UNASSIGNED: The soft-tissue tension is closely associated with postoperative hip dislocation in patients undergoing total hip arthroplasty (THA), especially for those patients with neurological disorders and insufficient muscle tension. The aim of this study is to explore the effect of limb lengthening on the incidence of complications following THA in patients with neurological disorders and insufficient muscle tension.
UNASSIGNED: This retrospective analysis examines individuals with neurological disorders, such as ischemic stroke and poliomyelitis, who underwent primary total hip arthroplasty (THA) at our medical center between January 2015 and April 2021. Demographic and baseline characteristics (such as age, gender, muscle strength) were obtained from medical records. The limb length, offset and the positional parameters of both acetabular and femoral component were measured on pre- and postoperative plain radiograph. The primary outcome was the occurrence of hip dislocation. The secondary outcome included the incidence of other complications and the hip function (determined by Harris score). The correlation between the occurrence of hip dislocation and limb lengthening was analyzed.
UNASSIGNED: A total of 258 patients were finally analyzed. The hip dislocations were identified in 35 patients (overall incidence = 13.57%). The incidence of early dislocation was lower in patients whose limb-length discrepancy (LLD) was over 20 mm (incidence = 4.1% for LLD >20 mm, 12.2% for LLD 10 mm-20 mm and 17% for LLD <10 mm). The odds ratio (OR) was 0.206 and 95% confidence interval (CI) was 0.058-0.737 (compared between LLD <10 mm and LLD >20 mm). But the no difference was identified regarding on the incidence of late dislocation among patients with different LLD. Moreover, the overall incidence of other complications was elevated in patients with LLD >20 mm (incidence = 17.58% for LLD >20 mm, 11.11% for LLD 10 mm-20 mm and 3.19% for LLD <10 mm; OR = 6.464, 95% CI = 1.768-23.640). And the Harris scores, which reflected the hip function, was gradually decreased with the increasing in LLD. In terms of the relationship between the offset and dislocation rate, it was found that increased offset discrepancy was associated with decreased dislocation incidence (incidence = 4.71% for offset discrepancy >10 mm, 12.5% for offset discrepancy 5 mm-10 mm and 17.20% for offset discrepancy <5 mm; OR = 0.238, 95% CI = 0.076-0.742). Furthermore, increased offset discrepancy also bring a reduction in late dislocation. The incidences of late dislocation were 0%, 2.5% and 10.8% for offset discrepancy >10 mm, offset discrepancy 5 mm-10 mm and 17.20% for offset discrepancy respectively. Different from that of LDD, the incidences of other complications were similar among patients with different offset discrepancy. Besides, no influence of offset discrepancy on the hip function was identified in this study.
UNASSIGNED: Unfortunately, although increasing in limb length could partially reduce early dislocation postoperatively, it could not affect the incidence of late dislocation in those patients with neurological disorders and insufficient muscle tension. Moreover, over limb lengthening was associated with other postoperative complications and worse hip function. Instead, additional offset could reduce the probability of postoperative dislocation, without increasing the incidence of other complications. Therefore, femoral stem with lower cervico-diaphyseal angle (higher offset) should be recommended to patients with neurological disorders who were in high risk of postoperative dislocation. Isolated increasing in limb length should be avoided.

The manufacturing process for wrought Ti alloys with the hexagonal close-packed (HCP) structure introduces a complicated microstructure with abundant intra- and inter-grain boundaries, which greatly influence performance. In the hexagonal close-packed (HCP) structure, two types of grain boundaries are commonly observed between grains with ~90° misorientation: the basal/prismatic boundary (BPB) and the coherent twin boundary (CTB). The mechanical response of the BPB and CTB under external loading was studied through molecular dynamic simulations of HCP-Ti. The results revealed that CTB undergoes transformation into BPB through the accumulation of twin boundary (TB) steps and subsequent emission of Shockley partial dislocations. When the total mismatch vector is close to the Burgers vector of a Shockley partial dislocation, BPB emits partial dislocations and further grows along the stacking faults. When a pair of CTBs are close to each other, severe boundary distortion occurs, facilitating the emission and absorption of partial dislocations, which further assists the CTB-BPB transformation. The present results thus help to explain the frequent observation of coexisting CTB and BPB in HCP alloys and further contribute to the understanding of their microstructure and property regulation.

The harsh service environment of aeroengine hot-end components requires superalloys possessing excellent antioxidant properties. This study investigated the effect of pre-strain on the oxidation behavior of polycrystalline Ni3Al-based superalloys. The growth behaviors of oxidation products were analyzed by scanning electron microscope, transmission electron microscope, X-ray Photoelectron Spectroscopy and Raman spectroscopy. The results indicated that the 5% pre-strained alloys exhibited lower mass gain, shallower oxidation depth and more compact oxide film structures compared to the original alloy. This is mainly attributed to the formation of rapid diffusion paths for Al atoms diffusing to the surface under 5% pre-strain, which promotes the faster formation of protective Al2O3 film while continuing to increase the pre-strain to 25% results in less protective transient oxidation behavior being aggravated due to the increase in dislocation density within the alloy, which prevents the timely formation of the protective Al2O3 film, resulting in uneven oxidation behavior on the alloy.

