bluuebunny/crossref_metadata_2025 huggingface dataset:
Drop-Jump Landing Varies With Baseline Neurocognition
Authors: Herman Daniel C. , Barth Jeffrey T.
Published: July 2016

Background:

Neurocognitive status may be a risk factor for anterior cruciate ligament (ACL) injury. Neurocognitive domains such as visual attention, processing speed/reaction time, and dual-tasking may influence ACL injury risk via alterations to neuromuscular performance during athletic tasks. However, the relationship between neurocognition and performance during athletic tasks is not yet established.

Hypothesis:

Athletes with low baseline neurocognitive scores will demonstrate poorer jump landing performance compared with athletes with high baseline neurocognitive score.

Study Design:

Controlled laboratory study.

Methods:

Neurocognitive performance was measured using the Concussion Resolution Index (CRI). Three-dimensional kinematic and kinetic data of the dominant limb were collected for 37 recreational athletes while performing an unanticipated jump-landing task. Healthy, nonconcussed subjects were screened using a computer-based neurocognitive test into a high performers (HP; n = 20; average CRI percentile, 78th) and a low performers (LP; n = 17; average CRI percentile, 41st) group. The task consisted of a forward jump onto a force plate with an immediate rebound to a second target that was assigned 250 milliseconds before landing on the force plate. Kinematic and kinetic data were obtained during the first jump landing.

Results:

The LP group demonstrated significantly altered neuromuscular performance during the landing phase while completing the jump-landing task, including significantly increased peak vertical ground-reaction force (mean ± SD of LP vs HP: 1.81 ± 0.53 vs 1.38 ± 0.37 body weight [BW]; P < .01), peak anterior tibial shear force (0.91 ± 0.17 vs 0.72 ± 0.22 BW; P < .01), knee abduction moment (0.47 ± 0.56 vs 0.03 ± 0.64 BW × body height; P = .03), and knee abduction angle (6.1° ± 4.7° vs 1.3° ± 5.6°; P = .03), as well as decreased trunk flexion angle (9.6° ± 9.6° vs 16.4° ± 11.2°; P < .01).

Conclusion:

Healthy athletes with lower baseline neurocognitive performance generate knee kinematic and kinetic patterns that are linked to ACL injury.

Clinical Relevance:

Neurocognitive testing using the CRI may be useful for identification of athletes at elevated risk for future ACL injury.
Performance of AlTiN- and diamond-coated carbide tools in dry high-speed milling of electro discharge machining graphite
Authors: Xu Yinchao , Chen Kanghua , Wang Shequan , Chen Songyi , Zhu Changjun , Yu Xinwei
Published: July 2016

Electrodes made of graphite material are widely used for electro discharge machining. The performance of physical vapor deposition AlTiN and chemical vapor deposition diamond-coated carbide end-milling tools in dry high-speed milling of electro discharge machining graphite was investigated, also adopting an uncoated one as a comparison. The quality of as-deposited diamond film was evaluated by Raman spectroscopy. The adhesion between the coating and the substrate was assessed by indentation test. The tool life and wear mechanism of the milling tools, the cutting forces during tests, as well as the roughness of processed surfaces were systematically studied. It is found that the diamond coating has lower adhesion than the AlTiN coating under the same load. Coating delamination and chipping, irregularly zigzag side flank wear, concave structure on the cutting edge are primary wear patterns for the diamond-coated tool. While different primary wear patterns, including uniform polishing abrasive flank wear and crater rake wear, are observed on the AlTiN-coated tool. Besides, the total cutting force of the diamond-coated tool is larger than that of the AlTiN-coated tool when the diamond-coated tool side flank wear value reaches 0.06 mm, attributed to the different wear patterns. Another notable result is clarified that the chipping of the diamond coating can cause significant increment in the feed force, radial force and worked surface roughness.
Stability properties of a pneumatic-actuated rehabilitation system
Authors: Fathi Morteza , Najafi Farid
Published: July 2016

Affected by discontinuous nature of the discrete controller and patients’ different characteristics, the stability analysis in servo pneumatic rehabilitation systems remains a challenge. Hence, the authors propose an approach to obtain stability boundaries of the admittance controller parameters so that a compliant interaction can be ensured. As the zero-order hold function adds nonlinear exponential terms to the continuous transfer function of the system, a discrete closed-loop root-locus analysis is presented describing how the changes in patients’ characteristics and system parameters shift the stability boundaries. The reasonable matches between the analytical and experimental stability boundaries demonstrate that the presented approach is reliable.
Regulation of oncogenes and gap junction intercellular communication during the proliferative response of zearalenone in TM3 cells
Authors: Zheng W , Huang Q , Pan S , Fan W , Wang G , Yuan Y , Gu J , Liu X , Liu Z , Bian J
Published: July 2016

