Thumb base Osteoarthritis /Rhizarthrosis

Published on 2 April 2024 at 02:38

Painful thumb is a complaint often seen in Hand Therapy clinics and whist in the past the sufferers were mainly ladies over 55, nowadays we see more younger women and men with the same complaint. Whilst there are many reasons why the thumb gives trouble, one of the main one is Trapeziometacarpal osteoarthritis also know as Rhizarthrosis in European literature. Recent article by Collona and Borghi gives a thorough literature overview of this condition with conservative treatment options described in detail.

This blog post highlights the main takeaways from the overview, for the full article look here. I added some observations and suggestions of what works for my patients.


Rhizarthrosis or Trapeziometacarpal osteoarthritis affects primarily women of post-menopausal age. It is a degenerative disease affecting the first joint of the thumb, where the wrist meets the first metacarpal bone.

There are various factors that contribute to developing of the CMC O/A: previous history of injury to ligaments or fracture, laxity of ligaments surrounding the joint (hormonally induced or as part of systemic disease like Marfan Syndrome or Ehler-Danlos syndrome), repetitive strain of the CMC joint as part of occupation or vocation.

The symptoms include: pain and weakness when gripping or pinching that leads to difficulties with everyday tasks like using the keys, opening jars, holding and carrying heavy objects.

The anatomical alteration of the joint leads to high joint stiffness, especially in the extension/abduction movement of the thumb. This rigidity becomes chronic over time also due to the fact that the person tends to immobilize the area to limit the evocation of pain. In advanced stages, the thumb can deform into the so-called "Z thumb".

Several other conditions affecting the thumb could have similar symptoms and proper assessment is important to establish the cause of the problem. There are manual examinations that therapist or physician can perform like Grind test or Lever tests, but pain on direct palpation over the volar part of the joint is considered an accurate confirmation of the origin of the problem.  Pain assessment, joint mobility examination, and palpation are crucial for a correct differential diagnosis. The differential diagnosis includes: Scaphoid fracture, Dequervains Ds, Flexor Carpi Radialis tendonitis, trigger thumb, arthritis of the wrist.

Radiographic examination reveals joint space degeneration and osteophytes and helps classify RA stages.

Treatment depends on the severity of the disease, how far it has progressed, symptoms and functional deficits. Generally, conservative treatment aims to reduce pain, stabilise the joint and reduce the stress on the joint. In advanced cases or if conservative treatment didn’t bring desired effect, surgery is another option.

The conservative treatment involves:

  • bracing to provide support and protection to the joint
  • therapeutic exercises to improve dexterity and strength
  • manual therapy
  • modalities to decrease pain and inflammation
  • infiltrative therapy to decrease pain and inflammation


Bracing / Splinting / Orthoses / Soft splinting:

The orthosis applied to the thumb prevents movement in the affected joint and provides support for activities that would normally cause pain. There are many thumb braces on the market, generally the more rigid ones are more effective in protecting the joint but limit the functionality of the thumb (e.g. long opponent splint or thermoplastic thumb spika), the softer and shorter splints offering less support but more free movement of the thumb (CMC Push brace). In our clinic we have recently started using NRX strap and SRX strap by Swedish company Mediroyal; this soft splinting method has given us better results in allowing near-full range of movement but also adequate support; the material is also offering proprioceptive feedback and acts as a thermal layer all of which helps to reduce the pain.

As regards the conservative treatment of RA through the use of Kinesio tape, two studies report good results, one associating it with therapeutic exercise and one with manual therapy.


Therapeutic exercises:

The thumb relies on dynamic stability supported by the combined strength of muscles, bones, and ligaments. According to Poole and Pellegrini, reinforcing the thenar muscles, specifically the long abductor and the long extensor, is beneficial in preserving the dynamic stability of the thumb's basal joint complex.

Equally significant is proprioceptive training and strengthening of the 1st dorsal interosseus.

Set of five exercises within an exercise program has been suggested: thumb opposition, tearing paper, tracing a line on a ball's surface, employing sticks to grasp objects, and performing ball squeezes. These specific exercises combine maintaining or increasing the thumb movement range, improving neuromuscular control of thumb alignment and muscle endurance and working on the CMC I proprioception. Emphasis is placed on executing the exercises to prevent the collapse or overextension of the TMj while maintaining proper abduction. These exercises are grounded in recent evidence highlighting the significance of proprioception training and strengthening the 1st DI, aiming for practicality by simulating daily activities. You can follow this set of exercises here.


Manual Therapy:

The authors who published the most on manual therapy applied to RA are Villafañe and colleagues. These authors, in the four works mentioned above, proposed four different manual therapy techniques: neurodynamic (Butler), Kaltenborn, Mulligan, and Maitland.

Neurodynamic technique: Neurodynamic techniques target neural structures by manipulating the position and movement of multiple joints. The work of Villafañe et al. reports, a better result in terms of pain at direct pressure and in the tip and tripod pinch.

Kaltenborn technique: The specific mobilization of Kaltenborn is the anteroposterior sliding with TMj grade 3 distraction. The article didn’t mention if this technique has any significant effect on reducing symptoms of the RA.

Mulligan technique: Mulligan has developed and taught the unique "mobilization with movement" approach for joint dysfunction. Correct execution of this technique improves the patient's ability to move the joint with less pain in previously painful angles. 

Maitland technique: This method included a specific mobilization technique known as anteroposterior gliding of the TMj. The findings indicated significantly reduced pressure-induced pain, however, this treatment did not lead to increased pinch or grip strength.


Therapeutic Modalities

The article mentions Laser therapy (class IV) but the research into this was at the time of publication only a study project.  Research has been published on the use of shock waves compared to hyaluronic acid infiltration. A significant improvement in strength is observed in both groups, but the shock waves group shows better results on the pinch test since the end of treatment and for at least six months.

Our clinic uses also TECAR therapy in treatment of RA. TECAR© is a non-invasive technology using currents of high frequency, usually in the range between 300 KHz and 1 Mhz to affect pain transmission and accelerate healing. It is a relatively new technology and there were no studies made to date specifically for use on RA and data supporting the use of TECAR© is still preliminary. We use the TECAR as an adjunct to the manual therapy and the exercises - the currents passing the tissue generate pleasant heat and reduce pain, which increases the range of movement in the thumb. 

Another modality that works very well, and we use it with most of our arthritic hand patients, is hydrotherapy - hand bath with jets directed at the palm, dorsum and thenar area. The massage effect of the jets together with the temperature around 38C helps to increase the range of movement, decrease the pain and prepare the patient for the rest of the session.


Infiltrative Therapy

For intra-articular injection of the TMj, hyaluronic acid or steroids are usually used. These treatments produce good results for pain and hand function. Injections with hyaluronic acid, however, show a longer-lasting effect and better results. More recently, the use of platelet-rich plasma has been proposed in the literature.



In conclusion, RA is an arthritic degenerative process that affects the first joint of the thumb, i.e., the one between the trapezium bone and the base of the first metacarpus. RA manifests as pain at the base of the thumb, limiting grip strength and hindering everyday tasks. Pain initially occurs during specific movements but can progress to constant discomfort, joint stiffness, muscle atrophy, and severe deformities, like the "Z thumb," which seriously impact daily life. Prevalent in females, especially post-menopause, and linked to age, RA involves ligament and muscle structures, with causes ranging from hormonal influences to mechanical factors. Understanding the biomechanics, stability, and factors contributing to RA is crucial for effective intervention.


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