Explore the vast range of titles available.

In materials science, dislocations are irregularities within the crystal structure or atomic scale of engineering materials, such as metals, semi-conductors, polymers, and composites.Discussing this specific aspect of materials science and engineering, Introduction to Dislocations is a key resource for students.

Background Congenital dislocation of the knee is characterised by excessive knee extension or dislocation and anterior subluxation of the proximal tibia, and this disease can occur independently or coexist with different systemic syndromes. Nevertheless, significant controversy surrounds treating this disease when combined with hip dislocation. This paper presents a case of a 4-month-old patient diagnosed with bilateral hip dislocation combined with this disease. The study discusses the pathophysiology, diagnosis, and treatment methods and reviews relevant literature. Case presentation We reported a case of a 4-month-old female infant with congenital dislocation of the right knee joint, which presented as flexion deformity since birth. Due to limitations in local medical conditions, she did not receive proper and effective diagnosis and treatment. Although the flexion deformity of her right knee joint partially improved without treatment, it did not fully recover to normal. When she was 4 months old, she came to our hospital for consultation, and we found that she also had congenital dislocation of both hip joints and atrial septal defect. We performed staged treatment for her, with the first stage involving surgical intervention and plaster orthosis for her congenital dislocation of the right knee joint, and the second stage involving closed reduction and plaster fixation orthosis for her congenital hip joint dislocation. Currently, the overall treatment outcome is satisfactory, and she is still under follow-up observation. Conclusions Early initiation of treatment is generally advised, as nonsurgical methods prove satisfactory for mild cases. However, surgical intervention should be considered in cases with severe stiffness, unresponsive outcomes to conservative treatment, persistent deformities, or diagnoses and treatments occurring beyond the first month after birth.

Out-of-hospital analgosedation in trauma patients is challenging for emergency physicians due to associated complications. We compared peripheral nerve block (PNB) with analgosedation (AS) as an analgetic approach for patients with isolated extremity injury, assuming that prehospital required medical interventions (e.g. reduction, splinting of dislocation injury) using PNB are less painful and more feasible compared to AS. Thirty patients (aged 18 or older) were randomized to receive either ultrasound-guided PNB (10 mL prilocaine 1%, 10 mL ropivacaine 0.2%) or analgosedation (midazolam combined with s-ketamine or with fentanyl). Reduction-feasibility was classified (easy, intermediate, impossible) and pain scores were assessed using numeric rating scales (NRS 0-10). Eighteen patients were included in the PNB-group and twelve in the AS-group; 15 and 9 patients, respectively, suffered dislocation injury. In the PNB-group, reduction was more feasible (easy: 80.0%, impossible: 20.0%) compared to the AS-group (easy: 22.2%, intermediate: 22.2%, impossible: 55.6%; p = 0.01). During medical interventions, 5.6% [1/18] of the PNB-patients and 58.3% [7/12] of the AS-patients experienced pain (p<0.01). Recorded pain scores were significantly lower in the PNB-group during prehospital medical intervention (median[IQR] NRS PNB: 0[0-0]) compared to the AS-group (6[0-8]; p<0.001) as well as on first day post presentation (NRS PNB: 1[0-5], AS: 5[5-7]; p = 0.050). All patients of the PNB-group would recommend their analgesic technique (AS: 50.0%, p<0.01). Prehospital ultrasound-guided PNB is rapidly performed in extremity injuries with high success. Compared to the commonly used AS in trauma patients, PNB significantly reduces pain intensity and severity.

