A low-profile consolidated metastructure for multispectral signature management

This work pertains to the design, numerical investigation, and experimental demonstration of an optically transparent, lightweight, and conformable metastructure that exhibits multispectral signature management capabilities despite its extremely low-profile configuration. In comparison to the existing hierarchical approaches of designing multispectral stealth solutions, attention has been paid to accommodate the conflicting requirements of radar and infrared stealth using a single metasurface layer configuration, which required a few constraints to be incorporated during the design stage to ensure compatibility. This methodlogy promulgates the desired multispectral response with minimal manufacturing footprint and facilitates an efficient integration with the other existing countermeasure platforms. The resulting design exhibits a polarization-insensitive and incident angle stable broadband microwave absorption with at least 90% absorption ranging from 8.2 to 18.4 GHz. Concomitantly it also exhibits an averaged infrared emissivity of 0.46 in the 8-14µm long-wave infrared regime, along with high optical transparency (71% transmission at 632.8nm). Notably, the total thickness of the metastructure stands at 0.10λ_L (λ_L corresponds to the wavelength at lowest frequency). The metastructure has been fabricated with ITO coated PET sheets, on which the frequency selective pattern is machined using Excimer laser micromachining, and the performances are verified experimentally. Furthermore, a hybrid theoretical model has been developed that not only provides crucial insights into the operation of metastructure but also presents a methodical semi-analytical approach to design.

Functional and radiological outcomes of distal humerus fractures treated with pre-contoured locking compression plate

<p><strong>Background: </strong>Distal humerus intra-articular fractures are one of the complicated fractures managed by orthopaedic surgeons. We did a prospective and a retrospective study on 21 patients with these fractures treated with pre-contoured locking compression plate.</p><p><strong>Methods: </strong>The<strong> </strong>21 patients in this series were followed for a minimum of 1 year. The prospective study cases were followed at 3 months, 6 months and annually. The rating system of the Mayo elbow functional scoring system was used. The radiological evaluation was done using standard AP and lateral views.<strong></strong></p><p><strong>Results: </strong>We had 14 patients with range of motion of 50-100 degrees. There was only one patient with range of motion of &lt;50 degrees. 6 patients had the maximum range motion of &gt;100 degrees. We had 6 (23.57%) excellent, 9 (42.85%) good, 5 (23.80%) fair and 1 (4.7%) poor in the Mayo elbow scoring at the end of 1 year. We were able to compare our outcomes with a study done by Kumar et al done in 2017. They had 27 (89.66%) of excellent and good results as opposed to 27 (79.4%) in our study. Out of 21 patients in our study 17(80.95%) patients had good 11 (52.5%) / excellent 6 (28.5%) results. This was comparable with Jupiter et al. His study of 34 patients 26 (79.40/0) patients showed good 14 (41%) / excellent 13 (38.4%) result.<strong></strong></p><p><strong>Conclusions: </strong>Pre-contoured locking compression plate appears to be technically an ideal implant for comminuted osteoporotic bone providing an angle stable construct.</p>

Preliminary mechanical evaluation of two novel veterinary angle-stable-threaded interlocking nail systems

ABSTRACT: The interlocking nail represents an excellent option as a surgical approach to treat fractures in long bones in veterinary medicine. However, failures were reported mainly due to a slack present in the interface of the rod with the screws. The present study tested and mechanically compare axial compression loads of two novel models of stable angle interlocking nails with threaded holes. Among the two models, one was uniplanar and the other was multiplanar with orthogonally arranged distal holes. Twenty-one specimens made of polylactic acid were used for the implantation of interlocking nail´s rods, divided into three groups: conventional interlocking nail (G1), novel interlocking nail with a stable angle with holes arranged in a single plane (G2), and novel interlocking nail with a stable angle in two planes, with the penultimate hole at 90 degrees from the others (G3). Biomechanical tests were performed using axial, cyclic, and destructive compression load for comparison between them. All the specimens showed plastic deformation in the screws after destructive tests, in both proximal and distal sides, being highly intense in G1. G2 and G3 of the stable angle rods supported higher loads than G1 in all tests performed (P<0.05). The novel stems did not differ statistically from each other (P>0.05). The initial hypothesis that the novel models would provide increased stability was confirmed; however, no differences were demonstrated between them. The screw locking system on the rods allowed high resistance values in the tests performed, proving to be effective and potentially applicable in real clinical situations.

