bluuebunny/crossref_metadata_2025 huggingface dataset:
Management of Viral Central Nervous System Infections: A Primer for Clinicians
Authors: Bookstaver P Brandon , Mohorn Phillip L , Shah Ansal , Tesh Lauren D , Quidley April M , Kothari Ravish , Bland Christopher M , Weissman Sharon
Published: May 2017

Viruses are a common cause of central nervous system (CNS) infections with many host, agent, and environmental factors influencing the expression of viral diseases. Viruses can be responsible for CNS disease through a variety of mechanisms including direct infection and replication within the CNS resulting in encephalitis, infection limited to the meninges, or immune-related processes such as acute disseminated encephalomyelitis. Common pathogens including herpes simplex virus, varicella zoster, and enterovirus are responsible for the greatest number of cases in immunocompetent hosts. Other herpes viruses (eg, cytomegalovirus, John Cunningham virus) are more common in immunocompromised hosts. Arboviruses such as Japanese encephalitis virus and Zika virus are important pathogens globally, but the prevalence varies significantly by geographic region and often season. Early diagnosis from radiographic evidence and molecular (eg, rapid) diagnostics is important for targeted therapy. Antivirals may be used effectively against some pathogens, although several viruses have no effective treatment. This article provides a review of epidemiology, diagnostics, and management of common viral pathogens in CNS disease.
Leading education beyond what works
Authors: Møller Jorunn
Published: May 2017

Currently, the issue of inequality is one of the most pressing concerns in education and educational research. Factors such as increased socio-economic inequality, movement of people across national boundaries and refugees create major challenges for local communities and schools. Therefore, it is crucial to ensure that teaching and leadership are informed by the best available knowledge to meet these challenges. This article, which is based on research on successful school leadership and school reforms, aims to explore what type of knowledge is used and, given priority, when politicians and administrators make decisions about improving education. The article also discusses what we need to know to address equity-relevant progress and improvement.

In the analysis, the role the OECD has in setting the agenda in educational research is problematized and methodological shortcomings within research traditions focusing on successful school leadership are discussed. A main argument is that our thinking about educational leadership must be complemented and informed by research which focuses on recent changes in the political economy that have challenged public education severely. To lead education beyond the agenda of what works, we need different approaches to research, including critical studies addressing the power structures.
Education for Europe? Professionalization between effectiveness and autonomy
Authors: Hummrich Merle
Published: May 2017

This paper assumes that there has been a discourse shift in the understanding of internationalization from an idealistic view on overcoming national narrow-mindedness to an economic view of effectiveness and self-improvement, which also affects the discourse on Europeanization and building Europe by education. Against this background, the question of which consequences this discourse shift has for education and professionalization, is asked. In the end, two contradictions are pointed out as boundaries of professionalizing European education: the first lies in the opposed understanding of Europe and education for Europe; and the second in the replacement of politics by education (understood not only as bottom up control of political aims by education but also as a specific idea of humanity).
Simultaneous Antegrade-Retrograde Subintimal Revascularization of a Femoropopliteal Chronic Total Occlusion by a Reentry Device–Facilitated Puncture of a Retrogradely Inserted Balloon
Authors: Goltz Jan Peter , Anton Susanne , Wiedner Marcus , Barkhausen Jörg , Stahlberg Erik
Published: May 2017

Purpose: To report a rendezvous technique for subintimal revascularization of a chronic total occlusion (CTO) of the superficial femoral artery (SFA). Technique: This maneuver is appropriate after failure to cross a long SFA CTO via intra- and subintimal approaches from the ipsilateral femoral as well as retrograde posterior tibial artery (PTA) access sites. After predilation of the subintimal space from the femoral access, a reentry device was placed at the level of the first popliteal artery segment. A balloon was delivered via the retrograde PTA access and inflated at the corresponding level of the reentry device. The balloon was punctured with the needle of the reentry device under fluoroscopic control, and a 0.014-inch guidewire was placed within the punctured balloon. The balloon and the antegrade guidewire were retracted from the retrograde access while the guidewire was gently pushed from the femoral site. Conventional balloon angioplasty of the SFA occlusion was performed via the femoral access, followed by overlapping stent-graft implantation. Complete revascularization of the CTO was documented. Conclusion: In selected cases a transfemoral reentry device–assisted puncture of a retrogradely inserted balloon within the subintimal space may facilitate a rendezvous and revascularization if standard techniques to cross long CTOs have failed.
Free-Riders or Competitive Races? Strategic Interaction across the American States on Tobacco Policy Making
Authors: Pacheco Julianna
Published: May 2017

This article contributes to our understanding of policy diffusion in two ways. First, by explicitly focusing on the competition mechanism of diffusion, I consider how policy externalities contribute to free-rider dynamics or competitive races across the American states. The second contribution is the focus on the interdependence of the early stages of agenda setting as well as policy enactments. Using a unique dataset on four different types of tobacco policies that are introduced and eventually enacted in the states from 1990 to 2010, I find evidence that states engage in free-riding dynamics and that strategic interaction exists in the early stages of agenda setting. There is also evidence that states respond to legitimate policy threats in neighboring states. Overall, the results stress the importance of scholars to explore the conditional nature of policy diffusion dynamics by focusing on variations in policy content and stages of the policymaking process other than policy enactment.
Celebrity Endorsements and Voter Emotions: Evidence From Two Experiments
Authors: Nownes Anthony J.
Published: May 2017

