Nanoindentation into a bcc high-entropy HfNbTaTiZr alloy-an atomistic study of the effect of short-range order

The plastic response of the Senkov HfNbTaTiZr high-entropy alloy is explored by means of simulated nanoindentation tests. Both a random alloy and an alloy with chemical short-range order are investigated and compared to the well understood case of an elementary Ta crystal. Strong differences in the dislocation plasticity between the alloys and the elementary Ta crystal are found. The high-entropy alloys show only little relaxation of the indentation dislocation network after indenter retraction and only negligible dislocation emission into the sample interior. Short-range order-besides making the alloy both stiffer and harder-further increases the size of the plastic zone and the dislocation density there. These features are explained by the slow dislocation migration in these alloys. Also, the short-range-ordered alloy features no twinning plasticity in contrast to the random alloy, while elemental Ta exhibits twinning under high stress but detwins considerably under stress relief. The results are in good qualitative agreement with our current knowledge of plasticity in high-entropy alloys.

Fractures and Dislocations on the Playing Field: Which Are Emergent and What to Do?

High-energy injuries, including fractures and dislocations, are occurring with increasing frequency in athletic competitions with the increasing size and speed of players. Common fractures and dislocations will be discussed in this article. We will evaluate emergent versus routine injuries and discuss appropriate treatment at the athletic venue. Fractures that can be seen with athletic activities include cervical spine; knee osteochondral fractures; tibia, ankle, and clavicle. Dislocations that will be considered include knee, patella, hip, shoulder, sternoclavicular joint, and proximal interphalangeal joint of the finger. These injuries vary significantly both in severity and in the emergent nature of the injury.

[Posterior cervical pedicle screw rod short-segment internal fixation for the treatment of atlantoaxial fracture and dislocation]

OBJECTIVE

To investigate the clinical efficacy of posterior cervical pedicle screw short-segment internal fixation for the treatment of atlantoaxial fracture and dislocation.

METHODS

The clinical data of 60 patients with atlantoaxial vertebral fracture and dislocation underwent surgery between January 2015 and January 2018 were retrospectively analyzed. The patients were divided into study group and control group according to different surgical methods. There were 30 patients in study group, including 13 males and 17 females, with an average age of (39.32±2.85) years old, were underwent short-segment internal fixation with posterior cervical pedicle screws. There were 30 patients in control group, including 12 males and 18 females, with an average age of (39.57±2.90) years old, were underwent posterior lamina clip internal fixation of the atlas. The operation time, intraoperative blood loss, postoperative ambulation time, hospitalization time and complications between two groups were recorded and compared. The pain visual analogue scale(VAS), Japanese Orthopedic Association(JOA) score of neurological function, and fusion status were evaluated between two groups.

RESULTS

All patients were followed up for at least 12 months. The study group was better than control group in operation time, intraoperative blood loss, postoperative off-bed activity time, and hospital stay (P=0.000). One case of respiratory tract injury occurred in study group. In control group, 2 cases occurred incision infection, 3 cases occurred respiratory tract injury, and 3 cases occurred adjacent segmental joint degeneration. The incidence of complications in study group was lower than that in control group (χ²=4.705, P=0.030). At 1, 3, 7 days after operation, VAS of study group was lower than that of control group(P=0.000). At 1, 3 months after operation, JOA score of study group was higher than that of control group(P=0.000). At 12 months after operation, all the patients in the study group achieved bony fusion. In control group, there were 3 cases of poor bony fusion and 3 cases of internal fixation fracture, the incidence rate was 20.00%(6/30). The difference between two groups was statistically significant (χ²=4.629, P=0.031).

CONCLUSION

Posterior cervical short-segment pedicle screw fixation for atlantoaxial fracture and dislocation has the advantages of less trauma, shorter operation time, fewer complications, and less pain, and can promote the recovery of nerve function as soon as possible.

Neglected simultaneous bilateral asymmetric traumatic hip dislocation in a young male managed by closed reduction manoeuvres in a resource-limited setting: A case report

Background

Asymmetric bilateral hip dislocations are rare, representing approximately 0.01 %-0.02 % of all joint dislocations. The treatment of neglected hip dislocations is difficult or impossible by closed reduction manoeuvres. This is a report of an unusual clinical entity of neglected simultaneous bilateral asymmetric traumatic hip dislocations in a young male, managed by closed reduction manoeuvres.

Case presentation

This is the case of a 29-years-old male who presented with neglected simultaneous bilateral asymmetric traumatic hip dislocations 5 weeks post injury. His condition was managed by closed reduction manoeuvres due to financial constraints. Under spinal anaesthesia, the left hip was successfully reduced. Due to an associated posterior acetabular wall fracture, the presence of osteo-chondral fragments and labral lesions, adequate reduction of the right hip was not achieved. The functional Harris Hip Score (HHS) of the left hip improved on every subsequent follow-up visits at the clinic from 70 at day 45 to 86 at day 90. The HHS of the right hip was poor at day 45 but however increased to 90 after total hip replacement was done.

Conclusions

This is an unusual case of neglected simultaneous bilateral asymmetric traumatic hip dislocations in a young male, managed by closed reduction manoeuvres. Closed reduction of such injury is difficult and seldom successful with uncertain long term functional outcome.

Dislocation rate, revisions and other complications of primary cemented hemiarthroplasty for displaced femoral neck fractures: a single-center cohort study of 743 unselected hips with a mean 2.7-year follow-up

INTRODUCTION

Evidence of whether to use hemiarthroplasty (HA) or total hip arthroplasty for displaced femoral neck fractures (FNF) is still widely debated, especially when taking ambulatory status, age, and patient cognitive status into account. The current study aims to report the rates of dislocations, revisions and other complications for primary cemented HA in patients with displaced FNF.

MATERIALS AND METHODS

Single-center retrospective follow-up study of an unselected historic cohort. 743 consecutive hips (551 W and 192 M) at mean (SD) age of 83.6 (8.4) years received primary cemented HA for displaced FNF by posterolateral surgical approach between January 2012 and December 2019. Patient files and radiographs were evaluated for dislocations, revisions, and other complications until death or end of the follow-up period, and the educational level of the surgeon was noted.

RESULTS

During a mean (SD) follow-up period of 2.7 (2.2) years, there were 6.1% (n = 45) dislocations, in which 82% (first dislocation) appeared within the first 30 postoperative days, and 51% (n = 23) of the dislocations requiring subsequent surgery. At the time of the last available follow-up, 57% (n = 421) of the patients were dead. A non-dislocation related revision was needed in 3.4% (n = 25) of the patients [in which infection accounted for 40% (n = 10) and traumatic periprosthetic fracture for 32% (n = 8)]. Thirty-day mortality was 9.2% and 1-year mortality 25.8%. There were no differences in patient's age, gender, or educational level of the surgeon between the dislocation and the no dislocation groups. Patients aged < 70 years presented with a higher dislocation rate (p < 0.001) than the patients aged > 70 years.

CONCLUSION

Primary HA presents a safe and robust approach with acceptable complication rates in a genuine unselected cohort of displaced FNF, particularly for patients aged > 70.

Existence of Ti3+ and dislocation on nanoporous CdO-TiO2 heterostructure applicable for degrading chlorophenol pollutant

This study addresses the significance of wastewater recuperation by a simple and facile treatment process known as photocatalyst technology using visible light. Titanium di-oxide (TiO₂) is the most promising photocatalyst ever since longing decades, has good activity under UV light, owing to its small band gap. Hence, TiO₂ has been modified with metal oxides for the positive response against visible light. Since this is an efficient process, the novelty has been made on nanometal oxide CdO (cadmium oxide) combined with TiO₂ to acquire the best efficiency of degrading organic chlorophenol contaminant. Initially, the composites were synthesized by sol-gel and thermal decomposition methods and investigated for their various outstanding properties. The characterized outcomes have exhibited heterostructures with reduced crystallite size from the X-ray diffraction studies. Then, the determination of nanoporous feature was recognized through HR-TEM analysis which was also detected with some dislocations. The EDX spectrum was identified the perfect elemental composition. The nitrogen adsorption-desorption equilibrium was attained that offers many pores measured with high surface area. The XPS result convinced that Ti³⁺ was accessible along with TIO₂/CdO composite. Further the absorption towards higher wavelength was obtained from UV-vis spectra. Finally, for the photocatalytic application of chlorophenol, the composite shows higher percentage of degrading efficiencies than the pristine TiO₂. The photocatalytic mechanism was discussed in detail.

