Dislocation Group Research Articles

The Forgotten Joint Score-12 as a valuable patient-reported outcome measure for patients after first-time patellar dislocation

BackgroundThe aim of this study is to assess joint awareness after first-time patellar dislocation using the Forgotten Joint Score-12 (FJS-12) and to compare performance of this measurement tool to acknowledged patient-reported outcome scores. MethodsA retrospective analysis of patients with confirmed first-time patellar dislocation was performed. Patients were assessed with the FJS-12, the Kujala and the WOMAC scores. Reference values for the FJS-12 were obtained from a matched healthy control group with no history of previous knee joint pathology. We calculated Cronbach's alpha, assessed the ceiling effect for all scores, and calculated the Spearman correlation coefficient between them ResultsFifty-six patients (mean follow-up 8.2 years, range 1.6–14.1) with a mean age of 26.4 years were analysed. Compared with the age- and gender-matched control group, the patellar dislocation group showed significantly lower (worse) mean FJS-12 scores (88 vs. 71, P < 0.001). Inter-score correlation between the FJS-12 and the Kujala was high (r = 0.74) and significant (P < 0.001), as well as between FJS-12 and WOMAC (r = 0.81, P < 0.001). Cronbach's alpha of the FJS-12 was 0.92 (95% confidence interval 0.90–0.94). The FJS-12 showed less ceiling effect (16%) compared with the Kujala score (23%) and the WOMAC score (32%). ConclusionsThe concept of joint awareness has been successfully applied to a patient population after patellar dislocation. The FJS-12 showed less ceiling effect compared with the Kujala and the WOMAC scores, suggesting the score was able to capture subtle knee problems in patients after patellar dislocation

Fractures around the Pelvis, Pelvic Rim &amp;amp; Acetabulum in the Elderly: Report on 54 Cases

The authors report on 34 patients with a pelvic rim disruption who were treated with percutaneous 7.3 mm screws. This technique is less invasive and gives immediate comfort. Screws were placed with conventional fluoroscopic assistance. In four cases, the screw tip was protruding out of the pelvic bone, two malposition screws were in the back, and two were in the front of the pelvic ring. A revision was needed in one case. We also report on 20 elderly patients with a fracture dislocation of the hip that ran into the pelvis. Eight of them were anteromedial dislocations, and the rest were central dislocations of the femoral head. In the group of anteromedial fracture dislocations, the results were excellent, with an open reduction and internal fixation (ORIF) achieved through a retroperitoneal approach. In the subgroup of central fracture dislocations, we performed the same type of osteosynthesis via the retroperitoneal approach. However, we obtained an excellent result for only two cases. We have a couple of results. First, a percutaneous screw fixation for pelvic fractures with fluoroscopic guidance gives excellent results in most cases. Second, central fracture dislocations of the hip perform poorly after osteosynthesis via the retroperitoneal approach. These fractures probably should be offered acute or delayed total hip arthroplasty (THA).

Diagnostic accuracy of Fresno-Quebec Rules and risk factors for an associated fracture in patients presenting to the emergency department with anterior shoulder dislocation: A retrospective study.

Anterior shoulder dislocation is the most common shoulder injury in patients presenting to the emergency department (ED). Up to 25% of these injuries are fracture-dislocations. In general, the standard approach is to obtain plain radiographs before and after reduction. Fresno-Quebec Rules (FQR) are described to identify the patients who require an x-ray before reduction to reduce radiation exposure and delays in treatment. We aimed to evaluate the efficacy of clinical predictors used in the Fresno-Quebec algorithm for detecting a shoulder fracture-dislocation. Records of patients who presented to the Emergency Department with presumed shoulder dislocation were retrieved and retrospectively analyzed according to 'Fresno-Quebec Rule (FQR)'. Sensitivity, specificity, and predictive values of FQR for detecting associated injuries were calculated. Eighty-nine (65.9%) men and 46 (34.1%) women were included. The mean age of patients was 46 years (16-89). Ninety-nine (73.3%) of the cases had their shoulder dislocated for the first time, whereas 36 (26.7%) patients had a recurrent dislocation. Fifty percent of the patients (18 cases) with recurrent dislocation presented with an atraumatic episode. The remaining 18 patients with a history of recurrent dislocations had their shoulder dislocated as a result of trauma, and four (22%) of them had fracture-dislocation. Using the Fresno-Quebec rules yielded 100% specificity for the diagnosis of fracture-dislocation. The severity of the injury mechanism was not predictive in traumatic but recurrent dislocations. Only one of four patients with a fracture-dislocation in the traumatic recurrent dislocation group had high energy trauma. FQR has 100% sensitivity in detecting fracture-dislocations in patients admitted to ED with anterior shoulder dislocation. It utilizes simple parameters that are easy to use and recall. Using these rules, 30% of unnecessary radiographs can be avoided, saving time and money and reducing radiation exposure in anterior dislocations.

