Direct Observation of Impurity Segregation at Dislocation Cores in an Ionic Crystal

Dislocations, one-dimensional lattice defects, are known to strongly interact with impurity atoms in a crystal. This interaction is generally explained on the basis of the long-range strain field of the dislocation. In ionic crystals, the impurity-dislocation interactions must be influenced by the electrostatic effect in addition to the strain effect. However, such interactions have not been verified yet. Here, we show a direct evidence of the electrostatic impurity-dislocation interaction in α-Al₂O₃ by visualizing the dopant atom distributions at dislocation cores using atomic-resolution scanning transmission electron microscopy (STEM). It was found that the dopant segregation behaviors strongly depend on the kind of elements, and their valence states are considered to be a critical factor. The observed segregation behaviors cannot be explained by the elastic interactions only, but can be successfully understood if the electrostatic interactions are taken into account. The present findings will lead to the precise and quantitative understanding of impurity induced dislocation properties in many materials and devices.

Intrathoracic fracture-dislocation of the humerus - case report and literature review

Shoulder fracture-dislocations are uncommon. Those associated with intrathoracic dislocation are very rare conditions, resulting from high-energy trauma; usually, the affected limb is in an abduction position. In Brazil, there is only one report of a teenager with displacement of the epiphysis into the chest cavity; the present is the first adult patient report of intrathoracic dislocation of the humerus. The authors present the case of a patient female, aged 56 years, who was hit by motorcycle and thrown approximately 5 meters away. She was rescued on site with thoracic, pelvic, and right upper limb trauma. Her chest was drained due to pneumothorax and multiple fractures of ribs; she was diagnosed with fracture-dislocation in four parts, with intrathoracic dislocation of the humeral head. Displaced forearm bones fracture was also diagnosed; the olecranon, scaphoid, and ischiopubic fractures were not displaced. The patient underwent a joint procedure with a cardiothoracic surgery team to remove the humeral head through thoracotomy and chest drainage; subsequently, a partial arthroplasty of the humerus was performed, with graft from the humeral head and fixation of forearm fractures. Conservative treatment was chosen for the other fractures. After three months, all fractures were healed with gradual functional improvement. The patient remained in physiotherapy and orthopedic monitoring, having been discharged from the thoracic surgery; in a severe depressive episode, the patient committed suicide after 11 months of the trauma.

Use of Mini-anchors and Rehabilitation with 0° Cusp Angle Teeth Complete Denture in Recurrent Condylar Dislocation: Technical Adequacy and Procedure

AIM

To report a case of association between the surgical treatment of temporomandibular dysfunction and rehabilitation with denture total prosthesis (TP) using nonanatomic teeth (cusp 0°) in patients with anterior recurrent dislocation of the temporo-mandibular joint (TMJ) and persistent uncontrolled mandibular movement, showing a technical adaptation and conduct.

INTRODUCTION

There are several treatment approaches available for dislocation of the TMJ. The use of condylar mini-anchors for recurrent TMJ dislocation is a valid option and should be considered since it does not alter the joint anatomy. In edentulous patients undergoing TMJ surgical procedures, prosthetic rehabilitation can be seen as a means of treatment preservation.

CASE REPORT

A 73-year-old female patient attended the oral and maxillofacial surgery clinic presenting with joint instability, ligament laxity, and chronic recurrent TMJ dislocations. She had already been through three previous unsuccessful surgical procedures. A treatment plan was done based on the installation of a mini-anchor in the patient's TMJ through the preauricular surgical access. Dislocations were then resolved, but the lack of mandibular control even to a lesser extent after surgery precluded the use of prosthetics even at rest. Thus, it was planned to manufacture two conventional TPs with 0° cusp angle teeth, a clinical protocol shortened to three sessions in an attempt to improve the stability of the prosthesis.

CONCLUSION

The use of an individual mini-anchor is simple and effective, and the use of artificial teeth is well suited to the case.

CLINICAL SIGNIFICANCE

A multidisciplinary intervention (surgery/ prosthesis) is of utmost importance for the resolution and preservation of the treatment of these complex cases.

Bilateral knee dislocation with associated bilateral popliteal arterial injury

Tibiofemoral unilateral knee dislocations are uncommon, making bilateral dislocations even rarer injuries. Knee dislocation is considered one of the most serious injuries that can affect this joint. Associated complications such as popliteal artery injury are responsible for the important morbidity in these patients. The authors report the case of a 52-year-old man with a traumatic bilateral knee dislocation with associated bilateral popliteal arterial injury. His clinical presentation along with radiographic and angiographic findings are described. Surgical and non-surgical treatment and functional outcomes are also reported.

Nonperturbative Quantum Nature of the Dislocation-Phonon Interaction

Despite the long history of dislocation-phonon interaction studies, there are many problems that have not been fully resolved during this development. These include an incompatibility between a perturbative approach and the long-range nature of a dislocation, the relation between static and dynamic scattering, and their capability of dealing with thermal transport phenomena for bulk material only. Here by utilizing a fully quantized dislocation field, which we called a "dislon", a phonon interacting with a dislocation is renormalized as a quasi-phonon, with shifted quasi-phonon energy, and accompanied by a finite quasi-phonon lifetime, which are reducible to classical results. A series of outstanding legacy issues including those above can be directly explained within this unified phonon renormalization approach. For instance, a renormalized phonon naturally resolves the decade-long debate between dynamic and static dislocation-phonon scattering approaches, as two limiting cases. In particular, at nanoscale, both the dynamic and static approaches break down, while the present renormalization approach remains valid by capturing the size effect, showing good agreement with lattice dynamics simulations.

Biomechanics of Internal Fixation Modalities for Middle Phalangeal Base Fracture Dislocation

BACKGROUND

Internal fixation modalities of unstable (>50 percent articular involvement) middle phalangeal volar lip fracture-dislocations include interfragmentary screw and volar buttress plating. This study investigates the mechanical properties (yield strength, ultimate tensile strength, and stiffness) of interfragmentary screw (IS), simple buttress plating (BP) and buttress plating with subchondral screw (BP+S).

