Thumb Arthritis
Thumb Arthritis (Basilar/CMC) | Denver, Colorado
Thumb arthritis of the carpometacarpal joint, often called thumb CMC or basilar thumb arthritis, is the second most common arthritis of the hand and a condition I treat daily in my hand surgery practice in the Denver metropolitan area.
In its simplest form, thumb CMC arthritis is a loss of the soft, protective cartilage layer between the base of the thumb (thumb metacarpal bone) and the wrist (trapezium bone). Loss of that layer can lead to painful grinding, development of bone spurs, and progressive deformity as the joint becomes unstable. This causes to pain with basic activities, a loss of grip strength, and decreased hand function.
While this is typically a degenerative condition that progresses with age, it can also occur as a result of a prior injury to the thumb CMC joint.
Thumb CMC Arthritis Symptoms & Diagnosis
Figure 1 - Thumb CMC arthritis is a loss of the cartilage between the base of the thumb metacarpal bone and the trapezium bone.
The primary symptoms of thumb CMC arthritis are pain and loss of grip strength. Most will experience an aching sensation at the base of the thumb in the palm, made worse with activities requiring pinch or grip. Patients will classically struggle with pain while opening jars, pulling up their pants, or turning a key.
Thumb CMC arthritis is straightforward to diagnose. A review of your symptoms and an examination with a hand surgeon will give many clues. The final diagnosis is made on X-ray. An X-ray will often reveal loss of the CMC joint space, the presence of bone spurs, and subluxation of the CMC joint. Additional imaging or tests are not typically needed in the diagnosis of thumb CMC arthritis.
Thumb CMC Arthritis Treatment
Early management of thumb CMC arthritis is primarily nonoperative. Many people develop this arthritis, but don’t know they have it because it never causes pain. Our goal is to turn a painful arthritis back into a not-painful arthritis. This is accomplished via many options, including activity modification, bracing, therapy, and even injections.
Most patients find a combination of nonoperative treatments that help them avoid surgery. But some do not. The surgery for this condition has a long history and is highly successful. The surgery is called a ‘CMC arthroplasty.’ This involves removing the trapezium bone and then using one of various techniques to suspend the thumb metacarpal so as to maintain the space left behind by the trapezium. Once there is no longer a bone for the base of the thumb to grind against, the pain dissipates.
There are many techniques to accomplish this goal. I will typically use a technique known as a suspensionplasty with an InternalBrace (Arthrex - I have no affiliation). The extra strength of the InternalBrace allows you a much faster return to the use of your hand and eliminates the need for casting after surgery.
Additional Information
This is a very brief overview of thumb CMC arthritis. This is an extensive topic, and I encourage you to read on below as I answer many of my patients’ most common questions. I also have a “Deep Dives” section to the right of the FAQs where you can access articles I have written on the topic of thumb CMC arthritis and its treatment.
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The Basics
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Thumb CMC arthritis, or basilar thumb arthritis, is a common condition resulting from the degeneration of the carpometacarpal (CMC) joint at the base of the thumb. As with any arthritis, loss of the protective cartilage between the thumb metacarpal and the trapezium bone leads to pain and functional impairment.
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The primary cause of thumb CMC arthritis is the cumulative impact of repetitive pinching motions over time, resulting in the gradual stretching of the supportive ligaments at the CMC joint, subsequent uneven wear patterns across the joint, and eventual erosion of the cartilage between the thumb metacarpal and the trapezium bone.
Though thumb CMC arthritis is extremely common as we age, recent studies have suggested a highly genetic component to developing this arthritis as well.
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Thumb CMC arthritis is commonly associated with aging. Genetics also certainly plays a role in who is more likely to develop the condition. The wear and tear on the joint accumulate over time, and thus, the condition is prevalent in those who live long enough.
In rare cases, younger patients can also suffer from thumb CMC arthritis after a traumatic injury to the joint.
