Prosthetic replacement of the trapezium. Technical aspects.

Abstract

Affections of the first carpometacarpal joint are often accompanied by chronic radial subluxation of the metacarpal base. It is suggested that the dislocation is caused by the pull of the abductor pollicis longus and thumb extensors being unopposed because of loss of ulnar capsular support. This situation is commonly found in degenerative arthrosis of the first carpometacarpal joint, for example, a lesion which can now be treated by prosthetic replacement of the trapezium. However, a primarily good result of implant arthroplasty may easily be spoilt by recurrent dislocation of the first metacarpal by thumb motion and power grip. Proper correction requires not only a satisfactory range of motion of the joint but also stability and retention in reduction. A procedure is described which seems to meet these functional requirements.