METHODS

Fifteen cadaveric digits (5 index, 5 middle, and 5 ring) were prepared by excising its skin envelope and flexor tendons while preserving the structures around the proximal interphalangeal joint. An oblique osteotomy involving 50 percent of the articular surface was performed, and this was fixed with based on its study group: interfragmentary screw (IS), simple buttress plating (BP) and buttress plating with subchondral screw (BP+S). These specimens were then loaded to failure.

RESULTS

Yield strength was as follows: BP+S (33.5±9.76 N), IS (13.6±5.46 N), and BP (8.1±3.84 N). Ultimate tensile strength was as follows: BP+S (49.1±21.4 N), IS (15.6±5.19 N), and BP (8.86±3.99 N). Stiffness was as follows: BP+S (4.77±1.32 N/mm), IS (2.44±0.86 N/mm), and BP (1.84±0.71 N/mm).

CONCLUSIONS

A buttress plate and screw construct confers significantly more stability than either interfragmentary screw or buttress plate only fixation in an experimental model.

Cementless Total Hip Arthroplasty Involving Trochanteric Osteotomy without Subtrochanteric Shortening for High Hip Dislocation

BACKGROUND

Total hip arthroplasty with subtrochanteric shortening osteotomy is widely performed for high hip dislocation. However, suboptimal leg length discrepancy correction and nonunion of the osteotomy site remain concerns. Although total hip arthroplasty using trochanteric osteotomy without subtrochanteric osteotomy was introduced, cemented implants have been more commonly used than contemporary cementless implants in this procedure. We evaluated the long-term results of cementless total hip arthroplasty with trochanteric osteotomy without subtrochanteric osteotomy for high hip dislocation.

METHODS

From 1990 to 2002, 27 cementless total hip arthroplasties using trochanteric osteotomy without subtrochanteric osteotomy were performed in 26 patients with Crowe III or IV high hip dislocation and a mean age of 36.4 ± 12.9 years. Seven ceramic-on-ceramic, 8 ceramic-on-polyethylene, 10 metal-on-polyethylene, and 2 metal-on-metal bearings were inserted. Mean follow-up was 15.1 ± 3.7 years. We retrospectively reviewed medical records and radiographic data and evaluated the clinical and radiological results including the Harris hip score, implant survival, correction of leg length discrepancy, and occurrence of complications.

RESULTS

The mean Harris hip score and leg length discrepancy improved significantly from 73.3 to 94.9 points and from 4.3 cm to 1.0 cm, respectively. With revision for loosening set as the end point, implant survival rates at 10 and 15 years postoperatively were 96.0% and 90.9% for stems and 74.1% and 52.3% for cups. In 8 of 10 hips with the metal-on-polyethylene bearing and 4 of 8 hips with the ceramic-on-polyethylene bearing, revision surgery was performed for aseptic loosening. However, no revision was performed in hips with the ceramic-on-ceramic bearing or the metal-on-metal bearing. Implant survival was significantly different by the type of bearing surface. Two permanent neurologic complications occurred in patients with a limb lengthening over 3.5 cm.

CONCLUSIONS

With proper selection of the bearing surface coupled with adjustment of lengthening, cementless total hip arthroplasty using trochanteric osteotomy without subtrochanteric osteotomy might be a favorable treatment option for high hip dislocation.

Seeking health care from a general hospital in Uganda following a fracture or a dislocation

Introduction

Selecting a treatment approach and a facility to get treated from, poses a challenge in musculoskeletal injuries in Africa. The study aimed at determining demographic and injury characteristics of patients with musculoskeletal injuries and how these impact the time and reason for presenting to a general hospital in Uganda.

Methods

An observational study was carried out at Entebbe general hospital on patients presenting with musculoskeletal injuries between 1 November 2014 and 28 February 2015. The patient demographics, injury characteristics, duration of injury to presentation for treatment and reason for seeking treatment from this hospital were noted.

Results

A total of 101 patients were recruited. Of these, 95 had fractures while six had dislocations. Patients took an average of 96 h before presenting for care, females taking significantly longer than males (191.2 and 58.6 h respectively, p = 0.005). The fractured segment of bone significantly influenced the patients’ choice for care at this hospital (p = 0.02).

Discussion

Entebbe General Hospital serves a young and unemployed population for musculoskeletal injuries. These patients present late for care, especially females. Patients base their choice for care from this hospital on the character of the injury.

Structural defects in cubic semiconductors characterized by aberration-corrected scanning transmission electron microscopy

The development of new electro-optical devices and the realization of novel types of transistors require a profound understanding of the structural characteristics of new semiconductor heterostructures. This article provides a concise review about structural defects which occur in semiconductor heterostructures on the basis of micro-patterned Si substrates. In particular, one- and two-dimensional crystal defects are being discussed which are due to the plastic relaxation of epitaxial strain caused by the misfit of crystal lattices. Besides a few selected examples from literature, we treat in particular crystal defects occurring in GaAs/Si, Ge/Si and β-SiC/Si structures which are studied by high-resolution annular dark-field scanning transmission electron microscopy. The relevance of this article is twofold; firstly, it should provide a collection of data which are of help for the identification and characterization of defects in cubic semiconductors by means of atomic-resolution imaging, and secondly, the experimental data shall provide a basis for advancing the understanding of device characteristics with the aid of theoretical modelling by considering the defective nature of strained semiconductor heterostructures.

An atypical case of medial radial head dislocation

Radial head dislocations are common in children who fall onto outstretched hands. We present a case of medial radial head dislocation without a concomitant ulna fracture in a 14-year-old girl and the long-term sequelae of the injury.

Randomized comparison of popliteal-sciatic perineural catheter tip migration and dislocation in a cadaver model using two catheter designs

BACKGROUND

New catheter-over-needle (CON) technology for continuous peripheral nerve blockade has emerged, but its effect on the risk of perineural catheter tip dislocation is unknown. Less flexible catheters may be more likely to migrate away from the nerve with simulated patient movement. In the present study, we evaluated catheter tip migration between CON catheters and traditional catheter-through-needle (CTN) catheters during ultrasound-guided short-axis in-plane (SAX-IP) insertion.

