Reduction Of Dislocation Research Articles

Atomic Mechanism of Strain Alleviation and Dislocation Reduction in Highly Mismatched Remote Heteroepitaxy Using a Graphene Interlayer.

Remote heteroepitaxy is known to yield semiconductor films with better quality. However, the atomic mechanisms in systems with large mismatches are still unclear. Herein, low-strain single-crystalline nitride films are achieved on highly mismatched (∼16.3%) sapphire via graphene-assisted remote heteroepitaxy. Because of a weaker interface potential, the in-plane compressive strain at the interface releases by 30%, and dislocations are prevented. Meanwhile, the lattice distortions in the epilayer disappear when the structure climbs over the atomic steps on substrates because graphene renders the steps smooth. In this way, the density of edge dislocations in as-grown nitride films reduces to the same level as that of the screw dislocations, which is rarely observed in heteroepitaxy. Further, the indium composition in InxGa1-xN/GaN multiquantum wells increases to ∼32%, enabling the fabrication of a yellow light-emitting diode. This study demonstrates the advantages of remote heteroepitaxy for bandgap tuning and opens opportunities for photoelectronic and electronic applications.

The influence of high-temperature nitridation process on the crystalline quality of semipolar [formula omitted] GaN epitaxial films

Semipolar (112‾2) GaN epitaxial films were grown on m-plane sapphire substrates by metal-organic chemical vapor deposition and additional high-temperature nitridation was introduced during the growth. The growth mechanism, surface microtopography, and the full width at half maximum (FWHM) of X-ray rocking curves (XRCs) of on-axis and off-axis (112‾2) GaN planes were investigated. The results demonstrate that additional high-temperature nitridation process could reduce surface roughness and anisotropy, and suppress the other orientations, and partially improve the crystalline quality of (112‾2) GaN epitaxial films. The XRCs FWHM of the off-axis (112‾2) GaN planes decrease and show a different varying tendency after additional high-temperature nitridation process associated with the partial dislocations and basal plane stacking faults (BSFs). The results of the modified Williamson-Hall (W–H) analysis and photoluminescence spectrum show the BSFs increased while the partial dislocations decreased after an additional high-temperature nitridation process. The improvement of crystalline quality was mainly correlated to the reduction of partial dislocations.

Neglected Monteggia fracture: a review.

Monteggia fracture is characterized by radial head dislocation combined with proximal ulnar fracture.If not diagnosed at an early stage, these lesions can gradually lead to forearm deformities and dysfunction, finally resulting in neglected Monteggia fracture. When the radial head is not reduced, several deformities develop at the humeroradial joint, including cubitus valgus and osteoarthritis.Adequate radiographs are crucial when the surgeons deal with forearm injuries.At present, proximal ulnar osteotomy and open reduction of chronic radial head dislocation provides satisfactory functional outcomes because of anatomic alignment reconstruction.Supplementary procedures, including transcapitellar pinning and repair or reconstruction of the annular ligament, which are performed in order to enhance stability of the humeroradial joint, should be thoroughly assessed based on joint rotational stability after reduction and on potential complications.

Proximal humeral fracture-dislocations: which patterns can be reduced in the emergency department?

Shoulder fracture-dislocations can represent a challenging management scenario in the emergency department (ED) because of concern for the presence of occult fractures that may displace during a reduction attempt. The alternative, a closed reduction attempt in the operating room, has the benefit of full paralysis but requires additional resource utilization. There is limited guidance in the literature about the risks of an initial reduction attempt in the ED as a function of fracture pattern to help guide physicians with this decision. This was a retrospective case review of adult patients with shoulder dislocations and fracture-dislocations seen in the ED at a level 1 trauma center over a 10-year period. Imaging and medical records were reviewed to evaluate whether the reduction attempt was successful, unsuccessful without worsening, or unsuccessful with worsening alignment of any fractures, as well as the ultimate clinical outcome. We identified 165 patients with fracture-dislocations and 484 patients with simple dislocations during the same period. Of the patients with fracture-dislocations, 103 had greater tuberosity fractures, 12 had nondisplaced surgical neck fractures, and 50 had displaced surgical neck fractures. None of the patients with simple dislocations had displacement during an ED reduction attempt, including 100 patients aged >65 years. Of the 103 patients with greater tuberosity fracture-dislocations, only 1 had displacement of a humeral shaft fracture during ED reduction. Displacement occurred in 6 of 8 patients with nondisplaced neck fractures who underwent an initial ED reduction attempt vs. 1 of 4 patients who underwent the initial reduction attempt in the operating room. ED reduction was attempted in 25 of the 50 displaced humeral neck fracture-dislocations and was successful in 10 of these (40%). For patients with greater tuberosity fracture-dislocations, there is a low rate of displacement with a reduction attempt in the ED, but an ED reduction attempt in nondisplaced neck fractures is not recommended because of the high rate of displacement. For displaced neck fractures, closed reduction can be successful in select patients. Finally, these data confirm prior reports that closed reduction of simple shoulder dislocations in patients aged >65 years is safe in the ED.