Baksi procedure for habitual dislocation of patella in children - Revisiting the key surgical steps

The pes anserinus transfer procedure for habitual dislocation of patella described by Baksi is a biomechanically sound technique with predictable long term results. The dynamic pes anserinus sling counteracts the lateral quadriceps contracture and keeps patella relocated till the vastus medialis activity is restored and takes over. The procedure is especially suitable for children with open physeal growth plates. Moreover, the surgery runs a low complication rate. In the present review, we recapitulated the steps of the procedure to illustrate its surgical basics. We also describe our experience and long term follow up results of 4 cases operated with same technique. The indigenous Baksi's procedure remains a viable option for managing habitual patellar dislocations in pediatric age group with immature skeleton.

Acute Rockwood type III ACJ dislocation: Conservative vs surgical approach. A systematic review and meta-analysis of current concepts in literature

BACKGROUND

The most appropriate approach, surgical or conservative, for acute Rockwood type III acromioclavicular joint (ACJ) dislocation is still under debate. In literature, similar results have been reported with both treatments. This review aims to analyze the operative and conservative outcomes of acute Rockwood type III ACJ dislocation to guide orthopedics in daily practice.

MATERIAL/METHODS

A systematic review and meta-analysis were performed according to PRISMA guidelines. A PICOS template was developed. Four databases (Pubmed, Scopus, Embase, and Medline) were searched, and eligible articles were evaluated according to the Levels of Evidence. The methodological quality of the articles was assessed through the ROBINS-I and the RoB-2. This review was registered in PROSPERO.

RESULTS

Five studies were included, with 73 and 110 patients treated with conservative and surgical approaches, respectively. Three outcomes, Constant Score (CS), coracoclavicular distance (CCD), and acromioclavicular distance (ACD) were analyzed. Only the acromioclavicular distance was statistically significant in the surgical group over the conservative one (p < 0.05); instead, the other two outcomes demonstrated no statistical difference between the two groups.

CONCLUSIONS

This study demonstrated statistically significant superiority of the mean ACD score in the radiological follow-up of the surgical group compared to the conservative one. A tendency for better radiological and clinical results, mean CCD and CS scores, respectively, although non statically significant, was reported in the surgical group. High-quality randomized controlled clinical trials should help determine the most appropriate treatment for acute Rockwood type III ACJ dislocations.

Recommendations on the preparation of silicon solar cell samples for defect etching

Research on the structural defects of silicon such as grain boundaries and dislocations, their spatial distribution and how they impact the resulting solar cell performance often proceed by polishing the sample, etching to reveal the dislocations and grain boundaries, and then scanning the surface to image the defects and record their corresponding positions. While a lot of work has been devoted to developing appropriate etches and how to correlate the etch pits to cell performance, materials pertaining to preparation of samples for defect etching, which is a crucial step to ensure successful imaging and analysis, are limited. This work describes a method of polishing multicrystalline silicon solar cell samples in preparation for defect etching. The method described herein:

• Utilizes both mechanical and chemical mechanical polishing.

• Can be applied to both fabricated silicon solar cells and as-cut wafers.

A new prognostic nomogram for heterotopic ossification formation after elbow trauma : the Shanghai post-Traumatic Elbow Heterotopic Ossification Prediction (STEHOP) model

AIMS

Heterotopic ossification (HO) is a common complication after elbow trauma and can cause severe upper limb disability. Although multiple prognostic factors have been reported to be associated with the development of post-traumatic HO, no model has yet been able to combine these predictors more succinctly to convey prognostic information and medical measures to patients. Therefore, this study aimed to identify prognostic factors leading to the formation of HO after surgery for elbow trauma, and to establish and validate a nomogram to predict the probability of HO formation in such particular injuries.

METHODS

This multicentre case-control study comprised 200 patients with post-traumatic elbow HO and 229 patients who had elbow trauma but without HO formation between July 2019 and December 2020. Features possibly associated with HO formation were obtained. The least absolute shrinkage and selection operator regression model was used to optimize feature selection. Multivariable logistic regression analysis was applied to build the new nomogram: the Shanghai post-Traumatic Elbow Heterotopic Ossification Prediction model (STEHOP). STEHOP was validated by concordance index (C-index) and calibration plot. Internal validation was conducted using bootstrapping validation.

RESULTS

Male sex, obesity, open wound, dislocations, late definitive surgical treatment, and lack of use of non-steroidal anti-inflammatory drugs were identified as adverse predictors and incorporated to construct the STEHOP model. It displayed good discrimination with a C-index of 0.80 (95% confidence interval 0.75 to 0.84). A high C-index value of 0.77 could still be reached in the internal validation. The calibration plot showed good agreement between nomogram prediction and observed outcomes.

CONCLUSION

The newly developed STEHOP model is a valid and convenient instrument to predict HO formation after surgery for elbow trauma. It could assist clinicians in counselling patients regarding treatment expectations and therapeutic choices. Cite this article: Bone Joint J 2022;104-B(8):963-971.

Complete Occlusion of Radial and Ulnar Arteries Following Hand Crush Injury with Multiple Carpometacarpal Joint Fracture-Dislocations

Multiple dorsal fracture-dislocations of the carpometacarpal joints (CMCJ) occur from very high-energy trauma and are often associated with soft tissue injury or ischaemia. We report a 54-year-old male manual worker and a smoker who presented to the emergency room with history of compression of his right hand in a press machine. Radiographs showed dorsal fracture-dislocations of the scapho-trapezio-trapezoidal and third to fifth CMCJ's. Despite emergent Guyon canal and carpal tunnel release and closed reduction and pinning, skin pallor persisted in all digits. Brachial angiography revealed total occlusion of the radial and ulnar arteries and loss of the palmar arch at the level of the fracture. Heparin and Alprostadil were injected directly. On follow-up angiography three weeks later, the vessels were still occluded and collaterals provided digital circulation. Although digital sensations recovered, cold intolerance and stiffness resulted in a poor functional outcome. Level of Evidence: Level V (Therapeutic).

3D reconstruction of curvilinear structures with stereo matching deep convolutional neural networks

Curvilinear structures frequently appear in microscopy imaging as the object of interest. Crystallographic defects, i.e dislocations, are one of the curvilinear structures that have been repeatedly investigated under transmission electron microscopy (TEM) and their 3D structural information is of great importance for understanding the properties of materials. 3D information of dislocations is often obtained by tomography which is a cumbersome process since it is required to acquire many images with different tilt angles and similar imaging conditions. Although, alternative stereoscopy methods lower the number of required images to two, they still require human intervention and shape priors for accurate 3D estimation. We propose a fully automated pipeline for both detection and matching of curvilinear structures in stereo pairs by utilizing deep convolutional neural networks (CNNs) without making any prior assumption on 3D shapes. In this work, we mainly focus on 3D reconstruction of dislocations from stereo pairs of TEM images.

Direct Visualisation of Skyrmion Lattice Defect Alignment at Grain Boundaries

We present a method to directly visualise a statistical analysis of skyrmion defect alignment at grain boundaries in the skyrmion host [Formula: see text]OSeO3. Using Lorentz transmission electron microscopy, we collected large data sets with several hundreds of frames containing skyrmion lattices with grain boundaries in them. To address the behaviour of strings of dislocations in these grain boundaries, we developed an algorithm to automatically extract and classify strings of dislocations separating the grains. This way we circumvent the problem of having to create configurations with well-defined relative grain orientations by performing a statistical analysis on a dynamically rearranging image sequence. With this statistical method, we are able to experimentally extract the relationship between grain boundary alignment and defect spacing and find an agreement with geometric expectations. The algorithms used can be extended to other types of lattices such as Abrikosov lattices or colloidal systems in optical microscopy.

Pediatric Trauma

Musculoskeletal injuries of the lower limb are frequent in pediatric patients and represent the most common cause of emergency department admissions. Acute sports-related injuries commonly involve the lower extremity, as the knee and ankle are the most frequently injured parts. Physeal fractures are common injuries in children and adolescents participating in contact sports, which may lead to growth disturbances and cause limb length discrepancy. It is imperative for pediatric trauma centers to implement evidence-based multispecialty protocols for the perimanagement of the injured child, especially through the postdischarge and rehabilitation phases, in order for the child to resume active daily living.