Zearalenone (ZEA) is a nonsteroidal estrogenic mycotoxin produced by Fusarium species. The exposure risk to humans and animals is the consumption of contaminated food and animal feeds. The aim of this study was to investigate ZEA-induced effects and its tumorigenic mechanism in TM3 cells (mouse Leydig cells). Cell proliferation, apoptosis, and gap junction intercellular communication (GJIC) were assessed in this study. Results showed that low concentrations of ZEA could significantly promote the growth of TM3 cells. The percentage of cell distribution was decreased significantly in G1/G0 phase and was increased significantly in S phase with 10 and 20 μg/L of ZEA for 72 h ( p < 0.05, p < 0.01). The expressions of cyclin D1 and Cdk4 were significantly increased in the exposure groups compared with the control group ( p < 0.05, p < 0.01). Compared with the control group, the apoptosis was significantly decreased in 10 and 20 μg/L groups ( p < 0.01), and the ratio of Bax/Bcl-2 protein level was significantly decreased in a dose-dependent manner. The protein levels of proto-oncogene c-Myc, c-Jun, and c-Fos were significantly elevated and the protein levels of anti-oncogene p53 and phosphatase and tensin homolog (PTEN) were decreased obviously compared with the control group ( p < 0.05, p < 0.01). ZEA affected the expressions of connexins and inhibited the activity of GJIC. These results demonstrated that ZEA can disturb the dynamic balance between proliferation and apoptosis and causes abnormal regulation of oncogenes, GJIC, and connexins in TM3 cells, which may easily induce the translation of normal cells into tumor cells.
A Multi-criteria Decision-making Approach for Prioritizing Reverse Logistics Adoption Barriers under Fuzzy Environment: Case of Indian Electronics Industry
Authors: Prakash Chandra , Barua Mukesh Kumar
Published: July 2016

Reverse logistics (RL) practices are gaining attention due to environmental and waste disposal issues, enforced law, rapidly changing technologies and corporate social concern. Reverse logistics has been seen as a part of sustainable development due to reduction in pollution by using a product again after the end of its life. The goal of this article is to evaluate and rank the barriers of RL implementation so that companies can design strategies to tackle them on a priority basis. This article proposes multi-criteria decision-making (MCDM) model based on fuzzy analytic hierarchy process (FAHP) to prioritize the barriers of RL adoption. The proposed approach is revealed by empirical case of Indian electronics industry. This proposed method considered fuzzy framework that can handle impreciseness and uncertainty easily. Totally, 38 barriers were identified through literature review and experts’ opinions. These barriers were classified into seven major criteria. The result of the study indicates that customer acuity about RL, lack of coordination/collaboration with third-party logistics (3PL) providers and uncertain quality and timing of return are the three most important barriers of RL adoption. Organizations should overcome these barriers on a priority basis for effective RL adoption. Finally, the robustness of the model is checked by sensitivity analysis.
Self-Directed Learning to Improve Science Content Knowledge for Teachers
Authors: van Garderen Delinda , Hanuscin Deborah , Thomas Cathy Newman , Stormont Melissa , Lee Eun J.
Published: July 2016

Students with disabilities often struggle in science and underperform in this important content area when compared to their typical peers. Unfortunately, many special educators have had little preparation to develop science content knowledge or skills in methods for teaching science. Despite their lack of content knowledge, special educators are often solely responsible for teaching science to students with disabilities in resource settings and self-contained classrooms; while in inclusive settings, special educators may be called on to coteach or consult. Given their increased role in teaching this content, special educators may experience anxiety about their own science knowledge. This column provides special educators, via self-directed learning, with information and resources to enhance their science content knowledge and build awareness of students’ ideas in science so they can provide high-quality instruction in science for students with disabilities.
Effects of Endurance-Focused Physical Activity Interventions on Brain Health
Authors: Halloway Shannon , Wilbur JoEllen , Schoeny Michael E. , Arfanakis Konstantinos
Published: July 2016

Physical activity intervention studies that focus on improving cognitive function in older adults have increasingly used magnetic resonance imaging (MRI) measures in addition to neurocognitive measures to assess effects on the brain. The purpose of this systematic review was to identify the effects of endurance-focused physical activity randomized controlled trial (RCT) interventions on the brain as measured by MRI in community-dwelling middle-aged or older adults without cognitive impairment. Five electronic databases were searched. The final sample included six studies. None of the studies reported racial or ethnic characteristics of the participants. All studies included neurocognitive measures in addition to MRI. Five of the six interventions included laboratory-based treadmill or supervised bike exercise sessions, while one included community-based physical activity. Physical activity measures were limited to assessment of cardiorespiratory fitness and, in one study, pedometer. Due to the lack of adequate data reported, effect sizes were calculated for only one study for MRI measures and two studies for neurocognitive measures. Effect sizes ranged from d = .2 to .3 for MRI measures and .2 to .32 for neurocognitive measures. Findings of the individual studies suggest that MRI measures may be more sensitive to the effects of physical activity than neurocognitive measures. Future studies are needed that include diverse, community-based participants, direct measures of physical activity, and complete reporting of MRI and neurocognitive findings.
Hope and doubt in the promise of neuroimaging: The case of autism spectrum disorder
Authors: Bertorelli Thomas Eugene
Published: July 2016

