Intermediate Dynamic Compression and Decreased Posterior Tilt With Interlocked Pins in Femoral Neck Fixation in Synthetic Bone

Fixation failure with resulting non-union is the key complication after femoral neck fixation. It can be avoided by permitting dynamic compression and reducing rotation and posterior tilt of the femoral head. To achieve this, a novel implant that features an interlocking plate with three hook-pins (The Hansson Pinloc® System) was developed from the original two hook-pins. Only an enhanced torsional fixation by the implant modification is reported. The purpose was to compare the biomechanical compressive and bending stability of the original and modified implant in femoral neck fixation. To analyze the contribution of both modified components, three individual pins were included, although not in regular use. Forty-eight synthetic femurs with mid-cervical wedge osteotomies were fixated by two pins or identical triangular pin patterns with or without the plate. Eight specimens of each group were loaded cyclically in compression with an inferior wedge to simulate stance and anteroposterior bending with a posterior wedge to imitate sitting down. The clinically relevant stability measurements were stiffness and deformation. Fissure formation defined failure. The novel implant improved bending stability by 30% increased stiffness, 44% reduced deformation, and less frequent posterior neck fissure formation (p < 0.001) while increased compressive stability was only evident with 25% reduced deformation and less frequent inferior neck fissures (p < 0.001). These impacts were mainly mediated by the third pin, while the plate prevented a lateral fissure in compression (p < 0.001). The clinical stability was improved by dynamic compression and decreased posterior tilt by implant modification.

Experimental Investigation of Thin-Walled UHPFRCC Modular Barrier for Blast and Ballistic Protection

The static response of ballistic panels and also its resistance to blast and ballistic impact is investigated in the framework of this study. By connecting individual ballistic panels together, the protective barrier can be constructed. The protective barrier can be featured as a system with high mobility and versatility that is achieved by linking basic interlocking plate elements together. The resulting protective barrier can be shaped according to many possible scenarios in a wall with various possible opening angles and a small post with the tetragonal base or a larger post with the hexagonal ground plan. The material solution of the protective barrier benefits from the application of ultra-high-performance fibre-reinforced cement-based composites (UHPFRCC), which meets the requirements for enhanced resistance against extreme loads such as blast or impact. Besides, by using UHPFRCC, thin and slender design can be adopted, which is advantageous in many ways. Slender design results in a lower weight, allowing for easy manipulation and replacement. To verify the behavior of the panels, the proposed barrier was subjected to various loadings at different strain rates. The experimental campaign demonstrated that the protective barrier has a reasonable load-bearing capacity and also sufficient resistance against projectile impact and blast effects.

Prospective Study of Radiological and Functional Outcome of Closed Subtrochanteric Fracture Fixation with Proximal Humerus Interlocking Plate in Adolescent Patients

Background: Subtrochanteric fractures constitute 1% in children. Subtrochanteric fractures in pediatric age defined as 10% length of total femur below the lesser trochanter. Mostly these fractures are unstable types. There are various treatment options available for the management of this fracture, depending on the age group of the patient. But there is no well-defined management for adolescent subtrochanteric fractures. Methods: This study includes five patients present to orthopedic emergency with closed subtrochanteric fracture without distal neurological deficit. Patients were managed operatively after informed consent with proximal humerus locking plate under regional anesthesia. Postoperatively patients were kept nonweight bearing with in-bed exercises. Follow-up was done at 2, 6, 12, 24, and 36 weeks. Patients were evaluated as functional and radiologically.

Structural design of the minute clypeasteroid echinoid Echinocyamus pusillus

The clypeasteroid echinoid skeleton is a multi-plated, light-weight shell construction produced by biomineralization processes. In shell constructions, joints between individual elements are considered as weak points, yet these echinoid skeletons show an extensive preservation potential in both Recent and fossil environments. The remarkable strength of the test is achieved by skeletal reinforcement structures and their constructional layouts. Micro-computed tomography and scanning electron microscopy are used for microstructural and volumetric analyses of the echinoid's skeleton. It is shown that strengthening mechanisms act on different hierarchical levels from the overall shape of the skeleton to skeletal interlocking. The tight-fitting and interlocking plate joints lead to a shell considered to behave as a monolithic structure. The plate's architecture features distinct regions interpreted as a significant load-transferring system. The internal support system follows the segmentation of the remaining skeleton, where sutural layout and stereom distribution are designed for effective load transfer. The structural analysis of the multi-plated, yet monolithic skeleton of Echinocyamus pusillus reveals new aspects of the micro-morphology and its structural relevance for the load-bearing behaviour. The analysed structural principles allow E. pusillus to be considered as a role model for the development of multi-element, light-weight shell constructions.

Stiffness Comparisons of SOP Interlocking Plate Configurations in 3D Printed Canine Lumbosacral Vertebrae

There are no published biomechanical studies evaluating the effect of stabilization techniques on the stability of the 3D printed models of the canine lumbosacral junction. The purpose of the study was to quantify stiffness of String of Pearls (SOP) interl ocking plating system on the lumbosacral junction in dogs. Testing was performed on five canine lumbosacral junction 3D printed models. Four - point bending was applied and displacement along the ventral aspect of the lumbosacral junction measured. Stiffness of six stabilization techniques was tested:  Models with contiguous polymer reconstruction articular facets.  Models with two dorsal SOP plate each with two pedicle screws in L7, two sacral screws and contiguous polymer reconstruction articular facets.  Models with two SOP plates with two L7 pedicle screws, two sacral screws and disarticulated L7 - S1 articular facets.  Models with two SOP plates with only the caudal L7 pedicle screw and two sacral screws and disarticulated L7 - S1 articular facets.  Models wit h two SOP plates with only the cranial L7 pedicle screw, two sacral screws and disarticulated L7 - S1 articular facets.  Models with one SOP plate, with two pedicle screws in L7 and two sacral screws and disarticulated L7 - S1 articular facets. The greatest st iffness was obtained in models with contiguous polymer reconstruction articular facets stabilized by two SOP plates with two screws engaging the pedicle of L7 (90.13 ±11.16 N/mm). There was no difference in gap stiffness between models with two SOP plates and disarticulated articular facets (54.43 ± 6.25 N/mm), and models with two SOP plates and only a cranial L7 pedicle screw (42.01 ± 8.64 N/mm). The lowest stiffnesses was recorded in constructs with two SOP plates and a caudal L7 pedicle screw (26.38 ± 4. 56 N/mm) and one SOP plate (26.94 ±5.83 N/mm) and intact models, contiguous polymer reconstruction articular facets, with no stabilization technique applied to the lumbosacral junction (16.16 ± .89 N/mm). The study - demonstrated stiffness using a single cra nial pedicle screw in the pedicle of L7 was no different from models with two pedicle screws in L7. Contiguous polymer reconstruction articular facets had a constructive effect on overall stiffness of the lumbosacral junction.