METHODS

We evaluated the migration of popliteal-sciatic catheters in a prone, unembalmed male cadaver. Thirty catheter placement trials were divided randomly into two groups based on the catheter type: CON or CTN. A single anesthesiology resident placed the catheters by SAX-IP insertion, and the catheters were then examined by ultrasound before and after ipsilateral knee range of motion (ROM) exercises (0°-130° flexion). A blinded expert regional anesthesiologist performed caliper measurements on the ultrasound images before and after the ROM exercises. The primary outcome was the change in distance from the catheter tip to the center of the nerve (cm) between before and after the ROM exercises.

RESULTS

The change in the tip-to-nerve distance (median [10th-90th percentile]) was 0.06 (-0.16 to 0.23) cm for the CTN catheter and 0.00 (-0.12 to 0.69) for the CON catheter (P = 0.663). However, there was a statistically significant increase in dislocation out of the nerve compartment for the CON catheter (4/15; 0/15 for CTN) (P = 0.043).

CONCLUSIONS

Although the use of different catheter designs had no effect on the change in the measured migration distance of popliteal-sciatic catheters, 27% of the CON catheters were dislocated out of the nerve compartment. These results may influence the choice of catheter design when using SAX-IP perineural catheter insertion.

Mandibular Range of Movement and Pain Intensity in Patients with Anterior Disc Displacement without Reduction

OBJECTIVE

Temporomandibular disorders (TMD) are the most common source of orofacial pain of a non-dental origin. The study was performed to investigate the therapeutic effect of the conventional occlusal splint therapy and the physical therapy. The hypothesis tested was that the simultaneous use of occlusal splint and physical therapy is an effective method for treatment of anterior disc displacement without reduction.

MATERIALS AND METHODS

Twelve patients (mean age =30.5 y) with anterior disc displacement without reduction (according to RDC/TMD and confirmed by magnetic resonance imaging) were randomly allocated into 2 groups: 6 received stabilization splint (SS) and 6 received both physical therapy and stabilization splint (SS&PT). Treatment outcomes included pain-free opening (MCO), maximum assisted opening (MAO), path of mouth opening and pain as reported on visual analogue scale (VAS).

RESULTS

At baseline of treatment there were no significant differences among the groups for VAS scores, as well as for the range of mandibular movement. VAS scores improved significantly over time for the SS&PT group (F=28.964, p=0.0001, effect size =0.853) and SS group (F=8.794, p=0.001, effect size =0.638). The range of mouth opening improved significantly only in the SS&PT group (MCO: F=20.971, p=0.006; MAO: F=24.014, p=0.004) (Figure 2). Changes in path of mouth opening differ significantly between the groups (p=0.040). Only 1 patient in SS&PT group still presented deviations in mouth opening after completed therapy while in the SS group deviations were present in 5 patients after completed therapy.

CONCLUSION

This limited study gave evidence that during the treatment period lasting for 6 months, the simultaneous use of stabilization splint and physical therapy was more efficient in reducing deviations and improving range of mouth opening than the stabilization splint used alone. Both treatment options were efficient in reducing pain in patients with anterior disc displacement without reduction. Despite of objectively diagnosed disruption of temporomandibular joint anatomy, physiological function was regained.

[Chronic bony instability of the elbow joint]

The high stability of the elbow joint is provided by the congruent articular surfaces in combination with soft tissue stabilizers. The main osseous contributor of elbow stability is the coronoid, which is therefore referred to as a primary stabilizer. The radial head as a secondary stabilizer together with the medial collateral ligament assures valgus stability and together with the coronoid it assures posterolateral stability. Insufficiency of the osseous stabilizers may lead to difficulties in the treatment of chronic dislocation and complex instability. Thereby reconstruction of the osseous constraints of the elbow joint is not performed in isolation from addressing insufficient soft-tissue stabilizers. Bony stabilizers and reconstructional procedures are discussed in this review.

[Fractures of carpal bones]

Fractures of the carpal bones are uncommon. On standard radiographs fractures are often not recognized and a computed tomography (CT) scan is the diagnostic method of choice. The aim of treatment is to restore pain-free and full functioning of the hand. A distinction is made between stable and unstable carpal fractures. Stable non-displaced fractures can be treated conservatively. Unstable and displaced fractures have an increased risk of arthritis and non-union and should be stabilized by screws or k‑wires. If treated adequately, fractures of the carpal bones have a good prognosis. Unstable and dislocated fractures have an increased risk for non-union. The subsequent development of carpal collapse with arthrosis is a severe consequence of non-union, which has a heterogeneous prognosis.

[Femoral neck fractures in young patients]

Femoral neck fractures in young patients are rare but of high clinical relevance due to the complexity of risk factors and complications. Early stabilization and accurate reduction are of high priority. Femoral head-preserving stabilization by dynamic hip screws or threefold screw osteosynthesis are the methods of choice. Postoperative results should be closely controlled in every case in order to be able to treat possible complications in time.

Risk Factors Associated with Dislocation after Bipolar Hemiarthroplasty in Elderly Patients with Femoral Neck Fracture

Purpose

We investigated the incidence and time of dislocation and other factors associated with dislocation of bipolar hemiarthroplasty related to the treatment of femoral neck fracture in old age patients.

Materials and Methods

Between January 2002 and April 2014, 498 femoral neck fractures (467 patients) were treated with bipolar hemiarthroplasty and included in this study. All surgeries were performed using the postero-lateral approach. The incidence of dislocation was investigated. A comparative analysis between a control group and dislocation group was performed with respect to patient factors including age, gender, body mass index, comorbidities, the ASA (American Society of Anesthesiologists) score, mental status and center-edge angle, and surgical factors including type of femoral stem, leg length discrepancy, femoral offset and method of short external rotator (SER) reconstruction.

Results

The incidence of dislocation was 3.8%, and the dislocation occurred on average 2.2 months (range, 0.6-6.5 months) after operation. No difference in patient-related factors was observed between the two groups. However, a smaller center edge (CE) angle was observed in the dislocation group (42.1°±3.2° vs. 46.9°±5.4°, P<0.001), and significantly lower incidence of dislocation was observed in tendon to bone repair group (0.7% vs 7.8%, P<0.001).

