CMC Arthritis

What is CMC Arthritis?

Carpometacarpal (CMC) arthritis is a form of osteoarthritis (OA). It is a slowlyprogressive degenerative disease at the base of the thumb joint as it attaches tothe wrist. Middle-aged and senior womensuffer from CMC arthritis more so than men. In fact, about 80% of women over the age of 80 suffer from CMC arthritis.

Just as with any other form of OA, CMC arthritis is where the cartilage breaks down, or thins, from wear and tear and eventually in severe cases the joint is bone on bone. It is also common with the thinning of the cartilage that bones spurs may develop.

So, how did the CMC joint get its name? Well, there are eightbones within the wristwhich are called the carpal bones:

  • Hamate
  • Capitate
  • Trapezoid
  • Trapezium
  • Pisiform
  • Triquetrum
  • Lunate
  • Scaphoid


The bones within our fingers are called metatarsals. Thusthe name CMC comes from the carpal and metatarsal bones. The CMC joint is where the thumb’s metatarsal bone meets up with the trapezium bone of the wrist. Think of how much we use our thumbs for activities-gripping, keying, texting, and pinching. This joint is highly mobile,and we use our thumbs for most of our daily activities including our work and hobbies. When this joint is affected by OA, the simplest of tasks like holding a pen or drinking glass can be extremely painful.

The CMC is a synovial joint. Meaning, it is highly mobile. The structure of the thumb includes cartilage which covers the thumb metatarsal and trapezium bones. Within the joint is a synovial membrane and fluid which help the joint glide throughout the movement. The membrane can also become inflamed with OA which may only add to the severity of the symptoms.

The thumb also has ligaments, tendons,and muscles to help with movement and stability. A muscle is flexible fibrous tissue that attaches to bones by a tendon. Most of our hand movements, including the thumb, comes from muscles inour forearms.

Ligaments are tough fibrous tissue that help holds the joint in place throughout the movement. When the thumb’s ligaments, tendons, or muscles have damagedthis trauma, if not properly treated, can cause a higher risk of OA development. The reason for this is our muscles, tendons, and ligaments helpstabilizethe joint space. When injured, this can cause undue stress within the joint.

Today, with all the keying and texting we do, CMC arthritis cases are growing amongst all ages and gender. Overuse is another cause for CMC arthritis. Repetitive and continuous use of our thumbs during keying and texting activities is a big culprit to this growing trend.

What causes CMC arthritis?

Carpometacarpal (CMC) arthritis is a form of osteoarthritis at the base of the thumb.  A breakdown of the cartilage within the joint due to either yearof wear and tear, or it may be one of the following:

  • Aging
  • BMI over 30
  • Hereditary
  • Poor biomechanics of the thumb with activities like typing and texting
  • Previous injury to the joint (e.g. sprain for fracture)

Symptoms of CMC Arthritis

CMC arthritis symptoms are progressive. At first you may experience mild pain at the base of the thumb; however, over timethis pain may become more sharp in nature especially after activities, while at rest. In more advanced stages as the cartilage continues to thin, some report hearing “squeaking or snapping” sounds with thumb movement, whichiscalled crepitus which is not a serious symptom. As the disease progresses, the thumb joint becomes stiff, you may experience loss of range of motion, and gripping can become very painful.

How is osteoarthritis diagnosed?

Your medical provider (e.g. family physician, rheumatologist, or orthopedist) will diagnose the condition by completing a full medical history review as well as a physical exam. Your physician will fully assess your hand and specifically your thumb’s range of motion and strength.

An X-Ray may be ordered to confirm the diagnosis as well as to define what stage the OA has progressed to. There are stages I-IV, stage I there is no obvious changes and stage IV there may be bone spurs and narrowing joint space.

The stage level of OA does not correlate with severity of symptoms, whichiswhere more research needs to be doneas some people in stage I may experience significant pain while others in stage IV may have minimal symptoms. The defined stage of the disease will notdetermine treatment.

Treatment of CMC Arthritis

Early diagnosis is key to preventing deformity or disability of the thumb. A good starting point with the early onset of symptoms is to seek treatment from a physical or occupational therapist (PT or OT).

Your PT or OT will collaborate with you on establishing and meeting your goals. Your therapist will work to reduce your symptoms, teach joint protective techniques, and prevent further joint deformity if present.

Reducing symptoms may include hot or cold applications, soft tissue mobilization, and splinting. Protective techniques may include using adaptive tools like a jar opener. Education on protecting the joint will focus onunderstanding what activities cause symptoms and what are modifications that can be done to minimize those symptoms.

Strengthening is a critical component to CMC arthritis. Your PT or OT will instruct you on proper exercises of the thumb and hand to help restore as much range of motion as possibleand to reduce symptoms of pain. As the muscles in hand and forearm become stronger, the joint becomes more stable; therefore, strengthening helps manage symptoms.

In cases where the symptoms are more significant, sometimes oral medications or an injection may be needed for symptom management. Medications and injections should be donein conjunction with PT or OT. The treatment is to help manage symptoms foryou to tolerate PT or OT as well as daily activities. Remember, you will still need to strengthen the muscles and use protective techniques to preserve and prevent joint deformity.

In severe cases when conservative treatment has failed,and the symptoms are severe, surgery maybe indicated. There are three types of surgical techniques that may be performed, and they are:

  • CMC Joint Fusion (Arthrodesis)-surgery conjoins the bones to allow them to fuse together; this surgery is performed onthose who need a strong grip for their work and activities
  • Artificial Joint Replacement (Arthroplasty)-the arthritic surface is removedand in its place is a plastic or metal implant; results for long-term success aremixed
  • Resection Arthroplasty (excision)-the arthritic surface of the joint is removed,and a rolled-up tendon takes the place of the cartilage; outcomes are typically successful for alleviating pain

Depending on the surgery, healing of the surgical site takes several weeks. You will mostly likely have your thumb immobilized during the healing process. PT or OT is recommended after the initial healing from surgery to help with managing symptoms, scar tissue, and to begin gentle range of motion and strengthening exercises when appropriate.

Next Steps

Early intervention to CMC arthritis is important to managing symptoms and preventing deformity. The sooner you address your symptoms, the more likely conservative care will work for you.

Most states have direct access to a physical therapist, meaning you can go directly to a physical therapist without a physician order. To determine if your state has direct access, please visit the American Physical Therapy Association’s website Physical Therapy Direct Access By State.

Most OTs work directly with your physician for treatment protocols and guidelines. He or she will work under the prescription of your physician. Both PTs and OTs have special certifications in hand, certified hand therapist (CHT), which means they’ve had extensive training in hand. With any hand injury, searching for a PT or OT with his or her CHT is recommended.

As a consumer of health care, you have a choice in finding the right provider for you. Do your homework and search for a health care provider, like a physical therapist, with excellent outcomes, great customer reviews, and can provide you the care you need for a reasonable cost.

To get started with conservative care today, you can find a highly qualified PT or OT in your area. There are many qualified PTs and OTs, so to find one near you, please click on the find a clinic link. This link will help you find a PT or OT that has top national rankings for treating hand conditions like CMC arthritis.

For those of you who are not familiar, the term “home exercise program” refers to a collection o

Read More

One of the hallmark symptoms of Read More

Over 80% of the adult population will experience back pain in their lifetime, and estimated losses i

Read More

Leave a Reply

Your email address will not be published. Required fields are marked *