Experimental Analysis of Aerodynamic Loads of Three-Bladed Rotor.

The purpose of the current study is the experimental analysis of the dynamics and aerodynamic loads of a three-bladed rotor. The experimental tests focus on the rotation with three different angular velocities; for each angular speed, four different preset angles of beam have been studied. During the laboratory experiment, strain gauges, as well as high-speed cameras, have been used as the measurement system. The images from the high-speed cameras have been used to obtain aerodynamic loads in the form of polynomials, while the signals from strain gauges mounted on each beam allowed us to observe the synchronization phenomenon between beams.

Pectoralis Major Rupture: Evaluation and Management.

Pectoralis major tendon ruptures are being reported with increasing frequency and primarily occur in young, high demand, male patients. The injury results from an eccentric contracture of the muscle most commonly while performing the bench press maneuver during weight training. In the setting of both acute and chronic injury, physical examination is critical for a timely and accurate diagnosis. During physical examination, comparison with the opposite side is imperative, and findings may include swelling, ecchymosis, loss of the anterior axillary fold, and a decreased pectoralis major index. Surgical treatment of acute ruptures is superior to nonsurgical treatment and results in improved functional outcomes and high levels of return to work and sport. Repair of chronic tears is more challenging and may require reconstruction with autograft or allograft tissue. Despite advances in surgical technique, tendon rerupture, persistent pain, and wound infection remain a concern.

Dynamic Behavior of Aviation Polymer Composites at Various Weight Fractions of Physical Modifier.

The aim of this study was to determine the effect of a selected physical modifier with different granularity and mass percentage on the dynamics of aerospace polymer composites. The tests were carried out on samples made of certified aerospace materials used, among other purposes, for the manufacture of aircraft skin components. The hybrid composites were prepared from L285 resin, H286 hardener, GG 280T carbon fabric in twill 2/2 and alumina (Al2O3, designated as EA in this work). The manufactured composites contained alumina with grain sizes of F220, F240, F280, F320 and F360. The mass proportion of the modifier in the tested samples was 5% and 15%. The tested specimens, as cantilever beams fixed unilaterally, were subjected to kinematic excitation with defined parameters of amplitude and frequency excitation in the basic resonance zone of the structure. The results, obtained as dynamic responses, are presented in the form of amplitude-frequency characteristics. These relationships clearly indicate the variable nature of composite materials due to modifier density and grain size. The novelty of this study is the investigation of the influence of the alumina properties on system dynamics responses.

Influence of the Selected Physical Modifier on the Dynamical Behavior of the Polymer Composites Used in the Aviation Industry.

In this research, an analysis of polymer composite with the matrix of L285-cured hardener H286 and six reinforcement layers of carbon fabric GG 280 T was provided. It involved a comparison of the dynamical behavior responses for three cases of composite structures in the context of the presence of the mass share modifier. The samples with the addition of a physical modifier with varying mass percentages were investigated by being subjected to dynamic tests with specific parameters, i.e., constant excitation amplitude and vibration frequency in the vicinity of the base resonance zone. The analysis allowed for indicating the relationship between the composition of the prepared composites and their dynamic response via stiffness characteristics. In addition, the investigation resulted in determining the range of harmful dynamical operating conditions, which may contribute to damage to the composite structures.

Pectoralis Major Ruptures: Tear Patterns and Patient Demographic Characteristics.

BACKGROUND: The pectoralis major (PM) is made up of multilaminar muscle segments that form a complex insertion on the proximal humerus; it is composed of an anterior and a posterior tendon layer. The tear patterns and patient characteristics of operatively treated PM ruptures in the general population remain poorly understood. PURPOSE: To comprehensively report the demographic characteristics of patients who are clinically diagnosed with structurally significant PM ruptures and to describe PM tear patterns identified during surgery. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: A retrospective analysis of surgically treated PM tears was performed for a single-surgeon case series between January 1, 2003, and November 1, 2017. Patient demographic characteristics, classification of tear pattern, and treatment (repair/reconstruction) were recorded. RESULTS: A total of 104 surgical cases of PM tendon rupture were identified; 100 patients underwent primary repair and 4 underwent dermal allograft reconstruction. All patients were male, with a mean age of 36.5 ± 9.2 years. Chronic tears (>6 weeks old) accounted for 63.6% of surgical cases, and 96% (n = 100) of tears occurred at or between the musculotendinous junction and tendinous insertion. A partial-thickness, complete-width tear of the posterior tendon layer at this same location was the most common tear pattern identified. CONCLUSION: PM ruptures occurred almost exclusively at or between the musculotendinous junction and tendinous insertion, with predominant involvement of the posterior tendon layer. Chronic tears can be safely treated with primary repair in the vast majority of cases.