This paper introduces a method for high-resolution lattice image reconstruction and dislocation analysis based on diffraction extinction. The approach primarily involves locating extinction spots in the Fourier transform spectrum (reciprocal space) and constructing corresponding diffraction wave functions. By the coherent combination of diffraction and transmission waves, the lattice image of the extinction planes is reconstructed. This lattice image is then used for dislocation localization, enabling the observation and analysis of crystal planes that exhibit electron diffraction extinction effects and atomic jump arrangements during high-resolution transmission electron microscopy (HRTEM) characterization. Furthermore, due to the method\'s effectiveness in localizing dislocations, it offers a unique advantage when analyzing high-resolution images with relatively poor quality. The feasibility of this method is theoretically demonstrated in this paper. Additionally, the method was successfully applied to observed edge dislocations, such as 1/6[211-], 1/6[2-11-], and 1/2[01-1], which are not easily observable in conventional HRTEM characterization processes, in electro-deposited Cu thin films. The Burgers vectors were determined. Moreover, this paper also attempted to observe screw dislocations that are challenging to observe in high-resolution transmission electron microscopy. By shifting a pair of diffraction extinction spots and superimposing the reconstructed images before and after the shift, screw dislocations with a Burgers vector of 1/2[011-] were successfully observed in electro-deposited Cu thin films.

Background: The most common types of wrist dislocation are trans-scaphoid lunate dislocation (TLD) and trans-scaphoid perilunate dislocation, in which the lunate and proximal scaphoid are dislocated through the midcarpal joint. There is another rare type of dislocation in which the proximal carpi are dislocated through the radiocarpal joint. The purpose of this study is to examine the clinical features of this type of dislocation. Methods: Six cases of the proximal carpal fracture dislocation via the radiocarpal joint were retrospectively reviewed. All patients underwent open reduction and internal fixation with the ligament reconstruction. A Mayo wrist score was assigned to each patient based on the assessment of pain, functional status, range of motion and grip strength at the last follow-up. Clinical subjective evaluation of function and pain was assessed using the patient-rated wrist evaluation (PRWE) method. Results: All patients were male and injured with a median age of 33.5 years. The median follow-up period was 10 months. There were three types of dislocations: Scaphoid fracture dislocation, TLD and scaphoid-lunate dislocation. All patients had satisfactory results with an average PRWE of 7.2 ± 4.7. The preoperative VAS was 6.7 ± 1.0 and the postoperative VAS was 0.7 ± 0.7 (p < 0.01). Postoperative grip strength accounted for 89.2% ± 9.8% of the contralateral side; the Mayo wrist score averaged 90.0 ± 6.5, with four patients obtaining excellent and two good results. Conclusions: Fracture dislocation of the proximal carpal bones through the radiocarpal joint is an independent type of wrist dislocation that tends to occur in young men with high-energy impact. The wrist is most often injured in a pronation hyperextension position. If treatment is timely and appropriate, the prognosis is quite good. Level of Evidence: Level IV (Therapeutic).

Na metal batteries using inorganic solid-state electrolytes (SSEs) have attracted extensive attention due to their superior safety and high energy density. However, their development is plagued by the unclear structural/volumetric evolution of SSEs and the corresponding Na+ migration mechanisms. In this work, NaSn2F5 (NSF) clusters are composed of nanoparticles (NPs) with matched lattices induced by dislocations, which can mitigate the volume swelling/shrinkage of the NPs. NSF behaves like a single ion conductor with a high Na+ transference number (tNa+) of 0.79. Specially, the ionic conductivity (σ) of NSF is increased from 7.64 × 10-6 to 5.42 × 10-5 S cm-1 after partial irreversible oxidation of Sn2+ (0.118 Å) → Sn4+ (0.069 Å) with the shrunk ionic radius during the charge process, giving more spaces for Na+ migration. Furthermore, a poly(acrylonitrile)-NaSn2F5-NaPF6 composite polymer electrolyte (NSF CPE) was fabricated with a σ of 4.13 × 10-4 S cm-1 and a tNa+ of 0.60. The NSF CPE-based symmetric cell can operate over 3000 h due to the couplings between the different components in NSF CPE, which is beneficial for ion transfer and the construction of stable solid electrolyte interface. And the quasi-solid-state Na|NSF CPE|Na3V2(PO4)3 full cell displays excellent electrochemical performance.