Although neuroimaging is currently not a component of the diagnostic process for autism spectrum disorders, some scientists hail these technologies for their promise to one day replace behaviorally based psychiatric diagnostic techniques. This article examines how psychiatrists understand the potential use of neuroimaging technologies within the context of clinical practice. Drawing on 10 semi-structured interviews with child and adolescent psychiatrists, I describe the hope and doubt that comprise their discourse of ambivalence. This analysis demonstrates that the uses and meanings of neuroimaging technologies are rearticulated in ongoing debates in the field of psychiatry regarding the role of the biopsychiatric model in the diagnosis and treatment of mental illness. This study highlights issues surrounding the perceived biopsychiatric focus of neuroimaging technologies within clinical practice, concerns regarding misdirected research attention, and the ways in which understandings of future utility mediate perceptions of technological utility.
Living with insecurity: Food security, resilience, and the World Food Programme (WFP)
Authors: O’Connor Daniel , Boyle Philip , Ilcan Suzan , Oliver Marcia
Published: July 2016

As the world’s largest humanitarian organization fighting hunger, and primary expositor of food insecurity in sub-Saharan Africa, the World Food Programme’s (WFP) activities offer a unique opportunity to examine the contemporary food-security nexus. In this article, we examine the ‘turn’ toward resilience in the practices and policies of the WFP. Our analysis emphasizes that resilience is one of a family of security strategies through which the WFP seeks to govern food security. As such, it is impossible to claim, as some have, that resilience is displacing security as the dominant logic for governing insecurity. Nevertheless, resilience is a cornerstone of the WFPs’ current activities. Whereas more familiar strategies of security attempt to pre-empt or contain disruptive events – in the context of food crises – resilience is a style of thinking that assumes the inevitability of unpredictable, high-impact events and aims to foster the capability for systems and people to adapt, absorb, and bounce back from their effects. Resilience, while championed as part of an overall solution to a range of ills afflicting human populations today, aims only to equip people and populations with the capacity to live with the instabilities of a neoliberal food system without questioning, destabilizing, or resisting the very sources of socio-economic and political instability.
Internal combustion engine exhaust gas analysis
Authors: Collings Nick , Glover Keith , Campbell Bruce , Fisher Stewart
Published: July 2016

A generalized approach, based on linear algebra, is described for processing exhaust gas analyser data. Systematic methods of deriving useful relationships from arbitrary data are proposed and used to produce several novel and useful results, as well as to show how existing relationships may be derived in forms that involve no approximations. The methods developed lend themselves to automatic real-time assessment of the consistency of gas analyser data, and in the case of inconsistencies, identifying plausible reasons. The approach is also used to develop methods to examine storage and release mechanisms within after-treatment devices, such as oxygen storage/release in three-way catalysts, soot oxidation in particle filters and water condensation/evaporation.
Chariots in Saharan rock art: An aesthetic and cognitive review
Authors: Anderson Helen
Published: July 2016

There are estimated to be around 1200 depictions of painted and engraved chariots in Saharan rock art, a number which has doubled in recent years. However, because of the nature of the environmental conditions in the Sahara, the chariot is regarded as having played a minor technological and cultural role, and archaeologists have been criticised for attributing too much importance to these images. This enquiry focuses on the aesthetic component of these depictions, addressing the variation in chariot representations. In reviewing the significance of these depictions beyond their technological significance, the aim is to consider how they functioned socially, culturally and cognitively within a Saharan context.
Understanding and taxonomy of uncertainty in modeling, simulation, and risk profiling for border control automation
Authors: Yanushkevich Svetlana N , Eastwood Shawn C , Drahansky Martin , Shmerko Vlad P
Published: July 2016

This paper addresses the problem of trust in Modeling and Simulation (M&S) technologies, and uncertainty in applications to homeland security. The key goal of this paper is an extension of the notion of trusted M&S techniques for traveler risk assessment in mass-transit applications such as e-borders. Theories of uncertainty suggest that different understandings of uncertainty result in different mechanisms of its reduction. We show that a taxonomy of uncertainty that is accepted in philosophical studies, as well as the NATO methodology of uncertainty assessment (known as the Admiralty Code), can be useful in M&S. This paper overviews various approaches to M&S and focuses on a framework that is based on multi-source fusion mechanisms using Dempster–Shafer (DS) theory. The DS metric is useful for the development of simulators, recommender machines, and risk profilers when expert knowledge is given in an imprecise form. The difference between the Bayesian and DS metrics is introduced via a demonstrative experiment from the area of traveler risk assessment using a biometric-enabled watchlist.
Answering Unresolved Questions About the Relationship Between Cognitive Ability and Prejudice
Authors: Brandt Mark J. , Crawford Jarret T.
Published: July 2016

Previous research finds that lower cognitive ability predicts greater prejudice. We test two unresolved questions about this association using a heterogeneous set of target groups and data from a representative sample of the United States ( N = 5,914). First, we test “who are the targets of prejudice?” We replicate prior negative associations between cognitive ability and prejudice for groups who are perceived as liberal, unconventional, and having lower levels of choice over group membership. We find the opposite (i.e., positive associations), however, for groups perceived as conservative, conventional, and having higher levels of choice over group membership. Second, we test “who shows intergroup bias?” and find that people with both relatively higher and lower levels of cognitive ability show approximately equal levels of intergroup bias but toward different sets of groups.
Differential Effects of Estrogen and Progesterone on Genetic and Environmental Risk for Emotional Eating in Women
Authors: Klump Kelly L. , O’Connor Shannon M. , Hildebrandt Britny A. , Keel Pamela K. , Neale Michael , Sisk Cheryl L. , Boker Steven , Alexandra Burt S.
Published: July 2016