Survival of the GAP II cage in the management of metastatic disease of the acetabulum.

The aim of this study was to assess the clinical and radiological outcomes of an antiprotrusio acetabular cage (APC) when used in the surgical treatment of periacetabular bone metastases. This retrospective cohort study using a prospectively collected database involved 56 patients who underwent acetabular reconstruction for periacetabular bone metastases or haematological malignancy using a single APC between January 2009 and 2020. The mean follow-up was 20 months (1 to 143). The primary outcome measure was implant survival. Postoperative radiographs were analyzed for loosening and failure. Patient and implant survival were assessed using a competing risk analysis. Secondary parameters included primary malignancy, oncological treatment, surgical factors, length of stay in hospital, and postoperative complications. A total of 33 patients (59%) died during the study period at a mean of 15 months postoperatively (1 to 63). No patient had radiological evidence of loosening or failure. Acetabular component survival was 100%. Three patients (5.4%) had further surgery; one (1.8%) underwent revision of the femoral component for dislocation, one required debridement with implant retention for periprosthetic joint infection, and one required closed reduction for dislocation. Using death as a competing risk, at 100 months, the probability of revision was 0.036 and the risk of death was 0.84. With appropriate patient selection, the antiprotrusio cage offers good implant survival, with a reasonable perioperative complication rate in this high-risk group of patients when managing metastatic disease or haematological malignancy around the acetabulum. Cite this article: Bone Joint J2022;104-B(4):504-509.

Thumb Carpometacarpal joint dislocation: Case report and short review

Thumb carpometacarpal (CMC) joint dislocation is rare, and the treatment options may vary from conservatives’ strategies to open reduction and fixation. In face of pain and joint instability persistence, surgical intervention is required. We present the case of a 67-year-old male that was referred to our hospital with pain and edema of the left hand, after the failure of a conservative treatment. After initial refusal of open surgery, due to the persistent joint instability, open reduction of the CMC joint dislocation was performed, and stabilized using two percutaneous Kirschner wires after repairing the joint capsule and dorsoradial ligament. Immobilization was required for 4 weeks. After that, the Kirschner wires were removed. Along with physiotherapy, the follow-up showed no pain persistence nor CMC joint luxation reoccurrence while the joint recovered its mobility. Further studies are required in order to determine the optimal therapy for such cases and to provide standardized recommendations, taking into account that the restoration of thumb CMC joint mobility is one of the most important goals in hand surgery.

Talus Fractures: An Update on Current Concepts in Surgical Management.

Talus fractures can be challenging injuries to treat because of complex talar shape, an abundance of articular cartilage, a potentially unforgiving soft-tissue envelope, and an easily injured blood supply. In addition, the spectra of energy involved, soft-tissue injury, and the fracture pattern are wide. Temporizing treatment is sometimes required, including débridement of open fractures, reduction of dislocations, and occasionally spanning external fixation. Definitive treatment first requires an understanding of the fracture pattern, including location and fracture line orientation. Multiple options for surgical exposure exist and are selected based on the fracture pattern and condition of the soft tissues. Newer fixation techniques, including the use of fixed-angle and minifragment implants, are useful in achieving stable fixation.