Conclusion

SERs should be repaired using the tendon-to-bone repair method to reduce dislocation rate in elderly patients who undergo bipolar hemiarthroplasty using the postero-lateral approach due to femoral neck fracture. In addition, patients with smaller CE angle should be carefully monitored due to high incidence of dislocation.

Study of {332}<113> twinning in a multilayered Ti-10Mo-xFe (x = 1-3) alloy by ECCI and EBSD

We have investigated the propagation of {332}<113> twins in a multilayered Ti-10Mo-xFe (x = 1-3) alloy fabricated by multi-pass hot rolling. The material contains a macroscopic Fe-graded structure (about 130 μm width) between 1 and 3 wt% Fe in the direction perpendicular to rolling. We observe strong influence of the Fe-graded structure in the twin propagation behavior. The propagation of {332}<113> twins that are nucleated in Fe-lean regions (~1 wt% Fe) is interrupted in the grain interiors at a specific Fe content, namely, about 2 wt% Fe. We ascribe this effect to the role of Fe content in solid solution on the stress for twin propagation. The interruption of twins in the grain interiors results in the development of characteristic dislocation configurations such as highly dense dislocation walls (HDDWs) associated to strain localization phenomena. The nucleation and propagation of these dislocation configurations is ascribed to the underlying plastic accommodation mechanisms of the stress field at the twin tips. We find that the crystallographic alignment of HDDWs is determined by the stress field at the twin tips and the deformation texture. The excellent plastic accommodation at the interrupted twin tips allows attaining the good ductility of the present material (total elongation of 28%).

Acute Dislocation of the Metacarpal-Trapezoid Joint

The trapezoid metacarpal dislocation is a rare event. In the literature, it is found in case reports. This injury is caused by direct or indirect high energy trauma. In most cases, the dislocation is dorsal and is difficult to reproduce because the joint is not very mobile. Given the low incidence and little evidence supported in the literature regarding the management, this injury can be treated by open or closed reduction; however, it has been published that most authors use Kirschner wire fixation with good results. Here we present our experience in the management of a male patient with acute trapezoid metacarpal dislocation handled with a splint with good functional results at 6 weeks.

Brachial artery injury due to closed posterior elbow dislocation: case report

An association between closed posterior elbow dislocation and traumatic brachial artery injury is rare. Absence of radial pulse on palpation is an important warning sign and arteriography is the gold-standard diagnostic test. Early diagnosis is essential for appropriate treatment to be provided. This consists of joint reduction and immobilization, along with urgent surgical restoration of arterial flow. Here, a case (novel to the Brazilian literature) of an association between these injuries (and the treatment implemented) in a 27-year-old male patient is reported. These injuries were sustained through physical assault.

How muscle relaxation and laterotrusion resolve open locks of the temporomandibular joint. Forward dynamic 3D-modeling of the human masticatory system

Patients with symptomatic hypermobility of the temporomandibular joint report problems with the closing movement of their jaw. Some are even unable to close their mouth opening wide (open lock). Clinical experience suggests that relaxing the jaw muscles or performing a jaw movement to one side (laterotrusion) might be a solution. The aim of our study was to assess the potential of these strategies for resolving an open lock and we hypothesised that both strategies work equally well in resolving open locks. We assessed the interplay of muscle forces, joint reaction forces and their moments during closing of mouth, following maximal mouth opening. We used a 3D biomechanical model of the masticatory system with a joint shape and muscle orientation that predispose for an open lock. In a forward dynamics approach, the effect of relaxation and laterotrusion strategies was assessed. Performing a laterotrusion movement was predicted to release an open lock for a steeper anterior slope of the articular eminence than relaxing the jaw-closing muscles, herewith we rejected our hypothesis. Both strategies could provide a net jaw closing moment, but only the laterotrusion strategy was able to provide a net posterior force for steeper anterior slope angles. For both strategies, the temporalis muscle appeared pivotal to retrieve the mandibular condyles to the glenoid fossa, due to its' more dorsally oriented working lines.

Management of Acute Patellar Dislocation: A Case Report

OBJECTIVE

The purpose of this case study is to describe the evaluation and management of patellar dislocations and the different approaches used from providers in different countries.

CLINICAL FEATURES

An individual dislocated her left patella while traveling abroad and received subsequent care in Thailand, China, and the United States.

INTERVENTION AND OUTCOME

Nonoperative treatment protocols including manual closed reduction of the patella, casting of the leg, and rehabilitation exercises were employed.

CONCLUSION

Receipt of care when abroad can be challenging. The patient's knee range of motion and pain continued to improve when she was diligent about performing the home exercise program. This case highlights the importance of a thorough examination, a proper regimen of care, and patient counseling to ensure a full recovery and minimize the chance of re-injury.

Irreducible Lateral Patellar Dislocation: A Case Report and Literature Review

BACKGROUND

Acute patellar dislocation is a common injury in young people, especially in adolescent females and athletes. Lateral dislocation is the most common form of patellar dislocation and often reduces spontaneously or with simple manipulation and closed reduction. We report a rare circumstance in which the patella was irreducible and required manipulation and closed reduction in the operating room.

CASE REPORT

While dancing, a 32-year-old female was knocked by a fellow dancer on her left knee, and she fell to the nightclub floor. She was unable to stand or bear weight because of the pain, and her knee was in fixed flexion with lateral displacement of the patella. Multiple attempts at closed reduction under sedation failed in the emergency department. Computed tomography (CT) images revealed a medial border patellar fracture and lipohemarthrosis that required closed reduction and manipulation in the operating room. The patient was placed in a Richards splint for follow-up and referred to a physiotherapist for conservative management.

CONCLUSION

This case highlights the fact that some lateral patellar dislocations are irreducible on initial attempts, particularly if a fracture is present or another mechanism of impingement impedes relocation. CT imaging is a valuable diagnostic tool, and manipulation under anesthesia or open reduction in the operating room may be necessary. Our review of the literature further highlights the complexity and potential problems associated with treatment of locked lateral patellar dislocations.

