How nuclear envelope dynamics can direct laminopathy phenotypes

The nuclear envelope separates the genome from the cytoplasmic environment. However, the nuclear envelope is also physically associated with the genome and exerts influence on gene expression and genome modification. The nucleus is dynamic, changing shape and responding to cell movement, disassembling and assembling during cell division, and undergoing rupture and repair. These dynamics can be impacted by genetic disease, leading to a family of diseases called laminopathies. Their disparate phenotypes suggest that multiple processes are affected. We highlight three such processes here, which we believe can be used to classify most of the laminopathies. While much still needs to be learned, some commonalities between these processes, such as proteins involved in nuclear envelope formation and rupture repair, may drive a variety of laminopathies. Here we review the latest information regarding nuclear dynamics and its role in laminopathies related to mutations in the nuclear lamina and linker of nucleoskeleton and cytoskeleton complex (LINC) proteins.

On the morphological relations of the Achilles tendon and plantar fascia via the calcaneus: a cadaveric study

Current treatments of plantar fasciitis are based on the premise that the Achilles tendon (AT) and plantar fascia (PF) are mechanically directly linked, which is an area of debate. The aim of this study was to assess the morphological relationship between the AT and PF. Nineteen cadaveric feet were x-ray imaged, serially sectioned and plastinated for digital image analyses. Measurements of the AT and PF thicknesses and cross-sectional areas (CSA) were performed at their calcaneal insertion. The fiber continuity was histologically assessed in representative subsamples. Strong correlations exist between the CSA of the AT and PF at calcaneal insertion and the CSA of PF's insertional length (r = 0.80), and between the CSAs of AT's and PF's insertional lengths. Further correlations were observed between AT and PF thicknesses (r = 0.62). This close morphological relationship could, however, not be confirmed through x-ray nor complete fiber continuity in histology. This study provides evidence for a morphometric relationship between the AT and PF, which suggests the presence of a functional relationship between these two structures following the biological key idea that the structure determines the function. The observed morphological correlations substantiate the existing mechanical link between the AT and PF via the posterior calcaneus and might explain why calf stretches are a successful treatment option for plantar heel pain.

CaFFEE: A program for evaluating time courses of Ca2+ dependent signal changes of complex cells loaded with fluorescent indicator dyes

Quantification of changes in intracellular free Ca2+ concentrations [Ca2+]i is fundamental to the understanding of the physiology of single cells in response to both environmental and endogenous stimuli. Here we present easy to use freeware that allows especially the evaluation of [Ca2+]i signals in complex and mixed cultures. The program CaFFEE (Calcium Fluorescent Flash Evaluating Engine) enables the user to evaluate the response of hundreds of cells to treat-ments that influence [Ca2+]i. CaFFEE processes large quantities of image data, automatically identifies individual cells in mixed, heterogeneous populations, and evaluates their fluorescence signal. All data are exported in spreadsheet format, and data on thousands of cells can be batch-processed. Moreover, the program optimizes the visual representation of time-lapse image data for user-guided data exploration (setting of parameters for semi-automated data processing). The freeware allows the standardized and transparent processing of imaging data independent of the platform used to gen-erate the data.

Human neuronal signaling and communication assays to assess functional neurotoxicity

Prediction of drug toxicity on the human nervous system still relies mainly on animal experiments. Here, we developed an alternative system allowing assessment of complex signaling in both individual human neurons and on the network level. The LUHMES cultures used for our approach can be cultured in 384-well plates with high reproducibility. We established here high-throughput quantification of free intracellular Ca2+ concentrations [Ca2+]i as broadly applicable surrogate of neuronal activity and verified the main processes by patch clamp recordings. Initially, we characterized the expression pattern of many neuronal signaling components and selected the purinergic receptors to demonstrate the applicability of the [Ca2+]i signals for quantitative characterization of agonist and antagonist responses on classical ionotropic neurotransmitter receptors. This included receptor sub-typing and the characterization of the anti-parasitic drug suramin as modulator of the cellular response to ATP. To exemplify potential studies on ion channels, we characterized voltage-gated sodium channels and their inhibition by tetrodotoxin, saxitoxin and lidocaine, as well as their opening by the plant alkaloid veratridine and the food-relevant marine biotoxin ciguatoxin. Even broader applicability of [Ca2+]i quantification as an end point was demonstrated by measurements of dopamine transporter activity based on the membrane potential-changing activity of this neurotransmitter carrier. The substrates dopamine or amphetamine triggered [Ca2+]i oscillations that were synchronized over the entire culture dish. We identified compounds that modified these oscillations by interfering with various ion channels. Thus, this new test system allows multiple types of neuronal signaling, within and between cells, to be assessed, quantified and characterized for their potential disturbance.