Here, I report the results of two randomized, posttest only, control group, survey experiments in which respondents were exposed to factual information about celebrity support for Hillary Clinton during the 2016 presidential election campaign. Based on previous research, I hypothesize that celebrity endorsements will affect the emotions of enthusiasm, anger, and anxiety vis-à-vis Secretary Clinton. My results provide support for the general notion that celebrity endorsements can affect voter emotions. Specifically, I find that celebrity endorsements profoundly decreased the negative emotions of anger and anxiety vis-à-vis Secretary Clinton. My research suggests that a broad range of stimuli may affect voter emotions, which in turn affect political attitudes and behavior.
Under Pressure
Authors: Poulos Christopher N.
Published: May 2017

In this autoethnography, I write my way through the contours of scrutiny, measurement, and control across the span of my life, and (eventually) write my way into a solution, of sorts, to the conundrum of a knowledgeable agent living in a neoliberal world. In my story, life-space in the academy has just been one of the many locales subjected to the corporate colonization of the lifeworld. Autoethnography emerges as a channel of resistance against neoliberal forces.
Academic Labor in the Age of Anxiety: Autoethnography Matters
Authors: Foster Elissa
Published: May 2017

In this autoethnographic essay, I reflect on three spheres of academic work—program administration, teaching, and scholarship—and find evidence of the effects of neoliberalism in each sphere of practice. Specifically, I articulate the prevailing emotional experience of my academic work as anxiety, which is a consequence of internalizing the construction of students-as-consumers and responding uncritically to the demands of academic organizations that require my compliance and neutrality. To the extent that academic freedom is a reward afforded to those with tenure, my essay argues that the cost of leading a privileged academic life is that we use our privilege to question the status quo, particularly in our own institutions of higher education.
Knowledge Work and Human Resource Development
Authors: Jacobs Ronald L.
Published: May 2017

There is increasing awareness that most work is changing, and the predominant trend is toward greater complexity, becoming known as knowledge work. Two fundamental questions remain essentially unresolved about knowledge work, which have importance to the human resource development field. First, what are the characteristics of knowledge work that make it unique from other work behaviors? Second, how should organizations develop employees to perform knowledge work? To address these questions, this article has the following goals. First, the article reviews the definitions of knowledge work and discusses four key points that provide a better understanding of the topic. Second, the article proposes a definition of knowledge work using the term knowledge-based tasks to describe instances of knowledge work. Third, the article presents an employee development system that helps individuals learn to perform knowledge-based tasks. The article concludes with a brief discussion about knowledge work and the challenges and opportunities it presents to the human resource development field.
Implementation of an evidence-based injury prevention program in professional and semi-professional soccer
Authors: Al Attar Wesam Saleh A , Soomro Najeebullah , Sinclair Peter J , Pappas Evangelos , Muaidi Qassim I , Sanders Ross H
Published: May 2017

The ideal implementation of soccer injury prevention programs is essential knowledge for soccer coaches. The objective of this study was to investigate and compare the implementation of injury prevention programs, specially the FIFA 11+ program, among Australian and Saudi Arabian soccer coaches. A Web-based survey was used to obtain information regarding the coaches’ implementation of injury prevention programs, the FIFA 11+ program, the Nordic hamstring exercise, pre- and post-training exercises. Sixty coaches—30 from both selected countries—responded to the survey (response rate = 75%). In Australia, 93% of the coaches implemented an injury prevention program; while 73% implemented the FIFA 11+ program, only 51% implemented all the FIFA 11+ exercise components as recommended. In Saudi Arabia, 70% of the coaches stated that they followed an injury prevention program, but only 40% followed the FIFA 11+ program. However, 70% reported using all the FIFA 11+ exercise components in their current practices, which they may have adapted from different exercise-based injury prevention programs. The Australian coaches were significantly more likely to implement injury prevention programs ( p = 0.020) and the FIFA 11+ program ( p = 0.009). Nonetheless, no significant difference in the full implementation of the FIFA 11+ exercises components was found ( p = 0.114). The Australian coaches had greater awareness of injury prevention programs and more familiarity with the FIFA 11+ program than the Saudi Arabian coaches. Nevertheless, there was a gap between the coaches’ knowledge and their actual practice.
Strength and conditioning roundtable: Strength and conditioning coach evaluation
Authors: Gillham Andy , Doscher Michael , Fitzgerald Craig , Bennett Scott , Davis Adam , Banwarth Adam
Published: May 2017

Evaluation is a necessary component of nearly every job and strength and conditioning coaches are no exception. However, the utility of that evaluation seems likely to vary tremendously across the sporting landscape. The literature is lacking information on how strength and conditioning coaches are evaluated. Therefore, the purpose of this project was to solicit responses from head strength and conditioning coaches regarding their experiences with evaluation of their work. Five coaches representing competitive levels from high school to professional American football responded to a series of 11 questions about evaluations and assessments. Their answers were more diverse than similar and combined to present a picture of evaluation that is entirely inconsistent and muddled.
(Mis)representing terrorist threats: Media framing of Bill C-51
Authors: Foley Rebecca I M
Published: May 2017

