The treatment of severely comminuted intra-articular fractures of the distal radius

Comminuted fractures of the distal end of the radius are caused by high-energy trauma and present as shear and impacted fractures of the articular surface of the distal radius with displacement of the fragments. The force of the impact and the position of the hand and carpal bone determine the pattern of articular fragmentation and their displacement and the amount and the extent of frequent concommitant ligament and carpal bone injury. The result of the osseous lesion in comminuted fractures was termed "pilon radiale", which emphasizes the amount of damage to the distal radius and the difficulties to be expected in restoring the articular congruity. Besides this the additional injury, either strain of disruption of the ligaments and the displacement of the carpus and/ or the triangular fibrocartilage complex will equally influence the functional outcome. This review will expand on the relevant anatomy, correct classification and diagnosis of the fracture, diagnostic tools and operative treatment options. Current treatment concepts are analysed with regard to actual literature using the tools of evidence based medicine criteria. A new classification of severely comminuted distal radius fractures is proposed using CT data of 250 complex intraarticular radius fractures. Finally a standardized treatment protocol using external fixation in combination with minimal invasive internal osteosynthesis is described

Min-Max Theorems for Packing and Covering Odd (u,v)(u,v)-trails

We investigate the problem of packing and covering odd $(u,v)$-trails in a graph. A $(u,v)$-trail is a $(u,v)$-walk that is allowed to have repeated vertices but no repeated edges. We call a trail odd if the number of edges in the trail is odd. Let $\nu(u,v)$ denote the maximum number of edge-disjoint odd $(u,v)$-trails, and $\tau(u,v)$ denote the minimum size of an edge-set that intersects every odd $(u,v)$-trail. We prove that $\tau(u,v)\leq 2\nu(u,v)+1$. Our result is tight---there are examples showing that $\tau(u,v)=2\nu(u,v)+1$---and substantially improves upon the bound of $8$ obtained in [Churchley et al 2016] for $\tau(u,v)/\nu(u,v)$. Our proof also yields a polynomial-time algorithm for finding a cover and a collection of trails satisfying the above bounds. Our proof is simple and has two main ingredients. We show that (loosely speaking) the problem can be reduced to the problem of packing and covering odd $(uv,uv)$-trails losing a factor of 2 (either in the number of trails found, or the size of the cover). Complementing this, we show that the odd-$(uv,uv)$-trail packing and covering problems can be tackled by exploiting a powerful min-max result of [Chudnovsky et al 2006] for packing vertex-disjoint nonzero $A$-paths in group-labeled graphs

Three-dimensional foam flow resolved by fast X-ray tomographic microscopy

Thanks to ultra fast and high resolution X-ray tomography, we managed to capture the evolution of the local structure of the bubble network of a 3D foam flowing around a sphere. As for the 2D foam flow around a circular obstacle, we observed an axisymmetric velocity field with a recirculation zone, and indications of a negative wake downstream the obstacle. The bubble deformations, quantified by a shape tensor, are smaller than in 2D, due to a purely 3D feature: the azimuthal bubble shape variation. Moreover, we were able to detect plastic rearrangements, characterized by the neighbor-swapping of four bubbles. Their spatial structure suggest that rearrangements are triggered when films faces get smaller than a characteristic area.Comment: 5 pages, 5 figure

Stress transfer and Quaternary faulting in the northern Alpine foreland

Within the SPP Mountain Building Processes in Four Dimensions (MB-4D) we studied postglacial and present seismic rupturing in the northern Alpine Foreland to better understand the impact and forces of mountain building. We started a seismological field experiment to densify the permanent monitoring networks and the AlpArray Seismic Network. The later was also supported as well as its predecessor UNIBRA (Hetényi et al., 2018; Schlömer et al., 2022). Our StressTransfer network consisted of five recording stations in the Upper Rhine Graben, five in the Molasse Basin and five around the Albstadt Shear Zone (Mader et al., 2021a). The latter are still operating due to the increased seismicity during the last years below the western Swabian Alb. We determined local minimum 1-D seismic velocity models to relocate known events in the study regions (Mader et al., 2021b). Waveform cross-correlation was done to detect hitherto unknown events and recover earthquake sequences around the Albstadt Shear Zone (Mader et al., subm.). To determine fault planes and rupture mechanisms we used relative event locations (hypoDD) and FOCMEC for fault plane solutions. For the Albstadt Shear Zone (ASZ), an NNE–SSW striking left-lateral strike-slip rupture zone, we determined a direction of the maximum horizontal stress (SHmax) of 140°–149°. Down to ca. 7–8 km depth, SHmax is bigger than SV (vertical stress); below this depth, SV is the main stress component. Beneath the shallow Hohenzollerngraben (ca. 2-3 km depth), which is nearly perpendicular to the ASZ, we found an NW-SE striking dextral strike-slip fault zone with very weak micro-seismicity in 11-15 km depth (Figure 1). This zone is possibly a reactivated old upper-crustal tectonic structure. At the interception of the ASZ and the NW-SE striking fault zone we observe NNW-SSE striking sinistral strike-slip and normal faulting micro-earthquakes which belong to a heterogeneous deformation zone with complex faulting. In Figure 1 we summarize our current model for the ASZ and its surroundings. The detection of many micro-earthquakes and the related active faults was only possible with the help of the additional temporal recording stations in the region and the studies of a PhD student (S.M.). We thank the DFG for funding our project and the State Earthquake Service Baden-Württemberg in Freiburg for providing data (Az. 4784//18_3303)