Risk Factors for Failure of Arthroscopic Revision Anterior Shoulder Stabilization.

BACKGROUND: Recurrent anterior instability following a failed Bankart repair in the shoulder represents a challenging clinical scenario. Few studies have examined the role of arthroscopic revision anterior stabilization as a treatment option in these cases. The purpose of this study was to evaluate the outcomes of arthroscopic revision anterior stabilization for patients with recurrent instability after a failed index procedure. METHODS: Ninety-two patients underwent arthroscopic revision anterior stabilization after a failed index (open or arthroscopic) stabilization procedure. Sixty-five patients with a minimum of 2 years of follow-up were included in this study. The mean age at the time of revision surgery was 26 years (range, 15 to 57 years). The rate of recurrent instability and risk factors for failure were evaluated; the mean duration of follow-up was 4.7 years (range, 2 to 10.8 years). Glenoid and humeral bone loss were quantitatively assessed using preoperative T1-weighted magnetic resonance arthrograms to determine if the lesions were on-track or off-track. RESULTS: Twenty-seven (42%) of the patients experienced recurrent instability at a mean of 2.3 years after arthroscopic revision anterior stabilization. On multivariate analysis, the presence of an off-track lesion, an age of <22 years, and ligamentous laxity were independent predictors of recurrence (p = 0.022, 0.028, and 0.031, respectively). Among a cohort with these risk factors excluded, the failure rate was 19%. CONCLUSIONS: Arthroscopic revision anterior stabilization is associated with a high rate of recurrent instability, and patient selection is of critical importance in order to minimize recurrence. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Proximal Long Head Biceps Rupture: A Predictor of Rotator Cuff Pathology.

PURPOSE: To investigate whether acute rupture of the proximal long head biceps is a harbinger of disease of the nearby supraspinatus and subscapularis tendons. METHODS: A retrospective chart review from February 1, 2008, to August 31, 2016, was performed at our institution identifying patients who presented with an acute (<12-week) history of "Popeye" deformity of the distal biceps and a magnetic resonance imaging (MRI) of the affected shoulder. MRI images were then reviewed in duplicate to determine supraspinatus and subscapularis tendon tear incidence, size, chronicity, and depth. The association between rotator cuff status and acute long head biceps rupture as well as patient age, sex, smoking status, hand dominance, and history of diabetes mellitus or trauma was then evaluated. RESULTS: A total of 116 patients were included in this study (mean age: 61.9 ± 10.9 years). A significant proportion (n = 99; incidence: 85%) were found to have some degree of supraspinatus or subscapularis tendon tearing on MRI (P < .001). These patients were also found to be significantly older compared with those with an intact rotator cuff (mean age 63.3 ± 10.7 vs 54.2 ± 9.2; P = .001). Full thickness rotator cuff tears were significantly more likely to involve the supraspinatus as opposed to the subscapularis (incidence: 44% and 21%; P = .002). CONCLUSIONS: Despite the expected association of rotator cuff disease with increasing patient age, the results of this study also affirm the hypothesis that inflammation in the rotator cuff interval signaled by rupture of the long head of biceps is a harbinger of rotator cuff disease. Clinicians should have a high index of suspicion regarding concomitant anterosuperior rotator cuff pathology in patients presenting with acute long head of biceps rupture. Early evaluation with advanced imaging should be strongly considered. LEVEL OF EVIDENCE: Level IV, case series.

A Layered Anatomic Description of the Anterolateral Complex of the Knee.

Variability in anatomic terminology, dissection protocols, and use of embalmed as opposed to fresh frozen specimens has led to the controversy surrounding the "anterolateral ligament of the knee." Conceptually the complex anatomy of the anterolateral knee is made up of the superficial, middle, deep, and capsulo-osseous layers of the iliotibial band. The anterolateral capsule is deep to these tissues and is directly attached to the lateral meniscus. These structures collectively form the anterolateral complex of the knee. The anterolateral complex in conjunction with the anterior cruciate ligament function to prevent anterolateral rotatory instability of the knee.