Recent data show shifts in genetic and environmental influences on emotional eating across the menstrual cycle, with significant shared environmental influences during pre-ovulation and primarily genetic effects during post-ovulation. Factors driving differential effects are unknown, although increased estradiol during pre-ovulation and increased progesterone during post-ovulation are thought to play a role. We indirectly investigated this possibility by examining whether overall levels of estradiol and progesterone differentially impact genetic and environmental risk for emotional eating in adult female twins ( N = 571) drawn from the Michigan State University Twin Registry. Emotional eating, estradiol levels, and progesterone levels were assessed daily and then averaged to create aggregate measures for analysis. As predicted, shared environmental influences were significantly greater in twins with high estradiol levels, whereas additive genetic effects increased substantially across low versus high progesterone groups. Results highlight significant and differential effects of ovarian hormones on etiologic risk for emotional eating in adulthood.
Postpartum Depressive Symptoms Following Consecutive Pregnancies
Authors: Dunkel Schetter Christine , Saxbe Darby E. , Cheadle Alyssa C. D. , Guardino Christine M.
Published: July 2016

Postpartum depression is a major mental health issue for women and society. We examined stability and change in symptoms of depression over two consecutive pregnancies and tested life stress as a potential mechanism. The Community Child Health Network followed an ethnically/racially diverse sample from 1 month after a birth for 2 years. A subset of 228 women had a second birth. Interview measures of depressive symptoms (Edinburgh Postnatal Depression Scale) and life stress (life events, perceived stress, chronic stress, interpersonal aggression) were obtained during home visits. Three-quarters of the sample showed intraindividual stability in depressive symptoms from one postpartum period to the next, and 24% of the sample had clinically significant symptoms after at least one pregnancy (9% first, 7.5% second, 3.5% both). Each of the four life stressors significantly mediated the association between depressive symptoms across two postpartum periods. Stress between pregnancies for women may be an important mechanism perpetuating postpartum depression.
Locked lateral patella dislocation: the role for the skyline view in the trauma setting
Authors: Fleming Tom
Published: July 2016

Objective:

Acute traumatic dislocation of the patella is a common problem. These cases often either spontaneously reduce or undergo successful closed reduction in Emergency Departments. We describe a rare case of an irreducible patella dislocation in a 15 year old boy following direct trauma.

Method:

Intra-operative skyline views revealed lateral dislocation of the patella with the patella ‘locked’ in internal rotation.

Result:

Closed reduction in theatre failed and open reduction was required.

Conclusion:

This case illustrates the benefit of the skyline view in the radiograph series following failed closed reduction, aiding the identification of atypical dislocations and osteochondral fracture fragments.
Osteochondral Fractures of the Lateral Femoral Trochlea in Young Athletes
Authors: Walsh Stewart
Published: July 2016

Method:

Between May 2012 and September 2014 cluster of five patients with large osteochondral fractures of the lateral femoral trochlea were treated at our institution. These all occurred in high level male athletes, one at a decathlete and the other four soccer players. The MRI scan showed a characteristic appearance of a large subchondral fracture involving most of the lateral femoral trochlea. All patients were symptomatic. The patients were treated with open reduction and internal fixation using headless compression screws. The operative technique and short term results will be outlined.

Results:

Fixation appears successful in most cases.

Conclusion:

This appears to be a repetitive trauma related injury that occurs in young high-level athletes.
Experience Rate of Elbow Pain and Morphological Abnormality of Humeral Medial Epicondyle among Youth Baseball Players
Authors: Kotoura Yoshihiro , Morihara Toru , Kida Yoshikazu , Sukenari Tsuyoshi , Furukawa Ryuhei , Kabuto Yukichi , MInami Masataka , Onishi Okihiro , Tsujihara Takashi , Hojo Tatsuya , Fujiwara Hiroyoshi , Kubo Toshikazu
Published: July 2016

Objectives:

The aim of this study was to investigate the experience rate of elbow pain and to clarify the relationship between morphological abnormality of the humeral medial epicondyle and positions among baseball players in elementary school (ES), junior high school (JHS) and high school (HS).

Methods:

In this study, 4353 baseball players who participated in our medical screening (2008-2015) were enrolled. There were 1545 players from ES, 1934 players from JHS, and 874 players from HS. We asked them to answer the questionnaire to investigate the experience of elbow pain, and the position they played. Ultrasonography of the humeral medial epicondyle was examined and irregularity, fragmentation, and malunion of the humeral medial epicondyle. The results were analyzed statistically. P < 0.05 was considered significant for all statistical analyses.

Results:

The experience rates of elbow pain among players in ES, JHS, and HS were 26.0%, 27.0%, and 68.3%. The rates of abnormality of humeral medial epicondyle among players in ES, JHS, and HS were 18.2%, 36.3%, and 39.9% (Table 1). The experience rate of elbow pain among pitchers and catchers was significantly higher than the fielders in ES (Table 2), however, there were no significant differences between positions in JHS and HS (Table 3,4). According to the rate of morphological abnormalities of humeral medial epicondyle, pitchers and catchers were significantly higher than fielders in ES, while only pitchers were significantly higher than the fielders in JHS and HS (Table 2,3,4).