Evaluation of Risk Factors Influencing Instability after Total Hip Replacement

Introduction: Total hip arthroplasty has been successful in relieving pain arising from hip joint diseases and maintains functional stability of hip joint. Instability can be rephrased as subluxation or dislocation of femoral head from the acetabulum. The study has been undertaken to find out causes related to instability after Total Hip Replacement (THR). Aim: To evaluate preoperative, intraoperative and postoperative risk factors influencing instability after THR. Materials and Methods: This retrospective study was carried out from June 2013 to June 2019. Preoperative, postoperative and six months follow-up data was recorded in the questionnaire. A total of eight patients were included in the group having postoperative dislocation and 122 patients were in normal THR group. Clinical outcome was measured using Harris Hip score. Data analysis was done by using Statistical Package for the Social Sciences (SPSS) software version 17.0 and parametric tests like paired t-test, Analysis of Variance (ANOVA) were used. Results: Majority of the patients in the study were in the age group of 31-40 years and 41-50 years (27.69% each) with total mean age of 41.14±12.40 years. About 77.69% were male and 22.31% were female. Mean Harris hip score of the total population was 74.73±5.35. Dislocation post THR was observed in 8 (6.15%) and all these patients were males. Six (75%) patients in hip dislocation group were chronic alcoholics while 41 (33.61%) in non-dislocation group were alcoholics and incidence of dislocation and alcoholism was statistically significant. Capsulectomy was done in 50% patients of hip dislocation group and 16.39% of non-dislocation group thus capsulectomy appears as a significant risk factor for postoperative hip dislocation. Conclusion: The incidence of hip instability after THR was 6.15%. Alcohol addiction was identified as a statistically significant independent preoperative risk factor. It was observed that capsulectomy was a significant risk factor for hip dislocation.

Increased Synovial Inflammatory Markers in Aseptic Total Hip Arthroplasty Dislocation

BackgroundIn cases of total hip arthroplasty (THA) dislocation, a synovial fluid aspiration is often performed to evaluate for periprosthetic joint infection (PJI). It is currently unclear how aseptic dislocation of a THA influences synovial fluid white blood cell (WBC) count and polymorphonuclear percentage (PMN%). The primary aim of this study is to investigate the influence of THA dislocation on synovial WBC count and PMN%. MethodsTwenty-eight patients who underwent a synovial aspiration of a THA between 2014 and 2019 were identified and enrolled in our case-control study. Patients with an aseptic THA dislocation and synovial hip aspiration were matched against patients without dislocation, patients undergoing hip aspiration before aseptic THA revision surgery, and patients undergoing hip aspiration before septic THA revision surgery. ResultsSynovial WBC count was significantly increased in the dislocation vs aseptic THA revision group (P = .015), as well as between the septic revision group vs dislocation and aseptic THA revision group (both P < .001). The PMN% did not differ significantly between the dislocation and aseptic revision groups (P = .294). Mean C-reactive protein values were 12.4 ± 14.9 mg/dL in THA dislocation, 24.1 ± 37.7 mg/dL in THA without infection compared to 85.7 ± 84.9 mg/dL in THA infection group (P < .001). ConclusionThis study shows that THA dislocation has a significant impact on synovial WBC count in joint aspiration. Our data suggest that in the setting of THA dislocation, synovial WBC and PMN% may not be the best method to evaluate for PJI. Further research should be performed to establish new thresholds for these synovial inflammatory markers in the setting of THA dislocation and PJI. Level of evidenceLevel III; retrospective trial.

