Basal Joint of Thumb
Other names: Basal Joint arthritis, 1st CMC arthritis
Does your thumb hurt when you try to open a jar? Do you have pain at the base of your thumb?
You may have a common condition called Basal Joint Arthritis, or arthritis at the base of the thumb.
What is Basal Joint Arthritis?
The thumb is made up of three highly mobile joints which allow for a high degree of motion. Normally, these joints are quite mobile and contain highly specialized cartilage covering the bone ends, allowing for shock absorption and smooth gliding coordinated movement.
Over time, this cartilage can wear down, causing a painful gliding surface with less shock absorption, a condition commonly known as arthritis. The thumb basal joint, called the carpometacarpal joint (see figure), is the most common joint in the hand to wear out and become symptomatic. You can feel for pain in this joint by palpating it in the fleshy part of the thumb side of the palm, about a centimeter above the wrist joint.
Who Gets Basal Joint Arthritis?
The common causes for arthritis at the base of the thumb include age, female gender, joint laxity and previous injury to the joint. Genetics probably has the greatest influence on the condition as the exact cause is still unknown.
The most common type of arthritis at the base of the thumb is osteoarthritis, which is the progressive wearing down of a joint over time due to age. The other common form of arthritis is rheumatoid arthritis, which is an autoimmune inflammatory disease that rapidly destroys joints throughout the body.
How do I know if I have Basal Joint Arthritis?
Pain at the base of the thumb is the hallmark of the condition, though there are other conditions that can also cause similar symptoms which should be ruled out such as carpal tunnel syndrome or wrist arthritis. Pain occurs with pinching, grasping, buttoning buttons or opening a jar and eventually the destruction in the joint surfaces alters the thumb mechanics causing deformity and weakness.
To fully evaluate the joint, routine x-rays are helpful in identifying the condition and quantifying the amount of joint destruction.
What can be done to treat the arthritis at the base of the thumb?
First, this is a common condition and should be generally considered a normal part of the aging process. In addition, there are no cures for this this type of arthritis (osteoarthritis) so treatments are generally aimed at symptom relief and functional recovery. Perhaps someday we will have treatments that can address the cause of this arthritis.
Many people with this form of arthritis need no treatment as the symptoms remain tolerable. Often anti-inflamatory medication such as Ibuprofen or Tylenol can decrease symptoms to a tolerable level, especially before significant activity. Thumb splints are also helpful in immobilizing the joint while allowing hand motion. These can be custom made by a hand therapist for optimal fit and function.
Some patients find relief with steroid injections into the joint, which can be repeated up to 3 times a year for symptomatic treatment. Eventually, some patients continue to have pain and elect to proceed to hand surgery, which consists of removing the offending joint and reconstructing the thumb ligaments to eliminate the bone-on-bone pain and restore function.
Interested in learning more about your symptoms? At Orthopedic Specialists of Seattle, we have two hand surgeons, Wayne Weil MD and Scott Ruhlman MD, experienced in helping you with your painful hands and discussing all treatment options with you, both nonsurgical and surgical.