Chronic glenohumeral dislocations treated with arthroplasty: a systematic review

Background

The aim of this systematic review was to summarize the clinical outcomes and associated predictors of outcomes for chronic glenohumeral dislocations treated with arthroplasty.

Methods

A systematic literature search was performed with Embase, PubMed, CENTRAL, BIOSIS, and CINAHL databases from the inception of these databases through January 1, 2021 to identify all articles that examined outcomes or predictors of outcomes of arthroplasty in patients with chronic glenohumeral dislocations. Studies that examined outcomes for patients with a chronic glenohumeral dislocation (≥3 weeks) treated with hemiarthroplasty, anatomic total shoulder arthroplasty, or reverse total shoulder arthroplasty were included. Those with acute or subacute dislocations (<3 weeks), fracture dislocations, and those treated with joint preserving treatment modalities were excluded.

Results

We identified 195 articles; of which, 22 (201 patients/205 shoulders) met our inclusion criteria. A total of 14 studies reported outcomes of hemiarthroplasty, 10 studies reported outcomes of anatomic total shoulder arthroplasty, and 9 studies reported outcomes of reverse total shoulder arthroplasty. All studies documented clinical improvement after arthroplasty. Among 16 studies that measured range of motion, all 16 studies demonstrated improvement in range of motion postoperatively. Thirty-one reoperations (15%) were performed across all studies.

Conclusion

We found improved clinical outcomes after arthroplasty for the treatment of chronic glenohumeral fewer dislocations at a long-term follow-up. Some evidence suggests that reverse total shoulder arthroplasty may have superior outcomes and less complications compared with hemiarthroplasty and anatomic total shoulder arthroplasty. There is insufficient evidence regarding the potential influence that duration of dislocation, direction of dislocation, addition of concomitant procedures, or humeral component retroversion have on outcomes.

Understanding mechanisms of shape memory function deterioration for nitinol alloy during non-equilibrium solidification by electron beam

Introduction

As an important advanced functional material, the memory effect of nitinol shape memory alloy (SMA) is the focus of research. According to the current research, the memory function of the alloy decreases after welding, and there is no sufficient explanation for the phenomenon.

Objectives

For the problem, this research is to explore the underlying causes of the decrease of shape memory function after welding by analyzing the microstructure and micro defects.

Methods

The vacuum electron beam welding tests of 1 mm thick Ni₅₀Ti₅₀ alloy plate was carried out to determine the appropriate welding process parameter. And the shape memory function of the welded joint was compared with that of the base metal to analyze the change of memory function.

Results

It was found that the shape memory function of the welded joint decreased significantly under different strain variables. And the phase transition temperature also changed.

Conclusions

This was due to the micro stress field produced by non-equilibrium solidification in molten pool promoted the formation and propagation of dislocations, increasing the dislocation density in the martensite. Dislocations entangled with each other in the martensite, showing a grid-like distribution, which destroyed the integrity of martensite substructure. At the same time, the twin substructure of martensite was often accompanied by vacancies, dislocations, stacking faults, and a consequently large stress field formed between twin planes due to lattice distortion. Secondary twin was identified inside martensite under micro shear stress, where the martensite showed the bending state. The habitual relationship between martensite phase and parent phase was destroyed, resulting in the decrease of shape memory function.

Anatomic reconstruction of the acromioclavicular joint provides the best functional outcomes in the treatment of chronic instability

PURPOSE

To systematically review the outcomes of surgical treatments of chronic acromioclavicular joint dislocation.

METHODS

Studies were identified by electronic databases (Ovid, PubMed). All studies reporting functional and radiological outcomes of surgical treatments of chronic acromioclavicular joint dislocations were included. Following data were extracted: authors and year, study design, level of evidence, number of patients, age, classification of acromioclavicular joint dislocation, time to surgery, surgical technique, follow-up, clinical and imaging outcomes, complications and failures. Descriptive statistics was used, when a data pooling was not possible. Comparable outcomes were pooled to generate summary outcomes reported as frequency-weighted values. Quality appraisal was assessed through the MINORS checklist.

RESULTS

Fourty-four studies were included for a total of 1020 shoulders. Mean age of participants was 38 years. Mean follow-up was 32.9 months. Arthroscopic techniques showed better results than open approach (p < 0.0001). Synthetic reconstructions demonstrated better functional outcomes compared to internal fixation and biologic techniques (p < 0.0001). Among biologic techniques, combined coracoclavicular and acromioclavicular ligaments reconstruction showed better Constant (p = 0.0270) and ASES (p = 0.0113) scores compared to isolated coracoclavicular ligaments reconstruction; anatomic biologic non-augmented graft reconstruction showed better Constant (p < 0.0001), VAS (p < 0.0001) and SSV (p = 0.0177) results compared to augmented techniques. No differences in functional outcomes could be found between anatomic biologic non-augmented graft versus synthetic reconstructions. Overall, methodological quality of the included studies was low.

CONCLUSION

Anatomic reconstructions, both synthetic and biologic, showed the best functional results.

LEVEL OF EVIDENCE

IV.

[Arthroscopic Bankart repair combined with Reimplissage for the treatment of recurrent anterior dislocation of shoulder in adults with Hill-Sachs defect]

OBJECTIVE

To investigate the method and clinical effects of the treatment of recurrent anterior dislocation of shoulder with Hill-Sachs injury by arthroscopic Bankart repair and Remplissage.

METHODS

From March 2016 to March 2019, 106 patients with recurrent anterior dislocation of shoulder with glenoid bone defect less than 20% underwent arthroscopic Bankart repair, including 76 males and 30 females, aged from 18 to 45 (27.3±8.6) years, 59 cases of left shoulder and 47 cases of right shoulder. Range of motion (ROM), American Shoulder and Elbow Surgeons(ASES) score, Constant-Murley score and Rowe score were used to evaluate shoulder functionand stability before and after operation.

RESULTS

All patients were followed up, and the duration ranged from 21 to 60 months, with a mean of (41.5± 8.5) months. One patient developed infection after operation, and the infection was controlled after arthroscopic debridement again. The remaining patients did not have clinical complications such as infection, intra articular hematocele and redislocation. Shoulder flexion and lifting increased from (158.33±15.72) ° preoperatively to (169.43±10.04) ° at the latest follow up, and internal rotation changed from T7 (T4 to T10) preoperatively to T8 (T5 to T10) at the latest follow up;the average lateral external rotation and abduction 90 ° external rotation decreased from (58.46±15.51) ° preoperatively and (99.37±14.09) ° to (53.18±14.90) ° and (92.52±13.10) ° at the latest follow up, respectively. The ASES score, Constant -Murley score and Rowe score were significantly improved.

CONCLUSION

The clinical effect of rehabilitation of Bankart repair combined with Remplissageunder arthroscopy in the treatment of recurrent dislocation of shoulder joint in adults with Hill-Sachs defect is satisfactory. Although the external rotation function is weaker than that before operation, it can effectively reconstruct the shoulder function and avoid the occurrence ofdislocation after operation.

[Novel sternoclavicular hook-plate for treatment of proximal clavicle fracture with dislocation of sternoclavicular joint]

OBJECTIVE

To explore the efficacy of a novel sternoclavicular hook-plate for treatment of proximal clavicle fracture with dislocation of sternoclavicular joint.

METHODS

Retrospective analysis of 13 cases of proximal clavicle fracture with dislocation of sternoclavicular joint treated with sternoclavicular hook-plate from June 2011 to January 2019 in our department. There were 9 males and 4 females, aged 26 to 78 years old, with an average age of (54.08±13.91) years old. All the patients had closed injuries without damage of blood vessels and nerves. The patient's operation time, intraoperative blood loss, hospital stay time, and postoperative complications were recorded. Fracture healing and reduction were evaluated according to X-ray and CT after operation. Constant-Murley score and Rockwood sternoclavicular joint score were used to evaluate limb function at 12 months after operation.