Examination of microcystin neurotoxicity using central and peripheral human neurons

Microcystins (MC) are a group of cyanobacterial toxins that comprises MC-LF and other cyclic heptapeptides, best known as potent hepatotoxicants. Cell culture and epidemiological studies suggest that MC might also affect the nervous system when there is systemic exposure, e.g., via drinking water or food. We asked whether in vitro studies with human neurons could provide estimates on the neurotoxicity hazard of MC-LF. First, we used LUHMES neurons, a well-established test system for neurotoxicants and neuropathological processes. These central nervous system cells express OATP1A2, a presumed carrier of MC-LF, and we observed selective neurite toxicity in the μM range (EC20 = 3.3 μM ≈ 3.3 μg/mL). Transcriptome changes pointed towards attenuated cell maintenance and biosynthetic processes. Prolonged exposure for up to four days did not increase toxicity. As a second model, we used human dorsal root ganglia-like neurons. These peripheral nervous system cells represent parts of the nervous system not protected by the blood-brain barrier in humans. Toxicity was observed in a similar concentration range (EC20 = 7.4 μM). We conclude that MC-LF poses a potential neurotoxic hazard in humans. The adverse effect concentrations observed here were orders of magnitude higher than those presumed to be encountered after normal nutritional or environmental exposure. However, the low μM concentrations found to be toxic are close to levels that may be reached after very excessive algae supplement intake.

Time and space-resolved quantification of plasma membrane sialylation for measurements of cell function and neurotoxicity

While there are many methods to quantify the synthesis, localization, and pool sizes of proteins and DNA during physiological responses and toxicological stress, only few approaches allow following the fate of carbohydrates. One of them is metabolic glycoengineering (MGE), which makes use of chemically modified sugars (CMS) that enter the cellular biosynthesis pathways leading to glycoproteins and glycolipids. The CMS can subsequently be coupled (via bio-orthogonal chemical reactions) to tags that are quantifiable by microscopic imaging. We asked here, whether MGE can be used in a quantitative and time-resolved way to study neuronal glycoprotein synthesis and its impairment. We focused on the detection of sialic acid (Sia), by feeding human neurons the biosynthetic precursor N-acetyl-mannosamine, modified by an azide tag. Using this system, we identified non-toxic conditions that allowed live cell labeling with high spatial and temporal resolution, as well as the quantification of cell surface Sia. Using combinations of immunostaining, chromatography, and western blotting, we quantified the percentage of cellular label incorporation and effects on glycoproteins such as polysialylated neural cell adhesion molecule. A specific imaging algorithm was used to quantify Sia incorporation into neuronal projections, as potential measure of complex cell function in toxicological studies. When various toxicants were studied, we identified a subgroup (mitochondrial respiration inhibitors) that affected neurite glycan levels several hours before any other viability parameter was affected. The MGE-based neurotoxicity assay, thus allowed the identification of subtle impairments of neurochemical function with very high sensitivity.

A field study of a roof bolter canopy air curtain (2nd generation) for respirable coal mine dust control

A 2nd generation roof bolter canopy air curtain (CAC) design was tested by National Institute for Occupational Safety and Health (NIOSH) at a Midwestern underground coal mine. During the study, the roof bolter never operated downwind of the continuous miner. Using a combination of personal Data Rams (pDR) and gravimetric samplers, the dust control efficiency of the roof bolter CAC was ascertained. Performance evaluation was determined using three methods: (1) comparing roof bolter operator concentrations underneath the CAC to roof bolter concentrations outside the CAC, (2) comparing roof bolter operator concentrations underneath the CAC to the concentrations at the rear of the bolter, and finally, (3) using the gravimetric data directly underneath the CAC to correct roof bolter operator concentrations underneath the CAC and comparing them to the concentrations at the rear of the bolter. Method 1 dust control efficiencies ranged from -53.9% to 60.4%. Method 2 efficiencies ranged from -150.5% to 52.2%, and Method 3 efficiencies ranged from 40.7% to 91%. Reasons for negative and low dust control efficiencies are provided in this paper and include: incorrect sampling locations, large distance between CAC and operator, and contamination of intake air from line curtain. Low dust concentrations encountered during the testing made it difficult to discern whether differences in concentrations were due to the CAC or due to variances inherent in experimental dust measurement. However, the analyses, especially the Method 3 analysis, show that the CAC can be an effective dust control device.

Corrigendum to A high-throughput approach to identify specific neurotoxicants / developmental toxicants in human neuronal cell function assays

In this manuscript, which appeared in ALTEX 35 , 235-253 ( doi:10.14573/altex.1712182 ), the Acknowledgements should read: This work was supported by the Land BW, the Doerenkamp-Zbinden Foundation, the DFG (RTG1331, KoRS-CB), the BMBF (NeuriTox), and it has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No. 681002 (EU-ToxRisk).

Corrigendum to Recommendation on test readiness criteria for new approach methods in toxicology: exemplified for developmental neurotoxicity

In this manuscript, which appeared in ALTEX 35 , 306-352 ( doi:10.14573/altex.1712081 ), the Acknowledgements should read: This work was supported by the Doerenkamp-Zbinden Foundation, EFSA, the BMBF, JPI-NutriCog-Selenius, and it has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No. 681002 (EU-ToxRisk).