On Friday, 30 January 2015, Steven Blaney, Minister of Public Safety and Emergency Preparedness, introduced Bill C-51, also known as the Anti-Terrorism Act in Canada’s House of Commons. This article delineates research into the media coverage of Bill C-51 in the month after its introduction, prior to its legislation. A qualitative content analysis of 23 articles from five Canadian news sources ( National Post, The Globe and Mail, The Toronto Star, The Tyee, and rabble.ca) was conducted. Data were coded and analysed using the qualitative research software NVivo 10. Themes that arose from the data include: terrorism and our need for protection; production and reinforcement of fear; oversight, accountability, and abuses of power; and dystopic future and ‘big’ government. Findings show that the differences between alternative and commercial news sources were not as evident as much of the literature regarding the differences between the types of media would hypothesize.
Performance analysis of nonlinear observers applied to the fixed-wing unmanned aerial vehicles flight under decoupled-reduced model
Authors: Parada Ricardo P , Espinoza A Tadeo , Dzul Alejandro E , Salas Francisco G
Published: May 2017

In this paper, we present the design and implementation of two nonlinear observers: nonlinear extended state observer and sliding mode observer for estimating the pitch, yaw and roll angles and angular rates of a fixed-wing unmanned aerial vehicles system under a decoupled-reduced model in real flight experiments. A backstepping control law is designed for control in a decentralized way for altitude, yaw and roll of the airplane. This scheme allows us to test experimentally the feasibility of using the online estimated data from the observers in flight control, which is useful for increasing the robustness of the control and the safety of flight. Furthermore, a comparative analysis of the performance of both nonlinear observers is conducted.
Can we use the ipsilateral Hamstrings for ACL Reconstruction in case of medial collateral ligament insufficiency?
Authors: Domnick Christoph , Herbort Mirco , Zoll Alexander
Published: May 2017

Aims and Objectives:

Semitendinosus and gracilis muscles (hamstring muscles) are frequently harvested autologous tendon grafts of the knee e.g. for cruciate ligament reconstruction. This study investigated the joint-stabilizing effects of these muscles in case of insufficiency of the medial collateral ligament (MCL). Hypotheses: First, both the semitendinosus and the gracilis muscles can actively stabilize the joint against valgus stress in the medial collateral unstable knee. Second, this stabilizing influence of these muscles decreases with increasing flexion angle

Meterials and Methods:

Kinematics were examined in ten fresh-frozen human cadaveric knees using a robotic/UFS testing system and an optical tracking system. The knee kinematics under 5 Nm and 10 Nm valgus stress were determined in the a) MCL intact and b) MCL deficient knee in different flexion angles, respectively using the following simulated muscle loads: 1) 0 N (Idle), 2) 200 N semitendinosus load (ST) and 3) 280 N combined semitendinosus and gracilis load (STGT).

Results:

Cutting the MCL increased valgus angle under all tested conditions and angles in contrast to the MCL intact knee by 4.3-8.1 degrees for 5 Nm, 6.5-11.9 degrees for 10 Nm valgus torque; P<.01; RM-ANOVA). Applied 200 N simulated ST load reduced the valgus angle significantly in 0°, 10°, 20° and 30° of flexion under 5 Nm and 10 Nm (P< .05) valgus stress. In 0°, 10° and 20° these values were close to the MCL intact joint under the respective torque (both P >.05). The combined 280 N simulated STGT load reduced significantly valgus angle in 0°, 10° and 20° of flexion under 5 Nm and 10 Nm of valgus stress (P< .05) to values near the intact joint (5 Nm: 0°, 10°; 10 Nm: 0°, 10°, 20° - P >.05). In 60° and 90° of flexion ST and STGT loads could not decrease resulting valgus angle of the MCL deficient knee (without hamstring load; P>.05 or valgus increase P<.05).

Conclusion:

In this human cadaveric study semitendinosus and gracilis muscles can successfully stabilize against valgus stress in the MCL insufficient knee in near-to-extension flexion angles. In the valgus-unstable knee, hamstring muscles should be preserved in (multi-) ligament surgery, but also in joint arthroplasty and osteosynthesis if possible.
Kinematics of the posterolateral corner of the knee: A human cadaveric cutting study.
Authors: Drenck Tobias , Domnick Christoph , Herbort Mirco , Raschke Michael , Frosch Karl-Heinz
Published: May 2017

Aims and Objectives:

The posterolateral corner of the knee consists of different structures, which contribute to instability when damaged after injury or within surgery. Knowing the kinematic influences may help to improve clinical diagnostics and surgical techniques. The purpose was to determine static stabilizing effects of the posterolateral corner by dissecting stepwise all fibers and ligaments (the arcuat complex, AC) connected with the popliteus tendon (PLT) and the influence on lateral stability in the lateral collateral ligament (LCL) intact-state.