RESULTS

All the patients were treated with sternoclavicular hook-plate. The operation time ranged from 50 to 76 min, with a mean of (54.08±13.91) min. The intraoperative blood loss ranged from 20 to 56 ml, with a mean of (46.08±11.15) ml. The hospital stay time ranged from 6 to 14 d, with a mean of (8.31±2.32) d. X-ray and CT examination on the second day after operation showed that all fractures and dislocations were anatomically reduced, and shoulder joint function exercise was performed early. All patients were followed up, and the duration ranged from 12 to 24 months, with a mean of (16.77±4.63) months. The healing time ranged from 9 to 13 d, with a mean of (11.00±1.75) d;and the bone healing time ranged from 3 to 4 months, with a mean of (3.65±0.46) months. There were no complications such as infection, internal fixation failure and nerve injury. At 12 months follow-up, the constant Murley score ranged from 78 to 100, with a mean of 87.83± 11.26; and Rockwood score ranged from 9 to 15, with a mean of 13.70±1.85. Among them, 11 cases were excellent, 1 case was good, and 1 case was general.

CONCLUSION

The use of the novel sternoclavicular hook-plate for treatment of proximal clavicle fracture with dislocation of sternoclavicular joint is an effectively internal fixation with high safety, allowing early functional exercise for patients.

Total Hip Arthroplasty Using a Hemispherical Uncemented Dual-Mobility Cup Results in Satisfactory Clinical Outcomes and No Dislocations at 2 years

BACKGROUND

The authors performed total hip arthroplasty (THA) using a novel hemispherical dual-mobility (DM) acetabular cup without a protrusive cylindro-spherical rim, intended to reduce risks of iliopsoas impingement without requiring changes to conventional intraoperative positioning as with unipolar cups. We aim to determine clinical scores and rates of dislocations, complications, and revisions of this hemispherical DM cup, with the hypothesis that this novel design would result in clinical scores and dislocation rates comparable to other contemporary DM cups with protrusive cylindro-spherical rims.

METHODS

We assessed 332 consecutive uncemented THAs performed using a hemispherical DM cup, at a minimum 2-year follow-up, using modified Harris Hip Score (mHHS) and Oxford Hip Score (OHS), and noting complications and revisions. Regression analyses were conducted to determine if mHHS and OHS depended on any independent factors.

RESULTS

At 2.8 ± 0.5 years (range, 2-5), 2 patients (0.6%) had stem and cup revisions, 3 patients (1%) had isolated stem revisions, 13 patients (4%) died, and none were lost to follow-up. No dislocations occurred. For the final cohort of 305 patients (314 hips) with their original implants in place, mHHS was 92 ± 12 (range, 46-100), and OHS was 57 ± 5 (range, 34-60). Multivariable analyses revealed that mHHS and OHS decreased significantly with age (β = -0.35, P < .001, and β = -0.15, P < .001, respectively).

CONCLUSIONS

With no dislocations and satisfactory clinical scores, this sizable cohort confirms that the novel hemispherical DM cup studied is effective at preventing dislocations, although longer-term follow-up remains necessary to ascertain the longevity of clinical outcomes and radiographic stability.

LEVEL OF EVIDENCE

Level IV, multicentric retrospective case series.

Strain controlled fatigue response of large-scale perfect and defect nickel nanowires: A molecular dynamics study

In this study, the response of the nickel nanowire (NW) subjected to constant strain amplitudes in the range of 0.02-0.12 during cyclic deformation is investigated. The studies are carried out using molecular dynamics (MD) simulations on perfect and defect nickel NW containing ∼ 925,965 atoms. Embedded atom method (EAM) potential is used to model the interactions between nickel atoms. Initially, tensile test is conducted to determine the yield stress and yield strain of the NW at strain rate of 10⁹ s^-1 and temperature of 300 K. The yield stress is observed to be 14 GPa and the corresponding strain is 0.17. The cyclic deformation tests are carried out at a temperature of 300 K. During the cyclic deformation at strain amplitudes of 0.02 and 0.04 the plastic deformation features such as slip lines or slip bands do not appear on the surface of the NW's even after 1000 cycles of straining. These features surface when the strain amplitudes are above 0.04 and their density increase with the strain amplitude and cycles. The NWs exhibit asymmetric stress-strain (compression-tension) hysteresis loops at all the strain amplitudes and up to 1000 cycles. The compressive stress is observed to be higher than the tensile stress for all the cycles. The defect nickel NWs have also exhibited similar behavior as that observed in perfect NWs. Further, it is observed that the width of the loops increases with an increase in the strain amplitude and also with the number of cycles due to softening. The NWs did not fracture even after cyclic deformation for 1000 cycles which could be due to the lower strain amplitudes employed in the present study. Cylindrical shape NWs of different sizes are also investigated by subjecting to similar cyclic deformation conditions as above and are found to show similar behavior.

[Treatment of severe acromioclavicular joint dislocation with double strand titanium cable and clavicular hook plate guided by self-made guide device]

OBJECTIVE

To compare the clinical efficacy of titanium cable biomimetic reconstruction of coracoclavicular ligament and clavicular hook plate in the treatment of acromioclavicular joint dislocation.

METHODS

The clinical data of 39 patients with severe acute acromioclavicular joint dislocation from January 2017 to December 2018 were retrospectively analyzed, 19 patients in double strand titanium cable group, including 13 males and 6 females, aged from 26 to 67 years old; Rockwood classification:10 cases of type Ⅲ, 4 cases of type Ⅳ and 5 cases of type Ⅴ;8 cases of traffic injury and 11 cases of fall injury;the time from injury to operation was 3 to 6 days. There were 20 patients in steel plate group, including 15 males and 5 females, aged from 25 to 71 years old. Rockwood classification:11 cases of type Ⅲ, 4 cases of typeⅣ, 5 cases of type Ⅴ;7 cases of traffic injury, 13 cases of fall injury;the time from injury to operation was 2 to 7 days. The length of incision, operation time, intraoperative blood loss, cost, VAS score before and after operation, and Constant-Murley score before and after operation were compared between two groups. Postoperative X-ray films were taken to observe the reduction and maintenance of acromioclavicular joint dislocation. Complications were recorded.

RESULTS

Thirty-six patients were followed up for 12 to 14 months. The amount of intraoperative blood loss in the two groups was basically the same. The operation incision in double strand titanium cable group was shorter, the operation time in steel plate group was shorter, and the operation cost in double strand titanium cable group was less. One week and one year after operation, the pain of double strand titanium cable group was less than that of steel plate group. One year after operation, the Constant-Murley score of double strand titanium cable group was higher than that of steel plate group. The postoperative X-ray showed that the acromioclavicular joint in double strand titanium cable group was well reduced, and there was 1 case with slight reduction loss. In the plate group, there was no reduction loss after removal of the clavicular hook plate, and 8 patients had distal clavicular bone atrophy or acromion bone resorption. In steel plate group, 4 cases had long-term postoperative pain, postoperative dysfunction and other complications.

CONCLUSION

The clinical effect of coracoclavicular ligament reconstruction with double strand titanium cable is better than that of clavicular hook plate in the treatment of severe acute acromioclavicular joint dislocation, with less trauma (no secondary operation) and lower cost.

Lateral retinacular release combined with MPFL reconstruction for patellofemoral instability: a systematic review

INTRODUCTION

The role of the lateral retinaculum in patellofemoral instability is still debated. Lateral retinacular release (LRR), has been extensively performed in combination with different surgical procedures, including reconstruction of medio-patellofemoral ligament (MPFL). Despite controversial indications, the results from these studies seem promising. The present study conducts a systematic review about current biomechanical and clinical evidence concerning the role of LRR in combination with MPFL reconstruction. We performed a comprehensive literature research, comparing the outcomes of MPFL reconstruction with and without LRR.

MATERIALS AND METHODS

This systematic review was conducted according to the PRISMA guidelines. The literature search was performed in August 2020. All articles describing the outcome of isolated MPFL reconstruction alone or in combination with a LRR in patients with recurrent patellofemoral instability were considered for inclusion. Only articles reporting data on patients with a minimum of 12-month follow-up were included. Only articles reporting quantitative data under the outcomes of interest were included.