Background/aimTo compare outcome of early mobilisation and plaster immobilisation in patients with a simple elbow dislocation. We hypothesised that early mobilisation would result in earlier functional recovery.MethodsFrom August 2009 to September 2012, 100 adult patients with a simple elbow dislocation were enrolled in this multicentre randomised controlled trial. Patients were randomised to early mobilisation (n=48) or 3 weeks plaster immobilisation (n=52). Primary outcome measure was the Quick Disabilities of the Arm, Shoulder, and Hand (Quick-DASH) score. Secondary outcomes were the Oxford Elbow Score, Mayo Elbow Performance Index, pain, range of motion, complications and activity resumption. Patients were followed for 1 year.ResultsQuick-DASH scores at 1 year were 4.0 (95% CI 0.9 to 7.1) points in the early mobilisation group versus 4.2 (95% CI 1.2 to 7.2) in the plaster immobilisation group. At 6 weeks, early mobilised patients reported less disability (Quick-DASH 12 (95% CI 9 to 15) points vs 19 (95% CI 16 to 22); p<0.05) and had a larger arc of flexion and extension (121° (95% CI 115° to 127°) vs 102° (95% CI 96° to 108°); p<0.05). Patients returned to work sooner after early mobilisation (10 vs 18 days; p=0.020). Complications occurred in 12 patients; this was unrelated to treatment. No recurrent dislocations occurred.ConclusionsEarly active mobilisation is a safe and effective treatment for simple elbow dislocations. Patients recovered faster and returned to work earlier without increasing the complication rate. No evidence was found supporting treatment benefit at 1 year.Trial registration numberNTR 2025.

We investigate the structure of 1/3 <0[bar.1]11> dislocations observed in [Bi.sub.2][Te.sub.3] nanowires. This particular type of dislocation is interesting because it has a large Burgers vector (b = 1.048 nm) with a component normal to the basal planes equal to the thickness of one full [Bi.sub.2][Te.sub.3] quintuple unit (i.e., c/3). Atomic-resolution high-angle annular dark-field scanning transmission electron microscopy observations show that the dislocations form with a complex dissociated core structure. This structure consists of two partial dislocations that separate a defected region consisting of a seven-plane-thick septuple unit, consistent with a local patch of [Bi.sub.3][Te.sub.4], rather than the normal [Bi.sub.2][Te.sub.3] quintuple layer structure. As we discuss, details of the core structure can be understood from an analysis of the crystallographic parameters of the observed partial dislocations. This analysis suggests a mechanism to accommodate the loss of tellurium through the heterogeneous nucleation and growth of seven-layer defects at 1/3 <0[bar.1]11>--type dislocations.

Dislocations are the intrinsic origin of crystal plasticity. However, initial high-density dislocations in work-hardened materials are commonly asserted to be detrimental to ductility according to textbook strengthening theory. Inspired by the self-organized critical states of non-equilibrium complex systems in nature, we explored the mechanical response of an additively manufactured medium entropy alloy with segregation-dislocation self-organized structures (SD-SOS). We show here that when initial dislocations are in the form of SD-SOS, the textbook theory that dislocation hardening inevitably sacrifices ductility can be overturned. Our results reveal that the SD-SOS, in addition to providing dislocation sources by emitting dislocations and stacking faults, also dynamically interacts with gliding dislocations to generate sustainable Lomer-Cottrell locks and jogs for dislocation storage. The effective dislocation multiplication and storage capabilities lead to the continuous refinement of planar slip bands, resulting in high ductility in the work-hardened alloy produced by additive manufacturing. These findings set a precedent for optimizing the mechanical behavior of alloys via tuning dislocation configurations. Textbook theory asserts that dislocation hardening inherently sacrifices ductility. Here, the authors report that high-density dislocations with segregation-modified configurations produced by additive manufacturing increase strength without compromising ductility.

