"Stabilized arthroplasty" for old fracture dislocations of the fifth carpometacarpal joint.

The procedure of stabilized arthroplasty we present in this paper aims at a global functional restoration of old fracture dislocations of the fifth carpometacarpal joint. The conflict is eliminated by resecting the base of the metacarpal, whereas length of the fifth digit ray is restored by fusion to the adjacent fourth metacarpal. Fifth metacarpal mobility is maintained via transfer to the fourth carpometacarpal joint. The base of the fifth metacarpal is resected through a dorso-lateral approach to the fourth-fifth intermetacarpal space. The preferred plane of resection is not perpendicular to the shaft of the metacarpal but parallel to the distal articular surface of the hamatum which faces 30 degrees anteriorly. A 5 to 10 mm resection is possible without compromising the insertion of extensor carpi ulnaris. The fifth metacarpal must then be temporarily fixed by 1 or 2 intermetacarpal K-wires in the preferred position. The cortical bones on both sides of the proximal fourth intermetacarpal space must then be refreshed over 1 to 1.5 cm and the space filled with cancellous bone graft. The osteosynthesis of the lateral fusion is secured by 2 transverse screws including the 4 cortices. A temporary distal metaphyseal wire relieves forces until bone fusion. Compared with the more commonly used operative procedures, stabilized arthroplasty provides a better mobility than arthrodesis and restores metacarpal length better than nonstabilized resectional arthroplasty. Nevertheless, it can only be done given the fourth carpometacarpal joint is intact.