Arthritis is arthritis of the basal joint of the thumb which is where the thumb meets the wrist bone called the trapezium. This type of arthritis causes pain in the joint at the base of the thumb.
-
The first carpometacarpal joint is a saddle type joint where the first metacarpal (thumb bone) sits on the trapezium (wrist bone) and is held in place by multiple ligaments
-
Patients will complain of pain at the base of the thumb and difficulty with pinching and grasping. It is the second most common arthritis in the hand and is more common in women. It can affect both hands but it is often more symptomatic in the non dominant hand.
-
The pinching motion involving the thumb places a great amount of force on the first CMC (thumb base) joint. This significant force over years wears down the joint cartilage and can eventually lead to arthritis. Additionally, a loose joint results in more force applied to the cartilage on a consistent basis resulting in more joint destruction.
-
Due to the misalignment of the joint and bone spurs (small bone growths) in the joint will often causes the joint to appear enlarged and swollen. The joint will be tender. Pushing on the first metacarpal base will result in a painful grind (positive grind test)
-
An X-Ray is obtained to confirm the diagnosis. It will show joint space narrowing, bone spurs, and subluxation of the joint. An MRI is not necessary for diagnosis.
-
Mild symptoms can typically be controlled with bracing and anti-inflammatory medication or Tylenol. If patients have an increase in pain they will wear a brace to immobilize the thumb for a few days until the pain subsides. They will often wear the brace when doing activities that aggravate the joint as a preventive measure.
-
Moderate symptoms are often treated with cortisone injections for temporary relief. The injections typically help for several months and can be administered 2-3 times per year. The injection at the base of the thumb is somewhat painful but the procedure only takes a few seconds.
-
Severe symptoms that interfere with activities of daily living and do not respond to bracing, medications, or injections are treated with surgery. The most common procedure involves removing the arthritic trapezium bone and using a tendon from the wrist (Flexor Carpi Radialis Tendon) to reconstruct and cushion the thumb joint. On occasion patients with a hypermobile metacarpophalangeal joint (adjacent thumb joint) will need a fusion of this joint to provide a stable thumb. This involves placing screws across the joint to stabilize the thumb. This will limit motion but will improve pain and function.
Additional Considerations:
Anesthesia- the surgery is outpatient and is most often performed with sedation and a regional anesthesia. The anesthesiologist will inject numbing medicine in the shoulder region to numb or block the nerves and give sedation. Patients will require a pre op evaluation form their PCP, will need to abstain from eating or drinking the night prior to the procedure and will need a ride home after surgery.
Recovery- The nerve block usually lasts 6-8 hours but could last longer. Most patients require pain meds for 1-3 days after surgery. You will be in a splint that wraps the thumb and the wrist but the fingers will be free. In two weeks the sutures will be removed and you will start wearing a velcro thumb spica brace that can be removed for bathing. At six weeks many patients are still swollen and sore, but it is necessary to start weaning from the brace and begin therapy.. The total recovery time is typically 3-6 months.
Results- The majority of patients are much improved after 6 months. Your pinch strength may not return to the level of your pre arthritic thumb but it is often as strong or stronger than your arthritic thumb. Revision surgery is rarely required but usually involves reinforcing the reconstructed ligament with another wrist tendon.
Treatment
There is little that can be done to avoid the wearing of the joint cartilage that occurs with age as a result of the significant forces applied to this joint over time.
However many patients have far less symptoms because they have less chronic inflammation. Basilar thumb arthritis is a disease of chronic inflammation thus decreasing your chronic inflammation will decrease the severity of your symptoms. Improving your nutrition, fitness, sleep, and stress can decrease your chronic inflammation and therefore improve the symptoms of your thumb arthritis.