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Unfortunately, there is no tried and true way to prevent arthritis. That being said, managing thumb mechanics (see below), avoiding excessive pinching, and promptly addressing symptoms through therapies and bracing can significantly mitigate the impact of thumb CMC arthritis. Early intervention and lifestyle adjustments play a crucial role in managing the condition.
For thumb mechanics, the most common error we make on a routine basis is that of ‘narrow pinch.’ If you imagine how your thumb and fingers pinch to pull up your pants or turn a key, that is what we call narrow pinch. This is in contrast to a ‘C’ pinch, the way the thumb and fingers come together when making the ‘OK’ sign. If you can manage more daily activities with the ‘C’ pinch and fewer with narrow pinch, you will be on your way to decreasing your thumb base pain.
Thumb CMC Arthritis Symptoms & Diagnosis
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The symptoms of thumb CMC arthritis typically begin with increasing soreness at the base of the thumb. This is noticed especially during pinching or gripping activities such as opening jars, turning keys, or pulling up pants/socks.
Additional symptoms include a sense of hand weakness, difficulty with fine motor tasks, and, in some cases, numbness or tingling in the thumb, index, or middle fingers.
If you do have this associated numbness, you may have carpal tunnel syndrome. While a separate condition, it has a high association with thumb CMC arthritis. You can read more about the condition here.
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I can typically detect thumb CMC arthritis following a detailed discussion of your symptoms and a basic examination of your hand. There will often be tenderness over the thumb CMC joint, and some advanced cases have a visible deformity of the thumb.
X-rays will then confirm the diagnosis. These will reveal a narrowing of the joint space, subluxation of the CMC joint, and the presence of bone spurs (our body’s natural response to developing arthritis).
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Additional testing or imaging studies are not necessary for the diagnosis of thumb CMC arthritis. All decisions can be made through discussion, examination, and X-rays.
Thumb CMC Arthritis Treatment
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Yes, the mainstay of early thumb CMC arthritis is all nonoperative. Our options include hand therapy, bracing, anti-inflammatory medications, and steroid injections into the joint. A combination of these tactics provides substantial relief to most patients. In many cases, this is all a patient needs to avoid surgery and manage their arthritis for the longterm.
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If you are concerned you may have thumb CMC arthritis, there are a few at-home strategies to try to manage your pain. The most important is activity modification. Be especially mindful of your thumb mechanics (see above in ‘How can I prevent thumb CMC arthritis’) and avoid activities that exacerbate symptoms. Over-the-counter anti-inflammatory medications are always a good first step as well.
Finally, the use of a thumb brace during specific tasks can go a long way toward symptom relief. Certainly, you will find many options on the market, but any brace that stabilizes the base of your thumb in the palm is what you want to look for if you are trying to manage these symptoms on your own.
A word of caution: if you have any associated numbness or tingling, please do not delay in seeing a physician. This could indicate nerve compression that can progress over time to a point of irreversible symptoms.
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Hand therapy, particularly with a certified hand therapist, is highly effective for thumb CMC arthritis. This time spent in therapy works in a multitude of ways. The first is in-depth education on thumb mechanics. Simple changes in daily tasks add up to big wins in terms of pain and suffering. Beyond this, our therapists have the ability to make low-profile, custom braces that stabilize your thumb but allow for many daily activities to continue - I’ve even had a therapist mold a brace to bike handlebars! The last benefit of therapy is a progression of targeted exercises to strengthen your thumb muscles around the CMC joint, thereby improving the joint-stabilizing soft tissues around your arthritis.
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Steroid injections into the thumb CMC joint can be considered if the above conservative measures are insufficient. In this procedure, an anti-inflammatory steroid medicine is injected directly into the CMC joint. This will reduce the inflammation and associated pain in your thumb.
While providing temporary relief by reducing inflammation, the results vary among individuals in terms of degree and length of relief. Repeated injections may be necessary.
