Adjunctive Dorsal Spanning Plate Fixation in the Stabilization of Perilunate Dislocations

Abstract

To compare the biomechanical properties of adjunctive dorsal spanning plate (DSP) fixation with traditional K-wire fixation of perilunate dislocations in a cadaveric model. Fourteen fresh-frozen cadaveric wrists underwent simulated perilunate injury. The specimens were randomly allocated to either K-wire fixation versus K-wire and DSP fixation. Scapholunate (SL) ligament repair was performed in all specimens. The constructs were tested using a robot cyclically and to failure. Fluoroscopic images were obtained of the specimens prior to simulated injury, after fixation, after 10 and 100 loading cycles, and at construct failure. Differences in carpal alignment parameters (SL interval, SL angle, lunotriquetral interval, and capitolunate angle) and load to failure were recorded. There were no statistically significant differences between the two group's carpal alignment parameters after fixation. Specimens fixated with K-wires and DSP required significantly higher loads to achieve construct failure. The only significant difference between the two groups' carpal alignment parameters was SL interval change at failure. Compared with K-wire fixation alone, adjunctive DSP fixation resulted in significantly increased loads to failure and decreased change in SL interval at the time of failure. Adjunctive DSP may be a useful technique in the polytraumatized patient in whom providing back a weight-bearing extremity may be advantageous in the rehabilitation process.