Lateral femoral notch depth is not associated with increased rotatory instability in ACL-injured knees: a quantitative pivot shift analysis.

PURPOSE: A deep lateral femoral notch (LFN) on lateral radiographs is indicative of ACL injury. Prior studies have suggested that a deep LFN may also be a sign of persistent rotatory instability and a concomitant lateral meniscus tear. Therefore, the purpose of this study was to evaluate the relationship between LFN depth and both quantitative measures of rotatory knee instability and the incidence of lateral meniscus tears. It was hypothesized that greater LFN depth would be correlated with increased rotatory instability, quantified by lateral compartment translation and tibial acceleration during a quantitative pivot shift test, and incidence of lateral meniscus tears. METHODS: ACL-injured patients enrolled in a prospective ACL registry from 2014 to 2016 were analyzed. To limit confounders, patients were only included if they had primary ACL tears, no concurrent ligamentous or bony injuries requiring operative treatment, and no previous knee injuries or surgeries to either knee. Eighty-four patients were included in the final analysis. A standardized quantitative pivot shift test was performed pre-operatively under anesthesia in both knees, and rotatory instability, specifically lateral compartment translation and tibial acceleration, was quantified using tablet image analysis software and accelerometer sensors. Standard lateral radiographs and sagittal magnetic resonance images (MRI) of the injured knee were evaluated for LFN depth. RESULTS: There were no significant correlations between LFN depth on either imaging modality and ipsilateral lateral compartment translation or tibial acceleration during a quantitative pivot shift test or side-to-side differences in these measurements. Patients with lateral meniscus tears were found to have significantly greater LFN depths than those without on conventional radiograph and MRI (1.0 vs. 0.6 mm, p < 0.05; 1.2 vs. 0.8 mm, p < 0.05, respectively). CONCLUSION: There was no correlation between lateral femoral notch depth on conventional radiographs or MRI and quantitative measures of rotatory instability. Concomitant lateral meniscus injury was associated with significantly greater LFN depth. Based on these findings, LFN depth should not be used as an indicator of excessive rotatory instability, but may be an indicator of lateral meniscus injury in ACL-injured patients. LEVEL OF EVIDENCE: Prognostic level IV.

Does Femoroacetabular Impingement Contribute to the Development of Hip Osteoarthritis? A Systematic Review.

Femoroacetabular impingement (FAI) has been linked to specific patterns of cartilage damage. The goal of this systematic review is to answer the following questions: (1) Does FAI contribute to the development and progression of hip osteoarthritis (OA)? (2) If FAI does contribute to the development and progression of hip OA, does CAM-type or pincer-type impingement play a greater role? A search of the electronic databases, MEDLINE and EMBASE, was performed to identify relevant studies performed between January 1, 2000 and January 1, 2015 that link the pathophysiology of OA to FAI. Methodological quality of included studies was assessed by 2 reviewers using the Methodological Index for Non-Randomized Studies criteria. An intraclass correlation coefficient with 95% confidence intervals was used to determine agreement between reviewers on quality scores. Overall 35 studies were identified that met inclusion criteria. Certain morphologic features of CAM-type FAI, particularly elevated alpha angle, do seem to predispose select patients to radiographic progression of hip OA. In comparison with pincer-type impingement, the association between CAM-type impingement and hip OA is better understood. Long-term surgical outcome studies will further delineate the role of FAI in the development and progression of hip OA.

Posterior tibial translation resulting from the posterior drawer manoeuver in cadaveric knee specimens: a systematic review.

PURPOSE: The purpose of this systematic review of cadaver-based biomechanical studies is to accurately quantify how much posterior tibial translation occurs during posterior drawer testing in normal and PCL-deficient knees. METHODS: A search of the electronic databases, MEDLINE and EMBASE, was performed to identify relevant cadaveric studies that reported posterior tibial translation during posterior drawer testing. Studies were combined to determine overall increase in posterior tibial translation after PCL sectioning at 90° of flexion. Methodological quality of included studies was assessed by two reviewers using a novel clinometric tool. An intraclass correlation coefficient with 95 % confidence intervals (CIs) was used to determine agreement between reviewers on quality scores. RESULTS: Combined analysis of 244 cadaveric specimens from 23 studies in which the PCL was sectioned yielded a mean net increase in tibial translation of 10.7 mm (95 % CI 9.68-11.8) with posterior drawer testing. Posterior tibial translation among cadaveric specimens with no disruption to any ligamentous structures was found to be 5.4 mm (95 % CI 4.3-6.6). CONCLUSIONS: Cadaveric data support previous study findings of >8 mm of posterior tibial translation on stress radiographs being indicative of isolated PCL insufficiency. Use of fixed reference points and strict control of tibial rotation are imperative to ensure accurate results in cadaveric studies and in the clinical setting when performing the posterior drawer examination. LEVEL OF EVIDENCE: III.