Morphological risk factors associated with dislocation after bipolar hemiarthroplasty of the hip in patients with femoral neck fractures\u2014a nested case-control study

BackgroundThe relationship between preoperative hip measurements and dislocation after bipolar hemiarthroplasty is presently unclear. In the current study, we investigated the morphological risk factors associated with dislocation after bipolar hemiarthroplasty of the hip in patients with femoral neck fractures.MethodsBetween January 2011 and June 2017, a nested case-control design study was used to analyze the risk factors for dislocation in 348 patients who had undergone bipolar hemiarthroplasty because of femoral neck fractures. Twelve patients underwent at least one dislocation postoperatively. Sixty patients without dislocation were selected as controls matched in terms of time of surgery, age, and sex, at a ratio of 1:5. Patient acetabular measurements were compared between the dislocation group and the control group, including the center-edge angle, abduction angle, acetabular width and depth, depth-to-width ratio, femoral neck offset, leg length discrepancy, and femoral head coverage ratio. A multivariate logistic regression model was used to evaluate the morphological risk factors of dislocation.ResultsPostoperatively, the incidence of dislocation was 3.4%. A smaller center-edge angle was found to be a risk factor associated with dislocation after bipolar hemiarthroplasty of the hip. Patients with small acetabular depth and a small acetabular depth–width ratio were prone to dislocation. Patients with a center-edge angle of ≤ 45.4° or an acetabular depth of ≤ 19.12 mm were more likely to suffer dislocation.ConclusionsCareful preoperative measurements before bipolar hemiarthroplasty of the hip are important. Surgical intervention for femoral neck fracture patients with a shallow acetabulum should be carefully planned and total hip arthroplasty should be considered when necessary.

Os Odontoideum: Analysis of 190 Surgically Treated Cases

The aim of this study was to report an experience with 190 cases of os odontoideum over 20 years. The management outcome following atlantoaxial fixation was analyzed. From January 2000 to September 2018, 190 patients with os odontoideum were surgically treated. There were 113 male patients and 77 female patients; average age was 24 years (range, 2-68 years).The patients were divided into 3 groups depending on the nature of atlantoaxial dislocation (group 1, mobile and partially or completely reducible atlantoaxial dislocation; group 2, fixed or irreducible atlantoaxial dislocation; group 3, presence of basilar invagination). There were 65 pediatric patients (<18 years old). All patients underwent atlantoaxial joint manipulation and lateral mass plate and screw fixation. The goal of surgery was segmental atlantoaxial arthrodesis. No transoral or posterior foramen magnum bone decompression was done. Occipital bone was not included in the fixation construct. On direct bone handling and observation, atlantoaxial joint pathologic hyperactivity related instability was identified in all patients. Atlantoaxial segmental stabilization resulted in clinical symptomatic and neurologic improvement in 100% of patients. Os odontoideum signifies chronic or long-standing atlantoaxial instability. Segmental atlantoaxial fixation is a reliable form of surgical treatment. Bone decompression is not necessary. Inclusion of occipital bone and subaxial vertebrae in the fixation construct is not necessary.

Outcomes After Latarjet Procedure: Patients With First-Time Versus Recurrent Dislocations

Background: The preoperative number of dislocations has been previously proved to be a major factor influencing the results after Bankart repair with more preoperative dislocations correlated with higher recurrence rates and more reoperations. This could possibly be because of the lower quality of the tissue repaired during the procedure after multiple dislocations. On the other hand, the Latarjet procedure does not “repair” but rather reconstructs and augments the anterior glenoid. Purpose/Hypothesis: The main objective was to report the clinical outcomes of patients undergoing a Latarjet procedure after 1 dislocation versus multiple (≥2) dislocations. The hypothesis was that the preoperative number of dislocations would not influence clinical results. Study Design: Cohort study; Level of evidence, 3. Methods: Patients older than 18 years who had undergone a primary Latarjet procedure for shoulder instability with at least 2 years of follow-up were included. Three different techniques were used: a mini-open technique using 2 screws, an arthroscopic technique using 2 screws, and an arthroscopic technique using 2 cortical buttons. Patients were evaluated and answered a questionnaire to assess the number of episodes of dislocation before surgery, the time between the first dislocation and surgery, recurrence of the dislocation, revision surgery, the Walch-Duplay score, the Simple Shoulder Test score, and the visual analog scale (VAS) score for pain. Results: A total of 308 patients were included for analysis with a mean follow-up of 3.4 ± 0.8 years. Of that, 83 patients were included in the first-time dislocation group and 225 in the recurrent dislocation group. At last follow-up, the rates of recurrence and reoperation were not significantly different between groups: 4.8% in the first-time dislocation group versus 3.65% in the recurrent dislocation group and 6.1% versus 4.0%, respectively. The overall Walch-Duplay scores at last follow-up were also comparable between the 2 groups, 67.3 ± 24.85 and 71.8 ± 25.1, even though the first-time dislocation group showed a lower pain subscore (15.0 ± 8.6 vs 18.0 ± 7.5; P = .003). The VAS for pain was also significantly higher in the first-time dislocation group compared with the recurrent dislocation group (1.8 ± 2.3 vs 1.2 ± 1.7; P = .03). Conclusion: The number of episodes of dislocation before surgery does not affect postoperative instability rates and reoperation rates after the Latarjet procedure. However, patients with first-time dislocations had more postoperative pain compared with patients with recurrent dislocations before surgery.