Materials ans Methods:

Kinematics were examined in 13 fresh-frozen human cadaveric knees using a robotic/UFS testing system with an optical tracking system. The knee kinematics were determined for 134 N anterior/posterior loads, 10 Nm valgus/varus loads and 5 Nm internal/external rotational loads in 0°, 20°, 30°, 60° and 90° of knee flexion. The posterolateral corner structures were consecutively dissected: The I.) intact knee joint, II.) with dissected posterior cruciate ligament, III.) meniscofibular/-tibial fibers, IV.) popliteofibular ligament, V.) popliteotibial fascicle (last structure of static AC), VI.) PLT and VII.) LCL.

Results:

The external rotation angle increased significantly by 2.6° to 7.9° (P<.05) in 0° to 90° of knee flexion and posterior tibial translation increased by 2.9 mm to 5.9 mm in 20° to 90° of knee flexion (P<.05) after cutting the AC/PLT structures (with intact LCL) in contrast to the PCL deficient knee. Differences between dissected static AC and dissected PLT were only found in 60° and 90° external rotation tests (by 2.1° and 3.1°; P<.05). In the other 28 kinematic tests, no significant differences between PLT and AC were found. Cutting the AC/PLT complex did not further decrease varus, valgus or anterior tibial stability in any flexion angle in comparison to the PCL dissected state.

Conclusion:

The arcuat complex is an important static stabilizer for external rotatory and posterior tibial loads of the knee, even in the lateral collateral ligament intact-state. After dissecting the major parts of the arcuat complex, the static stabilizing function of the popliteus tendon is lost. The arcuat complex has no varus-stabilizing function in the LCL-intact knee. The anatomy and function of these structures for external-rotational and posterior-translational stabilization should be considered for clinical diagnostics and when performing surgery in the posterolateral corner.
Trends and incidence of cartilage, ligament- and arthroscopic surgery: Analysis of German in-patient records 2005-2013
Authors: Lodde Georg , Domnick Christoph , Herbort Mirco , Garcia Patric , Raschke Michael
Published: May 2017

Aims and Objectives:

Apart from some international cruciate ligament and arthroplasty register data, little epidemiological baseline facts are known about many joint surgical procedures. The German Federal Statistical Office collects the encoded population-based data of all medical in-patient procedures performed in Germany. The purpose of this study was to analyze these data to assess epidemiological trends and incidences in joint surgery.

Materials and Methods:

The comprehensive database of medical procedures of the German DRG system between 2005 and 2013, including 154 million anonymized in-patient records, were screened and analyzed for joint surgical procedures.

Results:

Trends of incidence rates of many joint surgical procedures have been detected. There was an increasing incidence of arthroscopic procedures in relation to the open procedures. Anterior cruciate ligament reconstruction or repair has a high incidence of 46 per 100,000 person-years, most popular grafts were hamstring tendon (90%) and patellar tendon (6.3%) autografts (2013).

Conclusion:

This is the first baseline epidemiological data out of 154 million in-patient records in Germany including joint and ligament surgical procedures with a focus on knee and shoulder surgery. The knowledge of the trends and incidences of these procedures help to validate and discuss the results of clinical studies and registers.
Plate osteosynthesis after patellar fracture: 1-year results of a prospective study
Authors: Ellwein Alexander , Katthagen Jan , Jensen Gunnar , Lill Helmut , Raschke Michael
Published: May 2017

Aims and Objectives:

Tension band wiring after patellar fractures is associated to a high number of implant related complications (22-53%). Revision surgery is necessary in 10-55% of the patients with mostly unsatisfactory results. The patella plate is an alternative treatment with the advantages of a locked plating implant. Biomechanical studies have shown a significant higher stability compared to tension band wiring. Therefore an immediate full weight bearing after surgery is allowed with the prophylaxis of knee-stiffness. The purpose of this study was to evaluate the first time clinical prospective results and complications of this new implant.

Materials and Methods:

Between April 2013 and May 2015 all patients that were treated with locked plating for patella fractures were included in this prospective study. Patients were examined after 6 weeks, 6 and 12 months. Information about patient satisfaction, pain situation and the functional result were collected. Additionally subjective scores (Tegner activity score, Lysholm-score, Kujala-score) were determined and compared to their value before trauma. Complications and revision surgeries were recorded and analysed.

Results:

17 patients, 6 women and 11 men, with a mean age of 58 (19-87) years were included in this study. The range of motion of the injured knee was 120° after 6 weeks and improved to 138° after 6 months, corresponding to 84% and 97% of the range of motion of the healthy opposite knee. The Tegner activity scale increased from 2,5 to 3,5 (initial value: 4), the Lysholm score from 78 to 92 points (initial value: 97) and the Kujala score from 72 to 88 points (initial value: 96). Two complications occurred: one patient had a reactive bursitis praepatellaris and one patient sustained a loss of reduction. Another two patients had their implants removed. Patient satisfaction reached 94% after one year.

Conclusion:

Locked plating of patella fractures is a reliable alternative treatment with good functional outcomes, low complication rates and high patient satisfaction. Already 6 months after surgery the functional results and subjective scores reached results as before trauma. Furthermore the aftercare with immediate full-weight bearing and motion exercise improves quality of life through an early return to daily life.
Radiographic analysis of Re-Ruptures of reconstructed ACLs - Evaluation of tunnel position as a possible cause of Failure
Authors: Sobau Christian , Zimmerer Alexander , Fallscheer Max , Ellermann Andree
Published: May 2017

Objectives:

Previous studies detected femoral and / or tibial tunnel malpositioning as possible causes for the failure of an anterior cruciate ligament reconstruction. We investigated various radiological angles and criterias for ACL revision surgery to find possible causes for the failure of the primary reconstructed ACLs based on digital X-ray images.

