Mucoadhesive polymers: Design of S-protected thiolated cyclodextrin-based hydrogels

AIM

This study aims to design chemically crosslinked thiolated cyclodextrin-based hydrogels and to evaluate their mucoadhesive properties via mucosal residence time studies on porcine small intestinal mucosa and on porcine buccal mucosa.

METHODS

Free thiol groups of heptakis(6-deoxy-6-thio)-β-cyclodextrin (β-CD-SH) were S-protected with 2-mercaptoethanesulfonic acid (MESNA) followed by crosslinking with citric acid. Cytotoxicity was assessed by hemolysis as well as resazurin assay. Hydrogels were characterized by their rheological and mucoadhesive properties. Ritonavir was employed as model drug for in vitro release studies from these hydrogels.

RESULTS

The structure of S-protected β-CD-SH was confirmed by IR and 1H NMR spectroscopy. Degree of thiolation was 390 ± 7 µmol/g. Hydrogels based on native β-CD showed hemolysis of 12.5 ± 2.5 % and 13.6 ± 2.7 % within 1 and 3 h, whereas hemolysis of just 3.5 ± 2.8 % and 3.9 ± 3.0 % was observed for the S-protected thiolated CD hydrogels, respectively. Both native and S-protected thiolated hydrogels showed minor cytotoxicity on Caco-2 cells. Rheological investigations of S-protected thiolated β-CD-based hydrogel (16.2 % m/v) showed an up to 13-fold increase in viscosity in contrast to the corresponding native β-CD-based hydrogel. Mucosal residence time studies showed that thiolated β-CD-based hydrogel is removed to a 16.6- and 2.4-fold lower extent from porcine small intestinal mucosa and porcine buccal mucosa in comparision to the native β-CD-based hydrogel, respectively. Furthermore, a sustained release of ritonavir from S-protected thiolated β-CD-based hydrogels was observed.

CONCLUSION

Because of their comparatively high mucoadhesive and release-controlling properties, S-protected thiolated β-CD-based hydrogels might be promising systems for mucosal drug delivery.

Fluorescent hydrophobic ion pairs: A powerful tool to investigate cellular uptake of hydrophobic drug complexes via lipid-based nanocarriers

HYPOTHESIS

Hydrophobic ion pairs (HIPs) between two fluorescent components and incorporation into nanoemulsions (NE) allows tracking in cellular uptake studies.

EXPERIMENTS

HIPs were formed between propidium iodide and 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine-N-(7-nitro-2-1,3-benzoxadiazol-4-yl) (NBD-PE), azure A chloride and NBD-PE or coumarin 343 and 4-(4-dihexadecylaminostyryl)-N-methylpyridinium iodide) (DiA). Fluorescence spectra of the resulting complexes were recorded. HIPs were loaded into zwitterionic NE and their size, stability in different media, haemolytic properties and cytotoxicity were evaluated. Furthermore, cellular uptake at 37 °C and 4 °C was investigated via flow cytometry and confocal microscopy.

FINDINGS

HIP-formation increased lipophilicity of the hydrophilic model drugs. NE exhibited a size between 80 and 150 nm and were not toxic in concentrations up to 0.1 % but showed high haemolytic properties. Cellular uptake of propidium, azure A and coumarin 343 were 8-fold, 115-fold and 1.3-fold improved by the formation of HIPs and up to 59-fold, 120-fold and 50-fold by incorporating these HIPs in NE, respectively. Lower uptake was observed at 4 °C. In case of propidium/ NBD-PE and azure A/ NBD-PE HIPs, propidium and azure A were delivered into the cytosol, whereas NBD-PE was unable to enter cells. In case of coumarin 343/ DiA HIPs, both components accumulated in the cell membrane. Therefore, HIPs between two fluorescent compounds are a powerful tool to investigate cellular uptake of hydrophobic complexes via nanocarriers by visualization of their cellular distribution.

Self-Emulsifying Drug Delivery Systems (SEDDS) Containing Reverse Micelles: Advanced Oral Formulations for Therapeutic Peptides

Alternative methods to hydrophobic ion pairing for the formation of lipophilic complexes of peptide drugs to incorporate them in lipid-based nanocarriers such as self-emulsifying drug delivery systems (SEDDS) for oral administration are highly on demand. Such an alternative might be reverse micelles. Within this study, SEDDS containing dry reverse micelles (dRMsPMB ) formed with an anionic (sodium docusate; AOT), cationic (dimethyl-dioctadecyl-ammonium bromide; DODAB), amphoteric (soy lecithin; SL), or non-ionic (polysorbate 85; P85) surfactant loaded with the model peptide drug polymyxin B (PMB) are developed. They are characterized regarding size, payload, release kinetics, cellular uptake, and peptide activity. SEDDS exhibit sizes from 22.2 ± 1.7 (AOT-SEDDS-dRMsPMB ) to 61.7 ± 3.2 nm (P85-SEDDS-dRMsPMB ) with payloads up to 2% that are approximately sevenfold higher than those obtained via hydrophobic ion pairing. Within 6 h P85-SEDDS-dRMsPMB and AOT-SEDDS-dRMsPMB show no release of PMB in aqueous medium, whereas DODAB-SEDDS-dRMsPMB and SL-SEDDS-dRMsPMB show a sustained release. DODAB-SEDDS-dRMsPMB improves uptake by Caco-2 cells most efficiently reaching even ≈100% within 4 h followed by AOT-SEDDS-dRMsPMB with ≈20% and P85-/SL-SEDDS-dRMsPMB with ≈5%. The peptide drug maintains its antimicrobial activity in all SEDDS-dRMsPMB . According to these results, SEDDS containing dRMs might be a game changing strategy for oral peptide drug delivery.

PEG vs. zwitterions: How these surface decorations determine cellular uptake of lipid-based nanocarriers

AIM

To evaluate the impact of polyethylene glycol (PEG) and zwitterionic surface decoration of lipid-based nanocarriers (NC) on cellular uptake.

METHODS

Anionic, neutral and cationic zwitterionic lipid-based NCs based on lecithin were compared with conventional PEGylated lipid-based NCs regarding stability in biorelevant fluids, interaction with endosome mimicking membranes, cytocompatibility, cellular uptake and permeation across intestinal mucosa.

RESULTS

PEGylated and zwitterionic lipid-based NCs exhibited a droplet size between 100 and 125 nm with a narrow size distribution. For the PEGylated and zwitterionic lipid-based NCs only minor alterations in size and PDI in fasted state intestinal fluid and mucus containing buffer were observed, demonstrating similar bioinert properties. Erythrocytes interaction studies revealed enhanced endosomal escape properties for zwitterionic lipid-based NCs compared to PEGylated lipid-based NCs. For the zwitterionic lipid-based NCs negligible cytotoxicity on Caco-2 and HEK cells, even in the highest tested concentration of 1 % (v/v) was recorded. The PEGylated lipid-based NCs showed a cell survival of ≥75 % for concentrations ≤0.05 % on Caco-2 and HEK cells, which was considered as non-toxic. For the zwitterionic lipid-based NCs up to 60-fold higher cellular uptake on Caco-2 cells was determined compared to PEGylated lipid-based NCs. For the cationic zwitterionic lipid-based NCs the highest cellular uptake with 58.5 % and 40.0 % in Caco-2 and HEK cells, respectively, was determined. The results were confirmed visually by life cell imaging. Ex-vivo permeation experiments using rat intestinal mucosa demonstrated up to 8.6-fold enhanced permeation of the lipophilic marker coumarin-6 in zwitterionic lipid-based NCs compared to the control. Up to 6.9-fold enhanced permeation of coumarin-6 in neutral zwitterionic lipid-based NCs compared to the PEGylated counterpart was recorded.

CONCLUSION

The replacement of PEG surfactants with zwitterionic surfactants is a promising approach to overcome the drawbacks of conventional PEGylated lipid-based NCs regarding intracellular drug delivery.

Oral drug delivery: Influence of mucus on cellular interactions and uptake of lipid-based nanocarriers in Caco-2 cells

This study aimed to investigate the impact of the mucus gel barrier on intestinal mucosal uptake of lipid-based nanocarriers (NCs). Zwitterionic- (ZW), polyglycerol- (PG) and polyethylene glycol- (PEG) surfactant-based o/w nanoemulsions were developed. NCs were assessed regarding their size and zeta potential, stability in biorelevant media and mucus, mucus permeation behavior, cellular interactions and uptake by Caco-2 cells with and without mucus and by a Caco-2/HT29-MTX co-culture. All NCs were in the size range of 178 - 204 nm and exhibited a zeta potential between -4.2 and +1.2 mV. ZW- and PG-NCs demonstrated mucus permeating properties comparable to PEG-NCs. In contrast, ZW- and PG-NCs showed high cellular uptake, whereas limited cellular uptake was observed in case of PEG-NCs. Furthermore, mucus on Caco-2 cells as well as the mucus secreting co-culture had a significant impact on the cellular uptake of all tested NCs. According to these results, ZW- and PG-NCs are advantageous to overcome the mucus and epithelial barrier of the intestinal mucosa. STATEMENT OF SIGNIFICANCE: Within this study the impact of mucus on cellular uptake of lipid-based nanocarriers (NCs) with different surface decorations was investigated. The potential of NCs with zwitterionic-, polyglycerol- and polyethylene glycol-surfactants on their surface to overcome the mucus and epithelial barrier was evaluated. Zwitterionic- and polyglycerol-NCs showed mucus permeating properties similar to PEG-NCs. In contrast, zwitterionic- and polyglycerol-NCs substantially outperformed PEG-NCs in their cellular uptake properties. According to these findings, zwitterionic- and polyglycerol-NCs have the potential to overcome both the mucus and epithelial barrier of the mucosa.

Beyond the behavioural phenotype: Uncovering mechanistic foundations in aquatic eco-neurotoxicology

During the last decade, there has been an increase in awareness of how anthropogenic pollution can alter behavioural traits of diverse aquatic organisms. Apart from understanding profound ecological implications, alterations in neuro-behavioural indices have emerged as sensitive and physiologically integrative endpoints in chemical risk assessment. Accordingly, behavioural ecotoxicology and broader eco-neurotoxicology are becoming increasingly popular fields of research that span a plethora of fundamental laboratory experimentations as well as applied field-based studies. Despite mounting interest in aquatic behavioural ecotoxicology studies, there is, however, a considerable paucity in deciphering the mechanistic foundations underlying behavioural alterations upon exposure to pollutants. The behavioural phenotype is indeed the highest-level integrative neurobiological phenomenon, but at its core lie myriads of intertwined biochemical, cellular, and physiological processes. Therefore, the mechanisms that underlie changes in behavioural phenotypes can stem among others from dysregulation of neurotransmitter pathways, electrical signalling, and cell death of discrete cell populations in the central and peripheral nervous systems. They can, however, also be a result of toxicity to sensory organs and even metabolic dysfunctions. In this critical review, we outline why behavioural phenotyping should be the starting point that leads to actual discovery of fundamental mechanisms underlying actions of neurotoxic and neuromodulating contaminants. We highlight potential applications of the currently existing and emerging neurobiology and neurophysiology analytical strategies that should be embraced and more broadly adopted in behavioural ecotoxicology. Such strategies can provide new mechanistic discoveries instead of only observing the end sum phenotypic effects.

Better Information From Survey Data: Filtering Out State Dependence Using Eye-Tracking Data

Ideally, survey respondents read and understand survey instructions, questions, and response scales, and provide answers that carefully reflect their beliefs, attitudes, or knowledge. However, respondents may also arrive at their responses using cues or heuristics that facilitate the production of a response, but diminish the targeted information content. We use eye-tracking data as covariates in a Bayesian switching-mixture model to identify different response behaviors at the item-respondent level. The model distinguishes response behaviors that are predominantly influenced either positively or negatively by the previous response, and responses that reflect respondents' preexisting knowledge and experiences of interest. We find that controlling for multiple types of adaptive response behaviors allows for a more informative analysis of survey data and respondents.

Analysis of tail coiling activity of zebrafish (Danio rerio) embryos allows for the differentiation of neurotoxicants with different modes of action

In (eco)toxicology, there is a critical need for efficient methods to evaluate the neurotoxic potential of environmental chemicals. Recent studies proposed analysis of early coiling activity in zebrafish embryos as a powerful tool for the identification of neurotoxic compounds. In order to demonstrate that the analysis of early tail movements of zebrafish embryos allows for the discrimination of neurotoxicants acting via different mechanisms, the present study investigated the effects of four different neurotoxicants on the embryogenesis (fish embryo toxicity test) and early tail coiling movements of zebrafish embryos. Cadmium predominantly increased the frequency of tail coiling at the late pharyngula stage. Dichlorvos delayed embryonic development and caused convulsive tail movements resulting in prolonged duration of tail coils. Embryos exposed to teratogenic concentrations of fluoxetine and citalopram displayed absence of spontaneous tail movements at 24 h post-fertilization. In contrast, a non-teratogenic test concentration of citalopram decreased coiling frequency at multiple time points. Results demonstrated that the analysis of tail coiling movements of zebrafish embryos has the potential to discriminate neurotoxic compounds with different primary modes of action. In addition, chemical-induced effects on coiling activity were shown to potentially overlap with effects on embryogenesis. Further studies are needed to clarify the interplay of unspecific developmental toxicity of neurotoxic chemicals and effects resulting from specific neurotoxic mechanisms.

[Epidemiology, injury entities and treatment practice for chest wall injuries : Current scientific knowledge and treatment recommendations]

BACKGROUND

Fractures of the bony chest wall are common injuries. They affect almost every second severely injured person and are gaining more and more importance even after low-energy accidents, especially among older people. Complications mainly occur due to respiratory insufficiency, secondary pulmonary complications and remaining deformities with a functional disorder of the chest wall. In addition to the important conservative therapeutic measures, such as a differentiated pain therapy and pneumonia prophylaxis, operative stabilization of fractures can be an option; however, this is still controversially discussed.

OBJECTIVE

A thematically structured overview provides basic knowledge on rib and sternal fractures as well as the treatment options.

MATERIAL AND METHODS

Epidemiological facts are presented based on the relevant literature and clinical experience. Anatomical principles are intended to improve understanding of the various entities of rib and sternal fractures. For this purpose, the new AO‑/OTA classification system is presented and finally therapeutic options including different osteosynthesis procedures are presented and their importance discussed.

RESULTS AND DISCUSSION

Multimodal therapy concepts and closely controlled follow-up examinations of fractures avoid complications or can detect them early. Bony chest wall injuries should still be evaluated for complications and typical fracture patterns identified and classified. Modern osteosynthesis procedures with high patient safety and soft tissue-preserving tissue preparation for the surgical access route to the ribs and sternum provide an excellent opportunity for successful restoration of the anatomical and physiological integrity of the bony thorax.

Spider prey-wrapping silk is an α-helical coiled-coil/β-sheet hybrid nanofiber

Solid-State NMR results on 13C-Ala/Ser and 13C-Val enriched Argiope argentata prey-wrapping silk show that native, freshly spun aciniform silk nanofibers are dominated by α-helical (∼50% total) and random-coil (∼35% total) secondary structures, with minor β-sheet nanocrystalline domains (∼15% total). This is the most in-depth study to date characterizing the protein structural conformation of the toughest natural biopolymer: aciniform prey-wrapping silks.

In search of a comprehensible set of endpoints for the routine monitoring of neurotoxicity in vertebrates: sensory perception and nerve transmission in zebrafish (Danio rerio) embryos

In order to develop a test battery based on a variety of neurological systems in fish, three sensory systems (vision, olfaction, and lateral line) as well as nerve transmission (acetylcholine esterase) were analyzed in zebrafish (Danio rerio) embryos with respect to their suitability as a model for the screening of neurotoxic trace substances in aquatic ecosystems. As a selection of known or putative neurotoxic compounds, amidotrizoic acid, caffeine, cypermethrin, dichlorvos, 2,4-dinitrotoluene, 2,4-dichlorophenol, 4-nonylphenol, perfluorooctanoic acid, and perfluorooctane sulfonic acid were tested in the fish embryo test (OECD test guideline 236) to determine EC₁₀ values, which were then used as maximum test concentration in subsequent neurotoxicity tests. Whereas inhibition of acetylcholinesterase was investigated biochemically both in vivo and in vitro (ex vivo), the sensory organs were studied in vivo by means of fluorescence microscopy and histopathology in 72- or 96-h-old zebrafish embryos, which are not regarded as protected developmental stages in Europe and thus - at least de jure - represent alternative test methods. Various steps of optimization allowed this neurotoxicity battery to identify neurotoxic potentials for five out of the nine compounds: Cypermethrin and dichlorvos could be shown to specifically modulate acetylcholinesterase activity; dichlorvos, 2,4-dichlorophenol, 4-nonylphenol, and perfluorooctane sulfonic acid led to a degeneration of neuromasts, whereas both vision and olfaction proved quite resistant to concentrations ≤ EC₁₀ of all of the model neurotoxicants tested. Comparison of neurotoxic effects on acetylcholinesterase activity following in vivo and in vitro (ex vivo) exposure to cypermethrin provided hints to a specific enzyme-modulating activity of pyrethroid compounds. Enhancement of the neuromast assay by applying a simultaneous double-staining procedure and implementing a 4-scale scoring system (Stengel et al. 2017) led to reduced variability of results and better statistical resolution and allowed to differentiate location-dependent effects in single neuromasts. Since acetylcholinesterase inhibition and neuromast degeneration can be analyzed in 72- and 96-h-old zebrafish embryos exposed to neurotoxicants according to the standard protocol of the fish embryo toxicity test (OECD TG 236), the fish embryo toxicity test can be enhanced to serve as a sensitive neurotoxicity screening test in non-protected stages of vertebrates.

An optimized method to assess ototoxic effects in the lateral line of zebrafish (Danio rerio) embryos

In order to clarify the suitability of the lateral line of zebrafish (Danio rerio) embryos as a model for the screening of ototoxic (neurotoxic) effects, existing neuromast assays were adapted, improved and validated with a series of chemicals known or unknown for their ototoxic potential (caffeine copper sulfate, dichlorvos, 2.4-dinitrotoluene, neomycin, 4-nonylphenol, perfluorooctanesulfonic acid). Present methods were improved by (1) the introduction of a 4-step scoring system, (2) the selection of neuromasts from both the anterior and posterior lateral line systems, (3) a combined DASPEI/DAPI staining applied after both a continuous and pulse exposure scenario, and (4) an additional screening for nuclear fragmentation. Acute toxicities of the model substances were determined by means of the fish embryo test as specified in OECD TG 236, and EC₁₀ concentrations were used as the highest test concentration in the neuromast assay. The enhanced neuromast assay identified known ototoxic substances such as neomycin and copper sulfate as ototoxic at sensitivities similar to those of established methods, with pulse exposure leading to stronger effects than continuous exposure. Except for caffeine, all substances tested (dichlorvos, 2.4-dinitrotoluene, 4-nonylphenol, perfluorooctanesulfonic acid) produced significant toxic effects in neuromasts at EC₁₀ concentrations. Depending on the test substances and their location along the lateral line, specific neuromasts differed in sensitivity. Generally, neuromasts proved more sensitive in the pulse exposure scenario. Whereas for neomycin and copper sulfate neuromasts located along the anterior lateral line were more sensitive, posterior lateral line neuromasts proved more sensitive for the other test substances. Nuclear fragmentation could not only be associated with all test substances, but, albeit at lower frequencies, also with negative controls, and could, therefore, not be assigned specifically to chemical damage. The study thus documented that for a comprehensive evaluation of lateral line damage both neuromasts from the anterior and the posterior lateral line have to be considered. Given the apparently rapid regeneration of hair cells, pulse exposure seems more appropriate for the identification of lateral line neurotoxicity than continuous exposure.

[Evidence-based trauma and orthopedic surgery : 20 years after Sackett]

The article "Evidence based medicine: what it is and what it isn't" published in the BMJ in 1996, is regarded as the foundation of the evidence-based medicine (EbM) movement. Approximately 5 years later David L. Sackett, one of the leaders of the movement, requested all experts to voluntarily abandon their position to make way for young researchers and fresh ideas. Since the term was first coined and the establishment of organizations and platforms fostering the idea, EbM has polarized clinicians and scientists around the world. Clinical and methodological developments during recent years have, however, overtaken the original principles of EbM. This review highlights the core concepts of EbM which have remained unchanged and valid for the current practice of trauma and orthopedic surgery and where revision is needed.

Acetylcholinesterase in zebrafish embryos as a tool to identify neurotoxic effects in sediments

In order to clarify the suitability of zebrafish (Danio rerio) embryos for the detection of neurotoxic compounds, the acetylcholinesterase assay was adapted and validated with a series of priority pollutants listed as relevant for the European water policy (Aroclor 1254, 2,3-benzofuran, bisphenol A, chlorpyrifos, paraoxon-methyl, quinoline, and methyl mercury chloride) as well as acetonic extracts from three sediments of known contamination. The acute toxicities of the model substances and the sediment extracts were determined by means of the fish embryo test as specified in OECD TG 236, and concentrations as low as the effective concentration at 10% inhibition (EC10) were used as the highest test concentration in the acetylcholinesterase test in order to avoid nonspecific systemic effects mimicking neurotoxicity. Among the model compounds, only the known acetylcholinesterase inhibitors paraoxon-methyl and chlorpyrifos produced a strong inhibition to about 20 and 33%, respectively, of the negative controls. For the sediment extracts, a reduction of acetylcholinesterase activity to about 60% could only be shown for the Vering Canal sediment extracts; this could be correlated to high contents of acetylcholinesterase-inhibiting polycyclic aromatic hydrocarbons (PAHs) as identified by chemical analyses. Co-incubation of the Vering Canal sediment extracts with chlorpyrifos at EC10 concentrations each did not significantly increase the inhibitory effect of chlorpyrifos, indicating that the mode of action of acetylcholinesterase inhibition by the sediment-borne PAHs is different to that of the typical acetylcholinesterase blocker chlorpyrifos. Overall, the study documents that zebrafish embryos represent a suitable model not only to reveal acetylcholinesterase inhibition, but also to investigate various modes of neurotoxic action.

The fish embryo test (FET): origin, applications, and future

Originally designed as an alternative for the acute fish toxicity test according to, e.g., OECD TG 203, the fish embryo test (FET) with the zebrafish (Danio rerio) has been optimized, standardized, and validated during an OECD validation study and adopted as OECD TG 236 as a test to assess toxicity of embryonic forms of fish. Given its excellent correlation with the acute fish toxicity test and the fact that non-feeding developmental stages of fish are not categorized as protected stages according to the new European Directive 2010/63/EU on the protection of animals used for scientific purposes, the FET is ready for use not only for range-finding but also as a true alternative for the acute fish toxicity test, as required for a multitude of national and international regulations. If-for ethical reasons-not accepted as a full alternative, the FET represents at least a refinement in the sense of the 3Rs principle. Objections to the use of the FET have mainly been based on the putative lack of biotransformation capacity and the assumption that highly lipophilic and/or high molecular weight substances might not have access to the embryo due to the protective role of the chorion. With respect to bioactivation, the only substance identified so far as not being activated in the zebrafish embryo is allyl alcohol; all other biotransformation processes that have been studied in more detail so far were found to be present, albeit, in some cases, at lower levels than in adult fish. With respect to larger molecules, the extension of the test duration to 96 h (i.e., beyond hatch) has-at least for the substances tested so far-compensated for the reduced access to the embryo; however, more research is necessary to fully explore the applicability of the FET to substances with a molecular weight >3 kDa as well as substances with a neurotoxic mode of action. An extension of the endpoints to also cover sublethal endpoints makes the FET a powerful tool for the detection of teratogenicity, dioxin-like activity, genotoxicity and mutagenicity, neurotoxicity, as well as various forms of endocrine disruption.

Standardised effect sizes in clinical research

The Bone & Joint Journal provides the latest evidence to guide the clinical practice of orthopaedic surgeons. The benefits of one intervention compared with another are presented using outcome measures; some may be specific to a limb or joint and some are more general health-related quality of life measures. Readers will be familiar with many of these outcome measures and will be able to judge the relative benefits of different interventions when measured using the same outcome tool; for example, different treatments for pain in the knee measured using a particular knee score. But, how should readers compare outcomes between different clinical areas using different outcome measures? This article explores the use of standardised effect sizes.

Cite this article: Bone Joint J 2014;96-B:853–4.

Intention-to-treat analyses for interventional studies

The importance for observing the intention-to-treat approach in clinical studies is explained.

Cite this article: Bone Joint J 2013;95-B:1443–4.

Acetabular fractures with marginal impaction

Over a five-year period, adult patients with marginal impaction of acetabular fractures were identified from a registry of patients who underwent acetabular reconstruction in two tertiary referral centres. Fractures were classified according to the system of Judet and Letournel. A topographic classification to describe the extent of articular impaction was used, dividing the joint surface into superior, middle and inferior thirds. Demographic information, hospitalisation and surgery-related complications, functional (EuroQol 5-D) and radiological outcome according to Matta’s criteria were recorded and analysed. In all, 60 patients (57 men, three women) with a mean age of 41 years (18 to 72) were available at a mean follow-up of 48 months (24 to 206). The quality of the reduction was ‘anatomical’ in 44 hips (73.3%) and ‘imperfect’ in 16 (26.7%). The originally achieved anatomical reduction was lost in12 patients (25.8%). Radiologically, 33 hips (55%) were graded as ‘excellent’, 11 (18.3%) as ‘good’, one (1.7%) as ‘fair’ and 15 (25%) as ‘poor’. A total of 11 further operations were required in 11 cases, of which six were total hip replacements.

Univariate linear regression analysis of the functional outcome showed that factors associated with worse pain were increasing age and an inferior location of the impaction. Elevation of the articular impaction leads to joint preservation with satisfactory overall medium-term functional results, but secondary collapse is likely to occur in some patients.

Cite this article: Bone Joint J 2013;95-B:230–8.

Operative vs conservative treatment of traumatic patellar dislocation: results of a prospective randomized controlled clinical trial

INTRODUCTION

Patellar dislocation is a common knee injury with mainly lateral dislocations, leading to ruptures of the medial patellofemoral ligament in most of the cases. Even though several prognostic factors for patellofemoral instability have been identified so far, the appropriate therapy for patients with patellar dislocation remains a controversial issue. The purpose of this study was to compare the outcome after conservative or operative treatment in patients after first-time patellar dislocation.

PATIENTS AND METHODS

This randomized controlled clinical trial was designed multicentric including patients from six German orthopaedic and trauma departments. Twenty patients with a mean age of 24.6 years with first-time traumatic patella dislocation were included and randomized into either a conservative arm or an operative arm. Plain X-ray images of the knee joint (a.p. and lateral view and tangential view of both patellae) were performed in all cases prior to therapy to exclude osteochondral fragments requiring refixation. An MRI was recommended, but not compulsory. Patients were consulted after 6, 12, and 24 months with a questionnaire including the criteria of the Kujala score, recurrent dislocation, and satisfaction.

RESULTS

The mean Kujala score of the conservative vs operative treatment group was 78.6 vs 80.3 after 6 months (p = 0.842), 79.9 vs 88.9 after 12 months (p = 0.165), and 81.3 vs 87.5 after 24 months (p = 0.339). Redislocation rate after 24 months was 37.5 % in the conservative group and 16.7 % in the operative group (p = 0.347). Due to the small number of patients that could be included, no significant difference between the groups could be detected. We see a tendency towards better results after operative treatment.

CONCLUSION

Our multicentric prospective randomized controlled trial revealed no significant difference between conservative and operative treatment for patients after first-time traumatic patellar dislocation. However, a tendency towards a better Kujala score and lower redislocation rates for patients with operative treatment was observed. The small number of patients is a limiting factor of the study, leading to results without statistical significance. A meta-analysis including other study's level I data is desirable for the future.

[Obligation to operate splenic injuries in polytrauma patients using MS-CT criteria]

PURPOSE

The aim of this study is to evaluate the validity of multi-slice computed tomography (MS-CT) in predicting the need to operate on spleen injuries in polytrauma patients using selected grading systems; the Thompson screening test (TST) and the extended TST (ETST).

PATIENTS AND METHODS

A retrospective evaluation of 2791 patients who presented spleen injuries in polytrauma MS-CTs in the period between 12/2002 and 06/2010 was undertaken. On the basis of CT morphology, and by using the above mentioned grading systems, the probability of the need to operate on a splenic injury was defined.

RESULTS

From a sample of 2791 patients, an MS-CT polytrauma scan was used to identify 139 splenic injuries. In correlation with the actual interventions carried out on the spleen, the applied grading systems showed sensitivities of 91 % (TST) and 69 % (ETST) as well as specificities of 78 % (TST) and 93 % (ETST). Regarding interventions on a splenic injury, positive predictive values were 57 % (TST) and 76 % (ETST), and the accordant negative predictive values were 96 % (TST) and 91 % (ETST). Thereby we ascertained significantly lower results than Thompson et al.

CONCLUSION

The applied grading systems based on the findings of MS-CT do not reliably predict the need to operate on spleen injuries in polytrauma patients.

[Accidents, illness and injuries involved in road haulage : consequences for medical care and prevention]

This article reviews basic characteristics of road traffic crashes of heavy vehicles and the current health status of truck drivers. It summarises previous findings from research with a focus on orthopaedic diseases and injuries. These findings comprise a risky health behaviour and high prevalence of associated diseases which can be attributed to both the occupational framework and personal risk-taking behavioural patterns. These are of major importance given the increasing number of drivers and the consequences for acute care and prevention. On the other hand there is a substantial lack of medical care for the drivers on the road. Therefore this article presents the"DocStop Initiative" for medical care on the road, an initiative that runs an international network of care providers (http://www.docstop-online.eu).

[Limits of clinical pathways. Implant-associated infections]

There are at present no valid guidelines for multimodal treatment of implant-associated infections; however, based on many years of experience gathered by specialized septic surgeons and likewise specialized treatment centers, established principles do exist. Treatment planning should always take into consideration the individual comorbidity of the patient, the underlying injury, the implant, the spectrum of germs, and the patient's compliance. The concept for managing implant-associated infections comprises five pillars and can be summarized as follows: first priority is given to rapid and radical surgical eradication of the infection by débridement of all infected and non-vital or underperfused tissue. We cannot propose clinical pathways as such for implant-related infections, i.e., by specifying interdisciplinary activities, control parameters, and responsibilities for a typical patient with clearly defined disease, but we can proffer strategic concepts for diagnostic work-up and treatment as we have already described.

[Complex pelvic trauma in elderly patients]

The definition of complex pelvic trauma has allowed a selection of those pelvic fracture patients with the highest mortality rate. The term complex pelvic trauma is used as a definition for pelvic fractures which are associated with serious soft tissue lesions in the pelvic region. These may include visceral and neurovascular, as well as extensive skin and muscle injuries. Haemodynamic instability particularly related to vascular injuries raises the mortality dramatically. Traumatic hemipelvectomy, which represents the worst case of a complex pelvic trauma, is associated with mortality rates of up to 60%. The pelvic study groups 1-3 of the German trauma association (DGU) and the Association for Osteosynthesis (AO) provide the worldwide largest database on pelvic injuries (group 1, 1991-1993: 1,722 patients from 10 hospitals; group 2, 1998-2002: 2,569 patients from 22 hospitals; and group 3, 2005-2007: 2,704 patients from 23 hospitals). Using this database this article reviews epidemiological data, therapy concepts, associated injuries as well as the incidence and mortality rates related to complex pelvic trauma over a 16-year time period. Special attention has been paid to complex trauma in the elderly (patients >60 years of age). An additional aim of this article is to analyze the correlation between different treatment modalities and the mortality rate of complex pelvic trauma and to investigate whether changes in the treatment of complex pelvic trauma have improved the outcome of these injuries. Taken together an increase in measures for an initial mechanical stabilization of the pelvic ring, such as the use of the pelvic C clamp, the external fixator or primary osteosynthesis was found over the 16-year observation period. In addition to stabilization of the pelvic ring, pelvic tamponade for mechanical haemostasis has been proven to be one of the most effective measures to control haemorrhaging. These treatment regimes did not differ between young patients and patients >60 years of age. Regarding the outcome of these treatment strategies only slight decreases in the mortality rate were found (pelvic study group 1: 21%; pelvic study group 2: 22%; pelvic study group 3: 18%). In all pelvic study groups the mortality rate in patients >60 years of age was found to be significantly higher than in individuals <60 years of age (pelvic study group 1: 57% versus 29.6%, pelvic study group 2: 33% versus 22.6%, pelvic study group 3: 41% versus 10.4%, p <0.05, respectively).

[Methods of health economic evaluation for health services research]

On August 30, 2010, the German Network for Health Services Research [Deutsches Netzwerk Versorgungsforschung e. V. (DNVF e. V.)] approved the Memorandum III "Methods for Health Services Research", supported by the member societies mentioned as authors and published in this Journal [Gesundheitswesen 2010; 72: 739-748]. The present paper focuses on methodological issues of economic evaluation of health care technologies. It complements the Memorandum III "Methods for Health Services Research", part 2. First, general methodological principles of the economic evaluations of health care technologies are outlined. In order to adequately reflect costs and outcomes of health care interventions in the routine health care, data from different sources are required (e. g., comparative efficacy or effectiveness studies, registers, administrative data, etc.). Therefore, various data sources, which might be used for economic evaluations, are presented, and their strengths and limitations are stated. Finally, the need for methodological advancement with regard to data collection and analysis and issues pertaining to communication and dissemination of results of health economic evaluations are discussed.

[Road traffic crashes in developing countries]

Road traffic crashes pose a major threat to individuals and national health systems. Developing countries account for 48% of motorized vehicles, but for 91% of the 1.3 million fatalities per annum. While ranked ninth among the causes of disabilities adjusted life years lost in 2004, crash injuries are projected to rise to third position by 2030. This article reviews current prognoses of deaths and disabilities, the characteristics of crashes in low and middle income countries and evidence-based road safety interventions. This article is considered a wake-up call for trauma, orthopaedic, and emergency surgeons in high-income countries to join the global community in fighting the neglected yet potentially curable epidemic named road traffic injuries.

Is it possible to minimize overdrainage complications with gravitational units in patients with idiopathic normal pressure hydrocephalus? Protocol of the randomized controlled SVASONA Trial (ISRCTN51046698)

Overdrainage is a common complication observed after shunting patients with idiopathic normal-pressure hydrocephalus (iNPH), with an estimated incidence up to 25%. Gravitational units that counterbalance intracranial pressure changes were developed to overcome this problem. We will set out to investigate whether the combination of a programmable valve and a gravitational unit (proGAV, Aesculap/Miethke, Germany) is capable of reducing the incidence of overdrainage and improving patient-centered outcomes compared to a conventional programmable valve (Medos-Codman, Johnson & Johnson, Germany). SVASONA is a pragmatic randomized controlled trial conducted at seven centers in Germany. Patients with a high probability of iNPH (based on clinical signs and symptoms, lumbar infusion and/or tap test, cranial computed tomography [CCT]) and no contraindications for surgical drainage will randomly be assigned to receive (1) a shunt assistant valve (proGAV) or (2) a conventional, programmable shunt valve (programmable Medos-Codman).We will test the primary hypothesis that the experimental device reduces the rate of overdrainage from 25% to 10%. As secondary analyses, we will measure iNPH-specific outcomes (i.e., the Black grading scale and the NPH Recovery Rate), generic quality of life (Short Form 36), and complications and serious adverse events (SAE). One planned interim analysis for safety and efficacy will be performed halfway through the study. To detect the hypothesized difference in the incidence of overdrainage with a type I error of 5% and a type II error of 20%, correcting for multiple testing and an anticipated dropout rate of 10%, 200 patients will be enrolled.The presented trial is currently recruiting patients, with the first results predicted to be available in late 2008.

Factors determining quality of life and level of sporting activity after internal fixation of an isolated acetabular fracture

We investigated whether patients who underwent internal fixation for an isolated acetabular fracture were able to return to their previous sporting activities.

We studied 52 consecutive patients with an isolated acetabular fracture who were operated on between January 2001 and December 2002. Their demographic details, fracture type, rehabilitation regime, outcome and complications were documented prospectively as was their level and frequency of participation in sport both before and after surgery. Quality of life was measured using the EuroQol-5D health outcome tool (EQ-5D).

There was a significant reduction in level of activity, frequency of participation in sport (both p < 0.001) and EQ-5D scores in patients of all age groups compared to a normal English population (p = 0.001). A total of 22 (42%) were able to return to their previous level of activities: 35 (67%) were able to take part in sport at some level. Of all the parameters analysed, the Matta radiological follow-up criteria were the single best predictor for resumption of sporting activity and frequency of participation.

Topotecan weekly versus routine 5-day schedule in patients with platinum-resistant ovarian cancer (TOWER): A randomized, multicenter trial of the North-Eastern German Society of Gynecological Oncology (NOGGO)

5553

Background: In women with platinum-resistant recurrent ovarian cancer, weekly administration of topotecan (Tw) may be equally effective, but better tolerated than conventional 5-day dosing (Tc). We conducted a randomized multicenter trial to validate this assumption. Methods: The trial was pre-registered at clinicaltrials.gov ( NCT00170677 ). Women with platinum-resistant ovarian and fallopian tube cancers or primary peritoneal carcinoma, and measurable or assessable disease (GCIG criteria) were randomized to receive either Tw (d1,8,15/q28d, 4 mg/m2) or Tc (d1–5/q21d, 1.25 mg/m2). The predefined stopping rule, based on the primary endpoint of best CA-125 or tumor response, was not reached (presented at ASCO 2007, Abstract 5526). This permitted the accrual of 194 patients, 154 of whom could be assessed for CA-125 or tumor response (SD + CR + PR). We also compared progression-free (PFS) and overall survival (OS), as well as toxicity between trial groups. Results: Mean age was 61.8 (SD 9.8) years, and 59 women were on third-line treatment. Patients received a total of 809 cycles of chemotherapy. Demographic baseline characteristics, tumor stages and grades, and previous lines of chemotherapy were well balanced between treatment groups. There were 35 / 75 (47%) and 45 / 79 (57%) responses in the Tw and Tc groups, respectively (risk ratio [RR] 1.22, 95% CI 0.89–1.66). Median PFS and OS did not differ markedly between both regimens (3.2 versus 4.4 months, hazard ratio [HR] 1.30, 95% CI 0.96–1.77 and 9.8 versus 10.0 months, HR 1.08, 95% CI 0.77–1.52). The risk of grade III/IV hematological toxicity was significantly lower in the Tw group (anemia: RR 0.35, p = 0.007, neutropenia: RR 0.38, p = 0.0001, thrombopenia: RR 0.23, p = 0.0004). Conclusions: Weekly administration of topotecan shows no substantial difference in endpoints of effectiveness compared to conventional dosing, but is associated with a significantly lower likelihood of severe hematological toxicity. Weekly topotecan should be considered as a possible treatment alternative in women with platinum-resistant ovarian cancer because of its favourable benefit-risk-profile.

