Dr Steve Carter

ORTHOPAEDIC SURGEON

Carpometacarpal (CMC) Osteoarthritis

osteoarthritis "wear & tear" is very common in the base of the thumb particularly in women after age of 50. Very often on the non dominant side.

  • The thumb counts for 40% of the function of the hand, so there is a tremendous amount of force going through a shallow saddle shaped joint.
  • This results in excessive sheer forces and the cartilage of the thumb starts to wear out.

Patients present with pain in the base of the thumb. They may also notice a deformity of the thumb, with a swelling at the base. The hand may be weak and typically they are unable to open a tight jar or tap. There may also be a loss of dexterity and range of motion. Overall pain at the base of the thumb is the most important symptom.

Treatment

  • We initially adopt a conservative approach (anti-inflammatories may be useful or splinting of the thumb). Most importantly: many patients get significant long term relief with an intra-articular steroid injection.
  • If conservative treatment fails, surgical options are
    1. CMC joint arthrodesis (we very seldom do this and it is for the younger patient).
    2. CMC joint arthrosplasty (joint replacement). I do not favour this as there are quite a few complications with dislocations, component breakage, etc.
    3. CMC joint excision arthroplasty. In other words removing the arthritic bone and placing a tendon as a new spacer. This is my favoured approach. It is biological, in other words we are using your own tissue so it lasts forever, does not wear out, or dislocate. To date we have performed in excess of 300 of these procedures, with a high success rate.
  • The surgery is performed as day case surgery usually under general anaesthetic, but can also be done under a local regional block. The procedure takes 40min to perform and we use a 5cm incision over the base of the thumb.
  • Following the procedure you are placed in a bulky dressing for 3 days. This is then converted to a small dressing. The thumb is splinted by the Occupational Therapists for a period of 4 weeks and physiotherapy is commenced from day 3.
  • You are able to drive your car after 3-4 days or type on a computer from day 3.
  • The hand is a moving part so we want you to use it, but just protecting the base of the thumb.