Materials and Methods:

529 ACL revisions after previous reconstruction were carried out between 1993 and 2013, of which we were able to include 100 patients with digital radiographs in our study. We investigated the angles of the femoral and tibial tunnel position in the coronal and sagittal plane. Furthermore we analyzed the entry point on the femur in accordance with the quadrant method described by Bernard and Hertel. We divided into: A) adequate trauma (n = 87) and non-trauma group (n = 13); B) Hamstring (n = 76) and Patella-BTB group (n = 24); C) transtibial (n = 83) and anteromedial group (n = 17). In addition we built subgroups B1/C1 adequate re-trauma or B2/C2 no adequate trauma to analyze whether there were differences in these groups.

Results:

The trauma group differed significantly from the non-trauma group in the measured angle of the tibial tunnel in the ap radiograph (trauma group 28.4°, non-trauma group 22.67°; p = 0.013). The Hamstring group differed significantly from the BTB group in the measured inclination angle of the femoral tunnel in the ap radiograph (HS group 54.86°, BTB group 62.78°; p = 0.015). There was also a significant difference concerning the tibial tunnel in the ap radiograph (HS group 29.56°, BTB group 21.63°; p = 0.0001). Comparing the two groups for the femoral tunnel placement-techniques we could find significant differences in the femoral ap-radiographs (inclination angle: TT = 59.04°, AM = 45.64°; p = 0.0001). The analysis of the 4 subgroups revealed differences in the tibial ap images: The BTB trauma group had an average of 23.56° relative to the BTB non-trauma group of 16.91° (p=0.013). The HS groups among themselves did not differ significantly, but the HS non-trauma group had a significantly higher angle with 29.38° to 16.91° in the BTB non-trauma group (p = 0.0003). In addition there was a significant difference when comparing the transtibial trauma group with the transtibial non trauma group (TT trauma = 27.66°, TT non trauma = 21.15°; p = 0.017)

Conclusion:

Overall we could only find a few significant differences in the measured angles and only a few deviations from the values described within the literature. Therefore a real trauma was necessary to rupture the reconstructed ACL in 87%. In 13% we could find a possible cause within the tibial tunnel: the steeper the tibial tunnel was, less trauma was necessary for failure, especially when using the transtibial drilling method or Patella-BTB grafts. However the small sample size limits the results therefore further studies are necessary.
Bone Microarchitecture of the Tibial Plateau in Health and Osteoporosis
Authors: Krause Matthias , Hapfelmeier Alexander , Püschel Klaus , Amling Miachel , Frosch Karl-Heinz
Published: May 2017

Aims and Objectives:

A failure rate of up to 69% of surgically treated tibial plateau fractures in the elderly is attributed among others to the increasing incidence of osteoporosis resulting in renewed immobilization and revision surgery. Hence, ideally implants are fixed in regions with sufficient bone mass. However, data on region-specific structural alterations of the tibial plateau in osteoporosis do not exist. The primary aim of the study was to characterize region-specific changes of the bone structure in patients with osteoporosis compared to skeletally healthy controls.

Materials and Methods:

In a preclinical case-control study twenty-one human right proximal tibiae from females with postmenopausal osteoporosis (mean age: 84.3±4.9 years) and eight skeletally healthy, premenopausal female controls (45.5±6.9 years) were harvested during autopsy. Histomorphometric parameters were assessed by HR-pQCT (high-resolution peripheral quantitative computed tomography) after digital subdivision into different volumes of interest (VOI) according to a 10-segment classification in three levels of the tibial plateau. In the coronal plane, analysis was performed in the proximal 3 cm from the articular surface. Statistical analysis was based on evolutionary learning using globally optimal regression trees.

Results:

Skeletally healthy controls showed a better bone structure throughout the whole tibial plateau than osteoporotic patients. In osteoporosis, the greatest bone loss was found in the medio-medial VOI (antero-medio-medial, postero-medio-medial) compared to controls. The lowest bone volume, however, was found in the central VOI (antero-central, postero-central) representing the tibial spine. Trabecular connectivity was severely reduced. Most importantly, in the anterior and posterior 25% of the lateral and medial tibial plateau, the trabecular support and the subchondral lamella thickness itself was severely reduced.

Conclusion:

The bone structure deterioration of the tibial plateau due to osteoporosis is region-specific. The additional thinning of the subchondral lamella and marked bone loss in the anterior and posterior 25% of the tibial plateau may explain failure of fracture reduction in cases of unilateral plate fixation, specifically in postero-medial fragments. The understanding of region-specific architectural alterations of the tibial plateau may help to improve the long-term, fracture-specific fixation of tibial plateau fractures, especially in osteoporotic patients.
Survival rate after septic total knee arthroplasty- a comparison of two treatment algorithms
Authors: Baier Clemens , Maderbacher Günther , Grifka Joachim , Springorum Hans-Robert
Published: May 2017

Aims and Objectives:

To date there exists no golden standard of treatment of late periprosthetic joint infection. Different forms of treatment comprise single-stage or two-stage or multiple revisions. Respectively, mid- to long-term results are rare.