Recommendation on test readiness criteria for new approach methods in toxicology: Exemplified for developmental neurotoxicity

Multiple non-animal-based test methods have never been formally validated. In order to use such new approach methods (NAMs) in a regulatory context, criteria to define their readiness are necessary. The field of developmental neurotoxicity (DNT) testing is used to exemplify the application of readiness criteria. The costs and number of untested chemicals are overwhelming for in vivo DNT testing. Thus, there is a need for inexpensive, high-throughput NAMs, to obtain initial information on potential hazards, and to allow prioritization for further testing. A background on the regulatory and scientific status of DNT testing is provided showing different types of test readiness levels, depending on the intended use of data from NAMs. Readiness criteria, compiled during a stakeholder workshop, uniting scientists from academia, industry and regulatory authorities are presented. An important step beyond the listing of criteria, was the suggestion for a preliminary scoring scheme. On this basis a (semi)-quantitative analysis process was assembled on test readiness of 17 NAMs with respect to various uses (e.g. prioritization/screening, risk assessment). The scoring results suggest that several assays are currently at high readiness levels. Therefore, suggestions are made on how DNT NAMs may be assembled into an integrated approach to testing and assessment (IATA). In parallel, the testing state in these assays was compiled for more than 1000 compounds. Finally, a vision is presented on how further NAM development may be guided by knowledge of signaling pathways necessary for brain development, DNT pathophysiology, and relevant adverse outcome pathways (AOP).

Foam property tests to evaluate the potential for longwall shield dust control

Tests were conducted to determine properties of four foam agents for their potential use in longwall mining dust control. Foam has been tried in underground mining in the past for dust control and is currently being reconsidered for use in underground coal longwall operations in order to help those operations comply with the Mine Safety and Health Administration's lower coal mine respirable dust standard of 1.5 mg/m³. Foams were generated using two different methods. One method used compressed air and water pressure to generate foam, while the other method used low-pressure air generated by a blower and water pressure using a foam generator developed by the U.S. National Institute for Occupational Safety and Health. Foam property tests, consisting of a foam expansion ratio test and a water drainage test, were conducted to classify foams. Compressed-air-generated foams tended to have low expansion ratios, from 10 to 19, with high water drainage. Blower-air-generated foams had higher foam expansion ratios, from 30 to 60, with lower water drainage. Foams produced within these ranges of expansion ratios are stable and potentially suitable for dust control. The test results eliminated two foam agents for future testing because they had poor expansion ratios. The remaining two foam agents seem to have properties adequate for dust control. These material property tests can be used to classify foams for their potential use in longwall mining dust control.

A high-throughput approach to identify specific neurotoxicants/ developmental toxicants in human neuronal cell function assays

The (developmental) neurotoxicity hazard is still unknown for most chemicals. Establishing a test battery covering most of the relevant adverse outcome pathways may close this gap, without requiring a huge animal experimentation program. Ideally, each of the assays would cover multiple mechanisms of toxicity. One candidate test is the human LUHMES cell-based NeuriTox test. To evaluate its readiness for larger-scale testing, a proof of concept library assembled by the U.S. National Toxicology Program (NTP) was screened. Of the 75 unique compounds, seven were defined as specifically neurotoxic after the hit-confirmation phase and additional ten compounds were generally cytotoxic within the concentration range of up to 20 micromolar. As complementary approach, the library was screened in the PeriTox test, which identifies toxicants affecting the human peripheral nervous system. Of the eight PeriTox hits, five were similar to the NeuriTox hits: rotenone, colchicine, diethylstilbestrol, berberine chloride, and valinomycin. The unique NeuriTox hit, methyl-phenylpyridinium (MPP+) is known from in vivo studies to affect only dopaminergic neurons (which LUHMES cells are). Conversely, the known peripheral neurotoxicant acrylamide was picked up in the PeriTox, but not in the NeuriTox assay. All of the five common hits had also been identified in the published neural crest migration (cMINC) assay, while none of them emerged as cardiotoxicant in a previous screen using the same library. These comparative data suggest that complementary in vitro tests can pick up a broad range of toxicants, and that multiple test results might help to predict organ specificity patterns.

Respirable dust measured downwind during rock dust application

The Pittsburgh Mining Research Division of the U.S. National Institute for Occupational Safety and Health (NIOSH) conducted underground evaluations in an attempt to quantify respirable rock dust generation when using untreated rock dust and rock dust treated with an anticaking additive. Using personal dust monitors, these evaluations measured respirable rock dust levels arising from a flinger-type application of rock dust on rib and roof surfaces. Rock dust with a majority of the respirable component removed was also applied in NIOSH's Bruceton Experimental Mine using a bantam duster. The respirable dust measurements obtained downwind from both of these tests are presented and discussed. This testing did not measure miners' exposure to respirable coal mine dust under acceptable mining practices, but indicates the need for effective continuous administrative controls to be exercised when rock dusting to minimize the measured amount of rock dust in the sampling device.