Clinical and radiological evaluation of surgical management in olecranon fracture-dislocations.

The treatment of olecranon fracture-dislocations (OFDs) remains challenging. OFDs are often misdiagnosed as Monteggia lesions, and the real frequency is actually higher. However, studies on OFDs are limited. This study aimed to report on the surgical management of OFDs and to highlight the importance of three-dimensional computed tomography (3D CT) evaluation in the treatment of OFDs. The study participants included 18 patients (11 men, 7 women, mean age 44years (range 24-78) with OFDs. Each patient's medical records, radiographs, and 3D CT scans were reviewed for demographics, injury details, operative findings, and information about radiological and functional outcomes. The patients were divided into 2 groups according to the direction of the dislocation: the posterior dislocation group (group 1, 7 patients) and anterior dislocation group (group 2, 11 patients). The clinical evaluation was performed according to Broberg-Morrey and the American Shoulder and Elbow Surgeons-Elbow (ASES-E) scoring systems. The mean follow-up period was 39months (range 25-62months). The Broberg-Morrey results were excellent in 4, good in 9, fair in 3, and poor in 2 patients. The mean ASES-E score was 84.83 (range 48-100) points. There were signs of ulna-humeral arthrosis in 5 elbows. Arthrosis was graded as grade 1, grade 2, and grade 3 in 3, 1, and 1 elbows, respectively. Partial sensory recovery was observed in one patient with postoperative ulnar neuropathy at the last follow-up visit. OFDs are complex injuries of the proximal ulna and may involve the radial head, coronoid process, and lateral collateral ligament. The effective treatment of OFDs begins with the proper identification of the injury with 3D CT. A secure fixation including the coronoid process is mandatory for the elbow joint stability. Insufficient restoration of the trochlear notch may lead to problems with loss of motion and arthrosis. Although an application of a pre-contoured locking anatomical olecranon plate can simplify the fixation procedure in most cases, the surgeons' equipment should also include radial head implant, coronoid plates, headless screws, small cannulated screw system, suture anchors, fluoroscopy, and articulated external fixator.

Atomic structures and migration mechanisms of interphase boundaries during body- to face-centered cubic phase transformations

Atomic structures and migration mechanisms of interphase boundaries have been of scientific interest for many years owing to their significance in the field of phase transformations. Though the interphase boundary structures can be deduced from crystallographic investigations, the detailed atomic structures and migration mechanisms of interphase boundaries during phase transformations are still poorly understood. In this study, a systematic study on atomic structures and migration mechanisms of interphase boundaries in a body-centered cubic (b.c.c.) to face-centered cubic (f.c.c.) massive transformation was carried out using the phase-field crystal model. Simulation results show that the f.c.c./b.c.c. interphase boundaries can be classified into faceted interphase boundaries and side surfaces. The faceted interphase boundaries are semi-coherent with a group of dislocations, leading to a ledge migration mechanism, while the side surfaces are incoherent and thus migrate in a continuous way. After a careful analysis of the simulated migration process of interphase boundaries at atomic scales, a detailed description of the ledge mechanism based on the motion and nucleation of interphase boundary dislocations is presented. The ledge-forming process is accompanied by the nucleation of new heterogeneous dislocations and motions of original dislocations, and thus the barrier of ledge formation comes from the hindrance of these two dislocation behaviors. Once the ledge is formed, the original dislocations continue to advance until the ledge height reaches 1/|Δg|, where Δg represents the difference in reciprocal lattice vectors between two phases. The new heterogeneous dislocation moves along the radial direction of the interphase boundary, resulting in ledge extension. The interface dislocation behaviors greatly affect the migration of the interphase boundary, leading to different migration kinetics of faceted interphase boundaries under the Kurdjumov–Sachs and the Nishiyama–Wasserman orientation relationships. This study revealed the mechanisms and kinetics of complex structure transition during a b.c.c.–f.c.c. massive phase transformation and can shed some light on the process of solid phase transformations.