Materials and Methods:

We retrospectively analysed 66 patients with septic total knee arthroplasty treated by two different therapy algorithms: Until 2009 patients were treated routinely by implant removal and implantation of an articulating spacer in combination with at least 6 weeks of antibiotic administration. After an antibiotic-free period of two weeks persistent infection was ruled out by punctation. In case of negative antimicrobial cultures after another 14 days patients were treated by reimplantation (n=36, group 1). After 2009 persistent infection was ruled out by open revision and change of the articulating spacer instead of a punctuation. In case of negative antimicrobial cultures after another 14 days patients were treated by reimplantation (n=30, group 2). After a follow-up of 61 months (group 1), respectively 36 months (group 2), patients and their family doctors were contacted by phone concerning the survival rate of the new implant.

Results:

In group 1 persistent infection was ruled out in every patient by punctuation. During reimplantation tissue samples of 8 patients (22%) showed positive microbiological results again, within 4 patients with a change of the underlying bacteria. After a follow-up of 61 months 31 patients showed no signs of reinfection of their implant and were not operatively revised (86%). In group 2 all patients were treated with open revision and change of the articulating spacer for at least once. 8 patients showed a change of the underlying bacteria during these procedures. During reimplantation tissue samples of 8 patients (27%) showed positive microbiological results again. After a follow-up of 36 months 27 patients showed no signs of reinfection of their implant and were not operatively revised (90%). The difference between both groups was not significant (p>0.05). Concerning the overall complication rate no significant differences between both groups could be found (p>0.05).

Conclusion:

Concerning reinfection rate we could not detect significant differences between both groups. Patients of group 2 were treated operatively significantly more often and showed a significantly more frequent change of the underlying bacteria. If these results are confirmed in big cohort studies the elaborate treatment algorithm of open revision and change of the articulating spacer might become dispensable.
Subluxation of knees in TKA - a neglected fact? An in vitro study.
Authors: Maderbacher Günther , Springorum Hans-Robert , Grifka Joachim , Baier Clemens , Keshmiri Armin
Published: May 2017

Aims and Objectives:

Correct implant alignment is a well known factor for good functional results and increased implant survival after total knee arthroplasty (TKA). However, in present studies only coronal, sagittal and rotational alignment parameters have been considered, while translational parameters, the relative position between the femur and the tibia in medio-lateral, ventro-dorsal and proximo-distal direction are widely neglected. Due to variable mediolateral, proximodistal and ventrodorsal component placement in TKA, we hypothesised changed relative positions between the femoral and tibial bone resulting in a subluxation of knees after TKA.

Materials and Methods:

In nine Thiel embalmed whole body cadavers without any history of orthopaedic surgeries, fracutres and osteoarthritis, the relative positions between the femoral and tibial bones were measured between 0 and 90° of flexion before and after TKA (DePuy PFC Sigma, CR, fixed bearing) by means of a navigation system (Brainlab 2.6, Feldkirchen). To compare femoral positions before and after TKA, a paired t-test was used. A two-sided p-value of <0.05 was considered statistically significant.

Results:

In full extension, the femoral bones shifted 5.7 mm laterally(SD 4.0, p=0.003), and 2.7 proximally (SD 3.1, p=0.030), which decreased up to 90° of flexion to a lateral shift of 3.7 mm (SD 3.5, p=0.006) and proximal shift of 0.9 mm (SD 1.6, p=0.144). The femoral bones were located more dorsal in extension (2.8 mm dorsally (SD 4.8, p=0.113) which changed to a more ventral position in flexion (2.8 mm, SD 4.2, p=0.077).

Conclusion:

In the present setting, total knee arthroplasty resulted in significant changes of translational positions between the femoral and tibial bones, thus subluxation of knees. Major reasons for that might be a non centered placement of tibial or femoral implants, symmetric implants which do not respect individual anatomy, operative techniques, and large steps between two component sizes. Subluxation might cause an altered tension of the ligaments and consequently change tibiofemoral or patellar kinematics or tensioning of the periarticular soft tissue resulting in pain. However, clinical trials are necessary to evaluate clinical impact of the presented results.
Biomechanical Investigation of Different Preparation Techniques of Tripled Soft Tissue ACL Grafts
Authors: Achtnich Andrea , Föhr Peter , Herbst Elmar , Imhoff Andreas , Braun Sepp
Published: May 2017

Aims and Objectives:

The purpose was to investigate biomechanical properties of different preparation techniques of tripled soft tissue ACL grafts to avoid early mechanical graft failure. It was hypothesized that 1) a graft with a quadrupled femoral portion results in higher load to failure and stiffness compared to a uniformly tripled graft, and 2) a Krackow stitch technique is superior to both baseball stitch and whipstitch technique.