Solid solutions are ubiquitous in metals and alloys. Local chemical ordering (LCO) is a fundamental sub-nano/nanoscale process that occurs in many solid solutions and can be used as a microstructure to optimize strength and ductility. However, the formation of LCO has not been fully elucidated, let alone how to provide efficient routes for designing LCO to achieve synergistic effects on both superb strength and ductility. Herein, we propose the formation and control of LCO in negative enthalpy alloys. With engineering negative enthalpy in solid solutions, genetic LCO components are formed in negative enthalpy refractory high-entropy alloys (RHEAs). In contrast to conventional \'trial-and-error\' approaches, the control of LCO by using engineering negative enthalpy in RHEAs is instructive and results in superior strength (1160 MPa) and uniform ductility (24.5%) under tension at ambient temperature, which are among the best reported so far. LCO can promote dislocation cross-slip, enhancing the interaction between dislocations and their accumulation at large tensile strains; sustainable strain hardening can thereby be attained to ensure high ductility of the alloy. This work paves the way for new research fields on negative enthalpy solid solutions and alloys for the synergy of strength and ductility as well as new functions.

UNASSIGNED: Injuries involving severe spinal axial loading may be accompanied by sacroiliac joint dislocations. In children, these injuries are relatively rare, and there is little information on their optimal management in young patients. We conducted a multicentre study to investigate the outcome of surgical treatment of unstable pelvic fracture with sacroiliac joint dislocation in children.
UNASSIGNED: We assessed the quality of surgical reduction and functional outcome at follow-up in 7 patients (5 girls, 2 boys) with a median age of 6.4 years (range: 4.2-14.8 years). Patients with pelvic fractures and sacroiliac joint dislocations were treated at four international paediatric level 1 trauma centres between January 2008 and August 2023. We applied the Matta criteria to assess the quality of fracture reduction and graded the functional follow-up results using adjusted Majeed score.
UNASSIGNED: At follow-up, 3 patients showed excellent fracture reduction, with 2 patients showing good reduction and 2 patients exhibiting fair fracture reduction according to the Matta criteria. At follow-up visits at a median of 12 months (range: 3-84 months) after the injury, patients achieved a median adjusted Majeed score of 76 (range: 63 to 76).
UNASSIGNED: Unstable pelvic injuries with sacroiliac joint dislocation without comminution can be stabilised with a single iliosacral screw in children. Comminuted pelvic fractures with unstable sacroiliac dislocation require stabilisation with lateral compression screws or plates. In case of residual pelvic instability after internal fixation, an additional external fixator or pelvic hammock should be applied to optimize the stability of fixation.

The effect of aging treatments at various temperatures on the mechanical properties and microstructure of 10B21 cold heading steel with a 20% reduction in area (ε = 0.1) was investigated. The mechanical properties were evaluated based on tensile tests and hardness tests, while the evolution of microstructure was observed by using an optical microscope (OM), scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray diffraction (XRD). The results reveal that aging treatment enhance the strength and hardness of 10B21 cold heading steel after drawing, and the highest values of strength and hardness are attained at an aging temperature of 300 °C. Specifically, the yield and ultrahigh tensile strength after aging at 300 °C are measured at 620 MPa and 685 MPa, respectively, which are 30 MPa and 50 MPa higher than the cold-drawn sample. Moreover, the hardness after aging at 300 °C reaches 293 HV, which has an increase of 30 HV compared to the cold-drawn state. The improvement in mechanical properties may be related to the strain-aging mechanism and the increased density of dislocations. In addition, the analysis of the TEM results reveal that the presence of the second-phase Ti(C,N) contributes to pinning the dislocations, whereas the dislocations are pinned between the cementite (Fe3C) lamellar and stacked at the grain boundaries, leading to strain hardening of the material.

Dislocation of the metatarsophalangeal joint (MTPJ) by trauma commonly occurs in adults. Most dislocations of the MTPJ could be reduced by closed reduction. However, isolated traumatic irreducible dislocation of the fifth MTPJ is an extremely rare injury, particularly in children. We report the case of a 10-year-old boy with irreducible dislocation of the fifth MTPJ who presented with a dorsiflexion injury of the right foot 1 year previously. Closed reduction was attempted but failed. Computed tomography showed the dorsolateral dislocation of the fifth MTPJ. We performed an open reduction and metatarsal bone osteotomy, with a short osteotomy at approximately 0.8 cm. The osteotomy was adjusted to a reduction of the MTPJ and fixation by a lock compression plate. The distal growth plate in the metatarsal bone was protected to avoid pre-closure of the growth plate. There were no instances of dislocation or signs of avascular necrosis of the head of the metatarsal bone. The results of this study demonstrated that open reduction and metatarsal bone osteotomy could be an optional treatment for irreducible dislocation of the fifth MTPJ in children. We should pay more attention to the distal growth plate in the metatarsal bone to avoid pre-closure of the growth plate.