After removal of the trapezium, imbrication of abductor pollicis longus and fixing it with a strip of flexor carpi radialis tendon, we obtained a stable arthroplasty having three quarters of normal mobility and half to full power. Of the first 100 operated thumbs, 15 patients had slight pain on heavy use; the rest were painfree. Three patients had radial nerve lesions with minor complaints. Seven patients developed de Quervain's syndrome and two had rupture of abductor pollicis longus; these complications have since been avoided by routinely splitting the first extensor compartment. Four cases with unstable joints required further surgery, and one joint became stiff due to extra-articular conditions.