Neglected isolated scaphoid dislocation

The authors present a case of isolated scaphoid dislocation in a 40-year-old male that was undiagnosed for 2 months. The patient was treated by open reduction, Kirschner wire fixation, interosseous ligament repair using a suture anchor and Blatt's dorsal capsulodesis. At 6 years followup, his radiographs of wrist showed a normal carpal alignment with a scapholunate gap of 3 mm and no evidence of avascular necrosis (AVN) of the scaphoid.

Intra-articular dislocation of patella reduced by closed method - A rare case report

Intra-articular dislocation of the patella is a rare injury. Two types of intra-articular dislocations have been described in literature. In horizontal type, the patella has rotated on its horizontal axis. In the second type, the patella rotates on its vertical axis. These dislocations frequently are difficult to reduce by closed methods, and open reduction generally is required. We describe here a case of horizontal intra-articular dislocation of patella in a young 25-year-old male managed successfully by closed reduction.

Dislocation is a risk factor for poor outcome after supination external rotation type ankle fractures

INTRODUCTION

Ankle fractures are one of the most common fractures requiring surgical treatment. Ankle fracture-dislocations are significant injuries to the osseous and soft tissue envelope, but studies focused on the effect of dislocation on radiographic and functional outcomes are lacking. The objective of this study was to evaluate the effect of dislocations on postoperative outcomes in SER IV ankle fracture patients.

MATERIALS AND METHODS

From 2004 through 2010, all operative SER IV ankle fractures treated by a single surgeon were enrolled in a prospective database. SER IV ankle fractures were separated into two groups based on clinical or radiographic evidence of dislocation. The primary and secondary functional outcomes measures were the Foot and Ankle Outcome Score (FAOS) and ankle and subtalar range of motion (ROM) with a minimum of 1-year follow-up, respectively.

RESULTS

108 patients with SER IV ankle fractures were identified, with 73 in the non-dislocation group (68%) and 35 patients in the dislocation group (32%). Patient demographics and co-morbidities were similar between the two groups. The incidence of open fractures and the application of an external fixator were significantly higher in the dislocation group (p = 0.037 and p = 0.003, respectively). The dislocation group showed a significant decrease in the accuracy of articular reduction (p = 0.003). At a mean follow-up of 21 months, ankle fracture-dislocation patients had increased pain (p = 0.005) and decreased activities of daily living (p = 0.014) on FAOS outcome measures and significantly worse ankle and subtalar ROM.

CONCLUSIONS

The results of this study suggest that concurrent dislocation at time of ankle fracture is associated with worse radiographic and functional outcomes, but not an increase in superficial or deep infection. The results from this study may be helpful in counseling patients regarding expected clinical outcomes after ankle fracture-dislocation and in the surgical management of this complex injury.

The binding of cellulase variants to dislocations: a semi-quantitative analysis based on CLSM (confocal laser scanning microscopy) images

Binding of enzymes to the substrate is the first step in enzymatic hydrolysis of lignocellulose, a key process within biorefining. During this process elongated plant cells such as fibers and tracheids have been found to break into segments at irregular cell wall regions known as dislocations or slip planes. Here we study whether cellulases bind to dislocations to a higher extent than to the surrounding cell wall. The binding of fluorescently labelled cellobiohydrolases and endoglucanases to filter paper fibers was investigated using confocal laser scanning microscopy and a ratiometric method was developed to assess and quantify the abundance of the binding of cellulases to dislocations as compared to the surrounding cell wall. Only Humicola insolens EGV was found to have stronger binding preference to dislocations than to the surrounding cell wall, while no difference in binding affinity was seen for any of the other cellulose variants included in the study (H. insolens EGV variants, Trichoderma reesei CBHI, CBHII and EGII). This result favours the hypothesis that fibers break at dislocations during the initial phase of hydrolysis mostly due to mechanical failure rather than as a result of faster degradation at these locations.

TERRIBLE TRIAD OF THE ELBOW: EVALUATION OF SURGICAL TREATMENT

Objectives: To evaluate the epidemiology of and surgical results from treating elbow fracture-dislocations, including only the cases in which dislocation is associated with fracture of the coronoid process and the radial head (terrible triad). Methods: Nineteen patients were evaluated: 12 males and 7 females. The medical records were analyzed to gather data about the mechanism of injury, fracture pattern, time elapsed until surgery and type of procedure applied. A clinical assessment was made to measure elbow range of motion, and the MEPS questionnaire was applied. Results: The most common mechanism of injury in our sample was a fall from a height (12 patients). All the patients underwent surgical treatment and the mean time elapsed between the date of the injury and the surgery was 16.1 days. The mean follow-up was 50.3 months. The mean range of flexion-extension obtained was 112° and the mean range of pronation-supination obtained was 127.9°. The mean score from the MEPS questionnaire was 86 points, and excellent and good results were obtained for 15 patients (79%). The time elapsed until surgery, final flexion-extension range greater than 100° and flexion contracture of less than 30° were shown to have a statistically significant relationship with a good final clinical result. Five patients had complications, of which three cases related to peripheral nerves, one case to pseudarthrosis and one case to recurrent instability. Conclusions: Despite the severity of the injuries found in the terrible triad of the elbow, most of the patients evaluated here achieved elbow stability with good clinical results. The factors that led to better clinical results were surgery not more than 14 days after the injury, flexion-extension range greater than 100° and flexion contracture less than 30°.

An Incidental Finding of a Radiopaque Pill following Cervical Spinal Surgery in a Parkinson's Disease Patient

There are previous reports of the identification of radiopaque medications on abdominal X-rays or computed tomography (CT). We describe an interesting case of the incidental identification of a radiopaque medication on cervical spinal CT following cervical spinal surgery. A sixty seven-year-old male patient with Parkinson's disease (PD) visited our emergency center with a C5-6 dislocation and fracture. Surgery was performed with open reduction and pedicle screw fixation through the posterior approach. No abnormal events occurred during the perioperative period. However, a radiopaque incidental foreign body in front of the C6 vertebrae was found on a cervical spinal CT and X-rays that were performed as routine examinations on postoperative day 3. After 6 hours, we performed gastrofibroscopy (GFS) but were unable to find anything. Therefore, we checked all of his medications related to the neck and check X-ray again. One enteric-coated pill he had taken exhibited strong radiodensity. Although our patient underwent an unnecessary GFS, every spinal surgeon should keep in mind that radiopaque pills can appear similar to spinal instruments on X-ray and CT. In addition, we should also know the associated dysphagia is a possible cause of the delayed passage of medicine in PD with or without cervical osteophytes.