RESULTS

A total of 63 articles were eligible for this systematic review, including 2131 knees. The mean follow-up was 40.87 ± 24.1 months. All scores of interests improved in favour of the combined group: Kujala + 3.8% (P = 0.01), Lysholm + 4.2% (P = 0.004), Tegner + 0.8 points (P = 0.04), IKDC + 9.8% (P = 0.02). The ROM was comparable between the two groups (P = 0.4). Similarity was found in terms of positivity to the apprehension test (P = 0.05), rate of complications (P = 0.1), re-dislocations (P = 0.8), and revision surgeries (P = 0.1).

CONCLUSION

There is no evidence that adding a lateral release impacts positively on the outcome of MPFL reconstruction.

LEVEL OF EVIDENCE

IV, Systematic review.

[Retrospective analysis on treatment methods and curative effects of reducing the disability rate of multiple ligament injuries and dislocations of the knee joint]

OBJECTIVE

To investigate the clinical effects of individualized repair and reconstruction surgery for multiple ligament injury and dislocation of knee joint based on stage classification diagnosis.

METHODS

From January 2018 to January 2019, 42 patients with multiple ligament injury and dislocation of the knee joint were treated. There were 27 males and 15 females, aged from 30 to 63 (47.35±11.90) years old, including 17 left knees, 23 right knees and 2 bilateral knees. All patients with multiple ligament injuries and dislocations of the knee joint were classified by stages and improved Schenck diagnosis. Among them, 23 cases were in acute stage (≤3 weeks), 19 cases were in old stage (>3 weeks), 27 cases were type Ⅲ dislocation and type Ⅳ dislocation. There were 9 cases of dislocation and 6 cases of type Ⅵ dislocation. The corresponding repair methods such as closed manipulation and open release reduction, direct suture of ligament, anchor suture, bone penetrating suture, and routine ligament reconstruction were performed. The corresponding "progressive progressive excitation" rehabilitation program was adopted after the operation. After 2, 4, 6, 8 weeks and 3, 6, 9, 12 months after operation, the outpatient consultation and evaluation of knee joint function and stability were completed. The knee joint stability, excellent and good rate, disability rate and complication rate were compared before and after operation. Internation Knee Documentation Committee (IKDC) grade, IKDC subjective score, Lysholm score and Tegner score were used to evaluate knee joint function.

RESULTS

All patients completed the outpatient follow-up and follow-up on schedule. All patients had gradeⅠwound healing, 4 patients had lower extremity venous thrombosis after operation, and there were no serious complications after anticoagulant treatment; 5 patients with common peroneal nerve injury were treated with release surgery and active postoperative rehabilitation, and neurological function gradually recovered. At 12 months after operation, the muscle strength of the affected limb reached grade Ⅴ and the active and passive range of motion recovered to more than 120 degrees. In the acute stage, the IKDC subjective scores were 20.46±12.61, 22.58±16.83, 0.71±1.14, 69.55±16.57, 77.73±15.14 and 3.14±1.67, respectively. One year after operation, IKDC subjective score was 67.04±19.07, Lysholm was 74.87±14.58, Tegner was 3.06±1.70, and 6 of them were grade A. After 12 months, the knee function scores of all patients were significantly improved compared with those before operation(P<0.01).

CONCLUSION

According to the classification of multiple ligament injuries and dislocations of the knee joint, the corresponding surgical repair and reconstructiontreatment were adopted, and the corresponding rehabilitation program was adopted after the operation. The patients achieved good clinical treatment effect 12 months after operation, and the patients' satisfaction was high, which improved the excellent and good rate of treatment and reduced the disability rate.

Absence of instabilities and intra-prosthetic dislocations at 7 to 11 years following THA using a fourth-generation cementless dual mobility acetabular cup

PURPOSE

Dual-mobility (DM) cups are increasingly used in total hip arthroplasty (THA) but there lacks literature on their long-term results. We aimed to investigate outcomes of a fourth-generation cementless DM acetabular cup at 7-11 years.

METHODS

We retrospectively evaluated 240 consecutive hips that received cementless THA using the same dual mobility cup (Novae Sunfit TH) and femoral stem (Corail). Patients were recalled at ≥7 years to collect Oxford hip scores (OHS), Harris hip scores (HHS), and inspect for radiolucent lines and granulomas. Multi-variable analyses were performed to determine whether HHS or OHS were associated with pre- or intra-operative variables.

RESULTS

At 8.4 ± 0.8 years (range, 7-11), 6 hips were revised (2.5%), 54 deceased (22.5%), and 14 could not be reached (5.8%). Four revisions (2 cup+stem, 2 liners only) were due to sepsis (1.7%), one (cup and stem) for trauma (0.4%), and one (stem) due to aseptic loosening (0.4%). For the remaining 166 hips, HHS was 83.6 ± 13.2 and OHS was 20.3 ± 6.7. Multi-variable analysis confirmed that HHS (β = - 0.38; p = 0.039) and OHS (β = 0.36; p < 0.001) worsened with age, and that OHS was worse for Charnley C patients (β = 3.17; p = 0.009). Neither granulomas nor radiolucenies were observed around any cups, but radiolucenies were seen around 25 stems (20.3%).

CONCLUSIONS

This fourth-generation DM cup demonstrated satisfactory outcomes at 7-11 years, with no instabilities or cup revisions due to aseptic loosening. Better OHS was observed for younger patients and those presenting higher Charnley grade.

LEVEL OF EVIDENCE

Level IV, retrospective case study.

The serious full-length forearm injury - a case report and literature review

Background

Among upper limb injuries, carpal bone fractures and dislocation, Essex-Lopresti injury, and the terrible triad injury of the elbow are serious and relatively rare injuries. These injuries require surgical intervention. The surgical method is difficult, and the treatment effect is poor. These injuries have not been described in the same limb in the literature.

Case presentation

A 21-year-old male patient fell from a height in our institution and sustained multiple injuries, including carpal bone fracture-dislocation, Essex-Lopresti injury, and the terrible triad injury of the elbow of his right upper limb. After 2 surgeries and rehabilitation, he returned to work. We reviewed available reviews and related literature on serious upper-limb damage.

Conclusions

Full-length forearm injury is very rarely encountered, and the management of such fractures is difficult. Radial head replacement with a metal prosthesis, reconstructed the IOM with Tightrope, and fixed the DRUJ with a K-wire pin is appropriate treatment.

[Correlation analysis of the influence of direct lateral approach and posterolateral approach on reoperation and dislocation in patients with femoral neck fracture]

OBJECTIVE

To compare the relationship between direct lateral approach and posterolateral approach in the treatment of femoral neck fracture, and to provide reference for the choice of the best approach.

METHODS

From January 2015 to December 2018, 266 patients with femoral neck fracture underwent hip replacement were selected, including 154 males and 112 females, aged 58 to 74 (69.8±8.1) years. Direct lateral approach and posterolateral approach were used in 133 cases in each group. The difference of reoperation rate and dislocation rate between the two groups was compared. Cox proportional risk regression model was used to evaluate the potential factors of reoperation and dislocation after total hip replacement.

RESULTS

The rate of reoperation and dislocation in direct lateral approach group was lower than that in posterolateral approach group (P<0.05) . Cox proportional risk regression model showed that posterolateral approach had higher postoperative reoperation rate and dislocation rate than direct lateral approach, and its relative risk ratio (95%CI) was, reoperation［2.65 (1.23- 5.36) , P=0.02］; dislocation［5.15 (1.68-9.15) , P=0.01］.

CONCLUSION

Posterolateral approach is the influencing factor of reoperation and dislocation after hip replacement. Age, gender, cognitive dysfunction, replacement position, ASA score and other factors have no effect on reoperation and dislocation.

Datasets for the analysis of dislocations at grain boundaries and during vein formation in cyclically deformed Ni micropillars

The dataset together with the corresponding Python scripts and Jupyter notebooks presented in this article are supplementary data for the work presented in Samaee et al., 2019 [1]. The data itself consists of two parts: the simulation data that was used in [1] to analyze the effect of a particular grain boundary on curved dislocations and the precession electron diffraction (PED) strain maps together with post-processed data for analyzing details of the observed dislocation vein structures. Additionally, the complete stress tensor components, which are not shown in [1], have also been included. The data sets are accompanied by Python code explaining the file formats and showing how to post-process the data.