No significant financial relationships to disclose.

[Do injuries of the upper extremity in geriatric patients end up in helplessness? A prospective study for the outcome of distal radius and proximal humerus fractures in individuals over 65]

In a prospective study 104 patients >or=65 years with distal radius fractures (DRF; n=52) and proximal forearm fractures (PHF; n=52) were followed up for a period of 4 months after injury. As an inception- cohort study, influence on treatment pattern was not part of the examination. A total of 53% of the DRF and 74% of the PHF patients underwent surgery. There were no significant changes in the ability of daily living management (IADL) with either fracture form. Functional outcome was better in PHF than DRF patients. PHF patients showed a high incidence in "fear of falling" throughout the whole study, whereas fear of falling rose significantly in DRF patients. 4% of DRF and 9.6% of PHF patients died during the observation period, while 6% of DRF and even 17% of PHF patients had to give up their own housekeeping. One third of both patient groups did not receive physiotherapy. In only 12% of DRF and 6% of PHF patients was osteoporosis treated. In both groups of patients there was a significant worsening in the ability of walking after injury, leading to two or more new falls in 24% of DRF and 28% of PHF patients.

[Outcomes research: definitions, methods and challenges in trauma and orthopaedic surgery]

BACKGROUND

Besides basic, illness- and patient-oriented research, outcomes research is regarded as the fourth pillar of modern health care systems. Outcomes research investigates both the desirable and adverse effects of medical and surgical interventions under day-to-day conditions.

METHOD

Because of rigorous entry criteria and selection of eligible subjects, the efficacy of a certain treatment derived from clinical experiments (i.e. classic randomized trials) may not necessarily be transferred to common patient populations or clinical settings. Apart from efficacy, a valuable (thus reimbursable) diagnostic or therapeutic procedure must prove its effectiveness in clinical practice as well. Demanding study designs are necessary to model effectiveness and to separate the observed intervention-related effects from bias and confounding.

RESULTS

Registries and pragmatic randomized trials may represent the most appropriate modalities to establish outcomes research in trauma and orthopaedic surgery. Good examples for interventions still needing proof of effectiveness are kyphoplasty and vertebroplasty, navigated surgery, damage control, interlocking implants and bone growth factors. Revealing over- and undersupply, generating negative lists (i.e. interventions of questionable or almost nil effectiveness) and integrating patients as co-therapists requires networking between hospitals and private practitioners.

CONCLUSION

Also, since outcomes research is a societal need, its development and funding must be ensured by all providers and payers of health care services.

Topotecan weekly versus routine 5-day schedule in patients with platinum-resistant ovarian cancer (TOWER): A randomized, two-stage phase-II study of the North-Eastern German Society of Gynaecological Oncology (NOGGO)

5526

Background: Optimizing the therapeutic index (that is, maintaining drug effectiveness while reducing toxicity) is a major goal in chemotherapy for platinum-resistant ovarian cancer. Early phase-I/II studies suggest that weekly topotecan (T) might be effective and apparently better tolerated than the established 5-day regimen. As yet, no randomized comparison of both regimes was attempted. To prove the hypothesis of an improved therapeutic index with weekly T, we conducted a randomized, multicenter, two-stage phase-II trial, and herein present the data of the planned interim analysis. Methods: Pts with platinresistent ovarian and fallopian tube cancers or primary peritoneal carcinoma, measurable or assessable disease (GCIG-CA-125 response criteria), were eligible. Pts were randomized to receive either weekly T (d1,8,15/q28d, 4 mg/m2) or T from d1–5/q21d at a dose of 1.25 mg/m2. According to Gehan’s two-stage-design, both arms were handled as independent studies. Overall response rate (CR + PR) was defined as primary study endpoint, secondary endpoints of the interim analysis were toxicity and safety. Results: 28 pts in the weekly and 21 pts in the conventional group, enrolled at 38 centers form the basis of this report. 230 cycles of chemotherapy were evaluated for toxicity analyses. Median age was 61 years (range, 36 - 82 years). Demographic baseline characteristics, including tumor stage and grade were well balanced between treatment arms. There were 2/28 and 5/21 responses in weekly and the conventional arm, respectively (Risk Ratio [RR] 0.30, 95% confidence interval [CI] 0.06 - 1.40, p=0.122). The risk of early treatment termination due to tumor progression (RR 1.39, 95%CI 0.75 - 2.56), haematological (RR 0.20, 95% CI 0.01 - 3.97) or non- hematological toxicities (RR 1.96, 95% CI 0.18 - 20.83) did not differ significantly between groups. The only three events of neutropenic fever occurred in the conventional arm (RR 1.70, 95% CI 0.99 - 1.16). Conclusions: Weekly T is well tolerated and potentially active. The second stage of this study will require additional 46 patients each arm. Complete enrolment is expected to be accomplished in May 2007.

No significant financial relationships to disclose.