THE DEVELOPMENT, TECHNIQUE, AND EARLY CLINICAL RESULTS OF TOTAL JOINT REPLACEMENT FOR THE METACARPOPHALANGEAL JOINT OF THE FINGERS

Abstract

A metal-on-plastic semi-joined snaplock prosthesis has been developed for the metacarpophalangeal joint of the fingers. The components are cemented in place. Results were satisfactory in 55% of 160 joints replaced with the first design and in 86% of 272 joints replaced with an improved model that had a lower center of rotation. Pain was relieved in 94% of the patients and ulnar deviation was corrected in 87%. The current model is associated with motion that averaged -17° extensions to 63° flexion. Complications included infection in two patients, dislocation in two, and fracture of the component in two. Roentgenographic evidence of loosening of the distal components was seen in 18% of joints that had follow-up of more than one year, but such loosening has not as yet been symptomatic. Factors in cementing technique and prosthesis positioning have been identified which may decrease the rate of roentgenographic loosening.Key Words: Total joint replacement; metacarpophalangeal joints; finger joints; metacarpophalangeal prosthesis; prosthesis for rheumatic diseases; finger prosthesis.