Head-neck movement may predispose to the development of arytenoid dislocation in the intubated patient: a 5-year retrospective single-center study

Background Arytenoid dislocation is a rare laryngeal injury that may follow endotracheal intubation. We aimed to determine the incidence and risk factors for arytenoid dislocation after surgery under general anaesthesia. Methods We reviewed the medical records of patients who underwent operation under general anaesthesia with endotracheal intubation from January 2014 to December 2018. Patients were divided into the non-dislocation and dislocation groups depending on the presence or absence of arytenoid dislocation. Patient, anaesthetic, and surgical factors associated with arytenoid dislocation were determined using Poisson regression analysis. Results Among the 25,538 patients enrolled, 33 (0.13%) had arytenoid dislocation, with higher incidence after anterior neck and brain surgery. Patients in the dislocation group were younger (52.6 ± 14.4 vs 58.2 ± 14.2 yrs, P = 0.025), more likely to be female (78.8 vs 56.5%, P = 0.014), and more likely to be intubated by a first-year anaesthesia resident (33.3 vs 18.5%, P = 0.048) compared to those in the non-dislocation group. Patient positions during surgery were significantly different between the groups (P = 0.000). Multivariable Poisson regression identified head-neck positioning (incidence rate ratio [IRR], 3.10; 95% confidence interval [CI], 1.50–6.25, P = 0.002), endotracheal intubation by a first-year anaesthesia resident (IRR, 2.30; 95% CI, 1.07–4.64, P = 0.024), and female (IRR, 3.05; 95% CI, 1.38–7.73, P = 0.010) as risk factors for arytenoid dislocation. Conclusion This study showed that the incidence of arytenoid dislocation was 0.13%, and that head-neck positioning during surgery, less anaesthetist experience, and female were significantly associated with arytenoid dislocation in patients who underwent surgeries under general anaesthesia with endotracheal intubation.

Effect of Tensile Deformation on Residual Stress of GH4169 Alloy

In order to reduce the residual stress of the GH4169 alloy, the effect and micro-mechanism of the tensile deformation were studied. The residual stress, dislocation density, and distribution of the GH4169 alloy were analyzed by X-ray residual stress tester, X-ray diffractometer (XRD), and electron backscatter diffraction (EBSD). The results show that: with the increase of tensile deformation, the residual stress relief first increases and then decreases. When the tensile deformation is 3%, the reduction rate of residual stress reaches the maximum, which is 90%. The mechanism of residual stress relief by the tensile treatment is that the dislocation group in the alloy is activated by tensile treatment, and the dislocation distribution in the alloy is more uniform by dislocation movement, multiplication, and annihilation so that the residual stress can be eliminated.

Evaluation of risk correlation between recurrence of patellar dislocation and damage to the medial patellofemoral ligament in different sites caused by primary patellar dislocation by MRI: a meta-analysis

Purpose Non-surgical treatment of primary patellar dislocation has a high risk of recurrent dislocation; thus, we tried to identify injuries in which sites of the medial patellofemoral ligament (MPFL) were most associated with recurrent dislocation by analyzing relevant original literature in order to provide improved suggestions on early surgical treatment. Methods According to the preset retrieval strategy, the original studies were retrieved until January 2020 using MEDLINE, Embase and Cochrane Library. Review Manager 5.3 software was used to summarize and compare the differences of recurrent dislocation of MPFL injuries at different attachments. Results Although the incidence of recurrent patellar dislocation at the femoral attachment of MPFL was higher overall (femoral only vs. patellar only vs. combined: 37.6% vs. 32.3% vs. 35.8%), no statistical difference was found among the three groups (femoral only vs. patellar only, RR = 1.32 [95% CI 0.89–1.95]; P = 0.17) (femoral only vs. combined, RR = 1.15 [95% CI 0.59–2.22]; P = 0.68) (patellar only vs. combined, RR = 0.94 [95% CI 0.69–1.29]; P = 0.72). In addition, the sulcus angle of recurrent dislocation group is significantly greater than that in the non-recurrent dislocation group (MD = 3.06 [95% CI 0.42–5.70]; P = 0.02). Conclusions Based on the pooled data collected from the original studies available, the risk of recurrent patellar dislocation due to damage to the MPFL at different sites did not differ. Additionally, the sulcus angle in the group with recurrent dislocation was considerably higher when comparing with the group without recurrent dislocation, that is, the shallower and flatter of the trochlear groove, the higher the risk of recurrent patellar dislocation.

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.

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.

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

Introduction High 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. Materials We 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. Results A 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. Conclusion The 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.

