dislocation

摘要： Introduction: Neglected elbow dislocations are much more common in developing and underdeveloped countries. The main reason for the delay in diagnosis is that patients initially seek treatment from traditional healers. These will immobilize the elbow in extension, which will lead to the retraction of the triceps muscle and collateral ligaments. Patients and Method: We carried out a prospective study over five years (2014-2019). The study involved patients with unreduced elbow dislocation older than 21 days. All patients with a dislocated fracture and those whose x-ray showed joint fusion were not included in the study. We collected 26 patients, 20 men and 6 women with an average age of 27.5 years (17 and 45 years). The average consultation time was 8.9 months (3 - 13). The approach was posterior about 8 cm above the olecranon and 2 cm below the olecranon, the ulnar nerve was identified and isolated. The triceps tendon was cut in a Z from its myotendin junction to the beak of the olecranon, and then lengthened. Results: The patients were reviewed after a mean follow-up of 24 months (12 - 36). The Mayo Clinic’s average elbow performance index was 77.1 (60 - 85), with 19 good and 6 average results. The mean flexion was 114° (100° - 135°) and the mean extension deficit was 31.15° (10° - 55°). The average range of motion was 82.5° (60° - 120°). We did not find a correlation between the duration of the lesion and functional recovery (p > 0.05). The Wilcoxon test showed that surgery significantly improved the overall range of motion of the elbow (p = 0.001). Discussion: Based on this study, open reduction with tendon lengthening should remain a treatment option regardless of the age and chronicity of the dislocation.

摘要： Numerous correlations between magnetic and seismic events unambiguously indicate that the magnetic control of the earthquakes is a fundamental phenomenon. It proceeds from the remarkable physics of magneto-plasticity of solids, which implies acceleration of dislocations by microwaves. The motion of dislocations provides release of dangerous elastic energy of the earthquake focus and transforms elastic energy into the safe energy of plastic deformation. Magneto-plasticity seems to be the most important mechanism of the magnetic control because the piezoelectric effect as a suggested mechanism of magnetic control should be excluded (Chelidze et al.). Magnetic control certifies earthquake focus as a receiver of microwaves;on the other side, numerous observations exhibit emission of microwaves generated by earthquake focus, so that it can be considered as a permanent generator of microwaves. The idea of this paper is to offer a mechanism of self-excitation of the focus: self-triggering is suggested to be induced by microwaves generated by earthquake focus itself. The more intensive is the crack formation, the higher is the density of microwaves, which accelerate dislocations and intensify crack formation: it is a feedback breeding, avalanche-like process. Both functions of earthquake focus, to be simultaneously generator and receiver of microwaves, are integrated into the same space and time. It excludes such limitation of the magnetic control as the penetrability of the rocks for microwaves.

摘要： Large plastic deformation commonly occurs during the practical forming process in industries.Compared with uniaxial tension/compression,torsion is a more effective approach to investigate mechanical behavior under large deformation.The response of the large strain torsion of magnesium alloy is sensitive to the initial texture and twinning.Therefore,an extruded AZ31 alloy was pre-stressed in tension and compression to introduce dislocations and twins in the current work.Subsequently,torsion tests were conducted to clarify the effects of twinning and dislocation on subsequent deformation responses.The corresponding microstructure and deformation mechanisms were explored on the basis of viscoplastic self-consistent(VPSC)modeling.The experimental observations on stress-strain responses and pole figures were captured by simulation work.It was found that twins make less contribution to plastic deformation,which results in small change in texture direction under pure torsion and torsion after pretension.The activity of the slip/twin system and the mechanical properties are affected by different initial textures and active conditions of the system.Moreover,the stress state during combined tension-torsion loading benefits the reduction of texture intensity.

摘要： Carpo-metacarpal dislocations are rare traumatic injuries resulting from violent trauma;they are mostly observed in young subjects. The spatular form is often accompanied by metacarpal fractures. We report a clinical case of complete dorsal carpo-metacarpal spatular dislocation. This was a 34-year-old patient, admitted for a closed trauma of the right hand, in whom the clinical examination noted edema of the hand. The radiological workup showed a complete dorsal spatular dislocation associated with a fracture of the base of the 2nd metacarpal. The reduction of these lesions in closed focus followed by stabilization by metacarpal broaching associated with an intermetacarpal transverse broach was done under scopic control in emergency. Functional rehabilitation was started in the 3rd week. The broaches were ablated at the 6th week. The functional result at 3 months was satisfying with good muscle strength. Resumption of work was effective at 8 weeks. Carpo-metacarpal dislocations are rare injuries, often unrecognized, especially in polytrauma patients, and have a good functional prognosis if they are managed correctly in an emergency.