Our experience in the treatment of congenital hip dislocation in children of different ages

The experience in treatment of children with neglected congenital hip dislocation is presented. The main principles of management are defined. The successive complex of curative measures including conservative treatment using Ter-Egiazarov-Sheptun functional plaster bandage in children over 6 months is described in detail. In failed conservative treatment the reduction of dislocation is performed using over head technique. In children over 3 years descent of femoral head and reduction of dislocation are carried out on distraction system followed by surgical correction of all dysplastic elements of the hip joint. Technique of detorsion-varus osteotomy with application of distraction system and closed reduction is described. Long-term results were evaluated using CITO score system in 255 patients. Good and satisfactory results were in 91.7% of cases.

Treatment of patients with congenital joints dislocation (Larsen’s syndrome)

Treatment results of 10 patients with Larsens syndrome is presented. Step-by-step treatment regimen including closed reduction of hip joint in functional devices for preparation of tendinous-muscular system of the knee joint, closed reduction of ankle joint with transarticular pin fixation and subsequent plaster immobilization is proposed. If cicatrical degeneration of ankle extensors is confirmed and closed reduction of the ankle dislocation failed the open bilateral reduction with lengthening of anterior femur muscles is indicated. Proposed regimen of operative treatment allowed to achieve early and long-term satisfactory functional and cosmetic results in all patients.

Early reduction of acute anterior shoulder dislocations in a ski field setting.

The present study describes the management of suspected shoulder dislocations in ski field clinics. Data were collected from two clinics in Queenstown, New Zealand. Suspected anterior shoulder dislocations, with no suspicion of significant fractures and without imaging, underwent attempted reduction. Ninety percent (n= 49) of dislocations were successfully relocated. No short-term complications because of this procedure were observed. This short report raises the possibility that early anterior shoulder reduction in a ski field clinic can be safe without imaging, in select cases. Prospective studies including patient centred data are recommended.

Characteristics and clinical significance of irreducible Pipkin type Ⅰ and Ⅱ femoral head fracture-dislocations

To summarize the characteristics and clinical significance of irreducible Pipkin type Ⅰ and Ⅱ femoral head fracture-dislocations. The clinical data of 4 patients with irreducible Pipkin type Ⅰ and Ⅱ femoral head fracture-dislocations between January 2010 and December 2019 were collected. There were 2 males and 2 females and the age ranged from 24 to 41 years, with an average age of 33.5 years. The cause of injury included traffic accident in 3 cases and falling in 1 case. Pipkin classification was 2 cases of type Ⅰ and 2 cases of type Ⅱ. The time from injury to operation was 1-2 days. The clinical features were that the hip joint of the affected limb was in a locked position, and the passive range of motion was poor. The affected limb was slightly flexed at the hip joint and shortened, in a state of neutral position or slight adduction and internal rotation. The imaging data suggested that the femoral head dislocated backward and upward, and the hard cortex of the posterior edge of the acetabulum was embedded in the cancellous bone of the femoral head, and the two were compressed and incarcerated. Patients of cases 1-3 underwent closed reduction of hip dislocation 1-2 times at 3, 1, and 3 hours after injury respectively, and femoral neck fracture occurred. The injury types changed to Pipkin type Ⅲ, and open reduction and internal fixation were performed. Patient of case 4 did not undergo closed reduction, but underwent open reduction and internal fixation directly. Patients of cases 1-3 were followed up 14, 17, and 12 months, respectively. They developed osteonecrosis of the femoral head at 9, 5, and 10 months after operation respectively, and all underwent total hip arthroplasty. Patient of case 4 was followed up 24 months and had no hip pain and limited mobility; the imaging data indicated that the internal fixator position was good and the fracture healed; no collapse or deformation of the femoral head was seen, and no osteonecrosis of the femoral head occurred. Clinicians need to improve their understanding of the unique clinical features and imaging findings of irreducible Pipkin type Ⅰ and Ⅱ femoral head fracture-dislocations. It is suggested that open reduction and simultaneous fixation of femoral head fracture should be directly used to reduce the incidence of osteonecrosis of the femoral head.

Awake Cranial Traction and Isolated Anterior Cervical Discectomy and Fusion in the Treatment of Traumatic Subaxial Cervical Facet Joint Dislocations: Analysis of a Cohort of 70 Patients and Predictors of Surgical Failure.