Assessing Regulatory Impact Analyses: The Failure of Agencies to Comply With Executive Order 12,866

None.Environment, Health and Safety, Regulatory Reform

Assessing the Quality of Regulatory Impact Analyses

This study provides the most comprehensive evaluation of the quality of recent economic analyses that agencies conduct before finalizing major regulations. We construct a new dataset that includes analyses of forty-eight major health, safety, and environmental regulations from mid-1996 to mid-1999. This dataset provides detailed information on a variety of issues, including an agency's treatment of benefits, costs, net benefits, discounting, and uncertainty. We use this dataset to assess the quality of recent economic analyses and to determine the extent to which they are consistent with President Clinton's Executive Order 12866 and the benefit-cost guidelines issued by the Office of Management and Budget (OMB). We find that economic analyses prepared by regulatory agencies typically do not provide enough information to make decisions that will maximize the efficiency or effectiveness of a rule. Agencies quantified net benefits for only 29 percent of the rules. Agencies failed to discuss alternatives in 27 percent of the rules and quantified costs and benefits of alternatives in only 31 percent of the rules. Our findings strongly suggest that agencies generally failed to comply with the executive order and adhere to the OMB guidelines. We offer specific suggestions for improving the quality of analysis and the transparency of the regulatory process, including writing clear executive summaries, making analyses available on the Internet, providing more careful consideration of alternatives to a regulation, and estimating net benefits of a regulation when data on costs and benefits are provided.

Efficacy of the A-V Impulse System versus cryotherapy in the reduction of postoperative oedema of the hand: a prospective randomised trial

In a prospective randomised trial, the effects of an intermittent compression hand pump vs. cryotherapy were compared on reduction of postoperative hand swelling and gain in finger movement after distal radius fractures. Although intermittent compression as a physical method for thromboprophylaxis and swelling reduction in orthopaedic and trauma patients of the lower leg are established, a prospective randomised trial for an objective evaluation of the effects of intermittent compression in the upper extremity has not been previously performed. Forty-three subjects (63±33 years, 32 women, 11 men) with a unilateral distal radius fracture treated with transarticular external fixation were randomised into two treatment groups. In group A 21 patients were treated with cryotherapy. In group B 22 patients were treated with an intermittent compression hand pump. Reduction in swelling of the treated hand and MP and PIP joint movement were recorded with computerised assessment software (EVAL Hand Evaluation System) in comparison to the uninjured contralateral side. Reduction of swelling in group A was not statistically significant (28.5% of total swelling or 0.61 cm, SD 0.39, p=0.42), but in group B it was significant (92% of total swelling, 3.62 cm, SD 1.48, p<0.001). Comparison of increases in MP and PIP joint movement (p<0.0016) showed statistically significant differences in favour of the intermittent compression pump. This study demonstrates that intermittent compression is more effective in the reduction of postoperative oedema and gain of finger movement of the hand than cryotherapy

The “floating forearm” injury in a child: a case report

The case of a eleven-year-old girl who had a fracture dislocation of the left elbow with entrapment of the ulnar nerve into the dislocated ulnar epicondyle anlage and unstable forearm fracture of the ipslateral upper extremity is described. This severe injury to the elbow and the ipsilateral forearm is termed “floating forearm” injury. The forearm was stabilized percutaneously and the elbow fracture dislocation, remaining unstable after internal fixation was treated with a pediatric elbow fixator with motion capacity