Conclusion:

The experience rate of elbow pain among baseball players rose as the age increased, and the rate in HS was almost 70%. The rates of morphological abnormality of humeral medial epicondyle among pitchers and catchers were high and the tendency was observed from a young age. The primary prevention of elbow injuries in youth baseball players of all ages should be considered.
Body Mass Index, Modulated by Lateral Posterior Tibial Slope, Predicts ACL Injury Risk
Authors: Bojicic Katherine M. , Beaulieu Melanie L. , Krieger Daniel Imaizumi , Ashton-Miller James A. , Wojtys Edward M.
Published: July 2016

Objectives:

Intervention strategies to prevent ACL injury rely on increasing knowledge of risk factors. While several modifiable and non-modifiable risk factors for ACL rupture have been identified, the interaction between them remains unknown. The aim of this study was to quantify the relationship between BMI and several knee geometries as potential risk factors for ACL injury. We hypothesized that an increased BMI in the presence of an increased posterior tibial slope or middle cartilage slope would increase risk of ACL injury. We also hypothesized that an increased BMI in the presence of a decreased posterior meniscal height or meniscal bone angle would result in an increased risk of ACL injury.

Methods:

Sagittal knee MRI files from 76 ACL-injured and 42 non-injured subjects were gathered from the institution’s archive. The PTS, MCS, PMH, and MBA were measured using the circle method and compared with BMI from the subject demographic. Data were analyzed using univariate and multivariate logistical regression. Figure 1 details measurements made for each knee geometry.

Results:

Univariate analysis of PTS showed increases in PTS significantly increase the odds of ACL tear (p = 0.043, OR =1.12). Univariate analysis of MCS showed increases of MCS significantly increase the odds of ACL tear (p = 0.037, OR = 1.12). Multivariate analysis of PTS and BMI centered around the mean (PTS*cBMI) showed increases of PTS in combination with increases in cBMI significantly increases the odds of ACL rupture (p value = .050, OR = 1.03). Table 1 shows predicted increases in ACL injury risk for combinations of increases in PTS and BMI.

Conclusion:

An increase in BMI will increase the risk of ACL tear when an increase in lateral posterior tibial slope is present. An increase in lateral posterior tibial slope or lateral middle cartilage slope increases the risk of an ACL tear.
Successful Return to Sport Following Distal Femoral Varus Osteotomy
Authors: Voleti Pramod Babu , Degen Ryan , Tetreault Danielle , Krych Aaron John , Williams Riley J.
Published: July 2016

Objectives:

Distal femoral varus osteotomy is an effective treatment for unloading valgus knee malalignment; however, there is limited evidence on the ability for patients to return to athletics following this procedure. The purpose of this study is to report the functional outcomes and return to sport for athletic patients that underwent distal femoral varus osteotomy.

Methods:

A consecutive series of athletic patients that had undergone distal femoral varus osteotomy for symptomatic lateral compartment overload and valgus knee malalignment were prospectively reviewed. All patients had a minimum of 2-year follow-up. Radiographs were assessed to determine pre-operative and post-operative alignment. Details regarding sport of interest, ability to return to sport, and timing of return were obtained from the patients. Prospective institutional registries were utilized to collect pre-operative and post-operative Marx Activity Scale and International Knee Documentation Committee Subjective Knee Evaluation Form (IKDC) scores; these values were compared using paired t-tests with p < 0.05 as the threshold for significance.

Results:

A total of 13 patients with a mean age of 24 years (range: 17-35) and a mean follow-up of 43 months (range: 24-74) were included in the study. Six patients underwent medial closing wedge osteotomy, and seven patients underwent lateral opening wedge osteotomy. The mean alignment correction was 8 degrees (range: 5-13). Nine patients underwent one or more concomitant procedures at the time of the osteotomy: 6 lateral femoral condyle osteochondral allografts, 2 partial lateral meniscectomies, 1 lateral meniscus allograft transplantation, and 1 revision anterior cruciate ligament reconstruction. All patients were able to successfully return to their sport of choice (4 soccer, 2 softball, 2 running, 1 football, 1 basketball, 1 ice hockey, 1 volleyball, 1 rowing) at a mean of 11 months (range: 9-13). Furthermore, all 13 patients demonstrated an improvement in both Marx Activity Scale and IKDC scores after surgery. The mean improvement in Marx Activity Scale was 7 (mean pre-op: 4, mean post-op: 11, p < 0.01), and the mean improvement in IKDC score was 36 (mean pre-op: 53, mean post-op: 89, p < 0.01).

Conclusion:

Valgus knee malalignment results in overload of the lateral compartment and can severely limit one’s ability to participate in athletic activities. Correction of valgus knee malalignment through distal femoral varus osteotomy - either medial closing wedge or lateral opening wedge - can reliably result in improvement in function and return to sport, provided that concomitant chondral, meniscal, and ligamentous pathology is addressed. Therefore, distal femoral varus osteotomy should be considered in the athletic population for correction of symptomatic valgus knee malalignment.
Quantitative MRI Evaluation of Articular Cartilage Using T2 Mapping Following Hip Arthroscopy for Femoroacetabular Impingement
Authors: Mayer Stephanie W. , Wagner Naomi , Fields Kara G. , Wentzel Catherine , Burge Alissa , Potter Hollis G. , Lyman Stephen , Kelly Bryan T.
Published: July 2016

Objectives:

Cam-type femoroacetabular impingement (FAI) causes a shearing and delamination injury to the acetabular articular cartilage due to a mismatch between the size of the femoral head and the acetabulum. This mechanism is thought to lead to early osteoarthritis in this population. Cam decompression has been advocated to eliminate impingement, with the ultimate goal of halting the progression of articular cartilage delamination. Although outcomes following this procedure in the young adult population have been favorable at short and medium term follow up, it is not known whether the articular cartilage itself is protected from further injury by changing the biomechanics of the joint with decompression of the cam morphology. The purpose of this study is to compare the pre- and post-operative integrity of the acetabular articular cartilage using T2 mapping to determine if hip arthroscopy is protective of the articular cartilage at short- to medium term follow up.

