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Ziel der operativen Versorgung einer akuten Kniegelenkluxation (Schenck IV) ist die Wiederherstellung einer stabilen Bandfuhrung und einer physiologischen Kinematik des Kniegelenkes. Demonstration der Operationstechnik bei einem Patienten mit akuter Kniegelenkluxation (Schenck IV) mit Ruptur beider Kreuzbander und zusatzlich der medialen und lateralen peripheren Gelenkstabilisatoren. Kritische Weichteilverhaltnisse, kritische Gefassituation, (Risiko eines intraoperativen Gefasverschlusses). Beginn mit einer kurzen Arthroskopie zu Identifikation und Adressierung von Meniskusverletzungen und ggf. Platzierung der Zieldrahte fur die Ersatzplastik des vorderen Kreuzbandes (VKB). Im Anschluss anteromediale Arthrotomie und „ligament bracing“ des hinteren Kreuzbandes. Das VKB wird mit einer autologen Sehne rekonstruiert. Rekonstruktion der medialen und lateralen Bandkomplexe mit Nahtankersystemen und augmentierende posterolaterale Bandplastik nach Arciero. Teilbelastung mit 20 kg fur 6 Wochen. Stufenweise Freigabe der Beweglichkeit mithilfe einer Bewegungsorthese unter engmaschiger klinischer Kontrolle im Sinne der gefuhrten Arthrofibrose. Das Konzept des Ligament bracing des zentralen Pfeilers bei der akuten Kniegelenkluxation wurde bereits wissenschaftlich untersucht und erzielt gute bis sehr gute Ergebnisse. In einer vergleichenden Untersuchung des „VKB internal bracing“ gegenuber der VKB-Ersatzplastik im Rahmen der Akutversorgung einer Kniegelenkluxation zeigt sich ein Trend fur uberlegene Stabilitatsergebnisse im Rolimeter®-Test (Fa. Aircast, Freiburg, Deutschland) sowie in der Stressradiographie (Fa. TelosTM, Wolfersheim, Deutschland) 12 Monate nach der operativen Versorgung.

Die physiologische Funktion des Patellofemoralgelenks (PFG) wird durch die Interaktion verschiedener anatomischer und biomechanischer Faktoren bedingt. Viele patellofemorale Krankheitsbilder entstehen auf der Grundlage von Dysbalancen, die auf Abweichungen dieser Faktoren zuruckzufuhren sind und die komplexe Kinematik des PFG in relevantem Ausmas beeintrachtigen. Die resultierenden Patholgien lassen sich drei grose Symptomkomplexe einteilen: vorderer Knieschmerz, Arthrose und Instabilitat. Die erfolgreiche Behandlung dieser Krankheitsbilder setzt eine genaue Kenntnis sowie eine grundliche klinische Analyse zugrundeliegender Pathologien voraus. Im Folgenden sollen die biomechanischen Grundlagen aktiver, passiver und statischer Stabilisatoren des PFG sowie deren Einfluss auf die patellofemorale Kinematik erortert und dargestellt werden. Zudem soll ein Uberblick klinischer Untersuchungsmethoden zur Diagnose einzelner Pathologien gegeben werden.

Si fluxes from the continents to the ocean are a key element of the global Si cycle. Due to the ability of coastal ecosystems to process and retain Si, the ‘coastal filter’ has the potential to alter Si fluxes at a global scale. Coastal zones are diverse systems, sensitive to local environmental changes, where Si cycling is currently poorly understood. Here, we present the first palaeoenvironmental study of estuarine biogenic silica (BSi) fluxes and silicon isotope ratios in diatoms (δ30Sidiatom) using hand-picked diatom frustules in two sediment cores (CBdist and CBprox) from the Chesapeake Bay covering the last 12000 and 8000 years, respectively. Constrained by the well-understood Holocene evolution of the Chesapeake Bay, we interpret variations in Si cycling in the context of local climate, vegetation and land use changes. δ30Sidiatom varies between + 0.8 and + 1.7‰ in both sediment cores. A Si mass balance for the Chesapeake Bay suggests much higher rates of Si retention (~ 90%) within the system than seen in other coastal systems. BSi fluxes for both sediment cores co-vary with periods of sea level rise (between 9500 and 7500 a BP) and enhanced erosion due to deforestation (between 250 and 50 a BP). However, differences in δ30Sidiatom and BSi flux between the sites emphasize the importance of the seawater/freshwater mixing ratios and locally variable Si inputs from the catchment. Further, we interpret variations in δ30Sidiatom and the increase in BSi fluxes observed since European settlement (~ 250 a BP) to reflect a growing human influence on the Si cycle in the Chesapeake Bay. Thereby, land use change, especially deforestation, in the catchment is likely the major mechanism.

Die Therapie der Patellainstabilitat bedarf einer genauen Vorgehensweise im Hinblick auf Klassifikation, Diagnostik und Therapieplanung. Ein undifferenziertes Vorgehen resultiert haufig in persistierender Instabilitat und ausbleibendem Therapieerfolg. Es sind verschiedene Ursachen und Therapieansatze der patellofemoralen Instabilitat bekannt, das mediale patellofemorale Ligament (MPFL) galt lange als Synonym fur die operative Therapie. Heute existieren Behandlungsalgorithmen und Systeme, welche die zugrunde liegenden Pathologien berucksichtigen und Erfolg versprechende Ergebnisse erlauben. Masgeblich ist hier die Unterscheidung zwischen Patellainstabilitat und -maltracking, die jeweils separat zu betrachten sind. Entsprechend der vorliegenden Hauptpathologie kann ein adaquater Algorithmus verfolgt und niedrige Reluxationsraten erreicht werden. Dieser Beitrag beleuchtet den Einfluss verschiedener Pathologien und die Moglichkeiten der operativen Stabilisierung des patellofemoralen Gelenks. Es wird dabei auf die jeweiligen Subtypen eingegangen, und die entsprechenden Optionen werden erlautert.