Management of Neglected Traumatic Bilateral Cervical Facet Dislocations Without Neurological Deficit

Introduction:

Sub axial cervical spine dislocations are common and managing these cases by closed reduction is successful in the majority of cases. However, treatment of old and neglected cases is difficult and the results may vary in terms of neurological and functional outcomes.

Case Presentation:

We present two cases of traumatic bilateral cervical facet dislocation with no neurological deficit (ND) who referred four months after the injury. They were managed via single stage anterior discectomy, posterior facet reduction, instrumentation, and then anterior reconstruction with bone graft and cervical plate. The patients had no ND in the postoperative period and returned to work.

Discussion:

Patients presenting with neck pain after a history of trauma should be evaluated thoroughly with radiographs and computed tomography. The management of old neglected facet dislocations is difficult, lengthy, and fraught with potential neurological complications; operative intervention can substantially improve the quality of life in these patients.

Turco's injury: diagnosis and treatment

The aim of this study was to alert doctors to the existence of Turco's injury and discus the existing treatments that have been described in the worldwide literature. A bibliographic survey of Lisfranc's injury and Turco's injury covering from 1985 to 2013 was conducted in the SciELO and PubMed databases. Among the 193 articles, those relating to bone-ligament injuries of the Lisfranc joint and high-energy trauma were excluded, as were the case reports. The patients selected were professional or amateur athletes who solely presented a ligament injury to the Lisfranc joint (Turco's injury), which was diagnosed from the history, physical examination, radiographs and magnetic resonance images. Non-athletic patients and those with associated bone injuries were excluded (10). According to the injury classification, the patients were treated by means of either an open or a closed procedure and then a standard rehabilitation protocol. Out of the 10 patients, five underwent conservative treatment and five underwent surgical treatment using different techniques and synthesis materials. We obtained two poor results, one satisfactory, five good and two excellent. We conclude that the correct diagnosis has a direct influence on the treatment and on the final result obtained, and that lack of knowledge of this injury is the main factor responsible for underdiagnosing Turco's injury. There is a need for randomized prospective studies comparing the types of synthesis and evolution of treated cases, in order to define the best treatment for this injury.

Scaphoid Excision and Four-Corner Fusion for Neglected Perilunate Dislocations: Preliminary Results

BACKGROUND

Perilunate dislocations are severe uncommon carpal injuries. They are sometimes missed with a reported incidence of up to 25%. Neglect for a period of time allows for soft tissue contractures, as well as bony changes that make reduction extremely difficult. For neglected cases, procedures such as staged open reduction, proximal row carpectomy, and wrist arthrodesis have been offered. The objective of this study was to examine whether scaphoid excision and four-corner fusion could be used to treat neglected perilunate dislocations.

METHODS

Ten patients with neglected perilunate dislocations were managed by scaphoid excision and four-corner fusion. The dominant hand was involved in eight cases. Graft material for the fusion was obtained from the excised scaphoid.

RESULTS

Six patients had complete relief of pain both at rest and during stressful activities. Two patients had no pain at rest and mild pain on stressful activities. The remaining two patients had mild pain at rest and moderate pain on stressful activities. The arc of extension/flexion of the wrist and grip strength both improved as compared to their preoperative levels. The average postoperative Quick DASH score was 12.5.

CONCLUSIONS

Scaphoid excision with four corner fusion could be used to treat neglected perilunate dislocations with good pain relief and good hand function.

[Superolateral dislocation of the temporomadibular joint: Case report]

INTRODUCTION

Superolateral disclocations of the temporomandibular joint are rare. They mostly occur after high-energy trauma and are frequently associated with fractures of the mandibular body.

CASE REPORT

A 35-year-old man was admitted for the management of a high-energy craniofacial trauma due to a road accident. The initial assessment revealed bilateral superolateral temporomandibular joint disclocations, with bilateral sagittal fractures of the condyle head and a fracture of the right parasymphysis. The treatment consisted in an external reduction of both condyles, followed by open reduction and internal fixation of the parasymphysis. The patient quickly started physiotherapy after the procedure and recovered a normal mouth opening after a month of follow-up.

DISCUSSION

For most authors, a quick management of superolateral dislocations is necessary in order to achieve a proper reduction of the temporomandibular joint dislocation and avoid surgical reduction. Temporomandibular joint ankylosis is the main complication of such lesions. Early physiotherapy is indicated in order to prevent ankylosis.

Functional evaluation of patients with surgically treated terrible triad of the elbow

OBJECTIVES

To evaluate the functional outcome of patients with surgically treated terrible triad of the elbow.

METHODS

A retrospective evaluation was performed using the MEPS score (Mayo Elbow Performance Score) of patients diagnosed with terrible triad of the elbow who underwent surgical treatment.

RESULTS

14 patients (nine men and five women) and 15 elbows (one bilateral case) were evaluated. A MEPS average score of 78 points and 86% good and excellent results was obtained. As complications, we had one case of infection and three of neuropraxia of the ulnar nerve.

CONCLUSION

The patients had stable elbow with good function, however with reduced range of motion. Level of Evidence IV, Case Series.

One-dimensional nonlinear scattering by localized hysteretic damage and its application to damage characterization

One-dimensional nonlinear scattering by a confined distribution of dislocations interacting with point defects distributed along their glide planes or their cores, and of microcracks with or without adhesion between their faces is predicted theoretically. The nonlinear properties of these forms of damage are modeled by macroscopic effective constitutive relationships, and a perturbation approach is used to solve the scattering problem. Backward and forward scattered fields are investigated and use of their main properties towards the development of selective imaging methods which are tailored to hysteretic material damage is briefly discussed. This model is also used to verify recent experimental results on steel samples containing small cracks or confined regions of macrograins. The mechanism associated to hysteresis of large grains is modeled by the interaction between dislocations and point defects along their glide planes. Theoretical predictions confirm that the exponent of a power law, which links the energy dissipated nonlinearly to the energy of a scaled linear field, is sensitive to the physical nature of damage. In turn, experimental findings are shown to provide convincing support to the effective constitutive relationships proposed in this work. Interactions of dislocations with glide and core PDs are characterized by different values of the exponent.