Diagnostic accuracy of physical examination for anterior knee instability: a systematic review.

PURPOSE: Determining diagnostic accuracy of Lachman, pivot shift and anterior drawer tests versus gold standard diagnosis (magnetic resonance imaging or arthroscopy) for anterior cruciate ligament (ACL) insufficiency cases. Secondarily, evaluating effects of: chronicity, partial rupture, awake versus anaesthetized evaluation. METHODS: Searching MEDLINE, EMBASE and PubMed identified studies on diagnostic accuracy for ACL insufficiency. Studies identification and data extraction were performed in duplicate. Quality assessment used QUADAS tool, and statistical analyses were completed for pooled sensitivity and specificity. RESULTS: Eight studies were included. Given insufficient data, pooled analysis was only possible for sensitivity on Lachman and pivot shift test. During awake evaluation, sensitivity for the Lachman test was 89 % (95 % CI 0.76, 0.98) for all rupture types, 96 % (95 % CI 0.90, 1.00) for complete ruptures and 68 % (95 % CI 0.25, 0.98) for partial ruptures. For pivot shift in awake evaluation, results were 79 % (95 % CI 0.63, 0.91) for all rupture types, 86 % (95 % CI 0.68, 0.99) for complete ruptures and 67 % (95 % CI 0.47, 0.83) for partial ruptures. CONCLUSION: Decreased sensitivity of Lachman and pivot shift tests for partial rupture cases and for awake patients raised suspicions regarding the accuracy of these tests for diagnosis of ACL insufficiency. This may lead to further research aiming to improve the understanding of the true accuracy of these physical diagnostic tests and increase the reliability of clinical investigation for this pathology. LEVEL OF EVIDENCE: IV.

Methodological quality of systematic reviews addressing femoroacetabular impingement.

PURPOSE: As the body of literature on femoroacetabular impingement (FAI) continues to grow, clinicians turn to systematic reviews to remain current with the best available evidence. The quality of systematic reviews in the FAI literature is currently unknown. The goal of this study was to assess the quality of the reporting of systematic reviews addressing FAI over the last 11 years (2003-2014) and to identify the specific methodological shortcomings and strengths. METHODS: A search of the electronic databases, MEDLINE, EMBASE and PubMed, was performed to identify relevant systematic reviews. Methodological quality was assessed by two reviewers using the revised assessment of multiple systematic reviews (R-AMSTAR) scoring tool. An intraclass correlation coefficient (ICC) with 95 % confidence intervals (CI) was used to determine agreement between reviewers on R-AMSTAR quality scores. RESULTS: A total of 22 systematic reviews were assessed for methodological quality. The mean consensus R-AMSTAR score across all studies was 26.7 out of 40.0, indicating fair methodological quality. An ICC of 0.931, 95 % CI 0.843-0.971 indicated excellent agreement between reviewers during the scoring process. CONCLUSIONS: The systematic reviews addressing FAI are generally of fair methodological quality. Use of tools such as the R-AMSTAR score or PRISMA guidelines while designing future systematic reviews can assist in eliminating methodological shortcomings identified in this review. These shortcomings need to be kept in mind by clinicians when applying the current literature to their patient populations and making treatment decisions. Systematic reviews of highest methodological quality should be used by clinicians when possible to answer clinical questions.

Trends in reporting of mechanisms and incidence of hip injuries in males playing minor ice hockey in Canada: a cross-sectional study.