Multiscale model to study dislocation dynamics in nonlinear resonance spectroscopy of crystalline solids

This letter reports on a multi-scale model which captures the dislocation dynamics due to applied vibration stress and its influence on the bulk nonlinear response in a nonlinear resonance spectroscopy experiment. Due to dislocation dynamics, a sinusoidal variation in frequency shift could be observed at the low applied stress range, which was consistent with NRS experiments carried out on cold drawn steel. Using the model, NRS response to "Buck hook" phenomenon was also explored. The results showed that the frequency shift can exhibit three strain regions similar to non-classical nonlinear materials. Further discussions highlight the non-classical nonlinear nature of crystalline solids with lattice defects.

Distal alignment procedures for patellofemoral instability: comprehensive review of the literature

Patellofemoral disorders are a common cause of complaint in adolescent patients. Several distal realignment procedures performed in isolation or combination with proximal alignment have been described. To clarify the role of distal alignment for patellofemoral instability, a systematic review of the literature was conducted. Two independent reviewers accessed the following databases: PubMed, Medline, CINAHL, Cochrane, EMBASE and Google Scholar. A total of 1478 patients with a mean age of 22.78 years were included. The mean follow-up was 86.53 months. The average Kujala score improved from 57.66 to 82.73. The average Lysholm score improved from 63.25 to 87.87, and the average Tegner score from 3 to 4.16. VAS score improved from an average 8 to 2.56. We account a total of 46 major complications, 45 minor complications and 95 recurrences. The risk of a recurrence is 6.42%. A total of 122 additional surgeries were performed during the follow-up. This systematic review of literature suggests the importance to identify the pathological background that predisposes patients for developing patellofemoral instability and its implications for the decision-making process. The optimal treatment for patellofemoral instability should be individualized to address the specific anatomical abnormalities that contribute to patellofemoral dislocations. Distal alignments are a feasible solution to restore correct patellar biomechanics and tracking, leading to an improvement of patients' quality of life.

Atomic Scale Origin of Enhanced Ionic Conductivity at Crystal Defects

In oxide materials, the presence of dislocations often strongly affects the properties of thin film and multilayer devices. Although it was reported that ionic conduction can be enhanced by introducing dislocations in ionic conductors, the underlying mechanism of such enhancement remains unclear. Here we analyzed the ionic conduction enhancement in an yttria-stabilized zirconia (YSZ) single edge dislocation from a structural point of view, using atomic resolution scanning transmission electron microscopy (STEM). First, the atomic structure and chemistry of a dislocation in YSZ were characterized by STEM and energy dispersive X-ray spectroscopy (EDS). A relative ionic conduction variation map around the dislocation was then estimated based on the well-established strain-conductivity and chemistry-conductivity relationships in YSZ. We propose that a faster ionic conductivity path can be formed around the dislocation core due to the coupling of the tensile strain field and dopant segregation, which could account for enhanced ionic conductivity along dislocations.

Prevention and management of early treatment failures in elbow injuries

The appropriate management of early treatment failures in patients with elbow injuries requires the identification of the cause of failure. In this work, six types of elbow injury are considered: (i) identification of early failed reduction of a dislocation or fracture-dislocation of the elbow should lead to a repeat reduction procedure, testing for elbow instability, and ligament repair, followed by the use of a hinged external fixator to allow early mobilisation. Differentiating an isolated dislocation from a dislocation combined with a fracture of the coracoid process is crucial. Re-implantation of the coronoid process allows repair of the ligaments and restoration of stability in the sagittal plane; (ii) early secondary displacement of a distal humeral fracture after internal fixation is usually due to insufficient fixation confined to a single humeral pillar. If both humeral pillars are fractured, then both must be repaired; (iii) early treatment failure of an intra-articular distal humeral fracture in an elderly patient with bone loss warrants distal humeral hemiarthroplasty or total elbow arthroplasty; (iv) in fractures of the olecranon, treatment failures are due to insufficient fixation or to a mistaken diagnosis of trans-olecranon fracture-dislocation; (v) in fractures of the radial head, causes of early revision include excessive tilting of the head in radial neck fractures, with secondary displacement due to insufficient internal fixation, and adverse effects on the wrist of radial head resection performed without assessing the ulnar variance. In patients with radial head fractures, no treatment decisions can be made before performing an anteroposterior radiograph of the wrist; (vii) in fracture-dislocations of both the radius and ulna, accurate reduction of the ulnar fracture is a pre-requisite to proper reduction of the radio-humeral and proximal radio-ulnar joints. An early postoperative assessment, within 10 days after surgery, is of paramount importance to re-evaluate the initial treatment and, if needed, to introduce modifications. Early failure of the initial treatment of an elbow injury should lead to the prompt implementation of corrective measures: follow-up anteroposterior and lateral radiographs must be obtained on day 8 to ensure the diagnosis of initial treatment failure and to allow the institution of an appropriate management strategy; the dogma stating that the elbow should never be immobilised remains valid, and every effort should be made to ensure that mobilisation starts as early as possible.

The effects of dislocations on crystallographic twins and domain wall motion in magnetite at the Verwey transition

Pure magnetite experiences a first-order phase transition (the Verwey transition) near 120-125 K wherein the mineral's symmetry changes from cubic to monoclinic. This transformation results in the formation of fine-scale crystallographic twins and is accompanied by a profound change in magnetic properties. The Verwey transition is critical to a variety of applications in environmental magnetism and paleomagnetism because its expression is diagnostic for the presence of stoichiometric (or nearly stoichiometric) magnetite and cycling through the Verwey transition tends to remove the majority of multidomain magnetic remanence. Internal and external stresses demonstrably affect the onset of the Verwey transition. Dislocations create localized internal stress fields and have been cited as a possible source of an altered Verwey transition in deformed samples. To further investigate this behavior, a laboratory-deformed magnetite sample was examined inside a transmission electron microscope as it was cooled through the Verwey transition. Operating the microscope in the Fresnel mode of Lorentz microscopy enabled imaging of the interactions between dislocations, magnetic domain walls, and low-temperature crystallographic twin formation during the phase transition. To relate the observed changes to more readily measurable bulk sample magnetic behavior, low-temperature magnetic measurements were also taken using SQUID magnetometry. This study allows us, for the first time, to observe the Verwey transition in a defect-rich area. Dislocations, and their associated stress fields, impede the development of monoclinic magnetite twin structures during the phase transition and increase the remanence of a magnetite sample after cooling and warming through the Verwey transition.

Simulation of kinematic Kikuchi diffraction patterns from atomistic structures

One of the limitations of atomistic simulations is that many of the computational tools used to extract structural information from atomic trajectories provide metrics that are not directly compatible with experiments for validation. In this work, to bridge between simulation and experiment, a method is presented to produce simulated Kikuchi diffraction patterns using data from atomistic simulations, without requiring a priori specification of the crystal structure or defect periodicity. The Kikuchi pattern simulation is based on the kinematic theory of diffraction, with Kikuchi line intensities computed via a discrete structure factor calculation. Reciprocal lattice points are mapped to Kikuchi lines using a geometric projection of the reciprocal space data. This method is validated using single crystal atomistic models, and the novelty of this approach is emphasized by simulating kinematic Kikuchi diffraction patterns from an atomistic model containing a nanoscale dislocation loop. Deviations in kinematic Kikuchi line intensities are explained considering the displacement field of the dislocation loop, as is done in diffraction contrast theory.

Guidelines for establishing an etching procedure for dislocation density measurements on multicrystalline silicon samples

With multicrystalline silicon becoming the main material used for photovoltaic applications and dislocations being one of the main material limitations to better solar cell efficiency, etch pit density measurements are gaining more importance. Traditionally, etch pit density measurements are based on selective etching of silicon samples. The majority of the etchants have been developed for monocrystalline samples with known orientation, while those developed for multicrystalline samples have been less investigated and might need some optimization. In this study, we use and compare the PVScan tool, which provides a quick way to assess dislocation density on selectively etched samples, and microscope image analysis. We show how the etching methods used for dislocation density measurements can affect the results, and we suggest how to optimize the Sopori etching procedure for multicrystalline silicon samples with high dislocation densities. We also show how the Sopori etchant can be used to substitute Secco while maintaining a high precision of dislocation density measurements, but without the toxic hexavalent chromium compounds.