Materials and Methods:

Forty-eight bovine flexor tendons (eight per group) with a final graft length of 8 cm were used for the present study and randomly assigned to the two graft configuration groups: A) quadrupled femoral portion with a tripled tibial portion, and B) uniformly tripled soft tissue graft. Within the two groups, three different stitching techniques were applied: 1) Whipstitch technique, 2) Krackow stitch, and 3) Baseball stitch. After preconditioning, the grafts were cyclically loaded for 1000 cycles between 50 and 200 N (1 Hz) with consecutive load to failure testing using a constant elongation of 30 mm/min. During biomechnical testing, graft elongation was evaluated with an optical tracking system. For statistical analysis a two-way analysis of variance with a post-hoc Holm-Sidak test was performed. To evaluate the failure mode the Fisher’s exact test was used. The significance level was set at p #CHR: lesslike# 0.05.

Results:

Considering load to failure, quadrupling the femoral portion of the graft significantly increased the load to failure (p = 0.003) while varying the stitching technique had no influence (p = 0.998). Additionally, graft elongation was lower in group A, but difference was not significant (p = 0.058). Lowest graft elongation was observed when a Krackow stitch was applied, followed by the baseball stitch, and the whipstitch technique (p = 0.035). In group A, all the constructs (graft including sutures) failed at the suture, whereas in group B the failure mode was a slippage of the free femoral graft strand in seven of eight grafts (p = 0.005).

Conclusion:

When using tripled ACL soft tissue grafts in combination with an extracortical fixation device, the femoral portion should be quadrupled whereas the stitching technique does not have a significant influence on the biomechanical properties. To achieve a higher load to failure with less graft elongation at time zero, the free femoral strand of the tendon graft should be wrapped around the femoral graft tendon loop. This could reduce early graft failure due to slippage of the third free femoral graft strand.
Long-Term Clinical and MRI Results after Refixation of osteochondral Fractures with resorbable Implants
Authors: Rüther Hauke , Raschke David , Frosch Stefan , Wachowski Martin , Seif Ali
Published: May 2017

Aims and Objectives:

Refixation with resorbable implants is a common surgical treatment in patients with an osteochondral fracture of the knee or the upper ankle joint. Up to date there are no studies, which outline long-term outcome of this procedure. As a consequence aim of this study was to evaluate the long-term clinical und MRI results.

Materials and Methods:

In this study 12 patients were examined 13,9 (#CHR: plusmn# 1,2) years after refixation of an osteochondral fragment of the knee (10) and the upper ankle joint (2) with a mean size of 3.16 cm2 (#CHR: plusmn# 2,27) by resorbable implants (SmartNail, Conmed). We used eight established clinical scores (VASS, Tegner, Lysholm, McDermott, KSS, WOMAC, AOFAS, FADI+Sports). Furthermore we ascertained integration of bone and cartilage morpholgy by MRI (3 Tesla) using proton-weighted- and cartilage-sensitive double-echo-steady-state (DESS) sequences. To identify a possible osteonecrosis we used T1-weighted sequences with a contrast agent (Gadolinum). The morphologic results were objectified with a modified MRI-Score based on Henderson et al. (2003).

Results:

After 13,9 (#CHR: plusmn# 1,2) years the patients with an injury of the knee as well as of the upper ankle joint showed good to excellent results (Knee: VASS: 1,3 (#CHR: plusmn# 1,7); Tegener 4,4 (#CHR: plusmn# 1,3); Lysholm 85,7 (#CHR: plusmn# 12,2); McDermott 90,7 (#CHR: plusmn# 8,6); KSS 189 (#CHR: plusmn# 15,9); WOMAC (6,16% (#CHR: plusmn# 8,45)) (Upper Ankle joint: VASS: 2,5 (#CHR: plusmn# 2,5); Tegener 5,5 (#CHR: plusmn# 1,5); Lysholm 87 (#CHR: plusmn# 13), McDermott 88 (#CHR: plusmn# 12); WOMAC (8,54% (#CHR: plusmn# 8,54); AOFAS 75,5 (#CHR: plusmn# 24,5); FADI+Sports 118 (#CHR: plusmn# 18)). There was a good integration of the osteochondral fragment in all cases in the MRI. 5 patients showed moderate subchondral cysts. There were changes of the cartilage contour in all patients. The mean Henderson-Score was 14,4 (#CHR: plusmn# 2,0) (Best: 8, Worst: 32), which correlates with good results.

Conclusion:

Because of its good clinical and MRI results the refixation by resorbable implants can be recommended to treat osteochondral flakes.
Pathobiochemistry of arthrofibrotic remodeling
Authors: Faust Isabel , Traut Philipp , Knappe Cornelius , Hendig Doris
Published: May 2017

Aims and Objectives:

Arthrofibrosis is defined as painful impairment of joint flexibility due to fibrotic tissue remodeling after joint trauma or surgery. The incidence of arthrofibrosis after knee replacement surgery is 5 to 10%. Although conventional therapeutic approaches as for instance mobilization and physiotherapy are applied, an effective and causative therapeutic regimen is not known.