Cervical facet dislocations are among the most common traumatic spinal injuries. The management of this type of lesions is still controversial. The objective of the present study was to analyze the results of subaxial cervical facet dislocations submitted to an isolated anterior cervical discectomy and fusion (ACDF) after attempted closed reduction with cranial traction and to identify risk factors for treatment failure. All patients who were operated on in a tertiary trauma center during an 11-year period (2008-2018) for traumatic single-level cervical facet joint dislocation (AO C F4 injuries) were retrospectively reviewed. Age, use of cranial traction, dislocation characteristics, neurologic injury, surgical data, and follow-up records were reviewed. A minimum of 18 months follow-up was required. A total of 70 patients with a mean age of 56 years (18-90) (72% men) were identified. The C6-C7 level was the most frequently affected (36/70 cases). Spinal cord injury (SCI) was present in 34% of the cases. Bilateral dislocations and rigid spines were risk factors for SCI. Cranial traction was performed in 59 cases with success in 52 cases (88%). There were 3 failures after anterior fusion, which required revision surgery with a 360° fusion, all occurring at the C7-T1 level. Cranial traction of the cervical spine is an effective and fast way to achieve closed reduction of cervical facet dislocations. After successful reduction, ACDF, as a single procedure, offers an excellent surgical option. All cases of failure occurred at the C7-T1 level, suggesting that a 360° fusion may be needed at this level.

Assessment of dislocation reduction on 100 mm diameter bulk GaN grown by the NEAT method

X-ray topography measurements on a 100 mm diameter GaN boule grown by the Near Equilibrium AmmonoThermal method revealed an improvement in dislocation density from >1 × 106 cm−2 to between 2 × 105 and 5 × 105 cm−2, an improvement greater than two to five times from seed to growth. This data builds on previous X-ray diffraction and defect selective etching to quantify the reduction in defect density that is closely associated with increasing growth thickness. This result indicates that there is a pathway to further dislocation reduction by increasing growth thickness for GaN crystals including those of 100 mm or larger diameter. Further reduction of the dislocation density of large-area substrates will lead to GaN power devices with reduced leakage current under reverse bias and better device performance.

Pediatric and Adolescent Fractures of the Acetabulum Treated With ORIF: What Are Their Functional Outcomes?

To evaluate the functional outcomes of pediatric and adolescent patients (<18 year old) who sustained acetabulum fractures that were treated with open reduction internal fixation (ORIF). Retrospective cohort. Level 1 trauma center. Thirty-four pediatric and adolescent patients underwent acetabulum fracture ORIF between 2001 and 2018. Of the operatively treated patients, 21 patients had sufficient follow-up (>6 months), one died after fixation secondary to other traumatic injuries, and 12 patients were lost to follow-up. Acetabulum fracture ORIF. The SF-36 Health Survey and Short Musculoskeletal Functional Assessment (SMFA) were compared with population norms. The modified Merle d'Aubigné clinical hip score, Matta radiologic outcome, and postoperative complications were also documented. Functional outcome data were available at a mean of 5 years 2 months. Mean SF-36 scores were 44.8 and 50.1 for the physical component score and mental component scores, respectively, which did not differ significantly from US population norms (physical component score mean: 50, P = 0.061 and mental component score mean: 50, P = 0.973). Furthermore, the mean SMFA Bother Index score was 18.6, which is not significantly different from the population norm mean of 13.8 (P = 0.268). However, the function index mean was 31.9, which was significantly worse than the population norm mean of 12.7 (P = 0.001). Two patients with a delayed reduction (>6 hours) of an acetabulum fracture dislocation had poor outcomes related to the development of avascular necrosis and post-traumatic osteoarthritis. In this small cohort, 86% (18/21) of these patients had a favorable functional outcome with the exception of the SMFA Functional Index that was significantly less than population norms. Although long-term follow-up is needed, we advocate for operative management of pediatric and adolescent acetabulum fractures when adult displacement and instability criteria are present. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Arthroscopic Reduction of a Missed/Neglected Anterior Shoulder Dislocation and Concomitant Repair of the Rotator Cuff Tendon

