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Background: Volar radiocarpal instability is often seen after loss of fixation of volar lunate facet fragments. The pathogenesis of post-traumatic volar radiocarpal instability is poorly understood. The purpose of this study was to determine if injury to the dorsal wrist extrinsic carpal ligaments contributes to volar radiocarpal instability. Methods: Six matched pairs of cadaveric upper extremities were tested using a dynamic hand testing system. In group 1, the intact wrist, the wrist with a volar lunate facet fracture, and the fractured wrist after 500 cycles of grip were tested. In group 2, in addition to the intact and fractured wrist, the fractured wrist with the dorsal extrinsic carpal ligaments cut and the fractured wrist with the dorsal extrinsic carpal ligaments cut after 500 cycles of grip were also tested. Volar-dorsal displacement of the lunate was measured from 45° wrist flexion to 45° wrist extension in 22.5° increments with the wrist flexors/extensors loaded for each condition. Results: Volar lunate translation did not significantly increase after the volar lunate facet fracture alone, and was not evident to a significant extent until the dorsal wrist extrinsic carpal ligaments were cut. Further instability of the lunate occurred after grip cycling only with the dorsal extrinsic capsular ligaments cut. Conclusions: Injury to the dorsal wrist extrinsic carpal ligaments exacerbates volar radiocarpal instability. Unrecognized dorsal sided injury may be a contributing factor to why stable fixation of volar lunate facet fragments remains problematic after volar plating of intra-articular distal radius fractures with displaced volar lunate facet fragments.

Following publication of the original article [1], we were notified that the first and last author names have been swapped. The original article has been corrected., SCOPUS: er.j, info:eu-repo/semantics/published

Personal 3D printers have come a long way since the Rep-Rap project started in 2004, and their features have continuously improved. It is even possible for users to improve their own machines as they are based on an open-source infrastructure. Amateurs and professionals have also created large communities in which they can share their ideas and experiments, including post-processing, on a daily basis. This article will focus on a type of post-processing that has not been explored in detail: using heat to produce curved pieces, thus obtaining a product with a better finish. Experiments will be conducted to determine how reliably curves of different complexities can be obtained, and also to ascertain whether the shrinkage of a piece subjected to heat can be predicted, so that any variation can be corrected at the design stage.

Personal 3D printers have come a long way since the Rep-Rap project started in 2004, and their features have continuously improved. It is even possible for users to improve their own machines as they are based on an open-source infrastructure. Amateurs and professionals have also created large communities in which they can share their ideas and experiments, including post-processing, on a daily basis. This article will focus on a type of post-processing that has not been explored in detail: using heat to produce curved pieces, thus obtaining a product with a better finish. Experiments will be conducted to determine how reliably curves of different complexities can be obtained, and also to ascertain whether the shrinkage of a piece subjected to heat can be predicted, so that any variation can be corrected at the design stage.