Percutaneous fixation of Lisfranc joint injuries: A systematic review of the literature

ObjectiveThe aim of this systematic review was to present the outcome of Lisfranc joint injuries treated with closed reduction and screw percutaneous fixation. MethodsWe searched in Pubmed and Google Scholar Databases for articles regarding screw percutaneous fixation of Lisfranc injuries. Seven studies in total were found to be compatible to our search, according to PRISMA guidelines. Four of those met the criteria of the review and they were included in the meta-analysis. A total number of 106 patients were separated into five groups according to the type of injury and the mean AOFAS score of each group was calculated. Cases in which percutaneous fixation was converted to open treatment due to poor reduction were not included in the study. In addition we compared the outcome score between types of injury according to Myerson classification as well as between purely ligamentous and osseoligamentous injuries. The characteristics of all seven selected studies, such as kind of screw used for fixation, post operative protocol, complications and outcome are mentioned as well. ResultsAverage AOFAS score was 86,2 for type A, 87,54 for type B, and 85 for type C injuries respectively. In pure dislocation group the average AOFAS score was 86,43 and in fracture dislocation group was 87,36. Good to excellent outcome can be expected in patients with different types of injury according to Myerson classification following percutaneous fixation of lisfranc joint injury. Patients with type B injury or a fracture dislocation injury might have better outcome, although this difference was not found to be statistically significant. ConclusionPercutaneous fixation of tarsometatarsal joint injuries is a relatively simple and safe method of treatment, leading to a good functional outcome, especially for Myerson type B as well as for fracture dislocation type of injuries, provided that an anatomical reduction has been achieved. Level of EvidenceLevel III, Therapeutic Study.

The dysplastic trochlear sulcus due to the insufficient patellar stress in growing rats

BackgroundDevelopmental factors were assumed to be the key factors that influenced the morphology of femoral trochlea. This study investigated the effects of insufficient patellar stress after birth on the morphological development of the femoral trochlea. Effects of insufficient patellar stress on femoral trochlea were investigated using surgical induced patellectomy and patellar dislocation in growing rat model.MethodsIn this study, two experimental groups and one sham group (SG) were established. Thirty-six Wistar rats (female, 28 days of age) were randomly assigned to three groups. The patellectomy group (PG), rats underwent the patellectomy in this group. The dislocation group (DG), rats underwent the surgery-induced patellar dislocation. Histological staining (Safranin-O and fast green), Micro-computed tomographic (Micro-CT) analysis in two experimental endpoints (3, 12 weeks postoperatively) were selected to evaluate morphological changes of the femoral trochlea.ResultsArticular cartilage on the trochlear sulcus was remodeled at 3 weeks after the surgery, and degenerated at 12 weeks through the histological staining. The femoral trochlear angle (FTA) did not show a significant difference at 3 week between the experimental groups and the sham group (PG vs SG P = 0.38, DG vs SG p = 0.05), but the FTA was significantly increased in experimental groups at 12 weeks(PG vs SG P = 0.001, DG vs SG p = 0.005). The Bone volume density (BV/TV), Trabecular number (Tb.N) under the trochlea groove were significantly reduced at 3 weeks postoperatively in the experimental groups (PG vs SG p = 0.001, DG vs SG p = 0.002). No significant difference was found in BV/TV and Tb. N among the three groups at 12 weeks postoperatively.ConclusionSurgical induced patellectomy and patellar dislocation leads to the dysplastic trochlear sulcus in growing rats. Besides the bone morphology of trochlear sulcus, the articular cartilage and subchondral trabecula under the trochlear sulcus were remodeled early stage after the surgery.

Periprosthetic joint infection in aseptic total hip arthroplasty revision.