Experimental study on foam coverage on simulated longwall roof

Testing was conducted to determine the ability of foam to maintain roof coverage in a simulated longwall mining environment. Approximately 27 percent of respirable coal mine dust can be attributed to longwall shield movement, and developing controls for this dust source has been difficult. The application of foam is a possible dust control method for this source. Laboratory testing of two foam agents was conducted to determine the ability of the foam to adhere to a simulated longwall face roof surface. Two different foam generation methods were used: compressed air and blower air. Using a new imaging technology, image processing and analysis utilizing ImageJ software produced quantifiable results of foam roof coverage. For compressed air foam in 3.3 m/s (650 fpm) ventilation, 98 percent of agent A was intact while 95 percent of agent B was intact on the roof at three minutes after application. At 30 minutes after application, 94 percent of agent A was intact while only 20 percent of agent B remained. For blower air in 3.3 m/s (650 fpm) ventilation, the results were dependent upon nozzle type. Three different nozzles were tested. At 30 min after application, 74 to 92 percent of foam agent A remained, while 3 to 50 percent of foam agent B remained. Compressed air foam seems to remain intact for longer durations and is easier to apply than blower air foam. However, more water drained from the foam when using compressed air foam, which demonstrates that blower air foam retains more water at the roof surface. Agent A seemed to be the better performer as far as roof application is concerned. This testing demonstrates that roof application of foam is feasible and is able to withstand a typical face ventilation velocity, establishing this technique's potential for longwall shield dust control.

Stem Cell-Derived Immature Human Dorsal Root Ganglia Neurons to Identify Peripheral Neurotoxicants

Safety sciences and the identification of chemical hazards have been seen as one of the most immediate practical applications of human pluripotent stem cell technology. Protocols for the generation of many desirable human cell types have been developed, but optimization of neuronal models for toxicological use has been astonishingly slow, and the wide, clinically important field of peripheral neurotoxicity is still largely unexplored. A two-step protocol to generate large lots of identical peripheral human neuronal precursors was characterized and adapted to the measurement of peripheral neurotoxicity. High content imaging allowed an unbiased assessment of cell morphology and viability. The computational quantification of neurite growth as a functional parameter highly sensitive to disturbances by toxicants was used as an endpoint reflecting specific neurotoxicity. The differentiation of cells toward dorsal root ganglia neurons was tracked in relation to a large background data set based on gene expression microarrays. On this basis, a peripheral neurotoxicity (PeriTox) test was developed as a first toxicological assay that harnesses the potential of human pluripotent stem cells to generate cell types/tissues that are not otherwise available for the prediction of human systemic organ toxicity. Testing of more than 30 chemicals showed that human neurotoxicants and neurite growth enhancers were correctly identified. Various classes of chemotherapeutic agents causing human peripheral neuropathies were identified, and they were missed when tested on human central neurons. The PeriTox test we established shows the potential of human stem cells for clinically relevant safety testing of drugs in use and of new emerging candidates.

SIGNIFICANCE

The generation of human cells from pluripotent stem cells has aroused great hopes in biomedical research and safety sciences. Neurotoxicity testing is a particularly important application for stem cell-derived somatic cells, as human neurons are hardly available otherwise. Also, peripheral neurotoxicity has become of major concern in drug development for chemotherapy. The first neurotoxicity test method was established based on human pluripotent stem cell-derived peripheral neurons. The strategies exemplified in the present study of reproducible cell generation, cell function-based test system establishment, and assay validation provide the basis for a drug safety assessment on cells not available otherwise.

Human Pluripotent Stem Cell Based Developmental Toxicity Assays for Chemical Safety Screening and Systems Biology Data Generation

Efficient protocols to differentiate human pluripotent stem cells to various tissues in combination with -omics technologies opened up new horizons for in vitro toxicity testing of potential drugs. To provide a solid scientific basis for such assays, it will be important to gain quantitative information on the time course of development and on the underlying regulatory mechanisms by systems biology approaches. Two assays have therefore been tuned here for these requirements. In the UKK test system, human embryonic stem cells (hESC) (or other pluripotent cells) are left to spontaneously differentiate for 14 days in embryoid bodies, to allow generation of cells of all three germ layers. This system recapitulates key steps of early human embryonic development, and it can predict human-specific early embryonic toxicity/teratogenicity, if cells are exposed to chemicals during differentiation. The UKN1 test system is based on hESC differentiating to a population of neuroectodermal progenitor (NEP) cells for 6 days. This system recapitulates early neural development and predicts early developmental neurotoxicity and epigenetic changes triggered by chemicals. Both systems, in combination with transcriptome microarray studies, are suitable for identifying toxicity biomarkers. Moreover, they may be used in combination to generate input data for systems biology analysis. These test systems have advantages over the traditional toxicological studies requiring large amounts of animals. The test systems may contribute to a reduction of the costs for drug development and chemical safety evaluation. Their combination sheds light especially on compounds that may influence neurodevelopment specifically.