Shoulder injuries from birth to old age: A 1-year prospective study of 3031 shoulder injuries in an urban population

INTRODUCTION

Shoulder injuries are commonly encountered in emergency departments. In spite of this, the epidemiology is only partly known, and soft tissue injuries in particular remain unclear. The aim of this study was to obtain an overview of shoulder injuries in a general population cohort, and to estimate the relative proportion of the main injury categories soft tissue injuries, fractures and dislocations, as well as their variation with age and gender.

PATIENTS AND METHODS

We registered prospectively all patients admitted with a suspected shoulder injury at a combined casualty and primary health care facility during one year. The facility serves all hospitals and all citizens of Oslo. The patient-reported questionnaires, electronic patient records and radiology reports were examined.

RESULTS

3031 shoulder injuries were registered from May 2013 through April 2014. The median age was 37 years (range 14 days-102 years), 51 years in women and 31 years in men (p < 0.001), 60% were male. The male/female shoulder injury incidence rate ratio in the 20-34 years age group was 3.6 (95%CI, 3.0 to 4.3; p < 0.001). Contrary, the female/male rate ratio above 75 years was 2.1 (95%CI, 1.6-2.8; p < 0.001). Almost half of the injuries were soft tissue injuries, 35% were fractures and 17% were dislocations. The age-stratified incidence rates differed substantially in men and women. Fractures dominated in children up to 10 years and in adults over 60 years, soft tissue injuries in the ages between. The highest dislocation incidence rates were found in young males. A rotator cuff tear was diagnosed in 4% of the injuries.

CONCLUSION

Which shoulder structures that are affected by injury vary substantially with age and gender. The shoulder injury incidence rates of young men and the elderly are high. The findings are important for the understanding of the shoulder and the diagnostic process in A&Es.

Terrible triad of the elbow: evaluation of surgical treatment

Objective

This study aims at analyzing retrospectively the clinical-functional and radiographic results of surgical treatment of the terrible elbow triad, with at least 12 months of postoperative follow-up evaluating elbow function.

Methods

A group of patients for retrospective analysis from 2004 to 2015 was defined, in which 12 patients were studied. They underwent surgery due to fracture of the radial head, coronoid fracture, and elbow dislocation; they were evaluated by the Disabilities of the Arm, Shoulder and Hand (DASH) score, the degree of patient satisfaction, the degree of trauma energy, radiographic images, range of motion, and complications.

Results

There was a higher incidence of Regan and Morrey type II coronoid process fractures; in relation to the injuries, nine patients had deinsertion of the brachialis. Half of the patients suffered a fall from their own height as the mechanism of trauma. The extent of elbow flexion and extension averaged 126.6 and 24.1 degrees, respectively; the averages for pronation and supination were 64.1 and 62.0 degrees, respectively. All patients presented muscle strength of grade IV or V. The mean DASH score was 14.3, the mean pain score was 2.5, and a majority of the patients were satisfied with the treatment.

Conclusion

Despite the total loss of range of motion of the elbow, especially in extension, the treatment was satisfactory for most patients.

Clinical and radiological outcome of non-surgical management of thoracic and lumbar spinal fracture-dislocations - a historical analysis in the era of modern spinal surgery

Context: It is well established that traumatic spinal dislocations (AO Type C injuries) should be surgically treated. However, no recent comparative study of surgical versus non-surgical management of type C injuries was found attesting the superiority of surgical treatment.Objective: Due to the lack of information about the natural history of non-surgical management of type C injuries, we evaluated the outcome of historical conservative treatment of type C injuries.Methods: An extensive manual search of articles was performed in the Pubmed Database. We included articles that reported the clinical and/ or the radiological outcome of non-surgical management of thoracic and/ or lumbar spinal fracture-dislocations.Results: Three well described retrospective studies where fracture-dislocations of the thoracolumbar spine were managed non-surgically were included. Non-surgical management typically consisted in postural reduction and prolonged bed rest (about 10-13 weeks on average). Residual deformity was common, and some studies reported a high rate of post treatment pain syndromes. Some studies reported surgery for gibbus deformity after conservative treatment or persistent instability requiring further bed rest. Neurological deterioration was rare, and some patients had some improvement, although the vast majority of the patients had persistent, severe neurological deficits.Conclusions: Compared with historical non-surgical care, surgery for type C injuries decreases the chances of post-operative pain, late spinal deformity and also allowed early rehabilitation, once no bed restriction is necessary. Ethical issues based on this historical analysis may preclude performing a comparative study of non-surgical versus surgical management of these injuries in the modern spine era.

Microstructure evolution and dislocation behaviour in high chromium, fully ferritic steels strengthened by intermetallic Laves phases

In the present study a stainless, high strength, ferritic (non-martensitic) steel was analysed regarding microstructure and particle evolution. The preceding hot-rolling process of the steel results in the formation of sub-grain structures, which disappear over time at high temperature. Besides that the formation of particle-free zones was observed. The pronounced formation of these zones preferentially appears close to high angle grain boundaries and is considered to be responsible for long-term material failure under creep conditions. The reasons for this are lacking particle hardening and thus a concentration and accumulation of deformation in the particle free areas close to the grain boundaries. Accordingly in-depth investigations were performed by electron microscopy to analyse dislocation behaviour and its possible effect on the mechanical response of these weak areas.

[Surgical treatment of intractable odontoid fracture with atlantoaxial dislocation in children with spinal cord injury]

Objective: To discuss the surgical treatment and its effectiveness of odontoid fracture complicated with atlantoaxial dislocation in children with spinal cord injury. Methods: From January 2010 to December 2014, 10 cases of children under 14 years old, with intractable odontoid fracture with atlantoaxial dislocation were enrolled. The mean duration between injury and admission was 8.5 d (range 1-30 d). The surgery was performed using posterior reduction and internal fixation or anterior release combined with posterior fixation. The medical date including preoperative and postoperative neurological function, degree of reduction and fusion. Results: All cases were followed-up for 12-48 months. The last follow-up X ray and CT examinations showed good reduction and fusion. No fixation failure was observed among all the patients. According to the Frankel, the preoperative neurological function was C in 2 cases, D in 4 cases, and E in 4 cases. At the last follow-up, out of 2 cases with Frankel C improved to D, and the other 8 cases were back to normal. Conclusions: Diagnosis of odontoid fracture complicated with atlantoaxial dislocation is usually delayed in children. One-stage posterior reduction and internal fixation or anterior release combined with posterior fixation is an effective and safe surgical procedure for such cases.

[Long-term follow-up of C(1)-C(2) pedicle screw fixation for pediatric atlantoaxial dislocation]

Objective: To investigate the clinical curative effect of C(1)-C(2) pedicle screw fixation for pediatric atlantoaxial dislocation after a long-term follow-up. Methods: From March 2005 to April 2011, a total of 12 male and 9 female patients were included, with age from 3 to 9 years old (mean, 6.1 years old). Among them, 14 cases (67%) had typeⅠinstability atlantoaxial dislocation, 7 cases (33%) had type Ⅱ reducible atlantoaxial dislocation. All 21 pediatric patients with atlantoaxial dislocation underwent posterior pedicle screw fixations. Frankel Grade was used to evaluate function before and after treatment. Furthermore, the information of C(1)-C(2) bony fusion, cervical spine alignment, angle of sagittal curvature, and instability of the subaxial spine were collected from all patients preoperatively, immediately postoperatively and during follow-up period. Results: All 21 patients had regular follow-up with an average duration of 96.4 months (range, 65 to 127 months). All children had good bony fusion within 6 months after treatment. There were 9 patients with lordotic alignment and 12 patients with straight alignment before surgery. After surgery, there were 12 patients with lordotic alignment and 9 patients with straight alignment. At the time of the last follow-up, 17 patients had lordotic alignment and 4 patients had straight alignment. No difference was found between pre- and post-operation (P=0.354). The same result was found between post-operation and last follow-up (P=0.095). Neither kyphotic nor swan-neck deformity was found in any of the 21 patients. The mean angle of sagittal curvature decreased from 31.7°±4.3°preoperatively to 15.5°±2.5°postoperatively (P<0.001). The mean angle of sagittal curvature increased from 15.5°±2.5°postoperatively to 19.1°±2.7°at the final follow-up (P=0.343). No spinal deformities or subaxial instabilities were found. Of the four patients with preoperative neurological defects, Frankel Grade was significantly improved at 3 months follow-up compared with pretreatment values. None of the patients experienced worsening neurological symptoms or injury to the vertebral artery. Conclusion: The results demonstrate that C(1)-C(2) pedicle screw fixation could achieve satisfactory clinical effects for the management of pediatric atlantoaxial dislocation with long-term follow-up.

