Radioscapholunate arthrodesis using low-profile dorsal pi plate.

Radioscapholunate arthrodesis is a desirable method to treat isolated radiolunate arthritis or ulnar translocation of the carpal bones. An intact midcarpal joint is a prerequisite for functional range of motion. Previously, high rates of nonunion were observed with these procedures, as rigid fixation was difficult to obtain with simple Kirschner wires and screws. A successful outcome depends on bringing the scaphoid, lunate, and the radius to an anatomic alignment, and rigid fixation of the arthrodesis. We describe a technique for the arthrodesis of the radioscapholunate joint from the dorsal side using a low-profile locking Pi plate. We observed the advantages of an easy approach, better visualization of the joint, and easier manipulation of the carpal bones. The Pi plate fits on the scaphoid, lunate, and the radius with minimal adjustment. It is not necessary to remove the Lister's tubercle. Pi plate allows for rigid fixation and compression between the scaphoid, lunate, and the radius by 1 compression and 1 locking screw in scaphoid and lunate, and by 2 eccentric compression screws in the radius. Rectangular retinacular flaps were used under and over the extensor tendons. We performed these arthrodeses in patients with lunate fossa arthritis after a distal radius fracture, and with ulnar translocation of the carpus. We have observed excellent clinical results with about 50% of wrist motion preserved and no cases of nonunion or delayed union.