Scaphotrapeziotrapezoid (STT) Joint Osteoarthritis

Epidemiology

STT osteoarthritis is commonly seen on x-rays.

Clinical Features

History

The clinical symptoms are similar to thumb CMC osteoarthritis. Symptoms include pain at the base of the thumb, distal radial aspect of the wrist, and thenar eminence. There may be pain and/or weakness with pinch and grip.

Examination

First ask the patient to extend their thumb to locate the anatomic snuff box. There is tenderness at the distal end of the anatomic snuff box and just radial to the extensor policis longus.

Then ask the patient supinate their arm and flex their wrist against resistance to identify the flexor carpi radialis tendon. Then ask the patient to relax and feel the scaphoid underneath the tendon, move your finger a little distal to palpate the junction of the scaphoid tuberosity and trapezium.

Imaging

An example of STT joint arthritis stage 3 according to the classification system used. There is also thumb trapeziometacarpal arthritis and distal radioulnar joint arthritis. There is no evidence of radiocarpal arthritis.