Reliable diagnosis of rhizarthrosis is based on a combination of listening to the symptoms, clinical examination and medical imaging.

Accurate diagnosis allows us to understand where the pain at the base of the thumb is coming from and helps with choosing appropriate treatment, from the early stages of the condition.

So diagnosis is a really important part of gaining an understanding of your rhizarthrosis, from the very first signs to progression. .

When should I think about asking for a diagnosis?

Some thumb pain may be temporary and purely caused by an incorrect movement or straining the joint. But when discomfort becomes recurrent or interferes with your day-to-day hand movements, tasks and activities (opening a jar, turning a key or carrying objects), or when you notice a loss of strength or slight deformation, it’s important to see a doctor.

You should keep a close eye out for the following early signs:

  • pain when you start moving your thumb;

  • discomfort when performing rotational movements;

  • muscle fatigue when pinching your thumb and index finger together.

The above may indicate incipient rhizarthrosis, even if the pain remains moderate. The earlier the diagnosis, the more likely it is that conservative treatment measures will be effective. Simple measures can be incorporated from the outset, to limit progression of the condition.

Preventing rhizarthrosis as soon as the first signs appear

Clinical examination – the essential starting point

The first phase of diagnosis is based on careful clinical examination by a GP, rheumatologist or hand surgeon.

The consultation focuses on identifying:

  • the location and frequency of the pain;

  • the location and frequency of the pain;

  • the onset of symptoms (sudden or gradual);

  • whether you have a relevant medical history or aggravating factors (manual work, menopause, etc.).

  • les antécédents ou facteurs aggravants (travail manuel, ménopause…).

The physical examination then assesses:

  • the mobility of your thumb, in particular the trapeziometacarpal joint;

  • whether there is instability, crepitus or provoked pain;

  • grip strength (pinching, squeezing);

  • visible signs: swelling, z-shaped thumb.

A specific test known as the grind test is often used. It involves rotating the joint with pressure to reproduce the pain typical of rhizarthrosis.

The role of medical imaging tests

A standard thumb X-ray is the main test used to confirm rhizarthrosis. It allows doctors to view:

  • joint pinching (cartilage wear);

  • whether there are osteophytes (bone spurs);

  • misalignment or subluxation of the joint.

Dell radiographic classification is used by doctors and healthcare professionals to describe how advanced your rhizarthrosis is on radiology images, from stage I (early stage) to stage IV (advanced stage with deformation). This system is useful for identifying appropriate treatments for each stage, in particular surgical procedures.

Clinical examination and X-rays are sufficient in most cases. Other tests and examinations may also be suitable though, depending on your specific case:

  • Ultrasound: useful for evaluating soft tissue and ligaments or for detecting associated inflammation.
  • CT scan or MRI: if the diagnosis is uncertain or to prepare for surgery.
  • Functional assessment: to measure strength, mobility and the effect on your grip.
  • Biological tests: if a differential diagnosis is suspected (inflammatory arthritis, early-stage infection, etc.).

Pain at the base of the thumb is not always due to rhizarthrosis. Similar symptoms can also be caused by other conditions, including:

  • arthritis of other joints in the fingers or thumb;
  • tendinitis (e.g. De Quervain’s tenosynovitis);
  • work-related musculoskeletal disorders.

Careful diagnosis by a trained professional helps avoid diagnostic errors and ensures that you are given the right treatment. Further information: What are the differences between thumb arthritis and rhizarthrosis?

Your GP can start the ball rolling and prescribe basic tests and examinations. In the event of doubt, or if pain persists despite first-line treatment, it is often recommended to seek the advice of a specialist such as a rheumatologist or hand surgeon.

They are often best placed to confirm the diagnosis and propose an overall treatment plan: brace or splint, injection, physiotherapy and even surgery in advanced cases.

You will find a directory of hand surgeons on our website, to help you find a specialist with experience in treating this condition.

Further reading: