Growth and aging in a few phase-separating active matter systems

Via computer simulations we study evolution dynamics in systems of continuously moving active Brownian particles. The obtained results are discussed against those from the passive 2D Ising case. Following sudden quenches of random configurations to state points lying within the miscibility gaps and to the critical points, we investigate the far-from-steady-state dynamics by calculating quantities associated with structure and characteristic length scales. We also study aging for quenches into the miscibility gap and provide a quantitative picture for the scaling behavior of the two-time order-parameter correlation function. The overall structure and dynamics are consistent with expectations from the Ising model. This remains true for certain active lattice models as well, for which we present results for quenches to the critical points.

Digital health applications from a government-regulated directory of reimbursable health apps in Germany-a systematic review for evidence and bias

Background

The Digital Healthcare Act, passed in November 2019, authorizes healthcare providers in Germany to prescribe digital health applications (DiGA) to patients covered by statutory health insurance. If DiGA meet specific efficacy requirements, they may be listed in a special directory maintained by the German Federal Institute for Drugs and Medical Devices. Due to the lack of well-founded app evaluation tools, the objectives were to assess (I) the evidence quality situation for DiGA in the literature and (II) how DiGA manufacturers deal with this issue, as reflected by the apps available in the aforementioned directory.

Methods

A systematic review of the literature on DiGA using PubMed, Scopus, and Web of Science was started on February 4, 2023. Papers addressing the evidence for applications listed in the directory were included, while duplicates and mere study protocols not reporting on data were removed. The remaining publications were used to assess the quality of the evidence or potential gaps in this regard. Results were aggregated in tabular form.

Results

The review identified fourteen relevant publications. Six studies suggested inadequate scientific evidence, five mentioned shortcomings of tools for validating DiGA-related evidence, and four publications described a high potential for bias, potentially influencing the validity of the results. Concerns about limited external generalizability were also raised.

Conclusions

The literature review found evidence-related gaps that must be addressed with adequate measures. Our findings can serve as a basis for a plea for a more detailed examination of the quality of evidence in the DiGA context.

[Secure app usage-Evaluation benchmarks for medical apps : Quality aspects for health apps based on 9 key criteria]

Smartphones and health apps are an integral part of everyday life. They are increasingly being used for medical purposes. However, there is no fundamental basis or consensus on the evidence on which decisions are made towards a unified digital strategy. Consequently, the understanding of the quality of health apps is only inconsistent and fuzzily defined. The 9 quality criteria presented by the Association of Medical Societies (AWMF)-transparency, appropriateness, risk appropriateness, ethical harmlessness, legal conformity, content validity, technical appropriateness, usability, resource efficiency-serve as a guide for individual and institutionalized quality assessment. The principles are based on a comprehensive compilation of existing (inter-) national standards and evaluation benchmarks. Analogously to usual medical practice, it is also obligatory to conduct one's own research for a suitable app and to weigh up the risks and benefits when using an app.

Evidence of Digital Health Applications from a State-Regulated Repository for Reimbursable Health Applications in Germany

17 RCTs for 15 digital health applications (DiGA) permanently listed in the state-regulated register were analyzed descriptively for methodological study aspects relevant to evidence analysis. The analysis revealed that several underlying studies had limitations, at least worthy of discussion, in terms of their power concerning sample size, intervention and control group specifications, drop-out rates, and blinding.

Orthopaedic and trauma surgeons' prioritisation of app quality principles based on their demographic background

BACKGROUND

Although apps are becoming increasingly relevant in healthcare, there is limited knowledge about how healthcare professionals perceive "quality" in this context and how quality principles that can aid them in assessing health-related apps may be prioritised. The objective was to investigate physicians' views of predefined (general) quality principles for health apps and to determine whether a ranking algorithm applied to the acquired data can provide stable results against various demographic influences and may thus be appropriate for prioritisation.

METHODS

Participants of an online survey of members of two German professional orthopaedics associations conducted between 02/12/2019 and 02/01/2020 were asked about their perception of a set of quality principles for health apps (i.e., "practicality," "risk adequacy," "ethical soundness," "legal conformity," "content validity," "technical adequacy," "usability," "resource efficiency," and "transparency"). Structured as a Kano survey, for each principle, there were questions about its perceived relevance and opinions regarding the presence or absence of corresponding characteristics. The available data were evaluated descriptively, and a newly developed method for prioritisation of the principles was applied overall and to different demographic strata (for validation).

RESULTS

Three hundred eighty-two datasets from 9503 participants were evaluated. Legal conformity, content validity, and risk adequacy filled ranks one to three, followed by practicability, ethical soundness, and usability (ranks 4 to 6). Technical adequacy, transparency, and resource efficiency ranked last (ranks 7 to 9). The ranking based on the proposed method was relatively stable, irrespective of demographic factors. The principles were seen as essential, with one exception ("resource efficiency"). Only those with little to no interest in digitisation (22/382, 5.8%) rated the nine principles indifferently.

CONCLUSIONS

The specified quality principles and their prioritisation can lay a foundation for future assessments of apps in the medical field. Professional societies build upon this to highlight opportunities for digital transformations in medicine and encourage their members to participate.

Unloader bracing in osteoarthritis of the knee - Is there a direct effect on the damaged cartilage?

BACKGROUND

Unloading knee braces represent a conservative treatment option for non-pharmalogical management of unicompartmental osteoarthritis of the knee. Though there is consensus on the clinical effectiveness of unloading, the effect mechanism of bracing remains part of a debate. Our study was designed to assess the effect of unloader bracing on damaged cartilage via MRI cartilage mappings.

METHODS

Fourteen patients (7 female, 7 male, mean age 43.1 ± 9.4 years) with unicompartmental cartilage wear in knees with varus or valgus malalignment were enrolled. Clinical scores, radiographs and MR-graphic properties (T2/T2* mapping, T1 Delayed Gadolinium Enhanced MRI of the cartilage (dGEMRIC) mapping, high-resolution PDw sequences) of knee cartilage were recorded before and three months after brace use.

RESULTS

Bracing the knees for a mean of 14.4 ± 2.0 weeks (range 11 to 18 weeks) resulted in significant pain reduction (VAS changed from 5.9 ± 2.0 to 2.0 ± 1.3, p < 0.001) and improvement in knee function (KOOS increased from 42.1 ± 22.7 to 64.8 ± 18.7, p < 0.001). In the affected cartilage regions T2 relaxation times significantly decreased from 56.1 ± 11.4 ms to 46.5 ± 11.2 ms (p < 0.05). No changes in T1-dGEMRIC and T2* relaxation times, thickness or the extent of the damaged cartilage area could be detected.

CONCLUSIONS

Our results suggest, that unloader bracing improves the biochemical properties of the damaged cartilage by increasing collagen and proteoglycan concentration as well as decreasing the cartilage edema.

Proposal of a New Rating Concept for Digital Health Applications in Orthopedics and Traumatology

BACKGROUND

Health-related mobile applications (apps) are rapidly increasing in number. There is an urgent need for assessment tools and algorithms that allow the usability and content criteria of these applications to be objectively assessed. The aim of this work was to establish and validate a concept for orthopedic societies to rate health apps to set a quality standard for their safe use.

METHODS

An objective rating concept was created, consisting of nine quality criteria. A self-declaration sheet for app manufacturers was designed. Manufacturers completed the self-declaration, and the app was examined by independent internal reviewers. The pilot validation and analysis were performed on two independent health applications. An algorithm for orthopedic societies was created based on the experiences in this study flow.

RESULTS

"Sprunggelenks-App" was approved by the reviewers with 45 (98%) fulfilled criteria and one (2%) unfulfilled criterion. "Therapie-App" was approved, with 28 (61%) met criteria, 6 (13%) unfulfilled criteria and 12 (26%) criteria that could not be assessed. The self-declaration completed by the app manufacturer is recommended, followed by a legal and technical rating performed by an external institution. When rated positive, the societies' internal review using independent raters can be performed. In case of a positive rating, a visual certification can be granted to the manufacturer for a certain time frame.

CONCLUSION

An objective rating algorithm is proposed for the assessment of digital health applications. This can help societies to improve the quality assessment, quality assurance and patient safety of those apps. The proposed concept must be further validated for inter-rater consistency and reliability.

Development of open backend structures for healthcare professionals to improve participation in app developments: A pilot study. (Preprint)

BACKGROUND

Efficient digitization in medicine still is in its infancy but undeniably has great potential for current and future challenges in health care. Thus far, the rollout of medical apps has not resulted in widespread use of smartphones in the German health care sector-the reasons for this have not been clarified so far. Nevertheless, the lack of user involvement in the development process and content creation might contribute to low acceptance of these products.

OBJECTIVE

This study aims to outline an approach to involve medical expertise without any coding knowledge for developing medical app content and functions.

METHODS

An end user-operable backend was built. Its usability was evaluated using a usability evaluation test protocol. The results of the usability tests were evaluated by the app development team, and the usability test was repeated for optimizing backend usability. In total, 40 criteria to measure the ease of app usage were defined a priori. The usability test comprised 20 tasks that had to be fulfilled. Usability tasks were analyzed for completion, dropout, and test duration. Due to the COVID-19 pandemic, digital videoconferencing platforms (Zoom and QuickTime Player) were used to complete usability questionnaires. Finally, several backend-based apps for several specialties (infectiology, plastic and reconstructive surgery, and orthopedics) were developed by health care professionals as prototypes.

RESULTS

Initial usability testing was conducted with 5 participants (4 men and 1 woman; mean age 39.2, SD 5.97 years). All of them could complete the assigned backend tasks with only a few workflow interruptions and some minor errors. After usability optimization, the workflow completion time decreased from 5.03 minutes to 3.50 minutes, indicating a time saving. The basic backend structure was clear to all test users and the handling was intuitive to learn. Some minor errors in the backend occurred during the test rounds. The apps developed using the aforementioned approach are in clinical use as a proof of concept.

CONCLUSIONS

Backends offering operability for medical professionals might have great potential for app development in the mobile health sector. Sophisticated and time-saving usability are pivotal for the acceptance of medical software, as illustrated by the backend-based apps presented herein, which are in clinical use as a proof of concept. Basic interventions are essential and sufficient for adequate usability optimization. Practicable, well-structured software usability evaluation is possible based on the usability evaluation test protocol.

Acceptance, Barriers, and Future Preferences of Mobile Health Among Patients Receiving Trauma and Orthopedic Surgical Care: Paper-Based Survey in a Prospective Multicenter Study

Background

Smartphones have become an essential part of everyday life and it is undeniable that apps offer enormous opportunities for dealing with future challenges in public health. Nevertheless, the exact patient requirements for medical apps in the field of orthopedic and trauma surgery are currently unknown.

Objective

The aim of this study was to define target groups, evaluate patient requirements, and the potential and pitfalls regarding medical apps specific for patients receiving orthopedic and trauma surgical care.

Methods

A prospective multicenter study was conducted between August 2018 and December 2019 at a German trauma center and 3 trauma surgery/orthopedic practices. A paper-based survey consisting of 15 questions evaluated information regarding smartphone and medical app usage behavior. In addition, suggested app functions were rated using Likert scales. Descriptive statistics and binary log-binomial regression were performed.

Results

A total of 1055 questionnaires were included in our statistical analysis. Approximately 89.57% (945/1055) of the patients in this study owned a smartphone. Smartphone ownership probability decreased with every decade of life and increased with higher levels of education. Medical information was obtained via mobile web access by 62.65% (661/1055) of the patients; this correlated with smartphone ownership in regard to age and educational level. Only 11.18% (118/1055) of the patients reported previous medical app usage, and 3.50% (37/1055) of the patients received an app recommendation from a physician. More than half (594/1055, 56.30%) of the patients were unwilling to pay for a medical app. The highest rated app functions were information about medication, behavioral guidelines, and medical record archival. An improved treatment experience was reported through the suggested app features by 71.18% (751/1055) of the patients.

Conclusions

Mobile devices are a widely used source of information for medical content, but only a minority of the population reported previous medical app usage. The main target group for medical apps among patients receiving orthopedic and trauma surgical care tends to be the younger population, which results in a danger of excluding fringe groups, especially the older adults. Education seems to be one of the most important pull factors to use smartphones or a mobile web connection to obtain health information. Medical apps primarily focusing on an optimized patient education and flow of information seem to have the potential to support patients in health issues, at least in their subjective perception. For future target group–oriented app developments, further evidence on the clinical application, feasibility, and acceptance of app usage are necessary in order to avoid patient endangerment and to limit socioeconomic costs.

Critical behavior in active lattice models of motility-induced phase separation

Lattice models allow for a computationally efficient investigation of motility-induced phase separation (MIPS) compared to off-lattice systems. Simulations are less demanding, and thus, bigger systems can be accessed with higher accuracy and better statistics. In equilibrium, lattice and off-lattice models with comparable interactions belong to the same universality class. Whether concepts of universality also hold for active particles is still a controversial and open question. Here, we examine two recently proposed active lattice systems that undergo MIPS and investigate numerically their critical behavior. In particular, we examine the claim that these systems and MIPS in general belong to the Ising universality class. We also take a more detailed look on the influence and role of rotational diffusion and active velocity in these systems.

Smartphone and App Usage in Orthopedics and Trauma Surgery: Survey Study of Physicians Regarding Acceptance, Risks, and Future Prospects in Germany

BACKGROUND

In the course of digitization, smartphones are affecting an increasing number of areas of users' lives, giving them almost ubiquitous access to the internet and other web applications. Mobile health (mHealth) has become an integral part of some areas of patient care. In contrast to other disciplines, routine integration of mobile devices in orthopedics and trauma surgery in Germany is still in its infancy.

OBJECTIVE

This study aimed to investigate physicians' current state of opinion regarding acceptance, future prospects, and risks of medical apps in the field of orthopedics and trauma surgery in Germany.

METHODS

A web-based survey among orthopedics and trauma surgeons in German university hospitals on the use of medical apps in everyday clinical practice was conducted between September 2018 and February 2019. The survey consisted of 13 open- and closed-ended or multiple-choice questions. A logistic regression analysis was performed to ascertain the effects of interindividual characteristics on the likelihood of participants' app and smartphone usage behavior.

RESULTS

A total of 206 physicians participated in the survey. All of the participants (206/206, 100%) owned a smartphone, and 79.1% (159/201) used the device, while 64.7% (130/201) used apps regularly in everyday clinical practice. Medical apps were perceived as beneficial, given their substantial future promise, by 90.1% (181/201) of the participants. However, 62.5% (120/192) of the participants were not satisfied with the current supply of medical apps in app stores. Desired specifications for future apps were "intuitive usability" (167/201, 83.1%), "no advertising" (145/201, 72.1%), and "free apps" (92/201, 45.8%). The attributes "transparent app development and app sponsoring" (75/201, 37.3%) and the existence of an "easy-to-understand privacy statement" (50/201, 24.9%) were of minor relevance. The majority of the participants (162/194, 83.5%) considered that future apps in the field of "medical research" would provide the greatest benefit. The greatest predicted risks were "data misuse" (147/189, 77.8%), "usage of untrustworthy apps" (135/189, 71.4%), and "alienation from patients" (51/189, 27.0%). Increasing age was significantly associated with a reduction in the likelihood of regular smartphone (odds ratio [OR] 0.91, 95% CI 0.86-0.97; P=.002) and app (OR 0.90, 95% CI 0.85-0.96; P=.001) usage, while the medical profession grade had no significant impact on the usage behavior.

CONCLUSIONS

The study demonstrates that young German doctors in orthopedics and trauma surgery already use smartphones and apps in everyday clinical practice. Medical apps are considered to play an important role in the future. However, a significant discrepancy exists between the supply and demand of mHealth applications, which creates a legal and ethical vacuum with regard to data protection.

A small series of pole sport injuries

Pole sport is a relatively new athletic sport that is gaining increasing popularity and for which national and international championships are held. It evolved from pole dance and harbours the risk of falls from heights of up to three metres. Currently, no studies on pole sport injuries are available. This is the first description of a small series of five pole sport injuries. A retrospective review of the case histories and radiological findings was performed, and in addition, a follow-up interview was carried out. All the patients were female and had a mean age of 27.2 years. Most injuries were located in the head, neck or spine. The use of proper training equipment like landing mats and grip aids could probably reduce accidents.

Magnetic Direct-Write Skyrmion Nanolithography

Magnetic skyrmions are stable spin textures with quasi-particle behavior and attract significant interest in fundamental and applied physics. The metastability of magnetic skyrmions at zero magnetic field is particularly important to enable, for instance, a skyrmion racetrack memory. Here, the results of the nucleation of stable skyrmions and formation of ordered skyrmion lattices by magnetic force microscopy in (Pt/CoFeSiB/W)_n multilayers, exploiting the additive effect of the interfacial Dzyaloshinskii-Moriya interaction, are presented. The appropriate conditions under which skyrmion lattices are confined with a dense two-dimensional liquid phase are identified. A crucial parameter to control the skyrmion lattice characteristics and the number of scans resulting in the complete formation of a skyrmion lattice is the distance between two adjacent scanning lines of a magnetic force microscopy probe. The creation of skyrmion patterns with complex geometry is demonstrated, and the physical mechanism of direct magnetic writing of skyrmions is comprehended by micromagnetic simulations. This study shows a potential of a direct-write (maskless) skyrmion (topological) nanolithography with sub-100 nm resolution, where each skyrmion acts as a pixel in the final topological image.

[Digitalization in orthopedics and trauma surgery: current status of clinical and practical aspects 2020]

Der vorliegende Beitrag behandelt aus Sicht von Orthopädie und Unfallchirurgie den aktuellen Stand Mitte 2020 im klinischen sowie im Praxisumfeld. Es wird auf Risiken, Schwierigkeiten ebenso wie Potenziale und Chancen im Detail eingegangen. Spezifisch werden die folgenden Themenbereiche erörtert: Telematikinfrastruktur, Apps und „mobile health“, Onlinevideosprechstunde, elektronische Patientenakte sowie Datenschutz. Es wird auf die Vor- und Nachteile und den jeweils aktuellen Stand im Spezialfall der Orthopädie und Unfallchirurgie eingegangen. Zudem werden 7 sinnvolle Beispiele aus dem Bereich der digitalen Anwendung genannt. Eine Mitgliederbefragung des Berufsverbandes der Orthopäden und Unfallchirurgen, BVOU, wird beschrieben und analysiert. Im abschließenden Ausblick werden die aktuellen Hürden und künftig zu klärende Themenbereiche adressiert.

Synovial bone sialoprotein indicates aseptic failure in total joint arthroplasty

Background

Until today, a reliable diagnostic discrimination between periprosthetic joint infections (PJI) and aseptic failure (AF) after total joint arthroplasty (TJA) remains challenging. Nearly all recent research focused on synovial markers to be elevated in PJI rather than in AF patients. In this study, synovial bone sialoprotein (sBSP) was investigated in PJI and AF arthroplasty patients before revision surgery.

Methods

sBSP and C-reactive protein (CRP) were determined in synovial fluid samples of PJI (n = 13) patients fulfilling the MSIS criteria and AF (n = 25) patients. Beside descriptive analysis and comparison, computed statistics determined the area under the receiver operating characteristics curve (AUC) to evaluate the discrimination ability of the tested synovial markers.

Results

In patients with PJI according to the MSIS criteria, mean sBSP was significantly lower: 14.8 ng/ml (95% CI 5.5-24.1) vs. 38.2 ng/ml in the AF group (95% CI 31.1-45.3), p ≤ 0.001. Conversely, mean sCRP was significantly higher in PJI patients: 8.4 μg/ml (95% CI 0-17.2) vs. 1.8 μg/ml in the AF group (95% CI 0.9-2.8), p = 0.032. The AUC of sCRP in PJI patients was 0.71. The AUC of sBSP in AF revision arthroplasty patients was 0.83. The detection of osteolyses was not associated with higher sBSP concentrations.

Conclusions

Considering the MSIS criteria, significantly higher sBSP concentrations were found in synovial fluid samples of AF compared to PJI patients. sCRP showed only fair, sBSP good discrimination potential. If it is not clear whether PJI is present or not, sBSP may be considered as an add-on synovial marker.

Analysis of Secure Apps for Daily Clinical Use by German Orthopedic Surgeons: Searching for the "Needle in a Haystack"

Background

It is undeniable that appropriate smartphone apps offer enormous opportunities for dealing with future challenges in orthopedic surgery and public health, in general. However, it is still unclear how the apps currently available in the two major app stores can be used in daily clinical routine by German orthopedic surgeons.

Objective

This study aimed to gain evidence regarding the quantity and quality of apps available in the two major app stores and their suitability for use by orthopedic surgeons in Germany.

Methods

We conducted a systematic, keyword-based app store screening to obtain evidence concerning the quantity and quality of commercially available apps. Apps that met the inclusion criteria were evaluated using the app synopsis–checklist for users and the German Mobile App Rating Scale for secure use, trustworthiness, and quality.

Results

The investigation revealed serious shortcomings regarding legal and medical aspects. Furthermore, most apps turned out to be useless and unsuitable for the clinical field of application (4242/4249, 99.84%). Finally, 7 trustworthy and high-quality apps (7/4249, 0.16%) offering secure usage in the daily clinical routine of orthopedists were identified. These apps mainly focused on education (5/7). None of them were CE (Conformité Européenne) certified. Moreover, there are no studies providing evidence that these apps have any positive use whatsoever.

Conclusions

The data obtained in our study suggest that the number of trustworthy and high-quality apps on offer is extremely low. Nowadays, finding appropriate apps in the fast-moving, complex, dynamic, and rudimentarily controlled app stores is most challenging. Promising approaches, for example, systematic app store screenings, app-rating developments, reviews or app libraries, and the creation of consistent standards have been established. However, further efforts are necessary to ensure that these innovative mobile health apps not only provide the correct information but are also safe to use in daily clinical practice.

The Digital Healthcare Act - a Turning Point in the German Digitisation Strategy?

The recently ratified Digital Healthcare Act - DVG - has paved the way, among other issues, for the prescription of health apps. The German DVG creates an entitlement to health apps for the very first time. However, this entitlement is initially limited to low-risk medical devices that have been included in the publicly accessible Register for Digital Health Applications by the German Federal Institute for Drugs and Medical Devices. Listing in the register is granted, if the manufacturer has submitted a health app and verified that it meets basic requirements for medical devices and data security as well as positive health care effects. It is questionable, whether the DVG will lead to sustainable improvements in future patient care. In order to pursue this question and align the DGOUC's digitization strategy closely with its basis, an online survey was conducted among the respective members on the DVG's content and its associated opportunities and risks. A total of 461 German-speaking, predominantly male, experienced and elderly physicians in leading positions took part in the survey. In this study, it was shown that the majority of the participating German orthopaedic and trauma surgeons is not familiar with the DVG's contents. Despite a fundamentally positive attitude towards digitization, scepticism about the use of "apps on prescription" and potential risks still prevails at present. The closing of ranks between medicine, IT and the legislature via interdisciplinary expert groups and the involvement of medical societies might be obligatory.

Results of advanced core decompression in patients with osteonecrosis of the femoral head depending on age and sex-a prospective cohort study

Background

Core decompression is a common surgical technique to treat osteonecrosis of the femoral head. The aim of this study is to evaluate the effect of the parameters “age” and “sex” on the outcome of this type of treatment.

Methods

A prospective cohort study was performed. Eighty-six osteonecrotic hips with a mean follow-up of 32.5 months (± 24.8) after advanced core decompression were analysed regarding age- and sex-dependent treatment failure. Additionally, the modified Harris Hip Score and Numeric Rating Scale were compared regarding the parameters age and sex.

Results

The mean hip survival of the male participants was 51.3 months (39.4% treatment failure), whereas females presented a longer, thus not significant, mean survival of 61.4 months (30% therapy failure; p = 0.48). The further evaluation revealed significantly better survival in the patients aged < 40 years (mean survival 66.09 months, 16% treatment failure) in comparison to those aged ≥ 40 years (mean survival 50.14 months, 46% therapy failure; p = 0.03). The modified Harris Hip Score and Numeric Rating Scale results of patients whose treatment did not fail during the study period were similar, irrespective of the patient’s sex or age.

Conclusions

The study shows that the number of therapy failures is significantly higher in older patients, with 40 years of age marking the borderline. Patients’ sex does not seem to affect the outcome of treatment, and postoperative clinical scores appear to be identical with individuals not affected by therapy failure. Since age and sex are unalterable parameters, the study helps to provide valuable predictions regarding the chances of long-term hip survival after treatment of osteonecrosis.

A Possible Mobile Health Solution in Orthopedics and Trauma Surgery: Development Protocol and User Evaluation of the Ankle Joint App

Background

Ankle sprains are one of the most frequent sports injuries. With respect to the high prevalence of ankle ligament injuries and patients’ young age, optimizing treatment and rehabilitation is mandatory to prevent future complications such as chronic ankle instability or osteoarthritis.

Objective

In modern times, an increasing amount of smartphone usage in patient care is evident. Studies investigating mobile health (mHealth)–based rehabilitation programs after ankle sprains are rare. The aim of this study was to expose any issues present in the development process of a medical app as well as associated risks and chances.

Methods

The development process of the Ankle Joint App was defined in chronological order using a protocol. The app’s quality was evaluated using the (user) German Mobile App Rating Scale (MARS-G) by voluntary foot and ankle surgeons (n=20) and voluntary athletes (n=20).

Results

A multidisciplinary development team built a hybrid app with a corresponding backend structure. The app’s content provides actual medical literature, training videos, and a log function. Excellent interrater reliability (interrater reliability=0.92; 95% CI 0.86-0.96) was obtained. The mean overall score for the Ankle Joint App was 4.4 (SD 0.5). The mean subjective quality scores were 3.6 (surgeons: SD 0.7) and 3.8 (athletes: SD 0.5). Behavioral change had mean scores of 4.1 (surgeons: SD 0.7) and 4.3 (athletes: SD 0.7). The medical gain value, rated by the surgeons only, was 3.9 (SD 0.6).

Conclusions

The data obtained demonstrate that mHealth-based rehabilitation programs might be a useful tool for patient education and collection of personal data. The achieved (user) MARS-G scores support a high quality of the tested app. Medical app development with an a priori defined target group and a precisely intended purpose, in a multidisciplinary team, is highly promising. Follow-up studies are required to obtain funded evidence for the ankle joints app’s effects on economical and medical aspects in comparison with established nondigital therapy paths.

Long-Term Radiographic Changes in Stemless Press-Fit Total Shoulder Arthroplasty

INTRODUCTION

Stemmed humeral implants have represented the gold standard in total shoulder arthroplasty (TSA) for decades. Like many other joints, the latest trends in TSA designs aim at bone preservation. Current studies have demonstrated that native proximal humeral bone stresses are most closely mimicked by stemless implants. Nevertheless, there are concerns about the long-term performance of stemless designs. The aim of the present study was to evaluate the long-term radiographic changes at the proximal humerus in anatomical stemless press-fit TSA.

MATERIALS AND METHODS

Between 2008 and 2010, 48 shoulders in 43 patients were resurfaced using an anatomic stemless shoulder prosthesis (TESS, Biomet). Thirty shoulders in twenty-five patients who were aged 65.7 ± 9.9 (34 to 82) years were available for clinical and radiographic review at a mean follow-up of 94.0 ± 8.9 (78 to 110) months.

RESULTS

Radiographic changes of the proximal humerus due to stress shielding were found in 38.4% of the stemless TESS implants. Mild stress shielding accounted for 80% of the observed radiographic changes. Radiographs exhibited stable fixation of the stemless humeral press-fit implant at early and late follow-up. In contrast, radiolucent lines at the glenoid implant were found in 96.1% of the cases. Irrespective of the degree of radiographic changes, clinical scores (VAS, Quick-DASH, Constant score) significantly improved at follow-up.

CONCLUSIONS

The anatomic stemless press-fit implant seems to be favorable in terms of implant-related stress shielding. Clinical outcome was not affected by radiographic changes, demonstrating an 8-year clinical performance that seems to be comparable to conventional stemmed TSA.

[Apps in clinical use in orthopedics and trauma surgery : The status quo in Germany]

In the course of digitalization the smartphone is penetrating more and more areas of life giving the user mobile and almost ubiquitous access to the internet and other web applications. The advantages of mHealth are an integral part in some areas of patient care but in contrast to other disciplines, routine integration of mobile devices into orthopedics and trauma surgery is still in its infancy. A survey among German orthopedists and trauma surgeons revealed which kind of apps have become established in everyday clinical practice to date. Apps published by representative institutions such as the AO Foundation demonstrated the highest usage rates. In summary, the number of regularly used apps is low; however, the causes of this lack of acceptance have not yet been conclusively clarified. The authors of this study proclaim a significant increase in the use of mHealth and mobile devices in daily clinical practice in the future.

Long-term results of the reverse Total Evolutive Shoulder System (TESS)

INTRODUCTION

Latest trends in shoulder replacement aim at bone stock preservation. Long-term results of stemless anatomical total shoulder implants compare favourably with stemmed designs in terms of function and survivorship. The Total Evolutive Shoulder System (TESS) has been one of the first designs offering a stemless implant not only for anatomical but also for reverse total shoulder arthroplasty with optional short stem attachment in cases with poor bone quality. The aim of the present study was to evaluate long-term results of the reverse Total Evolutive Shoulder System (TESS).

MATERIALS AND METHODS

Between 2006 and 2009, 49 shoulders in 47 patients were replaced using the Biomet reverse Total Evolutive Shoulder System (TESS). 29 shoulders in 27 patients who were aged 72.4 ± 6.7 (53-88) years were available for review at a mean follow-up of 101.6 ± 24.6 (75-142) months.

RESULTS

The implant survival rate was 93.1% at 101 months (8.4 years). The overall revision rate of the TESS implant was 17.2%. No implant associated complications to the reverse corolla implant could be observed. All reverse corolla implants showed solid fixation at follow-up. Scapular notching was found in 72.3% of the shoulders. Clinical scores significantly improved at long-term follow-up (VAS from 7.5 ± 1.2 to 1.4 ± 1.5, p < 0.001; quick-DASH from 70.9 ± 12.0 to 28.9 ± 22.9, p < 0.001 and Constant score from 13.0 ± 3.7 to 60.5 ± 16.8, p < 0.001).

CONCLUSIONS

In terms of clinical scores, radiographic loosening, complication rates and implant survivorship the reverse Total Evolutive Shoulder System provides results comparable to those of conventional stemmed reverse shoulder arthroplasty.

Neurodevelopmental outcome and pulmonary morbidity two years after early versus late surfactant treatment: does it really differ?

AIM

To investigate whether neurodevelopmental outcome or pulmonary morbidity at age two years might be different after early versus late surfactant treatment in intubated preterm infants with severe respiratory distress syndrome (RDS).

METHODS

In 185 ex-preterm infants of 27-32 completed weeks of gestation, who were enrolled in a controlled trial of early versus late surfactant treatment (31 +/- 19 min vs. 202 +/- 80 min, respectively), a standardized follow up of medical history, pulmonary morbidity and neurodevelopmental outcome using the Griffiths scales were carried out.

RESULTS

Neurobehavioural and motor development was comparable in both groups, as was medical history and actual morbidity. However, in the early treatment group a delay in the subscale 'personal social' of the Griffiths test and in one 'milestone' of motor development (rolling over from supine to prone) was noticed, and the rate of increased muscular tone was significantly higher.

CONCLUSION

In terms of long-term morbidity or neurological development there is no obvious advantage of an immediate surfactant administration after intubation in preterm infants with RDS. This is in line with our results published earlier on morbidity at discharge, so improvement of gas exchange after intubation can first be awaited before surfactant is indicated.

Production of polyunsaturated fatty acids by polyketide synthases in both prokaryotes and eukaryotes

Polyunsaturated fatty acids (PUFAs) are essential membrane components in higher eukaryotes and are the precursors of many lipid-derived signaling molecules. Here, pathways for PUFA synthesis are described that do not require desaturation and elongation of saturated fatty acids. These pathways are catalyzed by polyketide synthases (PKSs) that are distinct from previously recognized PKSs in both structure and mechanism. Generation of cis double bonds probably involves position-specific isomerases; such enzymes might be useful in the production of new families of antibiotics. It is likely that PUFA synthesis in cold marine ecosystems is accomplished in part by these PKS enzymes.

Estrogen-inducible, sex-specific expression of brain-derived neurotrophic factor mRNA in a forebrain song control nucleus of the juvenile zebra finch

The expression of brain-derived neurotrophic factor (BDNF) mRNA is increased significantly within the high vocal center (HVc) of male but not female zebra finches from posthatching day 30-35 on. The population of HVc cells expressing BDNF mRNA included 35% of the neurons projecting to the nucleus robustus of the archistriatum (RA). In the RA and in RA-projecting neurons of the lateral portion of the magnocellular nucleus of the anterior neostriatum, BDNF mRNA was expressed at very low levels in both sexes. The BDNF-receptor trkB mRNA was expressed in the RA, in RA-projecting neurons of lateral portion of the magnocellular nucleus of the anterior neostriatum, and in the HVc, except in most of its RA-projecting neurons. Premature stimulation and an inhibitory effect on the normal increase of the BDNF mRNA expression in juvenile males occurred after treatments with 17beta-estradiol and the aromatase inhibitor fadrozole, respectively. The up-regulation of the BDNF expression in the HVc could be a mechanism by which estrogen triggers the differentiation of cells within and connected to the HVc of male zebra finches.

"Cut and combine": an easy membrane-supported combinatorial synthesis technique

A combinatorial synthesis process involving sequential cycles of cutting a membrane support into pieces and combining these into groups and subjecting the groups to simultaneous solid-phase chemical reactions is demonstrated by the rapid assembly of four hundred N-terminally biotinylated, soluble, octameric peptide pools. Index patterns printed onto the synthesis membrane allowed a direct identification of the compounds. These were used to study protein kinase substrate selection in a parallel microplate adapted 32P-phosphorylation assay with subsequent spotting on a biotin-capture membrane.

Fatty acid elongation in yeast--biochemical characteristics of the enzyme system and isolation of elongation-defective mutants

Elongation of long-chain fatty acids was investigated in yeast mutants lacking endogenous de novo fatty acid synthesis. In this background, in vitro fatty acid elongation was dependent strictly on the substrates malonyl-CoA, NADPH and a medium-chain or long-chain acyl-CoA primer of 10 or more carbon atoms. Maximal activity was observed with primers containing 12-14 carbon atoms, while shorter-chain-length acyl-CoA were almost (octanoyl-CoA) or completely (hexanoyl-CoA, acetyl-CoA) inactive. In particular, acetyl-CoA was inactive as a primer and as extender unit. The Michaelis constants for octanoyl-CoA (0.33 mM), decanoyl-CoA (0.83 mM) lauroyl-CoA (0.05 mM), myristoyl-CoA (0.4 mM) and palmitoyl-CoA (0.13 mM) were determined and were comparable for fatty acid synthesis and elongation. In contrast, the affinity of malonyl-CoA was 17-fold lower for elongation (Km = 0.13 mM) than for the fatty acid synthase (FAS) system. With increasing chain length of the primer (> or = 12:0), fatty acid elongation becomes increasingly sensitive to substrate inhibition. Due to the activation of endogenous fatty acids, ATP exhibits a stimulatory effect at suboptimal but not at saturating substrate concentrations. In the yeast cell homogenate, the specific activity of fatty acid elongation is about 10-20-fold lower than that of de novo fatty acid synthesis. The same elongation activity is observed in respiratory competent and in mitochondrially defective cells. The products of in vitro fatty acid elongation are fatty acids of 15-17 or 22-26 carbon atoms, depending on whether tridecanoyl-CoA or stearoyl-CoA is used as a primer. In vitro, the elongation products are converted in part, by alpha-oxidation, to their odd-chain-length lower homologues or are hydrolyzed to fatty acids. In contrast, no odd-chain-length elongation products or very-long-chain fatty acids (VLCFA) shorter than 26:0 are observed in vivo. Hence, VLCFA synthesis exhibits a higher processivity in vivo than in the cell homogenate. In addition, the in vivo process appears to be protected against side reactions such as hydrolysis or alpha-oxidation. Yeast mutants defective in 12:0 or 13:0 elongation were derived from fas-mutant strains according to their failure to grow on 13:0-supplemented media. In vivo, 12:0 elongation was reduced to 0-10% of the normal level, while 16:0 elongation and VLCFA synthesis were unimpaired. It is concluded that yeast contains either two different elongation systems, or that the respective mutation interferes differentially with medium-chain and long-chain fatty acid elongation. The yeast gene affected in the elongation-defective mutants was isolated and, upon sequencing, identified as the known ELO1 sequence. It encodes a putative membrane protein of 32-kDa molecular mass with no obvious similarity to any of the known FAS component enzymes.

Pharmacokinetics of intrathecally applied BDNF and effects on spinal motoneurons

Brain-derived neurotrophic factor (BDNF) is a potential drug for treatment of amyotrophic lateral sclerosis. Previous studies have demonstrated little or no penetration of the blood-brain barrier by BDNF, hence systemic application does not result in significant penetration into the spinal cord to produce direct action on motoneurons. Intrathecal (i.th) application of BDNF to sheep was investigated as a mean of topical administration. After continuous infusion a caudalcranial gradient of BDNF concentration in cerebrospinal fluid (CSF) and at the meninges was observed. BDNF did not penetrate spinal parenchyma but accumulated in spinal motoneurons probably due to axonal uptake in ventral roots and subsequent retrograde transport. Spinal motoneurons showed reduced levels of tropomyosin receptor kinase (trk) B and increased levels of c-fos at high BDNF doses in comparison to treatment with saline, even after treatment periods of several months. After bolus injection and cessation of continuous delivery multiphasic reduction of the BDNF concentration in CSF was detected. Our study demonstrates that i.th. application of BDNF is feasible, setting the stage for future clinical trials.