Thumb CMC Arthritis Surgery
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The most common surgery for thumb CMC arthritis is called a ‘CMC arthroplasty.’ In this procedure, the trapezium bone is completely removed, along with any adjacent bone spurs. The remainder of the procedure is predicated on managing the space left behind following trapezium removal. Maintaining this space, without allowing the thumb metacarpal to slide down into this space, will allow for the thumb metacarpal to progress through daily activities without pain.
Various techniques exist to suspend the thumb metacarpal and maintain the space of the excise trapezium. I use a technique known as suspensionplasty with an "Internal Brace" (Arthrex - I have no affiliation) to accomplish this goal. This uses an extra tendon from your hand in addition to an extremely strong suture to hold the thumb in place. Because this construct is so strong, it eliminates the need for casting after surgery.
Alternative methods of doing this procedure require 1-3 months of casting after surgery.
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Therapy after a thumb CMC arthroplasty surgery is crucial. This is typically completed with a ‘certified hand therapist (CHT),’ most often by way of occupational therapy (rather than physical therapy).
Fortunately, we employ many CHTs in our practice, so you will have ready access to this service following surgery.
The initial post-operative phase involves intermittent use of a post-operative splint, gradually progressing to exercises for thumb range of motion, and eventually strengthening. It is difficult or impossible to achieve good surgical outcomes without a period of hand therapy following thumb CMC arthroplasty surgery.
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Remember that ‘recovery’ is a subjective term, depending on what you have in mind. Below is the typical outline of healing following this surgery in which I use the InternalBrace method outlined above:
Surgery - 12 days: Wear a post-operative splint full-time, no thumb use or motion
Begin 12 days: Removable splint made by hand therapy, begin to work on gentle thumb range of motion exercises. No physical use of the thumb.
Begin 4-6 weeks: Initiate light pinching activities with thumb, continue to work on range of motion. Wean out of brace for light activities.
Begin 8 weeks: Progress strengthening of thumb and continue to use the brace less and less.
3-4 months: Return to heavy activities and/or impact sports. Most patients feel 90% of their former selves by this point. Occasional aches and pains, or a bad day here or there are still expected.
9 months - 1 year: “Full” recovery, where you may have to stop and think to remember which thumb had surgery.
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In my practice, no cast is needed after surgery. You will wear a post-operative splint, full-time for the first 12 days after surgery and then intermittently thereafter as your surgery heals. This technique promotes early movement and the splint is gradually phased out as recovery progresses.
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All surgeries have risks, many of which are generic to surgery itself. I go over these in detail with you before surgery as part of the informed consent process. Examples include bleeding, infection, damage to surrounding nerves/vessels, anesthesia risks, or failure of the procedure.
There are a couple of risks specific to skier’s thumb ulnar collateral ligament repair that are worth highlighting.
The first is what we call a ‘neuropraxia.’ This is when a nerve ‘goes to sleep’ after surgery.
There is a sensory nerve branch that crosses directly over where I work to perform this surgery. In surgery, we have to carefully retract that nerve out of the way in order to repair the ligament. Sometimes, even just this light touch of retracting the nerve aside will cause the nerve to ‘panic’ and shut down for a period of time.
If this happens to you, you will notice an area of numbness or tingling over the back of your thumb towards your fingertip. This nerve is not involved in any of the movement, strength, or function of your thumb. The nerve will typically ‘wake up’ over a period of a few weeks to a few months after surgery.
The next big risk is that of hand weakness. Most studies put a loss of grip strength following CMC arthroplasty around 10-15%. These numbers are difficult to interpret though, given that they are typically compared to your other hand. In reality, many patients lost more than 10-15% of their grip strength before surgery because their thumb was hurting them so badly!
So in reality, many patients feel a relative increase in thumb strength after this surgery once they can use their thumb without pain. However, these findings are certainly ones to be aware of before proceeding with this surgical option.