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

<p class="abstract"><strong>Background:</strong> 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.</p><p class="abstract"><strong>Methods:</strong> 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.<strong></strong></p><p class="abstract"><strong>Results:</strong> Our study yielded excellent results in 92% of patients (mayo elbow performance score &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.</p><p class="abstract"><strong>Conclusions:</strong> Surgical fixation of medial epicondyle fractures yields excellent results and may be advisable when indicated.</p>

The Treatment of Distal Radius Fractures with Ipsilateral Elbow Injury

Background: The purpose of this study was to assess the functional outcomes of simultaneous distal radius fractures (DRFs) and ipsilateral elbow injuries (IEI) and to evaluate whether the DRFs and IEI affect each other’s outcomes. Methods: From February 2008 to March 2015, 29 of 846 patients treated for DRFs were found to be associated with IEI and 26 patients with follow-up over 12 months were enrolled. There were 12 men and 14 women with a mean age of 55 years (range, 17–86 years). Associated IEI was divided into fracture group (10 patients) and dislocation group (16 patients). Clinical outcomes of DRFs and IEI were evaluated using the Gartland and Werley score and Mayo Elbow Performance Score, respectively. A correlation between the wrist scoring and the elbow scoring was analyzed. In addition, the wrist scoring between fracture group and dislocation group of the elbow was compared. Results: The DRFs was rated as excellent in 14 patients, good in seven patients, and fair in five patients. The IEI was rated as excellent in 12 patients, good in 11 patients, fair in two patients, and poor in one patient. Acceptable outcome rate of both DRFs and concomitant IEI was 73%, although that of DRFs and IEI was 81% and 88%, respectively. A correlation between the wrist outcome and the elbow outcome showed a negative linear relationship (Spearman rho = −0.435, p = 0.026). In addition, there was no difference in the outcome of DRFs between ipsilateral elbow fractures group and dislocation group. Conclusions: As a correlation of DRFs and ipsilateral IEI have a linear relationship, the functional outcomes of both injuries are related to each other. Therefore, we recommend that combined injuries should be managed appropriately at the same time for contended recovery of the wrist and elbow.

Predictors and outcomes of treatment in hip hemiarthroplasty dislocation

Introduction Dislocation following hip hemiarthroplasty (HHA), its incidence, predictors, treatment outcomes and mortality were investigated in a single centre series. Methods The prospectively collected data on neck of femur fracture admissions compiled over 11 years were reviewed. Place of residence, place of fall, past medical history, intraoperative factors (grade of surgeon, delay in surgery, type of implant and operative time), postoperative complications and mortality were compared between patients who suffered a dislocation and those who did not. In the dislocation group, the mean number of dislocations, reduction method, type and fate of implant, and mortality were investigated. Results Prospective data on 8,631 admissions were collected; 41% of these were managed with a HHA. The dislocation rate was 0.76%. A delay in surgery of >24 hours was associated with a fourfold increase in the dislocation risk. The majority (81%) of dislocations occurred in the first six weeks and closed manipulation was the definitive treatment in only 23% of the cases. The mortality rate was not increased following HHA dislocation. Conclusions The delay in surgery was the most important predictor of HHA dislocation. Closed reduction was associated with a high failure rate. While an initial attempt at closed reduction for a first dislocation is recommended, for redislocators, we recommend early exploration/revision as an alternative to repeat manipulations.

Evaluating methods of mouse euthanasia on the oocyte quality: cervical dislocation versus isoflurane inhalation

Cervical dislocation is a commonly used method of mouse euthanasia. Euthanasia by isoflurane inhalation is an alternative method which allows the sacrifice of several mice at the same time with an anaesthesia, in the aim to decrease pain and animal distress. The objective of our study was to assess the impact of these two methods of euthanasia on the quality of mouse oocytes. By administering gonadotropins, we induced a superovulation in CD1 female mice. Mice were randomly assigned to euthanasia with cervical dislocation and isoflurane inhalation. Oviducts were collected and excised to retrieve metaphase II oocytes. After microscopic examination, oocytes were classified into three groups: intact, fragmented/cleaved and atretic. Intact metaphase II oocytes were employed for biomedical research. A total of 1442 oocytes in the cervical dislocation group were compared with 1230 oocytes in the isoflurane group. In the cervical dislocation group, 93.1% of the oocytes were intact, versus 65.8% in the isoflurane group ( P ≤ 0.001). In light of these results, we conclude that cervical dislocation is the best method of mouse euthanasia for obtaining intact oocytes for biomedical research.