There is no consensus regarding systematic screening for infection in aseptic revision total hip arthroplasty (THA). The rationale for systematic intra-operative samples is to increase the sensitivity of latent infections detection, which may require specific treatment. However, the incidence of occult infection in revision THAs is not precisely known. As such, the aim of the study was to evaluate the incidence of occult infection in presumed aseptic revision THAs and identify associated risk factors. Bacteriological samples from 523 aseptic THA revisions performed for five years were analyzed. Revisions performed for periprosthetic joint infection (PJI) or clinical suspicion of PJI were excluded. Microbiological cultures were performed using tissue samples in 505 cases (97%), synovial fluid in blood culture vials in 158 (30%), and in dry tubes in 263 (50%). Implants were sent for sonication in 12 cases (2.6%). The mean number of microbiological samples per patient was 3.6 (range, 1-15). Histology samples were collected for 300 patients (57%). The incidence of occult infection was 7% (36 cases) and contamination 8% (42 cases). Among occult infections, the primary reasons for revision were dislocation (42%), aseptic loosening (25%), fracture (19%), and others (14%). The infection rate in the dislocation group was significantly higher than that of other reasons for revision (p < 0.001). Among the patients determined with PJI, the revision THA was performed less than a year after primary in 19 (53%). The incidence of occult PJI justifies systematic intraoperative sampling. A short time between primary arthroplasty and revision or an early postoperative dislocation is a factor to suspect infections.

Retrospective study on the impact of ulnar nerve dislocation on the pathophysiology of ulnar neuropathy at the elbow.

IntroductionHigh resolution ultrasonography (US) has been used for diagnosis and evaluation of entrapment peripheral neuropathy. Ulnar neuropathy at the elbow (UNE) is the second most common focal entrapment neuropathy. The ulnar nerve tends to move to the anteromedial side and sometimes subluxates or dislocates over the medial epicondyle as the elbow is flexed. Dislocation of the ulnar nerve during elbow flexion may contribute to friction injury. We aimed to investigate the effects which the dislocation of ulnar nerve at the elbow could have on the electrophysiologic pathology of UNE.MaterialsWe retrospectively reviewed 71 arms of UNE. The demographic data, electrodiagnosis findings and US findings of ulnar nerve were analyzed. We classified the electrodiagnosis findings of UNE into three pathologic types; demyelinating, sensory axonal loss, and mixed sensorimotor axonal loss. The arms were grouped into non-dislocation, partial dislocation, and complete dislocation groups according to the findings of nerve dislocation in US examination. We compared the electrodiagnosis findings, ulnar nerve cross sectional areas in US and electrodiagnosis pathology types among the groups.ResultsA total of 18 (25.3%) arms showed partial dislocation, and 15 (21.1%) arms showed complete dislocation of ulnar nerve in US. In the comparison of electrodiagnosis findings, the partial and complete dislocation groups showed significantly slower conduction velocities and lower amplitudes than non-dislocation group in motor conduction study. In the sensory conduction study, the conduction velocity was significantly slower in partial dislocation group and the amplitude was significantly lower in complete dislocation group than non-dislocation group. In the comparison of US findings, patients in partial and complete dislocation groups showed significantly larger cross sectional areas of the ulnar nerve. The comparison of electrodiagnosis pathologic types among the groups revealed that there were significantly larger proportions of the axonal loss (sensory axonal loss or mixed sensorimotor axonal loss) in partial and complete dislocation groups than non-dislocation group.ConclusionThe ulnar nerve dislocation could influence on the more severe damage of the ulnar nerve in patients with UNE. It might be important to evaluate the dislocation of the ulnar nerve using US in diagnosing ulnar neuropathy for predicting the prognosis and determining the treatment direction of UNE.

Anesthetic Considerations of Intraoperative Neuromonitoring in Thyroidectomy.

Intraoperative neuromonitoring (IONM) might reduce the incidence of injury to the recurrent laryngeal nerve (RLN) during thyroidectomy. Although dislocation of endotracheal tube surface electrodes can lead to false-positive IONM results (loss of signal), the risk factors for dislocation and the effects of muscle relaxants are unclear. Therefore, to identify factors that affect IONM results, we examined the frequency and risk factors for tube dislocation after cervical extension before surgery, the effect of sugammadex administration, and the correlation between IONM results and postoperative RLN palsy. Thirty-nine patients scheduled for thyroidectomy from October 2016 to April 2017 were enrolled. All patients underwent standard IONM and pre- and postoperative laryngoscopy. Differences in patient characteristics in the tube dislocation group and non-dislocation group, and differences in amplitude during vagal stimulation before and after sugammadex administration, were assessed by the Mann-Whitney test or Fisher's exact test. Tube dislocation occurred in 27 patients (69%). Sterno-cricoid distance was significantly shorter in the dislocation group (n=27) than in the non-dislocation group (n=12) (43.88 [32.2-55.91] mm vs 49.46 [40.66-55.91] mm, respectively; p=0.048). Without sugammadex, amplitude during vagal stimulation was sufficient for monitoring. Nine patients had new-onset RLN palsy, which was transient in all patients. The sensitivity of IONM was 100%, the positive predictive value was 60%, and the negative predictive value was 100%. The present findings suggest that anesthesiologists should use video laryngoscopy to correct tube dislocation and that a rocuronium dose of 0.6 mg/kg, without sugammadex, is adequate for IONM.

