1st CMC Joint Osteoarthritis: Causes, Symptoms, and Treatment

Reviewed By – Dr. Sameer Gohir
PhD, MSc, PG Cert MSK ultrasound, PG Cert. Non-Medical Prescribing, MCSP, MAPPN

What Is 1st CMC Joint Osteoarthritis?

Thumb pain, particularly at the base, is a common issue that can significantly impact daily activities. Often, this pain is due to osteoarthritis (OA) affecting the first carpometacarpal (CMC) joint, also known as the basal joint of the thumb.

This joint, located at the base of the thumb where it meets the wrist, is crucial for pinch and grip movements, making it highly susceptible to wear and tear.

Thumb base pain making daily tasks difficult? Joint Injection Clinic, with clinics near Kent and Essex, offers targeted care to help restore comfortable hand use.

Schedule your consultation now!

Common Causes of 1st CMC Joint Osteoarthritis

Osteoarthritis in the 1st CMC joint is a degenerative joint disease characterized by the breakdown of cartilage, the protective tissue cushioning the ends of bones. This degeneration leads to bone-on-bone friction, causing pain, stiffness, and loss of function. Several factors contribute to the development of 1st CMC OA:

  • Cartilage Wear and Degeneration: The primary cause is the gradual deterioration of the articular cartilage over time, often due to repetitive use and mechanical stress on the joint.
  • Joint Instability: Ligament laxity or injury can lead to instability in the joint, causing abnormal movement and accelerating cartilage wear.
  • Mechanical Overload: Activities that involve forceful or repetitive pinching and gripping can put excessive stress on the 1st CMC joint, contributing to OA development.
  • Genetic Predisposition: A family history of osteoarthritis may increase the risk of developing the condition.
  • Anatomical Factors: The specific shape and alignment of the bones in the thumb and wrist can influence the mechanics of the 1st CMC joint and its susceptibility to OA.
  • Age and Gender: While anyone can develop 1st CMC OA, it is more common with increasing age and is significantly more prevalent in women, particularly after menopause.

How Is 1st CMC Joint Osteoarthritis Diagnosed?

Diagnosing 1st CMC OA typically involves a physical examination to assess pain, swelling, range of motion, and joint stability. X-rays are often used to confirm the diagnosis and evaluate the severity of cartilage loss and bone changes in the joint.

Treatment Options for 1st CMC Joint Osteoarthritis

Treatment for 1st CMC joint osteoarthritis aims to reduce pain, improve function, and slow disease progression. The approach varies depending on the severity of the OA and individual patient needs. Treatments generally fall into conservative, surgical, and emerging categories.

Conservative Treatments:

Conservative management is usually the first line of treatment for 1st CMC OA. These methods aim to alleviate symptoms and improve joint function without surgery.

  • Activity Modification: Adjusting activities to reduce stress on the thumb joint can help manage pain.
  • Splinting: Wearing a splint that supports the thumb base can reduce pain and improve stability during activities. Different types of splints are available, including soft supports and rigid orthoses.
  • Medications:
  • Over-the-counter pain relievers: Acetaminophen and non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen or naproxen can help reduce pain and inflammation.
  • Prescription NSAIDs: Stronger NSAIDs may be prescribed for more severe pain.
  • Topical creams and gels: These can provide localized pain relief.
  • Injections:
  • Corticosteroid injections: Injecting corticosteroids into the joint can provide significant, though often temporary, pain and inflammation relief.
  • Hyaluronic acid injections: These injections aim to supplement the natural lubricating fluid in the joint, potentially improving comfort and function, although their effectiveness for 1st CMC OA is debated.
  • Physiotherapy: Physiotherapists can provide exercises to strengthen the muscles around the thumb, improve range of motion, and teach techniques to protect the joint during daily tasks.

Surgical Treatments:

When conservative treatments fail to provide sufficient relief, or in cases of severe OA, surgical options may be considered. The goal of surgery is to reduce pain and restore function. Common surgical procedures include:

  • Trapeziectomy: This involves removing the trapezium bone, one of the carpal bones that forms the 1st CMC joint. This creates a space that can be filled with scar tissue or a tissue graft, allowing for movement without bone-on-bone friction.
  • Joint Fusion (Arthrodesis): This procedure involves fusing the bones of the 1st CMC joint together, eliminating movement but providing stability and pain relief. This option is typically considered for individuals who require strong, stable pinch and grip.
  • Joint Reconstruction (Arthroplasty): This involves replacing the damaged joint with an artificial implant or using a tissue graft to reconstruct the joint. Various techniques exist, including ligament reconstruction with tendon interposition.

Emerging and Regenerative Therapies:

Ongoing research is exploring regenerative medicine approaches to treat 1st CMC OA, particularly in earlier stages. These therapies aim to repair or regenerate damaged tissues.

  • Intra-articular Biologic Injections: Injections of substances like platelet-rich plasma (PRP) or stem cells derived from sources such as bone marrow or adipose (fat) tissue are being investigated for their potential to reduce pain, inflammation, and promote tissue healing. While some preliminary studies show promise in terms of pain relief and functional improvement, larger, long-term controlled trials are needed to establish their efficacy and optimal protocols.
  • Tissue Engineering: This involves developing biological substitutes to restore, maintain, or improve damaged tissues. Research is ongoing in this area for joint cartilage repair.

Natural History and Future Directions:

1st CMC joint osteoarthritis typically progresses over time, with periods of fluctuating pain and stiffness. While conservative treatments can effectively manage symptoms for many, the disease may eventually progress to a point where surgical intervention is necessary.

Future research is focused on better understanding the natural history of early-stage OA, identifying reliable early diagnostic markers, and developing more effective and predictable regenerative therapies. The goal is to potentially intervene earlier in the disease process to prevent or significantly delay the need for surgery and improve long-term outcomes for individuals with 1st CMC joint osteoarthritis.

If you are experiencing thumb pain, it is important to consult with a healthcare professional for an accurate diagnosis and to discuss the most appropriate treatment plan for your specific situation.

Get Help for 1st CMC Joint Osteoarthritis at Joint Injection Clinic

Osteoarthritis of the 1st CMC (carpometacarpal) joint at the base of your thumb can cause pain, stiffness, and weakness, making it hard to grip, open jars, or carry out everyday tasks. If thumb base pain is affecting your comfort and independence, you don’t have to manage it alone.

At Joint Injection Clinic, our team offers evidence-based treatments designed to reduce pain, improve thumb stability, and support your daily activities.

We welcome patients at all three of our clinics:

Dartford Clinic – ideal for those in Kent and South East London

Address: Unit 30, 1st Floor, The Base Dartford Business Park, Victoria Road, Dartford, DA1 5FS.

Romford Clinic – easily accessible from Essex and Greater London

Address: Room no 8, Alliance Office Space 2-4 Eastern Road, Romford, Essex, RM1 3PJ.

Canterbury Clinic – serving East Kent and surrounding areas

Address: 12-17 Upper Bridge Street, Canterbury, CT1 2NF, United Kingdom.


Using ultrasound-guided scans for precise assessment, targeted injection treatments, and tailored rehabilitation plans, we help reduce pain and improve thumb function so you can get back to your usual activities confidently.

Schedule your consultation now!