First Carpometacarpal Joint Osteoarthritis

Carpometacarpal Joint Osteoarthritis

What is First Carpometacarpal Joint Osteoarthritis?

First carpometacarpal joint (1st CMCJ) osteoarthritis, also known as base of thumb arthritis is a degenerative condition that affects the joint at the base of the thumb, where the trapezium bone meets the first metacarpal bone. This joint is important for thumb movement and plays a role in gripping, pinching, and lifting of the thumb.

Who is affected by 1st CMCJ osteoarthritis?

1st CMCJ osteoarthritis is more prevalent in women than men, with the incidence increasing significantly after the age of 50. It is estimated that up to 25% of women aged 75 years and older may experience this condition.

Risk factors for developing 1st CMCJ osteoarthritis include:

Affected by 1st CMCJ Osteoarthritis
  • Age:

    The risk of developing 1st CMCJ osteoarthritis increases with age.
  • Gender:

    Women are more likely to develop this condition than men.
  • Repetitive thumb movements:

    Engaging in activities that require repetitive thumb movements, such as typing, playing racquet sports, or gardening, can increase the risk of osteoarthritis.
  • Previous thumb injuries:

    A history of thumb injuries, such as fractures or dislocations, can make the joint more susceptible to osteoarthritis.
  • Joint laxity:

    People with hypermobility may have a higher risk of developing 1st CMCJ osteoarthritis.
  • Genetics:

    Some individuals may have a genetic predisposition to developing osteoarthritis in general or in specific joints.

What are the main symptoms of 1st CMCJ osteoarthritis?


The primary symptoms of 1st CMCJ osteoarthritis include:



Pain at the base of the thumb, often described as a sharp or aching sensation that worsens with thumb movement and may radiate into the palmar side of the thumb or into the back of the thumb, into the area between the thumb and index finger.

CMCJ Stiffness


Limited range of motion in the thumb, making it difficult to perform tasks like grasping, pinching, or rotating the thumb, i.e. turning a key to open a lock

CMCJ Swelling


Swelling around the base of the thumb, which may be visible or palpable.

CMCJ Tenderness


Increased sensitivity to touch at the base of the thumb.

CMCJ Weakness


Reduced grip strength and difficulty holding objects.

Shoulder Weakness

Creaking or popping sounds

Crepitus, or grating or clicking sounds, when moving the thumb.

Symptoms tend to worsen gradually over time and may fluctuate in severity. Activities that involve thumb movements, such as typing, gripping objects, or turning doorknobs, can exacerbate pain and discomfort.

CMCJ Osteoarthritis Diagnosed

How is 1st CMCJ osteoarthritis diagnosed?

Diagnosis of 1st CMCJ osteoarthritis typically involves a thorough medical history, physical examination, and imaging tests.

  • Medical history:

    The doctor will inquire about the patient's symptoms, their occupation or hobbies that involve repetitive thumb movements, any previous injuries to the thumb or hand, and family history of osteoarthritis.
  • Physical examination:

    The doctor will carefully examine the thumb and wrist, assessing range of motion, checking for tenderness and swelling into the base of the thumb, and evaluating grip strength and fine motor skills.
  • Imaging tests:

    X-rays are used to visualize the bones in the thumb and wrist, revealing any narrowing of the joint space, osteophytes (bone spurs), or other signs of osteoarthritis. Ultrasound can be used to demonstrate bony irregularity, thickening of the synovium (joint lining) and increased vascularity (blood flow) seen when the joint is inflamed. It can also be used to rule out de Quervain’s tenosynovitis which often closely mimics 1st CMCJ osteoarthritis.

How is 1st CMCJ osteoarthritis treated?


Treatment for 1st CMCJ osteoarthritis focuses on managing symptoms, improving function, and slowing the progression of the condition. Non-surgical treatments are usually tried first, and surgery is considered if non-surgical measures fail to provide adequate relief.

CMCJ Osteoarthritis Treatment

Non-surgical treatments:

  • Rest:

    Avoiding activities that aggravate the pain and allowing the thumb to rest can help reduce inflammation.
  • Splints or braces:

    Wearing a splint or brace can immobilize the thumb and wrist, providing support and reducing pain during activities.
  • Ice application:

    Applying ice packs to the affected area for 10-15 minutes at a time, several times a day, can help reduce inflammation and pain.
  • Over-the-counter pain relievers:

    Nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen or naproxen can help alleviate mild to moderate pain and inflammation.
  • Physiotherapy:

    Physiotherapy can help improve range of motion, strengthen the muscles around the thumb and wrist, and teach exercises to maintain joint mobility and function.
  • Corticosteroid injections:

    In some cases, corticosteroid injections into the 1st CMCJ can provide temporary pain relief and reduce inflammation.
AC Joint Arthritis Treatment

At The Joint Injection Clinic, these injections are performed after a thorough consent process, whereby the risk and benefits of the procedure are discussed in detail with your doctor. The experienced medical doctor will then place you in a seated position with your hand resting on the couch.  The hand is cleaned using a cleaning solution to ensure that the procedure is performed under sterile conditions.  The combined local anaesthetic and steroid is injected from the skin to the joint under ultrasound guidance. 

The injection itself is normally completed within 30 seconds, after which a plaster is applied and post-injection advice is given. The patient is advised to look out for any signs of infection, specifically to check whether the local area becomes red, hot, tender, swollen or if they develop a fever.  If this occurs then the patient is asked to contact the clinic immediately at which time a formal reassessment will occur and if needed oral antibiotics can be prescribed.  The patient is also warned that following this particular injection they may notice a short-term worsening or flare in their symptoms after the local anaesthetic has worn off (4-5 hours).  This may last for 3-5 days and the patient is advised to consider icing of the area using an ice pack for 10-15 minutes every hour as required.

The best treatment option for you will depend on the severity of your 1st CMCJ arthritis, your overall health, and your activity level.

If you are experiencing pain and stiffness in your thumb, it is important to see a doctor to get a diagnosis and discuss treatment options.