BACKGROUND: There has been a noted increase in the diagnosis and reporting of sporting hip injuries and conditions in the medical literature but reporting at the minor hockey level is unknown. The purpose of this study is to investigate the trend of reporting hip injuries in amateur ice hockey players in Canada with a focus on injury type and mechanism. METHODS: A retrospective review of the Hockey Canada insurance database was performed and data on ice hockey hip injuries reported between January 2005 and June 2011 were collected. The study population included all male hockey players from Peewee (aged 11-12 years) to Senior (aged 20+ years) participating in amateur level competition sanctioned by Hockey Canada. Reported cases of ice hockey hip injuries were analyzed according to age, mechanism of injury, and injury subtype. Annual injury reporting rates were determined and using a linear regression analysis trended to determine the change in ice hockey hip injury reporting rate over time. RESULTS: One hundred and six cases of ice hockey-related hip injuries were reported in total. The majority of injuries (75.5%) occurred in players aged 15-20 years playing at the Junior level. Most injuries were caused by a noncontact mechanism (40.6%) and strains were the most common subtype (50.0%). From 2005 to 2010, the number of reported hip injuries increased by 5.31 cases per year and the rate of reported hip injury per 1,000 registered players increased by 0.02 cases annually. CONCLUSION: Reporting of hip injuries in amateur ice hockey players is increasing. A more accurate injury reporting system is critical for future epidemiologic studies to accurately document the rate and mechanism of hip injury in amateur ice hockey players.

Complications following hip arthroscopy: a retrospective review of the McMaster experience (2009-2012).

BACKGROUND: The use of hip arthroscopy has been steadily rising as technology, experience and surgical education continue to advance. Previous reports of the complication rate associated with hip arthroscopy have varied. The purpose of this study was to report our experience with hip arthroscopy complications at a single Canadian institution (McMaster University). METHODS: We performed a retrospective chart review of 2 hip arthroscopists at the same institution to identify patients who had undergone the index surgery and had been followed for a minimum of 6 months postoperatively. We used a standard data entry form to collect information on patient demographic and clinical characteristics, including age, sex, surgical indication and type of complication if any. RESULTS: A total of 211 patients underwent 236 hip arthroscopies. The mean age at time of surgery was 37 ± 13 years and mean follow-up was 394 ± 216.5 days. The overall complication rate associated with hip arthroscopy was 4.2% (95% confidence interval 2.3%-7.6%). We identified 4 major and 6 minor complications. CONCLUSION: Overall, hip arthroscopy appears to be safe, with minor complications occurring more frequently than major ones. However, surgeons should recognize the possibility of serious complications associated with this procedure. Future research should focus on prospective designs looking for potential prognostic factors associated with hip arthroscopy complications.

CONTEXTE: Le recours à l'arthroscopie de la hanche augmente de manière constante, au rythme des progrès réalisés aux plans de la technologie, de l'expérience et de l'enseignement de la chirurgie. Les rapports précédents sur les taux de complications associés à l'arthroscopie de la hanche ont varié. Le but de cette étude était de faire état de notre expérience en ce qui concerne les complications de l'arthroscopie de la hanche dans un établissement canadien (Université McMaster). MÉTHODES: Nous avons procédé à une analyse rétrospective des dossiers de 2 spécialistes de l'arthroscopie de la hanche d'un même établissement pour recenser les patients qui ont subi une première chirurgie et qui ont été suivis pendant au moins 6 mois après leur intervention. Nous avons utilisé un formulaire standard d'entrée de données pour recueillir des renseignements sur les caractéristiques démographiques et cliniques des patients, notamment l'âge, le sexe, l'indication de la chirurgie et le type de complication, le cas échéant. RÉSULTATS: En tout, 211 patients ont subi 236 arthroscopies de la hanche. L'âge moyen au moment de la chirurgie était de 37 ± 13 ans et le suivi moyen a été de 394 ± 216,5 jours. Le taux global de complications associées à l'arthroscopie de la hanche a été de 4,2 % (intervalle de confiance de 95 %, 2,3 %­7,6 %). Nous avons recensé 4 complications majeures et 6 mineures. CONCLUSION: Dans l'ensemble, l'arthroscopie de la hanche semble sécuritaire, les complications mineures étant survenues plus souvent que les complications majeures. Toutefois, les chirurgiens doivent reconnaître le risque de complications graves associées à cette intervention. La recherche à venir devra s'attarder à des modèles prospectifs pour déceler les facteurs pronostiques potentiellement associés aux complications de l'arthroscopie de la hanche.