Double-Level Osteotomy in Severe Varus Malalignment to Optimize Knee Joint Restoration

Background: Lower extremity alignment-correcting procedures for unicompartmental osteoarthritis are experiencing a rapid rise. Medial open-wedge high tibial osteotomy (MOW-HTO) thereby represents the most common technique among osteotomies but is limited in cases of severe malalignment. Some cases make a double-level osteotomy necessary. Indications: If planning of malalignment correction using a MOW-HTO results in a mechanical medial proximal tibial angle (mMPTA) of more than 93° (causing an oblique joint line), double-level osteotomy is indicated to avoid nonphysiological knee kinematics. Technique Description: After clinical examination and detailed analysis of malalignment (full-weight-bearing long-leg radiograph: hip-knee-angle [HKA], mMPTA, mechanical lateral distal femoral angle [mLDFA], joint line convergence angle [JLCA]), as well as individualized planning of the correction, the surgical procedure starts with an arthroscopy to evaluate the cartilage conditions and eventually treat intraarticular pathologies. Then, the femoral supracondylar correction is performed (closed wedge, biplanar osteotomy [ to increase bony healing]) according to the presurgical planning by resecting the osteotomy wedge with the measured length. K-wires are placed to check the correction. An angle-stable plate is used for osteosynthesis. The wedge taken out will be used as bone stock for the MOW-HTO afterward. The biplanar open-wedge tibial osteotomy is then performed subsequently using a medial tibial approach and an angle-stable plate. Opening of the osteotomy is then performed and double checked with intraoperative fluoroscopy using an alignment rod. Postoperative partial weight bearing for 6 weeks is recommended. Results: In recent literature, only few publications report on results of double-level osteotomies. Babis et al reports that it is a valuable procedure for patients with large varus deformity. Nakayama et al noted a significant improvement in patient-registered clinical outcomes in early postoperative evaluation of 20 patients. Schröter et al reports on 37 knees and findings include good clinical results, despite progressive osteoarthritis. Discussion/Conclusion: In cases of severe malalignment, adequate axis correction may require a double-level osteotomy. Exact preoperative planning is essential. Results reported in recent publications are promising. By splitting 1 large correction into 2 smaller ones, complications like hinge fracture and delayed bone healing are lowered.

Cadomian orogenic collapse in the Ibor and Alcudia anticlines of the Central Iberian Zone, Spain

In the Central Iberian Zone, the Cadomian orogenic collapse is represented by chaotic megabreccias, olistostromes and mélange deposits reflecting a drastic change from slope-related deposits, fed by denudation of the Cadomian arc, to offshore-dominant settings episodically punctuated by phosphogenetic processes. In the Ibor and Alcudia anticlines, the pre-rift unconformity is marked by paraconformable to angular discordant contacts separating variable tilted strata of the Ediacaran Lower Alcudian – Domo Extremeño Supergroup and the upper Ediacaran – lower Terreneuvian Ibor Group from the overlying Terreneuvian San Lorenzo and Fuentepizarra formations. The sedimentation of the San Lorenzo Formation reflects two palaeogeographic scenarios: (i) a low-angle stable basement recording shoaling-upward siliciclastic cycles, and (ii) perturbations of basement fault scarps feeding slope-related conglomeratic channels, with NE-directed palaeocurrents, and sourced from topographic palaeohighs controlled by the movement along synsedimentary normal fault systems, such as the so-called El Guijo Fault. The intra-Fortunian age of the pre-rift unconformity is constrained by the ichno- and microfossil content of the succession, and is bracketed between the first occurrence of Treptichnus pedum in the Arrocampo Formation (Ibor Group) and of Anabarella plana in the Fuentepizarra Formation.

Results of revision intramedullary nailing with and without auxillary plate in aseptic trochanteric and subtrochanteric nonunion

Purpose Aim of this study was to investigate whether limited open auxiliary angle stable plate fixation has an effect on functional and radiologic outcomes one year after revision intramedullary nailing in aseptic trochanteric and subtrochanteric fracture nonunion. Methods In a retrospective analysis, surgically revised aseptic trochanteric and subtrochanteric nonunion was evaluated in a total of 190 consecutive patients ranging from 18 to 94 years between 12/2005 and 10/2018. Results One year after revision intramedullary nailing, nonunion healing was assessed in 129 out of 136 patients (95%) in group 1 without auxiliary plate fixation and in 51 out of 54 patients (94%) in group 2 with auxiliary plating (p = 0.23). In group 1, range of motion (ROM) was unrestricted in 88 patients and still restricted in 48 patients. In group 2, ROM was free in 34 patients and restricted in 20 patients (p = 0.25). The mean Lower Extremity Functional Scale (LEFS) was 56 points in group 1 and 55 points in group 2 (p = 0.55). Conclusion This study did not demonstrate significant differences in functional and radiologic outcomes following revision intramedullary nailing of aseptic trochanteric and subtrochanteric fracture nonunion. Limited open auxiliary plate fixation might be a reasonable option especially in cases of relevant varus axis deviation and comminuted or atypical fracture configurations, regardless of patients’ age. Retrospectively registered with the German Clinical Trials Register (01/25/2021; ID: DRKS00024112).