Methods:

Males between 18 and 35 years of age who had pre-operative T2 mapping MRIs, underwent hip arthroscopy for cam or mixed-type FAI with an alpha angle greater than 50°, and had at least 2 year follow-up were identified. Post-operative MRIs were performed and T2 relaxation times in the transition zone and weight bearing articular cartilage in the anterosuperior acetabulum at deep and superficial chondral layers were recorded at nine points on three sagittal sequences on pre and post-operative MRIs. A paired t-test was used to compare T2 relaxation values between pre-operative and post-operative scans.

Results:

Eleven hips were evaluated. Mean age was 26.3 years (range 21 - 35). Mean follow up time to post-operative T2 mapping MRI was 2.6 years (range 2.4 - 2.7). The change in T2 relaxation time was not significantly different between pre- and post-operative MRI scans for any of the nine regions in the deep zone of the acetabular cartilage (p=0.065 - 0.969) or the superficial zone of the acetabular cartilage (p= 0.133 - 0.966).

Conclusion:

There was no significant progression of acetabular cartilage degeneration as measured by structural collagen organization and integrity on T2 mapping from pre-operative imaging to the time of two year follow up. Based on this data, it appears that hip arthroscopy for decompression of cam- type FAI slows or halts the process of cartilage degeneration caused by the mechanical wear known to occur in cam-type FAI which is associated with progression to osteoarthritis.
Repair of the Ankle Syndesmosis
Authors: Backus Jonathan D. , Clanton Thomas O. , Whitlow Scott R. , Williams Brady T. , Liechti Daniel , Dornan Grant J. , Saroki Adriana , Turnbull Travis Lee , LaPrade Robert F.
Published: July 2016

Objectives:

Significant debate exists regarding the optimal repair techniques for unstable syndesmosis injuries. Techniques range from one to multiple screw fixation, suture-button fixation devices, or a combination of the two. The purpose of the current investigation was to biomechanically compare three common syndesmotic repair techniques using a simulated weight-bearing protocol with internal and external rotation of the foot.

Methods:

Twenty-four, lower leg specimens with mean age 54.25 years (range, 38 to 68 years) were utilized for testing. Following the creation of a complete syndesmotic injury (AITFL, ITFL, PITFL, interosseous membrane) specimens were repaired using one of three randomly assigned repair techniques: (1) one 3.5 mm syndesmotic screw, (2) one suture-button construct, and (3) two divergent suture-button constructs. For testing, specimens were oriented in neutral plantar/dorsiflexion and neutral internal/external rotation with the respect to the vertical tibia. Repairs were then cycled for 500 cycles between 7.5 Nm of internal/external rotation torque under a constant 750 N axial compressive load. At 0, 10, 100, and 500 cycles, torsional cyclic loading was interrupted to assess torsional stiffness and resistance to rotation within a physiologic range of motion. While axially loaded to 750 N, the foot was externally rotated to 15° and then rotated to 10° of internal rotation. Torsional cyclic loading was then resumed. Torque (Nm) and rotational position (degrees) were recorded continuously throughout testing. Three-dimensional data was also collected throughout testing to characterize the relative spatial relationships of the tibiofibular articulation.

Results:

Biomechanically, there were no significant differences between techniques when repairs were compared to the intact syndesmosis. Three-dimensional analysis revealed significant differences between all repair techniques for sagittal fibular translation with external rotation of the foot. Screw fixation had the smallest magnitude in sagittal translation (-2.5 mm), and a single suture-button construct demonstrated the largest magnitude of sagittal translation (-4.6 mm). Screw fixation also allowed for significantly lower sagittal translation with internal rotation of the foot (0.1 mm) when compared to both one (2.7 mm) and two (2.9 mm) suture-button repair constructs.

Conclusion:

All repairs provided a significant resistance to internal and external rotation, and only demonstrated mild reductions in strength and torsional stiffness throughout torsional cyclic testing.
Clinical Outcomes Following Arthroscopic Micro Fracture of the Hip
Authors: Begly John P. , Ryan Michael K. , Capogna Brian , Youm Thomas
Published: July 2016

Objectives:

Objective and clinical results of microfracture for treatment of chondral defects of the knee is well documented, yet outcomes for microfracture of the hip have not been extensively studied. Recently, several studies demonstrated clinical improvements in patients treated with microfracture of the hip. The purpose of this study is to examine clinical outcomes and survivorship in patients who underwent microfracture during arthroscopic hip surgery.