Background Dislocation after revision THA is a common complication. Large heads have the potential to decrease dislocation rate, but it is unclear whether they do so in revision THA. Questions/purposes We therefore determined whether a large femoral head (36 and 40 mm) resulted in a decreased dislocation rate compared to a standard head (32 mm). Methods We randomized 184 patients undergoing revision THA to receive either a 32-mm head (92 patients) or 36- and 40-mm head (92 patients) and stratified patients by surgeon. The two groups had similar baseline demographics. The primary end point was dislocation. Quality-of-life (QOL) measures were WOMAC and SF-36. The mean followup for dislocation was 5 years (range, 2–7 years); the mean followup for QOL was 2.2 years (range, 1.6–4 years). Results In the 36- and 40-mm head group, the dislocation rate was 1.1% (one of 92) versus 8.7% (eight of 92) for the 32-mm head. There was no difference in QOL outcomes between the two groups. Conclusions Our observations confirm a large femoral head (36 or 40 mm) reduces dislocation rates in patients undergoing revision THA at short-term followup. We now routinely use large heads with a highly crosslinked polyethylene acetabular liner in all revision THAs. Level of Evidence Level I, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Objective To evaluate surgical strategies and clinical outcomes for atlantoaxial instability/dislocation (AAI/AAD) in Down syndrome (DS) patients. Methods A retrospective review was conducted on 12 DS patients with AAI/AAD treated between March 2018 and June 2024. Surgical plans were tailored based on reducibility: reducible cases underwent posterior atlantoaxial/occipitocervical fusion ( n  = 8), while irreducible cases received transoral anterior release combined with posterior fixation ( n  = 4). Outcomes were assessed through complications, radiographic parameters (anterior atlantodental interval, ADI), and neurological status (JOA score). Results The cohort (5 males, 7 females) aged 5–28 years (mean 11.3 ± 6.4) completed 1–6 year follow-up. Clinical presentations included myelopathy (75.0%, 9/12) and neck pain (25.0%, 3/12). Radiographic anomalies included os odontoideum (66.7%, 8/12) and odontoid fracture (8.3%, 1/12). Postoperative ADI significantly decreased from 8.95 ± 3.19 mm to 3.40 ± 0.81 mm ( P  < 0.05), with JOA scores improving from 10.92 ± 4.40 to 15.50 ± 2.43 ( P  < 0.05). Complications occurred in 25.0% (3/12): one surgical site infection managed by debridement, one dural tear repaired intraoperatively, and one hardware displacement requiring revision. Median fusion time was 6 months (range 4.5–16). All patients demonstrated neurological improvement except one with residual lower limb weakness. Conclusion DS patients with AAI/AAD frequently present with os odontoideum and spinal cord compromise, necessitating surgical intervention. Reducible dislocations may be effectively managed with posterior fusion alone, whereas irreducible cases require combined anterior–posterior approaches. Early surgical intervention is recommended for DS patients exhibiting os odontoideum with AAI/AAD due to elevated risk of progressive myelopathy.

A wide variety of industrial applications require materials with high strength and ductility. Unfortunately, the strategies for increasing material strength, such as processing to create line defects (dislocations), tend to decrease ductility. We developed a strategy to circumvent this in inexpensive, medium manganese steel. Cold rolling followed by low-temperature tempering developed steel with metastable austenite grains embedded in a highly dislocated martensite matrix. This deformed and partitioned (D and P) process produced dislocation hardening but retained high ductility, both through the glide of intensive mobile dislocations and by allowing us to control martensitic transformation. The D and P strategy should apply to any other alloy with deformation-induced martensitic transformation and provides a pathway for the development of high-strength, high-ductility materials.

Validation study using data from a multicenter, randomized, clinical trial (RCT). To evaluate the reliability, validity, responsiveness, and minimal important change (MIC) of the Dutch version of the Oxford Elbow Score (OES) and the Quick Disabilities of the Arm, Shoulder, and Hand (Quick-DASH) in patients with a simple elbow dislocation. Patient-reported outcome measures are increasingly important for assessing outcome following elbow injuries, both in daily practice and in clinical research. However measurement properties of the OES and Quick-DASH in these patients are not fully known. OES and Quick-DASH were completed four times until one year after trauma. Mayo Elbow Performance Index, pain (VAS), Short Form-36, and EuroQol-5D were completed for comparison. Data of a multicenter RCT (n = 100) were used. Internal consistency was determined using Cronbach's alpha. Construct and longitudinal validity were assessed by determining hypothesized strength of correlation between scores or changes in scores, respectively, of (sub)scales. Finally, floor and ceiling effects, MIC, and smallest detectable change (SDC) were determined. OES and Quick-DASH demonstrated adequate internal consistency (Cronbach α, 0.882 and 0.886, respectively). Construct validity and longitudinal validity of both scales were supported by >75% correctly hypothesized correlations. MIC and SDC were 8.2 and 12.0 point for OES, respectively. For Quick-DASH, these values were 11.7 and 25.0, respectively. OES and Quick-DASH are reliable, valid, and responsive instruments for evaluating elbow-related quality of life. The anchor-based MIC was 8.2 points for OES and 11.7 for Quick-DASH.