Basal thumb arthritis

The joint at the base of your thumb is known as the basal joint. It's where the carpal bone (trapezium) meets the first metacarpal bone of your thumb. The joint is also known as a carpometacarpal (CMC) joint. 

Image credit: Miranda Buhler

The thumb base joint is a small joint that gets put under a lot of force with everyday use. The ends of the 2 bones are a shallow saddle-shape and sit together like a rider on a saddle. This allows a lot of movement but is not very stable.

If the short ropes that hold the bones together (ligaments) and muscles are not keeping the bone ends well-aligned, then the force that goes through the joint can cause injury to the covering on the bone ends (cartilage), ligaments and bone.

This gradual injury can cause swelling (inflammation), stiffness and pain at the base of your thumb. Recovery may be limited by repeated stress and strain and other factors such as age. 

The basal joint is very mobile, which allows the wide range of movement we need for hand use such as grip, pinch, and fine manipulation. This high mobility makes the joint less stable stability, which increases the risk of damage to the tissues around the joint. 

You are more at risk if:

• you are more than 40 years of age
• your work involves repetitive movement or loading of your thumb
• you've had a previous injury or fracture to your basal thumb
• you have other family members with thumb base osteoarthritis. 

Symptoms of basal thumb arthritis include:

• pain at the base of your thumb that gets worse when you use it
• pain at the base of your thumb that bothers you during the night
• loss of grip strength and fine movement control
• stiffness that's worse in the morning
• swelling at the base of your thumb
• a bony bulge at the base of your thumb 
• creaking or cracking sensations with thumb or hand movement 
• deformed thumb joints if the condition progresses to a later stage. 

Your healthcare provider will ask what you are able to do and what makes your pain worse. They’ll do a physical examination of your hand and wrist with close attention on your basal thumb joint. There are no specific blood tests for basal thumb arthritis, but tests may be made to exclude other forms of arthritis such as rheumatoid arthritis and septic arthritis.

X-rays are not needed to diagnose basal thumb arthritis but can be helpful in some cases. X-ray findings are not a good guide to how severe symptoms may become and don’t match the amount of pain or impairment you experience. X-rays are usually only helpful if it has been decided that you need surgery, to help the surgeon plan what surgery they should do. 

How you manage day-to-day activities can make a big difference in the impact basal thumb arthritis has on your lifestyle. Self-care measures that may be helpful include:

• using your thumb in a position where the joint surfaces are in most contact, eg, your thumb and index finger should make a circle when holding objects, not collapse towards each other
• taking frequent breaks when doing activities that involve your thumb
• using bigger joints such as your shoulder or elbow joint to carry out daily activities
• using 2 hands instead of 1 hand
• using special equipment to ease activities such as opening jars
• modifying equipment that is skinny or difficult to hold by making it fatter, and easier to grip
• using adaptive equipment for arthritis in hands and fingers that's available from a range of local and online outlets
• wearing a splint to support your thumb
• applying cold packs or gentle heat to reduce swelling and relieve pain – a good pair of warm gloves will help in winter
• wearing 'arthritis gloves' – these can help to keep your hand and thumb warm and give light compression, which may help with swelling and pain
• doing general exercise as it's recommended for reducing the impact of osteoarthritis in any joint
• healthy eating which can support joint health and arthritis management.

Hand exercises

Doing suitable hand exercises can make a difference. These are hand exercises you can try now for left basal thumb osteoarthritis and right basal thumb osteoarthritis. A physiotherapist or hand therapist can provide more information about hand exercises. 

General exercise

General exercise for example walking or in the pool is recommended for your general health and for reducing the impact of osteoarthritis in any joint.  Exercise should be comfortable.  Do little bits often, e.g. 10-20 minutes twice daily

Healthy eating

What you eat can affect your arthritis. A health, balanced diet supports your health and wellbeing. 

• Whole foods are connected to your arthritis symptoms 
• Whole foods come directly from plants or animals including: 
  • fruit
  • vegetables
  • dairy foods
  • nuts and seeds
  • whole grains
  • fish
  • red meat. 

Processed food is related to increased arthritis symptoms.

• Processed food has fewer nutrients and is often high in sugar, salt and additives which can increase inflammation.
• A healthy diet helps with arthritis management by supporting: 
  • joint health 
  • inflammation management 
  • pain management 
  • a healthy immune system.

Medicines

Medicines for basal thumb arthritis focus mainly on pain relief. Usually, the approach is to try the milder pain relief medications first, such as paracetamol and non-steroidal anti-inflammatory (NSAIDs) gels or sprays. If these don't provide relief talk to your healthcare provider about other options.

Apps reviewed by Healthify

You may find it useful to look at some arthritis apps. 

Treatment for osteoarthritis can't cure the condition, but can help with:

• reducing your pain
• maintaining your ability to work or do activities you enjoy
• reducing how often your joint becomes inflamed and painful (flare-ups)
• preventing joint changes from getting worse.

Your healthcare provider, physiotherapist, hand therapist or occupational therapist is likely to recommend treatment that takes into account the severity of the condition, your symptoms, other medical conditions, your age, job and everyday activities.

Medicines 

If paracetamol and non-steroidal anti-inflammatory (NSAID) gels or sprays haven't relieved your pain, your healthcare provider may advise a stronger medicine such as oral NSAIDS, or steroid injections in some cases. This approach reduces the risk of side effects. 

• Paracetamol is recommended as the pain reliever to try first. It is best taken regularly and not just when you have pain.
• Gels or sprays (also called topical agents) that you apply on your skin are useful for people with mild-to-moderate pain. Examples include NSAID gels or sprays such as ibuprofen gel, diclofenac gel or Voltaren gel.
• Oral (NSAIDs) have not been shown to be helpful in basal thumb arthritis.
• Steroid injections are given into the painful joint to reduce inflammation. These are reserved for extremely painful osteoarthritis and used for treating flares.

Read more about medicines on the osteoarthritis page. 

Surgery

If joint changes, pain and disability are all severe and a comprehensive management programme including the above measures isn't helping, surgery may be recommended. The surgical procedure might involve removing the trapezium, carpal and metacarpal bone fusion or a joint replacement. Your healthcare provider may be able to provide more details about the different surgical options. 

Publications

Buhler M, Chapple CM, Stebbings S, Potiki-Bryant KA, Baxter GD. Impact of thumb base osteoarthritis – a pragmatic qualitative study Arthritis Care & Research 2021;73(3):336–346
Buhler M, Chapple CM, Stebbings S, Sangelaji B, Baxter GD. Effectiveness of splinting for pain and function in people with thumb carpometacarpal osteoarthritis: a systematic review with meta-analysis Osteoarthritis and Cartilage 2019;27:547–559
Buhler M, Chapple CM, Stebbings S, Adams J, Gwynne-Jones D, Baxter GD. Splinting for thumb carpometacarpal osteoarthritis – protocol for a feasibility randomized controlled trial Phys Ther Rev. 2020;25(3):196–204

Professional development

Video: Orthopaedics – hand therapy (Craig Hawkyard) (4:00 mins)

Video: Osteoarthritis – wrist and hand conditions (Tom Sharpe) (35:23 mins)