Actions of CNTF and neurotrophins on degenerating motoneurons: preclinical studies and clinical implications

Spinal motoneurons innervating skeletal muscle were amongst the first neurons shown to require the presence of their target cells to develop appropriately. Isolated embryonic chick and rat motoneurons have been used to identify neurotrophic factors and cytokines capable of supporting the survival of developing motoneurons. Such factors include ciliary neurotrophic factor (CNTF), which is present physiologically in high amounts in myelinating Schwann cells of peripheral nerves, and brain-derived neurotrophic factor (BDNF) which is synthesized in skeletal muscle and, after peripheral nerve lesion, in Schwann cells. These factors have been further analyzed for their physiological significance in maintaining motoneuron function in vivo, and for their potential therapeutic usefulness in degenerative motoneuron disease. Both CNTF and BDNF are capable of rescuing injured facial motoneurons in newborn rats. Furthermore, CNTF prolongs survival and improves motor function of pmn mice, an animal model for degenerative motoneuron disease, by preventing degeneration of motoneuron axons and somata. Thus treatment of human motoneuron disease with neurotrophic factors should be possible, provided that rational means for application of these factors can be established considering also the appearance of potential side effects.

Identification of the mouse helper T lymphocyte differentiation antigen 3G11 as the ganglioside IV3(NeuAc)2-GgOse4Cer

The 3G11 antigen, originally defined by the monoclonal antibody SM3G11, is expressed to different extents by distinct murine CD4+ T helper cell subsets. This antigen was isolated from a 3G11+ murine thymoma by lipid extraction. Upon further purification 3G11 antigen was enriched in the disialoganglioside fraction and was finally purified by HPLC. Compositional and methylation analysis, liquid secondary ion mass spectroscopy (LSI-MS) and comparison with an authentic sample resulted in identification of the 3G11 antigen as the disialoganglioside IV3(NeuAc)2-GgOse4Cer.

Ciliary neurotrophic factor: pharmacokinetics and acute-phase response in rat

Ciliary neurotrophic factor (CNTF) supports the survival of motoneurons in vitro and in vivo. Recombinant CNTF is an investigational drug for the treatment of amyotrophic lateral sclerosis. We determined the pharmacokinetics of radioiodinated CNTF after intravenous injection into rats. CNTF shows a biphasic clearance with an initial plasma half-life of 2.9 minutes and is removed from the circulation by the liver. No accumulation of radioactivity was detectable in nerve tissue or skeletal muscle after intravenous injection of 0.1 microgram and 0.5 microgram of CNTF. Radioactive degradation products accumulate in the skin. Liver cells express specific binding proteins for CNTF, and the incorporation and degradation of intravenously injected CNTF by the liver may occur after association of CNTF with the soluble CNTF receptor alpha in the circulation. Probably as a consequence of its binding to hepatocytes, CNTF induces acute-phase responses in liver. The short half-life and the inflammatory side effect may limit the clinical usefulness of systematically administered CNTF in the treatment of human motoneuron disorders.

Characterisation of high-affinity and low-affinity receptors for ciliary neurotrophic factor

Ciliary neurotrophic factor (CNTF) supports the survival of a wide variety of neuronal cells in culture. To characterise the receptor(s) mediating the biological responses of CNTF we measured the binding of radiolabelled CNTF to chick sympathetic neurons and human neuroblastoma cells. Two distinct CNTF-binding sites with high and low affinity for the ligand were identified by steady-state binding experiments. Furthermore, two low-affinity binding sites could be discriminated on the basis of the dissociation rates. Cross-linking experiments showed that CNTF interacts with two proteins, one of 80 kDa and one of 140 kDa. The identity of the 80-kDa protein was determined by transient transfection experiments with the rat CNTF-binding protein CNTFR alpha while the properties of the 140-kDa protein correspond to those of gp130. Antisense experiments confirmed that CNTFR alpha is necessary for high affinity binding of 125I-CNTF and therefore a necessary subunit of the high-affinity receptor.

[Effect of phototoxic substances on simple biological systems. I. Standardizing the method with furocoumarins]

As a basis for the investigation of new substances in respect of their photosensitization effects, we established and standardized 3 microbiological test systems, which enabled us to do without animal experiments. Using several furocumarines and various sources of light, we performed a comparative study on the eukaryotes, Chlamydomonas reinhardii (CR) and Candida albicans, and the prokaryote, Bacillus subtilis. We found that, if different light qualities were employed, our test systems also allowed a comparison of different substances by means of half-quantitative evaluation of the inhibiting areolas, which appear after exposure. With regard to the furocumarines, 8- and 5-methoxypsoralene (MOP) had the strongest photosensitizing effect under all test conditions. The remaining furocumarines showed decreasing effectiveness from psoralene to trimethylpsoralene (TMP) and imperatorine; psoralene, however, was slightly more effective in CR than 5-MOP. With the exception of CR, TMP had a stronger effect on the micro-organisms than imperatorine.

[The effect of mucous excipient concentration on bioadhesion ex vivo]

The bioadhesion of aqueous solutions of polyacrylics (1-3), hydroxyethylcellulose (4), sodium carboxymethylamylopectin (5), polyvinylalcohol (6) and tragant (7) was investigated using a tensiometer and fresh intestine of pigs. It was dependent on the concentration of the excipient as described by a quadratic equation and found in the maximum from 244 Pa (7) to 554 Pa (4). The maximum of bioadhesion corresponds to the concentration of the excipient from 0.15% (2) to 23.7% (4) and to the viscosity of the solutions from 0.11 Pa.s (3) to 3.6.10(6) Pa.s (4). There was not a correlation between the viscosity and the bioadhesion.