Base of thumb arthritis affects up to 20% of women and 5% of men, with various levels of severity typically presenting with pain when undoing jars or pinch and opposition movements and deformity such as squaring of the thumb base and sometimes a z shaped position of the thumb.
After non operative treatment has been exhausted (anti-inflammatory drugs, steroid injections and thumb wraps) surgery is considered.
Traditionally surgical treatment is a trapeziectomy, removing the arthritic bone. This is an effective and reliable operation however rehabilitation can take up to 6 months of hand therapy before being able to return to normal activities.
In order to shorten the recovery process we can also consider a total prosthesis for this painful joint (trapeziometacarpal prosthesis), which will consequently retain all its mechanical qualities.
Today, this surgical procedure, developed over 40 years ago, benefits from a new generation of effective implants due to the quality materials and manufacturing technologies used.
Trapeziometacarpal Prosthesis
The MAIATM trapeziometacarpal prosthesis consists of:
- 1. One small stem inserted in the first metacarpal at the base of your thumb
- 2. One modular neck which will articulate over a ball-socket joint with
- 3. One cup positioned in the trapezium.
XRAY showing the thumb prosthetic in place.
Illustration of the bones of the hand with prosthetic.
The procedure will be performed through a 3-4 cm incision to the base of the thumb. It takes approximately 1 hour either by numbing the arm with regional anaesthesia or a short general anesthetic. Patients normally go home 1- 2 hours after the operation.
After surgery, your thumb will be protected with a plaster cast for 2 weeks and then the hand therapist will commence range of movement exercises.
Most patients return to driving at 3 to 4 weeks and normal pain free function between 4 and 8 weeks after the operation.
For patients with enough bone stock the joint replacement offers an excellent alternative to the traditional trapeziectomy with an earlier return to function through maintenance of the anatomical base of thumb position.