Patients with neglected/missed anterior shoulder dislocation and an associated rotator cuff tear present a dilemma for the correct surgical approach that will facilitate a reduction of the dislocation and repair of the rotator cuff tear. This report describes an arthroscopic technique using standard arthroscopic portals to reduce neglected (3-6 weeks) anterior shoulder dislocation and repair the rotator cuff tendon. The arthroscopy is performed in a beach chair position using anterolateral and anteromedial portals for reduction of the shoulder dislocation. The same anterolateral portal is used as a viewing portal, and the anteromedial portal and an additional lateral portal are used for subsequent rotator cuff repair.

Thermally induced metastability of InGaAs single-layer for highly strained superlattices by metal-organic chemical vapor deposition

In this study, the metastability of In0.68Ga0.32As layers on InP substrates was investigated at various growth temperatures. The thickness of each metastable In0.68Ga0.32As layer was 40 nm, which is four times the critical thickness of the stable lattice with a stress of approximately 1%. The surface morphologies and roughness of the metastable In0.68Ga0.32As layers were highly sensitive to the growth conditions. Cross-hatches were observed on their surfaces when they were grown at various growth temperatures, and over this range, the surface roughness varied from 0.11 nm to 0.16 nm. The lowest surface roughness of 0.11 nm was achieved at 770 °C, and the metastable In0.68Ga0.32As layer showed a flat surface morphology with terraces parallel to the step edges. These results corresponded to those of the strain relaxation analysis of the metastable In0.68Ga0.32As layers using X-ray diffraction spectra. The In0.68Ga0.32As layer grown at 770 °C was almost fully strained, whereas those grown at other growth temperatures were relieved by approximately 10%. The flat surface morphologies and almost fully strained lattices suggested that the growth conditions were suitable for preparing high-quality superlattices with well-defined interfaces. The intuitive results of the metastable In0.68Ga0.32As single layers were utilized to grow high-quality In0.67Ga0.33As/Al0.64In0.36As superlattices with a reduction in the misfit dislocation by 41.8%. The results obtained herein suggest that the growth conditions for superlattices can be easily and efficiently optimized using the metastability of the materials.

Evaluation and Management of the Contact Athlete's Shoulder.

Shoulder injuries are common in contact athletes and vary in severity because of the required complex interplay of shoulder stability and range of motion for proper function. Pathology varies based on sport but most commonly includes shoulder instability, acromioclavicular injuries, traumatic rotator cuff tears, and brachial plexus injuries. Acute management ranges from reduction of shoulder dislocations to physical examination to determine the severity of injury. Appropriate radiographs should be obtained to evaluate for alignment and fracture, with magnetic resonance imaging commonly being necessary for accurate diagnosis and management. Treatments range from surgical stabilization in shoulder instability to repeat examinations and physical therapy. Return-to-play decision making can be complex with avoidance of reinjury and player safety being of utmost concern. Appropriate evaluation and treatment are vital because repeat injury can lead to long-term effects due to the relatively high effectsometimes seen in contact sports.