Materials and Methods:

To characterize arthrofibrotic remodeling of the extracellular matrix, to develop new therapeutic approaches and to define diagnostic biomarkers and therapeutic targets, understanding of biochemical principles is urgently required. Fibrotic remodeling was described in several tissues, whereas synovial fibrosis is one of the least investigated fibrotic disorders. Nevertheless, molecular key events in fibrosis seem to be the same and are initiated by exogenic or endogenic tissue damage and differentiation of resident fibroblasts of the connective tissue to myofibroblasts. Known inductors of myofibroblast differentiation are fibrotic growth factors, which are secreted by platelets, damaged tissue and inflammatory cells, as well as mechanical strain. Research studies concerning cardiac fibrosis in tako-tsubo cardiomyopathy also define emotional stress and sympathicotonic destabilization as profibrotic stressors. Myofibroblasts generate contractile forces and synthesize extracellular matrix components, so that scar tissue accumulates. While myofibroblasts disappear by apoptosis in physiological wound healing, they persist in fibrosis.

Results:

Recently, we could demonstrate that increased expression of human xylosyltransferase (XT)-I, an enzyme which catalyzes the rate limiting step in proteoglycan glycosylation, is linked to abnormal extracellular matrix remodeling. Serum XT activity reflects proteoglycan synthesis rate and is known as fibrosis biomarker in liver fibrosis or scleroderma. Our data also indicate that XT-I is a cellular key mediator of arthrofibrosis. However, we suggest that molecular changes based on arthrofibrosis are, due to local restriction of the affected joint by the blood-synovial-barrier, not detectable in human serum. Currently, we study synovial XT activity of arthrofibrosis patients and controls in a multicenter study.

Conclusion:

In summary, we give insights into the complex pathobiochemistry of arthrofibrosis as well as current research projects. A deeper characterization of the involved mechanisms might not only contribute to control and inhibit fibrotic remodeling by interfering with components of fibrotic signal cascades but also to establish new therapeutic strategies.
Analysis of graft maturation after autologous chondrocyte implantation with T2 mapping
Authors: Niethammer Thomas R. , Loitzsch Ansgar , Pietschmann Matthias F. , Müller Peter E. , Horng Annie
Published: May 2017

Aims and Objectives:

It has been shown in numerous clinical studies that matrix-based autologous chondrocyte implantation (mb-ACI) leads to good clinical results in the medium-term course. But chondrogenic development of ACI grafts and the time of graft maturation are still unclear. The aim of this study was to investigate the graft maturation after mb-ACI with T2 mapping in the postoperative course of four years.

Materials and Methods:

In a total of 90 patients could be included after matrix-based autologous chondrocyte transplantation of the knee. All cartilage defects were treated with NOVOCART® 3D. The evaluation of the ACI grafts was conducted after 3, 6, 12, 24, 36 and 48 months by MRI. The T2 relaxation time values of the ACI graft and healthy native cartilage areas were determined to assess graft maturation using T2 mapping. MOCART score were used for morphological evaluation of ACI grafts.

Results:

The T2 relaxation time of ACI grafts showed a significant improvement during the postoperative course at all time points. The T2 relaxation improved from 48.0 ms after 3 months to 34.6 ms after four years. We found a significant influence of the patient’s age and the defect localization on the T2 relaxation time measuring. It could be detected an increasing integration of the ACI grafts into the healthy surrounding cartilage. No significant differences between the T2 relaxation time of ACI grafts and the surrounding healthy cartilage were found after 12 months postoperatively.

Conclusion:

Graft maturation after ACI in the knee joint needs at least 1 year, with ongoing adjustment of the T2 relaxation time values compared with native surrounding cartilage. Regarding the age and defect localization, significantly worse T2 relaxation times of the ACI grafts could be found with higher age and in cases with treated patellar defects.
The huddle-technique app - a new instrument imaging knee-instability of young high performance football players. Comparison of measured angles, KT1000, KLT and subjektiv instability
Authors: Braun Philipp-Johannes , Stoffels Thomas , Hünnebeck Sophia , Trendelbern Jenny , Stengel Dirk
Published: May 2017

Aims and Objectives:

Is there a correlation between measured frontal plane projection angle, KT1000, KLT and subjektiv instability recognized by player or examiner in a cohort of 101 young high performance football players. We want to establish a reproducible tool that recognizes knee instability in a dynamic movement to prevent knee injury in young high performance athletes.

Materials and Methods:

Rupture of anterior cruciate ligament (ACL) is a serious knee injury. Several epidemiological studies have shown a correlation between coordination, neuromuscular control and incidence of ACL injuries. In a prospective study of 101 young high performance football players we measured the frontal plane projection angle (FPPA) in drop test with the huddle-technique app. Furthermore we captured subjektiv instability in drop test, single hop test and figure of eight test as well as basic instability criteria as lachmann test, pivot shift test, KT 1000 and KLT.

Results:

Low FFPA angles (valgus knee) in drop test correlate with higher subjective knee instability recognized by players as well as by examiner. KT 1000 and KLT as a basic instability criteria are not reproducible relating to the subjective instability. Furthermore we investigate a correlation between measured instability with the huddle-technique app, shooting foot and shape of muscular system.

Conclusion:

The huddle-technique app is a new instrument which gives us an advise of knee instability of young high performance football players. With measuring the FFPA angle in drop test we have a reproducible tool that recognizes instability in a dynamic movement. Our aim is to identify high risk players and modify their movement pattern to avoid knee injury, especially rupture of anterior cruciate ligament. The FFPA angle measured with huddle-technique app additionally can help us to supervise success of special training programs.