Metallic hinged prostheses have been used in an attempt to restore some function to the metacarpophalangeal and proximal interphalangeal joints of fingers involved by rheumatoid arthritis.
Indications for prosthetic replacement at the proximal interphalangeal joint are considered to be: (1) gross joint destruction, (2) persistent swan-neck deformity, and (3) ankylosis of the joint in a non-functional position. At the metacarpophalangeal joint the indications are considered to be: (1) gross joint destruction, (2) palmar dislocation of the joint, and (3) persistent ulnar drift combined with joint destruction or palmar dislocation. It is a prerequisite of prosthetic replacement that there be adequate muscle power to control the joint. Six cases are described and illustrated. Some typical complications, such as boutonnière deformity, fracture of the phalanges, and lack of voluntary control, are discussed.
A total of fifty-seven prostheses have been placed at the present time. A table is presented giving the pertinent information concerning thirty-one prostheses which have been in place for six months or more.