Defect structure and properties of Zn diffusion doped Si after swift Xe ion irradiation

The electronic and optical properties of Si doped by Zn diffusion have been studied for a long time. Recently the defect structure and properties of n-Si (111) compensated by Zn during high-temperature diffusion annealing with subsequent quenching were investigated. The large-scale rod-like defects with μ-sizes have been observed. These defects were connected with Zn precipitates or/and dislocations. In the present paper we study the modification of defect structure and properties of Zn diffusion doped Si after swift heavy ion (SHI) irradiation. The SHI irradiation is known to lead to the formation of latent tracks (nanometer-sized disordered regions around ion trajectory) in many semiconductor and oxide crystals. It was established that the craters with a size of about 100nm surrounded by hillocks are fixed on the Si surface. The traces of dislocation group along Xe ion beam direction were revealed on Si surface. The small-angle boundaries and interstitial-type planar defects have appeared. After Xe ion irradiation with a fluence of 5×1012 cm−2 the number of radiating centres in dislocation core increasing so, that increasing the dislocation-related luminescence (DRL) from the lines D1 and D2. When the Xe ion irradiation fluence is increased to a value of 1×1014 cm−2 the DRL in the Si sample is almost extinguished.

Plain radiography findings to predict dislocation after total hip arthroplasty

BackgroundWith the improvements of modern surgical techniques and hip prosthesis, the causes for dislocation after total hip arthroplasty (THA) have changed. The aim of this retrospective analysis was to identify new plain radiography findings to predict dislocation after THA. MethodsFive thousand five hundred thirteen consecutive primary THAs performed between January 2000 and December 2014 were reviewed through a nested case–control study design. Among them, 38 patients with 39 hip dislocations (dislocation group) were selected and matched to 78 hips in 78 patients without dislocation (control group). The factors that might influence the prosthetic stability were identified by univariate analyses, and a multivariate logistic regression analysis was performed to determine the odds ratio of each factor. ResultsThe difference of the cup position was not statistically significant. The newly identified risk factors were the following: preoperative hip adduction deformity combined with limb lengthening of 2 cm postoperatively; a knee valgus combined with pelvic obliquity deformity and bilateral pathological hips. ConclusionsPatients with soft tissue imbalance, across joint deformity around hips and bilateral pathological hips seem more predisposed to suffer from dislocation after THA. Appropriate surgical intervention strategies along with meticulously postoperative management may help preventing dislocation after THA. The translational potential of this articleA better understanding of the probable causes of dislocation after THA proposed a new clinical application of plain radiography. This radiography-related clinical research may reveal the novel mechanism of dislocation after THA and new preventive measures.

Evolution of interfacial dislocation networks during long term thermal aging in Ni-based single crystal superalloy DD5

Interfacial dislocations found in single crystal superalloys after long term thermal aging have an important effect on mechanical properties. Long term thermal aging tests for DD5 single crystal superalloy were carried out at 1,100 °C for 20, 100, 200, 500 and 1000 h, and then cooled by air. The effect of long term thermal aging on the dislocation networks at the γ/γ' interfaces was investigated by FE-SEM. Results showed that during the long term thermal aging at 1,100 °C, misfit dislocations formed firstly and then reorientation in the (001) interfacial planes occurred. Different types of square or rectangular dislocation network form by dislocation reaction. Square dislocation networks consisting of four groups of dislocations can transform into octagonal dislocation networks, and then form another square dislocation network by dislocation reaction. Rectangular dislocation networks can also transform into hexagonal dislocation networks. The interfacial dislocation networks promote the γ' phase rafting process. The dislocation networks spacings become smaller and smaller, leading to the effective lattice misfit increasing from −0.10% to −0.32%.

