Distal interphalangeal joint arthrodesis with screw fixation: why and how.

Though DIP joint fusion can be successfully achieved with K-wires in both the osteoarthritic and rheumatoid patient, their use is often some-what of an inconvenience to the patient. They prohibit showering, may become infected, may back out and catch on clothing, and surely slowdown mobilization of the rest of the finger [1]. For optimal prehension, a modest amount of DIP joint flexion is required, however. Thus, one advantage of K-wires is that they allow fusion in 5 degrees to 10 degrees of flexion (Fig. 1). In the rheumatoid patient in particular, bone stock may be so com-promised that getting enough purchase with wires alone can be challenging. Since making the transition to the Herbert screw, hardware-related complications and patient dissatisfaction with obligatory postoperative functional limitations until union is achieved have been eliminated. Despite the fact that the fusion must occur without flexion-a necessity to ensure intramedullary placement of the screw-patients seem to adapt well (Fig. 2). One further potential disadvantage of screw fixation is the issue of size mismatch between phalanx and screw-especially in the small finger. Though cautious insertion is justified, precise technique allows use even in the small finger-a benefit when early motion is indicated; for example, when concomitant proximal interphalangeal (PIP) implant arthroplasty is performed in an adjacent digit. This device is contraindicated, obviously, if future PIP joint arthro-plasty is anticipated in the same finger (Fig. 3).