Segregation of In to dislocations in InGaN

Dislocations are one-dimensional topological defects that occur frequently in functional thin film materials and that are known to degrade the performance of InxGa1-xN-based optoelectronic devices. Here, we show that large local deviations in alloy composition and atomic structure are expected to occur in and around dislocation cores in InxGa(1-x)N alloy thin films. We present energy-dispersive X-ray spectroscopy data supporting this result. The methods presented here are also widely applicable for predicting composition fluctuations associated with strain fields in other inorganic functional material thin films.

Growth and dislocation studies of β-HMX

Background

The defect structure of organic materials is important as it plays a major role in their crystal growth properties. It also can play a subcritical role in “hot-spot” detonation processes of energetics and one such energetic is cyclotetramethylene-tetranitramine, in the commonly used beta form (β-HMX).

Results

The as-grown crystals grown by evaporation from acetone show prismatic, tabular and columnar habits, all with {011}, {110}, (010) and (101) faces. Etching on (010) surfaces revealed three different types of etch pits, two of which could be identified with either pure screw or pure edge dislocations, the third is shown to be an artifact of the twinning process that this material undergoes. Examination of the {011} and {110} surfaces show only one type of etch pit on each surface; however their natural asymmetry precludes the easy identification of their Burgers vector or dislocation type. Etching of cleaved {011} surfaces demonstrates that the etch pits can be associated with line dislocations. All dislocations appear randomly on the crystal surfaces and do not form alignments characteristic of mechanical deformation by dislocation slip.

Conclusions

Crystals of β-HMX grown from acetone show good morphological agreement with that predicted by modelling, with three distinct crystal habits observed depending upon the supersaturation of the growth solution. Prismatic habit was favoured at low supersaturation, while tabular and columnar crystals were predominant at higher super saturations. The twin plane in β-HMX was identified as a (101) reflection plane. The low plasticity of β-HMX is shown by the lack of etch pit alignments corresponding to mechanically induced dislocation arrays. On untwinned {010} faces, two types of dislocations exist, pure edge dislocations with b = [010] and pure screw dislocations with b = [010]. On twinned (010) faces, a third dislocation type exists and it is proposed that these pits are associated with pure screw dislocations with b = [010].

Graphical abstract

Search for Dislocation Free Helium 4 Crystals

The giant plasticity of [Formula: see text]He crystals has been explained as a consequence of the large mobility of their dislocations. Thus, the mechanical properties of dislocation free crystals should be quite different from those of usual ones. In 1996-1998, Ruutu et al. published crystal growth studies showing that, in their helium 4 crystals, the density of screw dislocations along the c-axis was less than 100 per cm[Formula: see text], sometimes zero. We have grown helium 4 crystals using similar growth speeds and temperatures, and extracted their dislocation density from their mechanical properties. We found dislocation densities that are in the range of 10[Formula: see text]-10[Formula: see text] per cm[Formula: see text], that is several orders of magnitude larger than Ruutu et al. Our tentative interpretation of this apparent contradiction is that the two types of measurements are somewhat indirect and concern different types of dislocations. As for the dislocation nucleation mechanism, it remains to be understood.

Assessment of the function and resistance of sternoclavicular ligaments: A biomechanical study in cadavers

BACKGROUND

Few biomechanical studies have assessed the resistance of the ligamentous structures of the sternoclavicular joint, and none have reproduced the physiological movements of the joint. Determining the structures that are injured in sternoclavicular dislocations is important for the surgical planning of acute or chronic ligament reconstruction.

METHODS

Forty-eight joints from 24 human cadavers were studied, and they were divided into 4 groups of 12 joints each (retraction, protraction, depression and elevation). Biomechanical testing assessed primary and secondary failures. The mechanical resistance parameters between movements that occurred on the same plane (depression versus elevation, protraction versus retraction) were compared.

RESULTS

The posterior sternoclavicular ligament was the most injured structure during the protraction test, but it was not injured during retraction. The anterior sternoclavicular ligament was the most affected structure during retraction and depression. The costoclavicular ligament was the most affected structure during elevation. Joint resistance was significantly greater during protraction movements when compared to retraction (P<0.05).

CONCLUSION

The anterior sternoclavicular ligament was the most affected structure during retraction and depression movements. During protraction, lesions of the posterior sternoclavicular ligament were most frequent during elevation, and the costoclavicular ligament was the most frequently injured ligament. The resistance of the sternoclavicular joint was significantly greater during protraction movement when compared to retraction.

LEVEL OF EVIDENCE

IV, basic science, biomechanics, cadaver model.

Temporomandibular joint dislocation: experiences from Zaria, Nigeria

OBJECTIVES

Dislocation of the temporomandibular joint may occur for various reasons. Although different invasive methods have been advocated for its treatment, this study highlights the value of non-invasive treatment options even in chronic cases in a resource-poor environment.

MATERIALS AND METHODS

A seven-year retrospective analysis of all patients managed for temporomandibular joint dislocation in our department was undertaken. Patient demographics, risk factors associated with temporomandibular joint dislocation and treatment modalities were retrieved from patient records.

RESULTS

In all, 26 patients were managed over a seven-year period. Males accounted for 62% of the patients, and yawning was the most frequent etiological factor. Conservative treatment methods were used successfully in 86.4% of the patients managed. Two (66.7%) of the three patients who needed surgical treatment developed complications, while only one (5.3%) patient who was managed conservatively developed complications.

CONCLUSION

Temporomandibular joint dislocation appears to be associated with male sex, middle age, yawning, and low socio-economic status, although these observed relationships were not statistically significant. Non-invasive methods remain an effective treatment option in this environment in view of the low socio-economic status of the patients affected.