Arthroscopic reduction of congenital hip dislocations in infants

Open reduction of congenital hip dislocations currently remains the standard treatment for those hip joints which are irreducible by closed means. The open reduction of the dislocated hip joint represents arelatively invasive surgical method. Thus, the goal was to develop aminimally invasive and safe procedure with alower complication rate as an alternative to open reduction. This work presents the arthroscopically guided reduction of dislocated hip joints, first described in 2009, as astandardized surgical technique. Failed closed reduction for congenital hip dislocation. Arthroscopic reduction of the dislocated femoral head using an arthroscopic two-portal technique, ahigh anterolateral and amedial subadductor portal. The arthroscope is inserted through the subadductor portal. The high anterolateral portal serves as working portal. Step-by-step identification and removal of obstacles to reduction such as the ligament of the femoral head, fat tissue, capsular constriction and psoas tendon. Reduction of the femoral head under arthroscopic control. The hip joint is retained in ahip spica cast with the legs in human position. Arthroscopic hip reduction of 20congenital hip dislocations: 13girls and 3boys with an average age at the time of operation of 5.8months (3-9months). All children had multiple, unsuccessful attempts of closed reduction by use of overhead traction, Pavlik harness or closed reduction and hip spica application. According to the Graf classification, there were 20typeIV hips. According to the radiological classification of Tönnis, there were 9 type4, 7 type3, and 4 typeII grades. The obstacles to reduction were capsular constriction, hypertrophic ligament of the femoral head, and an extensively large pulvinar in the acetabulum. An inverted labrum was not seen in any of the cases. In contrast, in 2/3 of the cases, there was considerable retraction of the dorsal edge of the socket due to the ligament of the femoral head expanding right over it. In all cases, postreduction transinguinal ultrasound and MRI were used to check the femoral head position in the cast postoperatively. In all cases there was adeep reduction of the femoral head in the acetabulum. There were no intra- or postoperative complications such as bleeding, infections or nerve lesions. There were no cases of redislocation or decentering of the femoral head, which was also confirmed after an average follow-up of 15months. The mean AC angle at follow-up was 24.5°. There was one coxa magna in the series and one avascular necrosis with afragmented femoral head according to the Salter classification.

Physical and technological analysis of the AlGaN-based UVC-LED: an extended discussion focused on cubic phase as an alternative for surface disinfection.

Crisis in coronavirus times requires understanding the effects on society and establishing efficient mechanisms to prevent infections. The disinfection of personal protection equipment by UVC light remains a key opportunity area. Therefore, this letter presents the main drawbacks and challenges on the fabrication of deep ultraviolet LEDs based on III-nitrides, such as the substrate selection, dislocation reduction, the increase of external quantum efficiency, enhancement of the radiative recombination in the active region, the complications to reach high Al content in AlGaN-based UVC LED avoiding the reduction of the p-doping, replacing the p-GaN contact layer by p-AlGaN without hindering the deposition of ohmic contacts. Furthermore, the cubic phase is suggested as a promising candidate for AlGaN UVC-LEDs applications as is discussed in this work.

The Clinical Significance of Infolded Limbus on Postreduction Arthrogram in Developmental Dysplasia of the Hip.

The purpose of this study was to investigate whether presence of an infolded limbus on hip arthrogram at index closed reduction was associated with increased residual dysplasia or secondary surgery. We retrospectively reviewed all patients who underwent closed reduction for dysplasia of the hip with a minimum 2-year follow-up between 1980 and 2016. Demographic data was obtained including the age at reduction and severity of dislocation based on the International Hip Dysplasia Institute (IHDI) classification. Arthrograms performed at time of closed reduction were separately reviewed by 3 fellowship-trained pediatric orthopaedic surgeons to evaluate for an infolded limbus. The primary radiographic outcome was acetabular indices at 2 and 4 years postreduction. We also assessed the presence of avascular necrosis and rate of secondary reconstructive surgery for residual dysplasia. A total of 182 hips in 165 patients underwent closed reduction at a mean age of 9.8±4.5 mo and were followed a mean of 9.0±4.9 y. An infolded limbus was identified in 20.3% (37/182) hips with substantial agreement among the 3 graders (Fleiss κ=0.75). The frequency of labral infolding increased with the severity of dislocation (8.8%% of IHDI II, 26.7% IHDI III, and 25.0% of IHDI IV hips; P=0.03). Hips with infolded limbus were older at reduction (12.4±5.3 vs. 9.2±5.8 mo, P=0.001). The mean acetabular index was higher in hips with infolded limbus than hips without at 2 years postreduction (34.8±4.8 vs. 32.6±5.8 degrees, respectively; P=0.04). However, multivariate analysis revealed that only the severity of dislocation predicted dysplasia at 2 years postreduction. No significant difference in acetabular index was seen at 4 years postreduction (27.2±7.4 vs. 25.4±6.5 degrees, P=0.24). There was no difference in avascular necrosis between groups (P=0.74). There was no difference in rate of secondary surgery between hips with labral infolding and those without (35% vs. 30%, respectively; P=0.52). An infolded limbus was more common in older patients with more severe dislocations. However, it is not associated with increased residual dysplasia or secondary surgery and may have limited utility in decision-making during closed reduction. Level II-prognostic study.