Introduction: Fractures of the radius distal to the watershed line show a significant risk factor for secondary dislocation especially when the lunate fossa is involved. These fracture patterns act as avulsion of the attachments of the strong radiocarpal ligaments and destabilize the carpus. If no proper fixation is done, the carpus pushes the fragments volarly leading to dislocation and carpal subluxation. Materials and Methods: Conventional plates usually cannot provide stable fixation. Depending on the size of the fragments, which is best analyzed by computed tomographic (CT) scan, decision making for fixation technique is done. In case of larger fragments, polyaxial plates preferably with the watershed design might be sufficient. New plates sparing the area of the flexor pollicis longus (FPL) tendon offer the advantage to mount the plate far distal without the risk for tendon irritation. However, when the fragments are very small, additionally fragment-specific devices are necessary. One option is small hook plates fixed with tiny self-drilling and self-cutting screws, which produce higher stability as K-wires. Nevertheless, after fixation, radiocarpal stability should be checked under x-ray control. If there are signs of instability, additionally temporary K-wire fixation dorsally through the radius into the lunate prevents carpal subluxation. Results: Analysis of 10 clinical cases demonstrates that when these guidelines are followed, risk for secondary dislocation can be significantly reduced, and vice versa if not frequently secondary dislocation occurs. Conclusion: The problem of the troublesome lunate facet should be recognized and needs adequate treatment. Secondary dislocation frequently causes fixed radiocarpal subluxation and arthritic changes with the need for salvage procedures like radio-scapho-lunate (RSL) fusion.