Terrible triad of the elbow: influence of radial head treatment

Objective

to test the null hypothesis that patients with the terrible triad of the elbow (dislocation together with fractures of the radial head and coronoid process) who are treated with open reduction and internal fixation of the radial head have final results that are comparable with those of patients treated with arthroplasty or partial resection of the radial head.

Methods

twenty-six patients with the terrible triad of the elbow who were operated by a single surgeon were evaluated on average 23 months after the surgery (range: 16–36 months). There were 17 men and nine women of mean age 41 ± 13.4 years. The fractures of the radial head were treated by means of osteosynthesis (12 patients), arthroplasty (nine) or resection of a small fragment or no treatment (five). Fixation of the coronoid process/anterior capsule was performed in 21 patients. The lateral ligament complex (LLC) was repaired in all the patients, while the medial ligament complex (MLC) was repaired in three patients whose elbows remained unstable after treatment for the radial head and LLC, but without fixation of the coronoid process.

Results

the mean final range of flexion and extension was 112°. The mean pronation was 70° and supination, 6°. The mean DASH score (Disabilities of the Arm, Shoulder & Hand) was 12 and mean MEPI (Mayo Elbow Performance Index) was 87. According to the MEPI scores, 21 patients (80%) had good and excellent results. There was no statistically significant difference in the results between the patients who underwent fixation of the radial head and those who underwent arthroplasty or resection of a small fragment.

Conclusion

there was no difference between the patients treated with arthroplasty of the radial head and those treated with other techniques.

Suppression of dislocations by Sb spray in the vicinity of InAs/GaAs quantum dots

The effect of Sb spray prior to the capping of a GaAs layer on the structure and properties of InAs/GaAs quantum dots (QDs) grown by molecular beam epitaxy (MBE) is studied by cross-sectional high-resolution transmission electron microscopy (HRTEM). Compared to the typical GaAs-capped InAs/GaAs QDs, Sb-sprayed QDs display a more uniform lens shape with a thickness of about 3 ~ 4 nm rather than the pyramidal shape of the non-Sb-sprayed QDs. Particularly, the dislocations were observed to be passivated in the InAs/GaAs interface region and even be suppressed to a large extent. There are almost no extended dislocations in the immediate vicinity of the QDs. This result is most likely related to the formation of graded GaAsSb immediately adjacent to the InAs QDs that provides strain relief for the dot/capping layer lattice mismatch.

PACS

81.05.Ea; 81.07.-b; 81.07.Ta.

Bilateral One-half Spica Cast After Open Reduction and Pelvic Osteotomy in the Developmental Dislocation of the Hip

Background:

The prevalence of DDH ranges from 1 per1000 to 3.4 per 100 live- births. One- and-one-half hip spica cast is the conventional technique of immobilization after the open reduction with or without osteotomy.

Objectives:

In this study, we evaluated the preference of bilateral one-half spica cast over the one-and-one-half spica cast.

Materials and Methods:

Eight hips in five patients with developmental dislocation of the hip have undergone open reduction. Salter osteotomy, Pemberton osteotomy and femoral shortening were done on two, two and six hips, respectively. Bilateral one-half spica cast with trochanteric molding was applied for all of the hips.

Results:

The patients’ age ranged from 1.5 to 7 years old. The only complications consisted of two osteonecrosis of the head and one superficial infection. No dislocation, graft displacement, nonunion and device failure was occurred.

Conclusions:

Bilateral one-half spica cast is sufficient after the open reduction with or without osteotomy in DDH patients and we can substitute the bilateral one-half spica cast above the knee cast for the conventional one and one-half spica cast.

Acromioclavicular dislocation type VI associated with diaphyseal fracture of the clavicle

The purpose is to present a very unusual case of the acromioclavicular joint inferior dislocation associated with the clavicle fracture. It concerns to a young patient who had a bike fall and had this type of pathology, had been operated and obtained excellent clinic result. The literature mentions many cases of subcoracoide dislocation, but there are only two subacromial similar to ours. The case is described, a literary revision is done and discussed and the treatment is discussed.

Bilateral asymmetrical traumatic sternoclavicular joint dislocations

Unilateral and bilateral sternoclavicular joint (SCJ) dislocations are rare injuries. The difficulty in assessing this condition often leads to delay in diagnosis and treatment. We report a rare case of bilateral asymmetrical traumatic SCJ dislocations in a 45-year-old male. The right anterior SCJ dislocation was reduced in the emergency room (ER) and resulted in residual instability. The left posterior SCJ dislocation was asymptomatic and unnoticed for six months. It is important for ER physicians and orthopaedic surgeons to be able identify and treat this condition. All suspected SCJ dislocations should be evaluated by computed tomography (CT) scan for confirmation of the diagnosis and evaluation of both SCJs. Posterior SCJ dislocation is a potentially fatal injury and should not be overlooked due to the presence of other injuries. Surgical intervention is often necessary in acute and old cases.

Autologous blood injection to the temporomandibular joint: magnetic resonance imaging findings

Purpose

The aim of this study was to investigate the effect of the autologous blood injection (ABI) for chronic recurrent temporomandibular joint (TMJ) dislocation using magnetic resonance imaging (MRI).

Materials and Methods

ABI was applied to 14 patients who had chronic recurrent TMJ dislocation. MRIs of the patients were taken and compared before and one month after the injection.

Results

All of the patients had no dislocations of their TMJs on clinical examination one month after the injection. In the pre-injection, unilateral or bilateral TMJ dislocations were observed on MRIs in all patients. One month after the injection, TMJ dislocations were not observed in MRI evaluation of any patients. A significant structural change that caused by ABI was not observed.

Conclusion

The procedure was easy to perform and it caused no foreign body reaction. However, it was unclear how the procedure prevented the dislocation.

Stabilisation of the elbow in cases of severe disruption of the lateral collateral complex

INTRODUCTION

Rupture of the lateral collateral ligamentous complex of the elbow is a serious injury. If direct repair of the ligamentous complex is not possible, then an alternative method must be found to stabilise the elbow.

MATERIALS AND METHODS

We describe a novel method of maintaining stability while allowing early movement in a severe injury to the elbow.

CONCLUSION

This technique is a viable alternative to hinged external fixation in patients with severe lateral instability of the elbow joint.