Methods:

A retrospective analysis of a prospectively collected database was performed. Thirty-eight patients with a mean age of 41 (range, 17-64) who underwent microfracture during arthroscopic hip surgery by a single surgeon (senior author) were identified. Demographic data, diagnosis, and details regarding operative procedures were collected. All patients were indicated for hip arthroscopy based on standard pre-operative examination as well as routine and advanced imaging. Baseline pre-operative modified Harris Hip Scores (mHHS) and Non-Arthritic Hip Scores (NAHS) were compared to mHHS and NAHS at two-year follow-up. Additionally, survivorship data was assessed to determine failure, defined as any subsequent revision arthroscopic surgery and/or hip arthroplasty of the same hip.

Results:

Thirty-four of the 38 (89.5%) patients were available for two-year clinical follow-up. Baseline mean mHHHS and NAHS for all patients improved from 50.6 (+/- 12.7) and 46.9 (+/-12.8) to 84.7 (+/- 12.5) and 85.6 (+/- 11.2) respectively. Both improvements were statistically significant (p < 0.05). Eight patients (23.5%) met failure criteria and underwent additional surgery at an average of 23.9 months. Two patients (5.8%) underwent revision arthroscopic surgery, and six patients (17.7%) underwent hip arthroplasty.

Conclusion:

Significant improvements in clinical outcomes are seen at two-year follow-up after microfracture treatment of chondral lesions of the hip. Despite overall success, failure rates are relatively high. As with microfracture of the knee, results favor short-term clinical improvements, but results may decline at two years. Larger studies are needed to fully assess the efficacy of microfracture in arthroscopic hip surgery.
Survivorship of Primary Hip Arthroscopy in New York State - A Population-Based Study
Authors: Nawabi Danyal H. , Degen Ryan , Pan Ting , Ranawat Anil S. , Kelly Bryan T. , Lyman Stephen
Published: July 2016

Objectives:

Hip arthroscopy utilization has significantly increased over the past decade, with annual rates increasing as much as 300-600% in that time period. While large sample data demonstrates significant improvement in clinical outcomes out to two years post-operatively, with low rates of associated post-operative complications, there is little information on the long-term survival of primary hip arthroscopy procedures. The purpose of this study is to report on the rates of revision hip arthroscopy and conversion to resurfacing or total hip arthroplasty (THA) following hip arthroscopy in the State of New York. We will also report on prognostic variables that may contribute to the need for repeat surgery.

Methods:

The Statewide Planning and Research Cooperative System (SPARCS) database, a census of all hospital admissions and ambulatory surgery in New York State, was used to identify cases of outpatient primary hip arthroscopy. Demographic information was collected for these patients. After case identification, unique identifiers were utilized to identify those patients that underwent revision hip arthroscopy or subsequent ipsilateral hip resurfacing or THA. The risks of each of these outcomes were modeled with use of age, sex, socio-economic status, hospital and surgeon volume as potential risk factors. Patients were also tracked for 30-day and 90-day complications requiring re-admission.

Results:

We identified 8,267 hip arthroscopy cases from 1998-2012 performed by 295 surgeons in 137 different surgical centers. Demographics revealed that 46.1% of patients were male, with 80.2% carrying private insurance. Annual hip arthroscopy rates increased 88-fold over the observation period, with a 750% increase over the last 10 years. Revision surgery (scope or arthroplasty) was required in 1,087 cases (13.1%) at a mean of 622 ± 603 days. More specifically, revision hip arthroscopy was required in 310 cases (3.8%) at a mean of 649 ± 586 days after the index procedure, while conversion to either resurfacing or THA was required in 796 (9.7%) cases at an average of 616 ± 616 days. The 30-day complication rate, excluding revision surgery, was 0.2%, while the 90-day complication rate was 0.3%. Thirty-day all-cause re-admission rate was 0.7%. Regression analysis revealed that age > 50 y.o. was associated with increased risk of re-operation (Hazard Ratio[HR] 2.30; CI 2.02-2.62), while males carried a slightly lower risk of re-operation (HR 0.88, CI 0.78 -1.0). Additionally, increased surgical volume, for both surgeon and center (≥75th percentile of annual cases), resulted in a lower risk of re-operation (HR 0.64; CI 0.53-0.77; HR 0.61; CI 0.51-0.73).

Conclusion:

Hip arthroscopy represents a viable treatment option for femoroacetabular impingement, with low rates of revision surgery and conversion to hip arthroplasty. Age less than 50 and higher surgeon and center surgical volume were associated with lower risk of re-operation.
Cabaud Award Winner
Authors: Hudgens Joshua L , Sugg Kristoffer B , Grekin Jeremy A , Gumucio Jonathan P , Bedi Asheesh , Mendias Christopher L
Published: July 2016

Background:

Tendon disorders are among the most common musculoskeletal conditions in active patients. Platelet rich plasma (PRP) has been used in the treatment of tendon disorders, but little is known as to the mechanisms by which PRP acts. PRP contains numerous different growth factors and cytokines which activate various cellular signaling cascades, but it has been difficult to determine precisely which signaling pathways and cellular responses are activated following PRP treatment. Additionally, macrophages are important in modulating tendon regeneration, but the influence of PRP on determining whether macrophages assume a proinflammatory or antiinflammatory phenotype remains unknown. Our objectives were to use genome wide expression profiling, bioinformatics and protein analysis to determine the cellular pathways activated in fibroblasts treated with PRP, and to also evaluate the effect of PRP on macrophage polarization.