摘要： Traditional metallic materials usually face a dilemma between high strength and poor strain hardening capacity.However,heterogeneous structured metallic materials have been found to obviously overcome the trade-of.Herein,gradient lamellar structure was fabricated through ultrasound-aided deep rolling technique in pure Ni with high stacking fault energy after heat treatment.The gradient lamellar Ni was successively divided into the four regions.In-situ micropillar compression tests were conducted in diferent regions to reveal the corresponding microscopic mechanical properties.Microscopic characterization techniques were performed to explore underlying deformation mechanisms and the efects of microstructural parameters on deformation behaviors.This work demonstrates that the micropillar with near nanoscale lamellar thickness possesses excellent strength and plasticity.On one hand,the reason for high strength of near nanoscale micropillar is that the strength of micropillar increases with the decrease of lamellar thickness according to the Hall-Petch efect.On the other hand,numerous lamellar grain boundaries perpendicular to the loading direction is found to hinder the motion of slip bands,resulting in great strain hardening capacity in the near nanoscale lamellar micropillar.

摘要： 寰枢椎脱位(atantoatlas dislocation, AD)是上颈椎最为常见的疾病之一;其发病原因较多,包括外伤骨折、发育畸形、肿瘤、炎症以及退变等。寰枢椎脱位容易导致延髓受压,造成严重的后果,甚至直接威胁到生命,所以寰枢椎脱位往往需要通过手术治疗解除其对脊髓的压迫,同时重建寰枢椎的序列和稳定。近年来,随着对寰枢椎解剖结构及生物力学的深入研究,手术内固定方式选择越来越具有多样性及科学性,同时手术融合的方式也逐步呈现出多样化的进展。

摘要： This article provides the numerical modeling of the dislocations in the Cosserat elastic plates based on the Cosserat Plates Theory developed by the authors. The dislocation is modeled by a sequence of domains that converge to the point of the dislocation and by a residual force distributed around that point. The plate deformation caused by the dislocation is calculated using the Finite Element Method. We also discuss the effect of the dislocation on the cavities present in the Cosserat plates.

摘要： Introduction: Complex post-traumatic facial disfigurements are caused by civilian or ballistic trauma. Their repercussions are functional, aesthetic and psychological. The initial emergency or secondary management of facial damage is difficult. The objective is to report, through the clinical observation of three patients, the results of the management of complex facial dislocations in a context of limited technical resources. Patients and methods: Three complex post-traumatic facial dislocations were managed between May 2006 and June 2017. Results: Primary treatment and secondary repair were established on a case-by-case basis. Local autoplasty was the indication of choice. Multidisciplinary management resulted in satisfactory functional and cosmetic outcomes. Two of the patients were lost to follow-up before the end of treatment. Discussion: The complete management of facial dislocations remains difficult and complex, in an extreme exercise situation. In an emergency, the priority is to save the life of the injured person. Several factors are involved in the therapeutic decision: the choice of the maxillofacial reconstruction technique, the availability of the technical platform, the financial capacity and the psychological state of the patient and his entourage. Sequential and multidisciplinary treatment gives satisfactory results in terms of morphology, function and aesthetics, despite the limited technical resources available. Psychological support is an essential complement for successful socio-professional and family reintegration.

摘要： Carpo-metacarpal dislocations are rare hand injuries. They are misdiagnosed due to their non-specific clinical signs. The authors report on their experience in the management of carpometacarpal dislocations in a specialized hand surgery center. Our study included patients received and treated in the department for a carpometacarpal dislocation. Dislocation fractures of Bennett and Rolando were excluded. The postoperative functional evaluation took place after 18 months by the DASH score. Twelve patients participated: one case of neuro-algodystrophy and one pin infection. The mean DASH functional outcome score was 1.10 at 18 months. Since carpometacarpal dislocations are rare and easily misdiagnosed, the surgeon should assume the possibility of them in patients with high-energy trauma, and imaging studies should be carefully evaluated. Pinning is an effective treatment option that provides good long-term functional results.

摘要： The deformation mechanism of CoCrNi alloy with high density of annealing twins was studied by in situ transmission electron microscopy. Dislocation transmission and reflection at the twin boundary were observed during in situ loading. We characterized these reaction processes by combining TEM, dislocation theory and crystallography of twin. Twin boundary not only strengthens the material by impeding the motion of dislocation, but also acts as dislocation source to produce large of slip bands. These processes generate large of slip bands to accommodate the plastic deformation or strengthening material.