Rotational Malalignment of the Knee Extensor Mechanism: Defining Rotation of the Quadriceps and Its Role in the Spectrum of Patellofemoral Joint Instability.

Background:Osseous rotational malalignment of the lower limb is widely accepted as a factor contributing to patellofemoral instability, particularly in pediatric patients. Patellar instability occurs when the lateral force vector generated by the quadriceps exceeds the restraints provided by osseous and soft-tissue anatomy. The anatomy and activation of the quadriceps are responsible for the force applied across the patellofemoral joint, which has previously been measured using the quadriceps (Q)-angle. To our knowledge, the contribution of the quadriceps anatomy in generating a force vector in the axial plane has not previously been assessed. The primary aim of this study was to introduce the quadriceps torsion angle, a measure of quadriceps rotational alignment in the juvenile population. The secondary aims of this study were to determine the inter-assessor and intra-assessor reliability of the quadriceps torsion angle in the juvenile population and to investigate whether a large quadriceps torsion angle is a classifier of patellar dislocator group membership in a mixed cohort of patellar dislocators and typically developing controls.Methods:Participants between the ages of 8 and 19 years were recruited as either controls or recurrent patellar dislocators. A total of 58 knees in both groups were assessed from magnetic resonance imaging scans of the entire lower limbs. Axial cuts midway between the superior aspect of the femoral head and the articular surface of the medial femoral condyle were used to calculate the proximal reference for the quadriceps torsion angle. The quadriceps torsion angle was defined as the angle between the line connecting the anterior aspect of the sartorius and the junction of the anterior and posterior compartments at the lateral intermuscular septum and the posterior condylar axis line. Inter-assessor reliability was calculated using the intraclass correlation coefficient. The relationship between the quadriceps torsion angle and the femoral torsion was assessed in the entire cohort. These values were compared between the control group and the dislocator group to determine if the raw values or an interplay between the 2 factors played a role in the pathoanatomy of recurrent patellofemoral dislocation.Results:The quadriceps torsion angle was a reproducible assessment in both inter-assessor and intra-assessor reliability analyses. A moderate positive correlation (r = 0.624; p < 0.01) was found between the femoral torsion and the quadriceps torsion angle. Although the quadriceps torsion angle was a fair classifier of patellar dislocation group membership, femoral torsion was not.Conclusions:This study has quantified the rotational alignment of the extensor mechanism using the quadriceps torsion angle. The measurement is shown to be reliable and reproducible and a fair classifier of patellofemoral instability.Clinical Relevance:This article introduces an objective measure of soft-tissue rotational malalignment in the pathogenesis of recurrent patellar dislocation.

Medial epicondyle fractures in children: a study of functional outcome of surgical fixation

&lt;p class="abstract"&gt;&lt;strong&gt;Background:&lt;/strong&gt; Medial epicondyle fracture is a common elbow injury in children. It is associated with elbow dislocation in many cases. Treatment of displaced medial epicondyle fracture with and without elbow dislocation is a debated topic. Surgical and non surgical methods are practiced with variable results.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Methods:&lt;/strong&gt; Our study was a prospective study of medial epicondyle fractures treated by surgical fixation with k wires. We studied total of 24 cases out of which 15 had elbow dislocation. The study period was from 2012 to 2015 and indications for surgery were displacement more than 5 mm, elbow instability, incarceration of fragment, ulnar nerve irritation. Open reduction and internal fixation with K wire done. We used joystick method while reducing the fragment with k wire which was a great help. We assessed the cases using mayo elbow performance score.&lt;strong&gt;&lt;/strong&gt;&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Results:&lt;/strong&gt; Our study yielded excellent results in 92% of patients (mayo elbow performance score &amp;gt;90). There was no major difference in clinical outcome between two groups of patients. Complications like instability and non-union not seen following surgical fixation with K wires. The mean loss of flexion, extension, supination, and pronation was 4, 5, 3 and 2 degrees respectively with elbow dislocation group and 2, 3, 1, 1 in without dislocation group. Pre op instability seen in 54% patients was absent in follow up period. Stiffness was more in elbow dislocation group but overall performance was almost equal.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Conclusions:&lt;/strong&gt; Surgical fixation of medial epicondyle fractures yields excellent results and may be advisable when indicated.&lt;/p&gt;