Methods:

Tendon fibroblasts or macrophages from rats were cultured and treated with either platelet poor plasma (PPP) or PRP. RNA or protein was isolated from cells and analyzed using microarrays, qPCR, immunoblot or bioinformatics techniques.

Results:

Bioinformatics analysis determined that the two signaling pathways predicted to be activated by PRP were the TNFα and NFκB pathways. PRP also downregulated several ECM genes, and induced the expression of autophagy related genes and reactive oxygen species (ROS) genes, as well as markers of protein oxidation in tendon fibroblasts. PRP failed to have a major impact on markers of macrophage polarization.

Conclusions:

PRP induces an inflammatory response in tendon fibroblasts which leads to the formation of ROS and activation of oxidative stress pathways. PRP does not appear to significantly modulate macrophage polarization.

Clinical Relevance:

PRP might act by inducing a transient inflammatory event which could then trigger a tissue regeneration response.
A frequent phenotype for paediatric sleep apnoea: short lingual frenulum
Authors: Guilleminault Christian , Huseni Shehlanoor , Lo Lauren
Published: July 2016

A short lingual frenulum has been associated with difficulties in sucking, swallowing and speech. The oral dysfunction induced by a short lingual frenulum can lead to oral-facial dysmorphosis, which decreases the size of upper airway support. Such progressive change increases the risk of upper airway collapsibility during sleep.

Clinical investigation of the oral cavity was conducted as a part of a clinical evaluation of children suspected of having sleep disordered breathing (SDB) based on complaints, symptoms and signs. Systematic polysomnographic evaluation followed the clinical examination. A retrospective analysis of 150 successively seen children suspected of having SDB was performed, in addition to a comparison of the findings between children with and without short lingual frenula.

Among the children, two groups of obstructive sleep apnoea syndrome (OSAS) were found: 1) absence of adenotonsils enlargement and short frenula (n=63); and 2) normal frenula and enlarged adenotonsils (n=87). Children in the first group had significantly more abnormal oral anatomy findings, and a positive family of short frenulum and SDB was documented in at least one direct family member in 60 cases.

A short lingual frenulum left untreated at birth is associated with OSAS at later age, and a systematic screening for the syndrome should be conducted when this anatomical abnormality is recognised.
Bmi1
+ cardiac progenitor cells contribute to myocardial repair following acute injury
Authors: Valiente-Alandi Iñigo , Albo-Castellanos Carmen , Herrero Diego , Sanchez Iria , Bernad Antonio
Published: July 2016

Background

The inability of the adult mammalian heart to replace cells lost after severe cardiac injury compromises organ function. Although the heart is one of the least regenerative organs in the body, evidence accumulated in recent decades indicates a certain degree of renewal after injury. We have evaluated the role of cardiac Bmi1
+
progenitor cells (Bmi1-CPC) following acute myocardial infarction (AMI).

Methods

Bmi1Cre/+;Rosa26YFP/+ (Bmi1-YFP) mice were used for lineage tracing strategy. After tamoxifen (TM) induction, yellow fluorescent protein (YFP) is expressed under the control of Rosa26 regulatory sequences in Bmi1
+
cells. YFP+ cells were tracked following myocardial infarction. Additionally, whole transcriptome analysis of isolated YFP+ cells was performed in unchallenged hearts and after myocardial infarction.

Results

Deep-sequencing analysis of Bmi1-CPC from unchallenged hearts suggests that this population expresses high levels of pluripotency markers. Conversely, transcriptome evaluation of Bmi1-CPC following AMI shows a rich representation of genes related to cell proliferation, movement, and cell cycle. Lineage-tracing studies after cardiac infarction show that the progeny of Bmi1-expressing cells contribute to de novo cardiomyocytes (CM) (13.8 ± 5 % new YFP+ CM compared to 4.7 ± 0.9 % in age-paired non-infarcted hearts). However, apical resection of TM-induced day 1 Bmi1-YFP pups indicated a very minor contribution of Bmi1-derived cells to de novo CM.

Conclusions

Cardiac Bmi1 progenitor cells respond to cardiac injury, contributing to the generation of de novo CM in the adult mouse heart.
Least-squares reverse time migration using controlled-order multiple reflections
Authors: Liu Yike , Liu Xuejian , Osen Are , Shao Yu , Hu Hao , Zheng Yingcai
Published: August 2016

Reverse time migration (RTM) using multiples generates inherent crosstalk artifacts due to the interference among multiples of different orders. We have developed a method to remove such crosstalk. This approach first separates the recorded seismic data into primary reflections and multiples using the surface-related multiples elimination algorithm and then isolates the multiples into different orders. We can take any specified, say the [Formula: see text]th, order of multiples data as the incident wave and the next higher order multiples data, ([Formula: see text])th order, as the corresponding primary reflection data for imaging. We have applied the least-squares migration scheme to these two successive orders of multiples. Our method is denoted as least-squares RTM using controlled-order multiples (LSRTM-CM). Our numerical tests demonstrated that LSRTM-CM can significantly improve imaging quality compared with straightforward seismic imaging using multiples without multiples separation.