[Is it possible to enhance our expert knowledge from Wikipedia?]

BACKGROUND

The so-called new media are always a kind of challenge for training supervisors, medical students and doctors-in-training. Especially Wikipedia has a significant position for obtaining important medical information on the internet. Beside many advantages of Wikipedia, there is always the doubt about the correctness of published articles by unknown authors. Therefore the aim of our survey was to investigate the relevance of Wikipedia articles about orthopaedic and traumatological issues in the daily clinical routine.

MATERIALS AND METHODS

In September 2013 two different questionnaires about medical issues were given to medical students, resident physicians and one medical specialist. The questioning was about diseases/symptoms, examinations/classifications and conservative therapy/surgery of the department of orthopaedics and traumatology. A total of 211 Wikipedia articles were evaluated. Additionally, the participants gave an subjective estimation about these articles.

RESULTS

Overall 134 of 211 separate medical items appeared on Wikipedia. The survey has proven the up-to-dateness of Wikipedia articles and their listing on the first or second position on Google. Wikipedia contains a lot of bibliographical references, high-quality images and video material. Almost half (42,5 %) of all evaluated articles are appropriate for use in medical exams and in the daily clinical work.

CONCLUSION

First and foremost young resident physicians, the so-called web 2.0 generation, are using the internet for daily work. Maybe the process of learning is developing and changing at the same time. Wikipedia gives the opportunity for everyone to acquire information for free and all over the place. The collaboration of everyone is necessary to improve the quality of medical issues on Wikipedia.

From transient transcriptome responses to disturbed neurodevelopment: role of histone acetylation and methylation as epigenetic switch between reversible and irreversible drug effects

The superordinate principles governing the transcriptome response of differentiating cells exposed to drugs are still unclear. Often, it is assumed that toxicogenomics data reflect the immediate mode of action (MoA) of drugs. Alternatively, transcriptome changes could describe altered differentiation states as indirect consequence of drug exposure. We used here the developmental toxicants valproate and trichostatin A to address this question. Neurally differentiating human embryonic stem cells were treated for 6 days. Histone acetylation (primary MoA) increased quickly and returned to baseline after 48 h. Histone H3 lysine methylation at the promoter of the neurodevelopmental regulators PAX6 or OTX2 was increasingly altered over time. Methylation changes remained persistent and correlated with neurodevelopmental defects and with effects on PAX6 gene expression, also when the drug was washed out after 3-4 days. We hypothesized that drug exposures altering only acetylation would lead to reversible transcriptome changes (indicating MoA), and challenges that altered methylation would lead to irreversible developmental disturbances. Data from pulse-chase experiments corroborated this assumption. Short drug treatment triggered reversible transcriptome changes; longer exposure disrupted neurodevelopment. The disturbed differentiation was reflected by an altered transcriptome pattern, and the observed changes were similar when the drug was washed out during the last 48 h. We conclude that transcriptome data after prolonged chemical stress of differentiating cells mainly reflect the altered developmental stage of the model system and not the drug MoA. We suggest that brief exposures, followed by immediate analysis, are more suitable for information on immediate drug responses and the toxicity MoA.

[How does our specialty present itself on the Internet?]

BACKGROUND

The huge amount of information on the internet about orthopaedic and trauma surgical issues is very often unclear and hard to control in reliability, autonomy and expertise. The aim of this work is to evaluate German-speaking internet sites with orthopaedic and trauma surgical contents.

MATERIAL AND METHODS

Over a period of two months (from May to June) in 2012 different websites about 20 common orthopaedic and trauma surgical diseases were analysed on the internet by Google search engine. The first ten search results were evaluated for the HON code principles (Health On the Net Foundation). Furthermore there was an evaluation about qualification of the first 50 websites. The best 1,000 placed websites on Google were analysed for the authoritative value: academic, commercial, media, non-medical, physicians, non-profit and miscellaneous.

RESULTS

Only 194 from 200 websites could be evaluated by the HON code principles. Overall 188 websites complied the principle of transparency, followed by privacy with 150 sites and authoritative with 134 sites. Only 90 websites give information about financial disclosure. Medical articles of the website Wikipedia appear most frequently. In the second part of this work it is shown that non-profit sites and sites by physicians are the most frequent. The fewest results are given by academic and commercial sites with 93 and 85 online hits.

CONCLUSION

In summary, it is shown that most of the websites about medical information have inadequate quality. This statement is in accord with some U. S. American publications. It is clear that Wikipedia has a top-ranking on the internet when it is about medical information. Wikipedia almost achieves all of the HON code principles. It is possible to give better medical online information about orthopaedic and trauma surgical issues published by professionals.

[Total knee arthroplasty in post-traumatic osteoarthritis]

BACKGROUND

This study aims to analyse the outcome and the complications after total knee arthroplasty in post-traumatic osteoarthritis in comparison to TKA in patients with degenerative osteoarthritis.

PATIENTS AND METHODS

In a period of six years 43 patients with a post-traumatic osteoarthritis were treated with a total knee arthroplasty (group PT). 38 (88 %) patients (age median 55 years, 22 female, 16 male) were investigated clinically and radiologically after an average follow-up time of 2.7 years. The OKS (Oxford Knee Score, max. 48 points), the Knee Society Scores "function" (max. 100 points) and "knee" (max. 100 points) as well as the visual analogue scale (VAS, 0 to 10 points) were recorded preoperatively and at follow-up. For comparison we chose a matched-pair selection of patients with degenerative osteoarthritis and TKA (group DO, age median 63 years, 22 female, 16 male). For statistical analysis we used common parametric tests (Wilcoxon and U test) and a level of significance of 0.05.

RESULTS

In 19 patients (50 %) of the group PT the osteoarthritis was caused by a bone injury. Furthermore in 19 patients a meniscal and/or ligamentous injury led to osteoarthritis. Out of all patients of group PT, 10 patients showed a preoperative valgus malalignment higher than 10°. KSS knee and KSS function added up to 76.9 and 84.9 points. So they are significantly less than in the matched group (DO, knee: 86.1; function: 94.4). Similarly, the OKS is significantly less in group PT after follow-up (PT: 32.3; DO: 38.4, p ≤ 0.05) although the preoperative values are equal in both groups. The VAS value decreased significantly in both groups. Initial level of pain was significantly higher in the group DO compared to the group PT. Patients with osteoarthritis after trauma showed complications in 17 cases (^ = 44.7 %) that led to 28 revision operations (^ = 0.7 operations per knee). The group with valgus malalignment had a revision rate of 1.4 operations per knee. In the group DO 8 complications occurred (^ = 21,1 %) that led to 11 revision operations (^=0.3 per knee). The deviation from the "ideal" leg axis could be reduced from 3.8° varus to 1.7° varus in the group DO and from 1.3° valgus auf 1.2° valgus in the group PT. Patients with a preoperative valgus deviation > 10° were reduced from 13.6° (± 3.9°) valgus to 0.5° (± 9.2°) varus.

CONCLUSION

Patients after TKA because of post-traumatic osteoarthritis show worse results concerning function and condition compared to patients with degenerative osteoarthritis. Heterogeneous pathogenesis and high rates of revision operations underline the complexity of this group of patients. The treatment has to be adjusted to the patient's requirements as well to the pathoanatomy.

[Minimally invasive unicondylar knee arthroplasty with simultaneous ACL reconstruction : treatment of medial compartment osteoarthritis and cruciate ligament defect]

BACKGROUND

Low postoperative pain level, decreased length of hospital stay and accelerated rehabilitation are the major benefits of unicondylar knee arthroplasty. Especially in comparably young, not yet retired and still active patients with an isolated medial gonarthrosis, these prostheses offer many advantages. However, one important requirement to be treated with such implants is a well functioning stability system of the muscles and ligaments. Thus in patients with degenerated or destroyed anterior cruciate ligaments it is contraindicated to use this method. In order to still take advantage of this therapy for treatment of isolated arthrosis, reestablishment of the proprioceptive structures through simultaneous or staged ACL reconstruction is mandatory.

PATIENTS AND METHODS

Pursuing this goal we performed unicondylar knee arthroplasty with simultaneous ACL reconstruction on eligible patients. Between 2003 and 2006 we treated 32 knees with this combined surgery and followed them for a mean of 31 months (range: 10-38).

RESULTS

The mean Knee Society Score significantly improved from 83.2 (44-103) to 167.6 (145-177) at a mean follow-up of 31 months (10-38).

CONCLUSIONS

Preliminary results of this short-term follow-up are promising. Especially the predominant number of patients who were able to return to work soon after rehabilitation and the significantly improved score postoperatively reflect the benefits of this prosthesis system in select patients. However, long-term follow-up and larger case numbers are necessary to confirm these encouraging results in the future.

[Reconstruction of the ligamentum cruciatum anterius during the performance of unicondylar knee arthroplasty by minimally invasive surgery. A salvage procedure for monocondylar arthrosis and downfall of the anterior cruciate ligament]

Opinions differ on unicompartmental knee replacement for treatment of unicompartmental ostearthritis of the knee. There is general agreement that well-functioning cruciate ligaments are necessary if use of this prosthesis is to be successful. Especially for younger people who are still working and who have advanced medial arthritis and lacking or inadequate anterior cruciate ligament, this therapy has its limitations. To exploit the advantages of unicondylar replacement in such patients, we combined this joint replacement operation with reconstruction of the anterior cruciate ligament using the semitendinosus/gracilis tendon and applying a transfix technique in 7 cases. The mean Knee Society Score was recorded preoperatively and after 12 and 28 months of follow-up. Long-term results are not yet available, but after this operation method average Knee Society Scores of 164.1 were recorded at 28 months, and all these patients were able to return to work after their rehabilitation. Thus, the short-term follow-up documents the efficacity of the treatment and benefit to the patients.

[Revision possibilities after failed unicompartmental knee arthroplasty--an analysis of 116 revisions]

AIM

A major advantage of the unicompartmental knee arthroplasty (UKA) is the quick rehabilitation, small traumatisation of tissue and the mostly uncomplicated revision to a total knee arthroplasty. The aim of the study is to examine whether the conversion to the total endoprosthesis, as is frequently is recommended at present in cases of defect of the sleigh system, is always necessary or whether a revision can have good chances of success with use of the unicondylar system under certain conditions.

METHOD

116 revisions were studied after unicompartmental knee arthroplasty at the first appearance of problems and during the follow-up of 45 months (range: 10-86 months) using the Knee Society Score and analyses of the various additional procedures as well as the anterior cruciate ligament substitute, the correction of slope etc. Revisions, with exchange of components or a conversion to a total arthroplasty, were included.

RESULTS

In 60.3 % of all cases a revision could be performed within the unicompartmental knee system, with a mean score of 167.4 (range: 144-173). The outcome score corresponded to the outcome of primary UKA implantations and to conversion operations to total endoprosthesis in the literature (p < 0.05 Wilcoxon test).

CONCLUSION

Under critical contemplation of the low case number and this short- to medium-term examination, individual revision solutions seem to have their entitlement within the unicondylar system as also do conversion operations to the TKA. Long-term results and larger case numbers are absolutely necessary prior to further judgment.

[Osteoporosis--a neglected issue in orthopaedics? Results of a survey amongst German orthopaedic surgeons]

AIM

Patients with fragility fractures have a significantly increased risk of sustaining additional fractures. Therefore one should consider avoidance of further fractures as the primary treatment principle. Since orthopaedic surgeons manage most of fragility fractures, but might not be well attuned to osteoporosis itself, it was the aim of the Bone and Joint Decade (BJD) and the International Osteoporosis Foundation (IOF) to survey orthopaedic surgeons in order to assess their knowledge of prevention, diagnosis, and treatment of osteoporosis.

MATERIAL AND METHODS

The multinational survey questionnaire was developed by a working group of national project co-ordinators in France, Germany, Italy, Spain, the United Kingdom, and New Zealand and based to some extent on an American survey. Following translation into the national language it was distributed in 2002 to the members of the orthopaedic societies to assess the management of prevention, diagnosis, and therapy of osteoporosis and fragility fractures, comparing both different health-care systems and different working environments. 5 700 questionnaires were distributed in Germany with a 20 percent response rate.

RESULTS

As the main result of the German survey -- independent of the working environment -- a substantial deficit concerning training and knowledge about the management of prevention, diagnosis, and treatment of osteoporosis and fragility fractures was seen. In addition, the majority of participants requested educational opportunities to become qualified for a better disease control.

CONCLUSION

In order to satisfy the increasing need for adequate management of prevention, diagnosis, and therapy of osteoporosis and fragility fractures, structured educational opportunities have to be offered to the German orthopaedic community. In the mean time first steps have been initiated: training courses to qualify as "Osteologe DVO" and the "White Book Osteoporosis", which was initiated by BJD and IOF and developed by several German medical societies and patient organisations it is based on the German DVO guidelines providing an evidence-based and structured overview concerning all relevant aspects of osteoporosis and fragility fractures.

[Wristing -- a new opportunity in digital migration analysis of uncemented total hip arthroplasty]

AIM

The aim of this study was to evaluate a computer program (Wristing) for digital migration analysis in hip endoprotheses and to assess the most accurate landmarks in hip-alone radiographs.

METHOD

Conventional radiographs of 52 patients with a minimum follow-up period of seven years and five consecutive radiographs were digitised and different landmarks were compared. The parameters with the greatest accuracy were analysed to calculate inter- and intra-observer variability in 30 radiographs. Digital and manual measurement techniques were compared with each other.

RESULTS

The obtained accuracy (95 % confidence interval) was 1.7 to 2.2 mm and 2.8 degrees to 3.2 degrees for the most accurate landmarks. The intra-observer variability was 0.12-0.3 mm; 0.28 degrees and the inter-observer variability ranged from 0.14 to 0.45 mm and 0.5 degrees to 0.53 degrees . In comparison to the migration measurement with pencil and ruler (precision: 0.24-0.67 mm; 0.57-0.74 degrees ) the new software (precision: 0.12-0.3 mm; 0.28 degrees ) was associated with a superior accuracy (t test: p < 0.001).

CONCLUSION

With the program "Wristing" migration in hip-alone radiographs could be recorded with high precision. The integrated sketch, zooming and the current possibility of comparing radiographs and patient data with previous follow-ups and examples leads to a high inter- and intra-observer accuracy and is very useful in day-to-day clinical practice.

Multimediale Patientenaufkl�rung in der Klinik

Due to heavy workloads and shortage of staff, doctors often find it difficult to explain operations to their patients with the legally required detail and timing (in Germany, 24 h preop). This is however mandatory for obtaining informed consent. We developed a computer program that generates films explaining 24 common orthopedic operations and blood transfusion. They explain the operation, early postoperative phase, and benefits and risks to the patient. At our clinic, this program is used in daily routine and precedes the actual doctor-patient conversation for informed consent. We asked 300 patients about their satisfaction with the newly developed program. The multimedia presentation gives the patient more time, enough detail and clarity, and the chance to repeat parts of the film. For the doctor, it saves time. The time gap required in Germany between explanation and operation is thus easily adhered to. In case of legal problems, the film can be used for evidence. The use of this multimedia presentation to help in getting informed consent is improving workflow considerably.

[Results of routine intraoperative cholangiography]

Most bile duct injuries result from an incorrect interpretation of bile duct anatomy. In 500 laparoscopic cholecystectomies we used a modified technique of cholecystcholangiography. This method is very easy and needs only 5 minutes. We found variants of bile duct anatomy in 74 cases and occult bile duct stones in 20 patients. We recommend this method which decreases the risk of bile duct injuries and gives the opportunity to approximate the golden standard of conventional cholecystectomy.

Correcting tritium concentrations in water vapor monitored with silica gel

A correction is needed to calculate the activity concentration of airborne tritium oxide when dried silica gel is used as the collector. A tracer study using tritiated water with silica gel showed that the concentration of tritium in desorbed water is lower than that in adsorbed water by a fraction that increases with the amount of adsorbed water. The hypothesis was tested that adsorbed tritiated water is diluted by isotopic exchange with both non-tritiated water and hydroxyl groups within the silica gel matrix. The extent of dilution was measured from 4% to 14% adsorbed water, which is typical of moisture on field collectors for monitoring airborne tritium oxide. For this range of percent adsorbed water, the inferred percent exchangeable water in the silica gel under study was 6.3 +/- 0.1%. This value compares to the silica gel weight loss of 5.3% after heating to 1,050 degrees C. An explanation of the difference between 6.3% and 5.3% is proposed. The contribution of the HTO/H2O vapor pressure isotope effect was considered in calculating isotopic exchange. A curve is presented for correcting the measured tritium concentration in the distillate from the silica gel as a function of the amount of adsorbed water. The tritium tracer procedure is recommended for determining the percent exchangeable water in other silica gels to correct tritium measurements of water vapor collected by them.

[Importance of appendix stump management in laparoscopic appendectomy]

In laparoscopic appendectomy several variants of technique have been proposed. In a randomized prospective trial we compared three common techniques: 1. application of two endoloops, 2. application of two endoloops and additional manual stump sinking 3. application of endo-cutter. The study included 150 patients, 50 each per technique. The application of two endoloops with additional manual stump sinking as well as the cutter technique were associated with a low risk for complications. In contrast, appendectomy by two endoloops without stump sinking was associated with a higher risk for local complications. The manual stump sinking requires a high level of manual experience, whereas the cutter technique can be learned rapidly by surgical residents. Therefore, we recommend the cutter technique as standard procedure, because it allows laparoscopic appendectomy to be performed with high reliability by experienced surgeons as well as by novice surgical residents.

[Bile duct injuries in laparoscopic cholecystectomy--assessment of current status]

The laparoscopic technique for cholecystectomy is associated with a increased rate of bile duct injuries. A conscientious preparation, the excessive application of electrocoagulation, anatomical variants and renunciation of cholangiography are reasons for injuries. The technique of operative treatment depends on type, range and location of injury.

[New aspects of laparoscopic cholangiography]

Cholangiography does not prevent bile duct injury, but if performed properly, it can identify impending injury before hand. We present a modified form of laparoscopic cholecystcholangiography; only 5 min are required to perform this technique. Some 408 consecutive peroperative cholangiographies are analyzed. We recommend this method, which decreases the risk of bile duct injuries, reveals occult bile duct stones in 4.2%, and gives the opportunity to approximate the gold standard of cholecystectomies.

[Technique and significance of stump management for outcome of laparoscopic appendectomy]

We compared 140 appendectomies in a prospective study with regard to length of operation, stay in hospital and intra- and postoperative complications. We operated by four methods and made up four groups, 35 patients in each: (1) application of RODER-loop and manual stump-sinking; (2) application of RODER-loop without manual stump-sinking; (3) application of Endo-GIA; (4) conventional appendectomy according to McBurney. Intraoperative complications occurred mainly in laparoscopic appendectomy, while disturbances of wound-healing were observed mainly in conventional appendectomy. The analysis of postoperative complications in laparoscopic appendectomy showed the most complications in the second group (RODER-loop without stump-sinking), while using the Endo-GIA involved only a little risk. In a clear situs the laparoscopic appendectomy with the RODER-loop with manual stump-sinking is recommended; in cases with a difficult preparation or advanced appendicitis the application of the Endo-GIA is a safe technique with the best results.