Thumb Osteoarthritis

Definition

This is osteoarthritis (cartilage wear) at the base of the thumb, particularly at the joint between two bones: the trapezium and the first metacarpal.

What are the causes?

Thumb osteoarthritis is most often degenerative and occurs with age; it is therefore very common in women over 50. It can also be post-traumatic and occur after a fracture of the trapezium or the base of the first metacarpal.

What are the symptoms?

It causes pain at the base of the thumb. There may be limited thumb mobility as well as pain when gripping objects with force.

What tests may be requested?

The diagnosis will be confirmed by performing X-rays of the base of the thumb.

How is this condition treated?

Medical treatment is always offered first with a custom thermoformed splint made by our orthotists, which can be more or less rigid depending on the level of daily activity. Cortisone infiltration treatment under radiographic or ultrasound guidance may also be offered.

If medical treatment fails, surgical treatment will be considered. This can be conservative (preserving the joint) in early stages, or non-conservative in more advanced stages. In the latter case, depending on the radiographic assessment and clinical examination, two types of treatment may be offered: implantation of a joint prosthesis or removal of the trapezium bone (trapeziectomy). With a joint prosthesis, immobilization is short (about two weeks) and use of the thumb can resume progressively. Prolonged stress on the thumb should be avoided to allow the longest possible lifespan of the prosthesis. With trapeziectomy, immobilization is generally four weeks, with longer postoperative recovery and pain-free outcome typically achieved within 6 months postoperatively. Recovery of grip strength is variable and depends on the patient's age.

What are the risks of the procedure?

They are rare:

• Risks inherent to any surgery (<1% of cases):

  • complex regional pain syndrome (formerly known as «algoneurodystrophic syndrome»): the hand becomes red, warm, swollen, and painful with persistent «electric» pain. This syndrome can last several months

  • osteoarticular infection

  • hematoma, which may resolve spontaneously or require surgical revision depending on its size.

• Tingling on the dorsal aspect of the thumb or the first web space which may be transient or permanent, related to a stretch/compression injury of a skin nerve (the sensory branch of the radial nerve) that passes near the trapeziometacarpal joint.

• Wear of the prosthesis, its loosening (it detaches from the bone) or its dislocation.

• Deformation of the thumb column in the trapeziectomy technique.