Comparison of dislocation characterization by electron channeling contrast imaging and cross-correlation electron backscattered diffraction

In this work, the relative capabilities and limitations of electron channeling contrast imaging (ECCI) and cross-correlation electron backscattered diffraction (CC-EBSD) have been assessed by studying the dislocation distributions resulting from nanoindentation in body centered cubic Ta. Qualitative comparison reveals very similar dislocation distributions between the CC-EBSD mapped GNDs and the ECC imaged dislocations. Approximate dislocation densities determined from ECC images compare well to those determined by CC-EBSD. Nevertheless, close examination reveals subtle differences in the details of the distributions mapped by these two approaches. The details of the dislocation Burgers vectors and line directions determined by ECCI have been compared to those determined using CC-EBSD and reveal good agreement.

Stereo-vision three-dimensional reconstruction of curvilinear structures imaged with a TEM

Deriving accurate three-dimensional (3-D) structural information of materials at the nanometre level is often crucial for understanding their properties. Tomography in transmission electron microscopy (TEM) is a powerful technique that provides such information. It is however demanding and sometimes inapplicable, as it requires the acquisition of multiple images within a large tilt arc and hence prolonged exposure to electrons. In some cases, prior knowledge about the structure can tremendously simplify the 3-D reconstruction if incorporated adequately. Here, a novel algorithm is presented that is able to produce a full 3-D reconstruction of curvilinear structures from stereo pair of TEM images acquired within a small tilt range that spans from only a few to tens of degrees. Reliability of the algorithm is demonstrated through reconstruction of a model 3-D object from its simulated projections, and is compared with that of conventional tomography. This method is experimentally demonstrated for the 3-D visualization of dislocation arrangements in a deformed metallic micro-pillar.

ANALYSIS OF THE PATTERN AND MECHANISM OF ELBOW INJURIES RELATED TO ARMBAR-TYPE ARMLOCKS IN JIU-JITSU FIGHTERS

Objective:

The objective of this study was to analyze elbow injuries and their probable mechanism in Jiu-Jitsu fighters resulting from the armbar-type armlock.

Methods:

We evaluated 5 high-performance Jiu-Jitsu fighters from the Gracie Elite gym who were injured during a tournament. All were healthy males with a mean age of 28.8 years. The right arm was involved in three patients (60%). The athletes were followed for approximately 4.6 months, and pain was present in all cases. Clinical examination of the elbow was performed immediately after the injury and when magnetic resonance imaging (MRI) was performed. The radiography showed no changes. Clinical examination detected specific tender points on the medial and anterior topography of the elbows, but no ligamentous instability of the elbow was seen during dynamic testing.

Results:

The main MRI findings were injury to the common flexor tendon and the ulnar collateral ligament, bone contusion of the distal humerus and olecranon, and joint effusion.

Conclusion:

The main pattern of injury indicated by the MRI in the athletes was injury to the medial elbow complex. The primary mechanism that determined the injury was most likely elbow hyperextension applied with the forearm in neutral position of forearm. Level of Evidence IV, Case Series.

[Chronic ligamentous instability of the elbow]

BACKGROUND

Chronic ligamentous instability of the elbow is an important pathology as it is accompanied with pronounced dysfunction. Moreover, it represents an established risk factor for the development of osteoarthritis. Posterolateral rotatory instability (PLRI) caused by insufficiency of the lateral collateral ligament (LCL) is the most common type of chronic elbow instability and is usually a sequel of traumatic elbow dislocation. Chronic overload can lead to insufficiency of the ulnar collateral ligament (UCL) with subsequent valgus instability, especially in overhead athletes.

DIAGNOSTICS

Subjective instability and recurrent elbow dislocations are not always the main symptoms but elbow instability is instead often characterized by pain and secondary joint stiffness. Many clinical tests are available yet eliciting them can be difficult and inconclusive. A "drop sign" on lateral radiographs as well as the detection of collateral ligament injuries and joint incongruity on MRI scans can support the suspected diagnosis. In some cases, instability can only be verified by diagnostic arthroscopy.

TREATMENT

Reconstruction of the lateral ulnar collateral ligament (LUCL) for treatment of PLRI generally leads to good clinical results, yet recurrent instability remains an issue and has been reported in 8 % of cases. UCL reconstruction for chronic valgus instability leads to a return-to-sports rate of about 86 % in the overhead athlete. Ulnar neuropathy, which is seen in approximately 6 % of patients, represents the most common complication. On the rare occasion of multidirectional instability, the box-loop technique can be used for simultaneous reconstruction of the LUCL and UCL with a circumferential graft. 15 cases with promising results have been reported in literature thus far.

Tailoring Superconductivity with Quantum Dislocations

Despite the established knowledge that crystal dislocations can affect a material's superconducting properties, the exact mechanism of the electron-dislocation interaction in a dislocated superconductor has long been missing. Being a type of defect, dislocations are expected to decrease a material's superconducting transition temperature (T_c) by breaking the coherence. Yet experimentally, even in isotropic type I superconductors, dislocations can either decrease, increase, or have little influence on T_c. These experimental findings have yet to be understood. Although the anisotropic pairing in dirty superconductors has explained impurity-induced T_c reduction, no quantitative agreement has been reached in the case a dislocation given its complexity. In this study, by generalizing the one-dimensional quantized dislocation field to three dimensions, we reveal that there are indeed two distinct types of electron-dislocation interactions. Besides the usual electron-dislocation potential scattering, there is another interaction driving an effective attraction between electrons that is caused by dislons, which are quantized modes of a dislocation. The role of dislocations to superconductivity is thus clarified as the competition between the classical and quantum effects, showing excellent agreement with existing experimental data. In particular, the existence of both classical and quantum effects provides a plausible explanation for the illusive origin of dislocation-induced superconductivity in semiconducting PbS/PbTe superlattice nanostructures. A quantitative criterion has been derived, in which a dislocated superconductor with low elastic moduli and small electron effective mass and in a confined environment is inclined to enhance T_c. This provides a new pathway for engineering a material's superconducting properties by using dislocations as an additional degree of freedom.

[Study on feasibility of enhanced recovery after surgery combined with mobile microendoscopic discectomy-transforaminal lumbar interbody fusion in the treatment of lumbar spondylolisthesis]

Objective: To explore the feasibility of enhanced recovery after surgery (ERAS) combined with mobile microendoscopic discectomy-transforaminal lumbar interbody fusion (MMED-TLIF) in the treatment of lumbar spondylolisthesis and its influence on postoperative rehabilitation. Methods: From October 1 2014 to July 1 2016 , a cohort of 52 patients with lumbar spondylolisthesis who received the program of ERAS-MMED-TLIF were retrospectively reviewed in Department of Minimally Invasive Spine Surgery, Tianjin Hospital.The primary outcomes include the operation time, intraoperative blood loss, length of hospital stay, VAS score (low back pain and leg pain) and Oswestry Disability Index (ODI) at different follow-up time and complication.The height of intervertebral space and fusion rate were also recorded as radiographic indicators. Results: All cases had an average follow-up of 12 months. The mean operative time was (115±30) min with a mean blood loss of (100±35) ml.Compared with preoperative condition, VAS score of low back pain (6.3±3.3 vs 3.5±2.3, P<0.05), VAS score of leg pain (7.1 ± 4.2 vs 3.1 ± 2.6, P<0.05) and the ODI disability index score (43.5±9.6 vs 20.9±7.3, P<0.05) at the postoperative 24 h were decreased and the difference was statistically significant.The mean hospitalized time were (4.9±1.3) days with mean postoperative hospital stay (2.1±1.2) days.Fusion rate was 92.31% (48/52) at the last follow-up time. Conclusion: ERAS combined with MMED-TLIF is feasible in the treatment of lumbar spondylolisthesis, which can significantly reduce intraoperative bleeding, shorten the total length of stay and postoperative hospital stay, improve postoperative pain and promote rapid rehabilitation of patients after operation without increasing the operation time and influencing the long-term effect, it can be applied in clinical practice.