Silicon isotope ratios (expressed as δ30Si) in marine microfossils can provide insights into silica cycling over geologic time. Here we used δ30Si of sponge spicules and radiolarian tests from the Paleogene Equatorial Transect (Ocean Drilling Program Leg 199) spanning the Eocene and Oligocene (~50–23 Ma) to reconstruct dissolved silica (DSi) concentrations in deep waters and to examine upper ocean δ30Si. The δ30Si values range from −3.16 to +0.18‰ and from −0.07 to +1.42‰ for the sponge and radiolarian records, respectively. Both records show a transition toward lower δ30Si values around 37 Ma. The shift in radiolarian δ30Si is interpreted as a consequence of changes in the δ30Si of source DSi to the region. The decrease in sponge δ30Si is interpreted as a transition from low DSi concentrations to higher DSi concentrations, most likely related to the shift toward a solely Southern Ocean source of deep water in the Pacific during the Paleogene that has been suggested by results from paleoceanographic tracers such as neodymium and carbon isotopes. Sponge δ30Si provides relatively direct information about the nutrient content of deep water and is a useful complement to other tracers of deep water circulation in the oceans of the past.

The Paleocene-Eocene Thermal Maximum (PETM, ca. 56 Ma) is marked by a negative carbon isotope excursion (CIE) and increased global temperatures. The CIE is thought to result from the release of 13C-depleted carbon, although the source(s) of carbon and triggers for its release, its rate of release, and the mechanisms by which the Earth system recovered are all debated. Many of the proposed mechanisms for the onset and recovery phases of the PETM make testable predictions about the marine silica cycle, making silicon isotope records a promising tool to address open questions about the PETM. We analyzed silicon isotope ratios (δ30Si) in radiolarian tests and sponge spicules from the Western North Atlantic (ODP Site 1051) across the PETM. Radiolarian δ30Si decreases by 0.6‰ from a background of 1‰ coeval with the CIE, while sponge δ30Si remains consistent at 0.2‰. Using a box model to test the Si cycle response to various scenarios, we find the data are best explained by a weak silicate weathering feedback, implying the recovery was mostly driven by nondiatom organic carbon burial, the other major long-term carbon sink. We find no resolvable evidence for a volcanic trigger for carbon release, or for a change in regional oceanography. Better understanding of radiolarian Si isotope fractionation and more Si isotope records spanning the PETM are needed to confirm the global validity of these conclusions, but they highlight how the coupling between the silica and carbon cycles can be exploited to yield insight into the functioning of the Earth system. (Less)

Fehlverheilte Tibiakopffrakturen fuhren haufig zu Fehlstellungen an der unteren Extremitat, Schmerzen, Bewegungseinschrankung und Instabilitat. Das Ausmas der Beschwerden und der Deformitat erfordert die exakte Analyse und ein standardisiertes Vorgehen. Echte ligamentare Instabilitaten sind von Pseudoinstabilitaten zu unterscheiden. Extra- und intraartikulare Fehlstellungen sind zu differenzieren. Bei Letzteren sollte die Lokalisation von Gelenkstufen, Spalten oder Defekten exakt evaluiert werden. Fur die Revision ist ein Zugang zu wahlen, mit dem die betroffene Region am Tibiakopf gut visualisiert, osteotomiert und anschliesend fixiert werden kann. Intraartikulare Osteotomien erzielen im Langzeitverlauf gute klinische Ergebnisse. Bei nichtrekonstruierbarer Zerstorung des Gelenks oder bereits fortgeschrittener posttraumatischer Arthrose kann die Implantation einer Endoprothese notwendig werden. Wann immer moglich und sinnvoll, sollte das Gelenk jedoch rekonstruiert und erhalten werden.

Wir berichten uber einen 17-jahrigen Patienten, der sich bei einem Verkehrsunfall eine Epiphysenverletzung (Salter-Harris IV) mit einer begleitenden ossaren Avulsion des vorderen Kreuzbands (VKB; Meyers-McKeever III) zuzog. Die arthroskopisch assistierte Versorgung der Epiphysenfraktur erfolgte mittels zweier kanulierter 7,3-mm-Schrauben unter Aussparung der Epiphysenfugen. Das VKB-Fragment wurde mittels FiberWire®-Fadencerclage transossar fixiert. Unter arthroskopischer Kontrolle war die stufenlose Reposition beider Verletzungen komplikationslos moglich. Der iatrogene Weichteilschaden war minimal.

Intensive agricultural practices can dramatically change the landscape, thereby increasing the concentrations and rates at which nutrients are delivered to aquatic ecosystems. In the United States, concerns about accelerating rates of lake eutrophication related to increases in nutrient loading require a method of quantifying ecological changes that have occurred since European settlement. Because the application of traditional quantitative total phosphorus transfer functions in paleolimnology has proven difficult in shallow, hypereutrophic lakes, we used several approaches in this study to assess ecosystem changes associated with eutrophication of 32 natural lakes in the state of Iowa, USA. In addition to traditional transfer function methods, we estimated changes in primary productivity from the flux of biogenic silica (BSi) and organic carbon accumulation rates (OC AR). Additionally, we compared pre-disturbance diatom communities to modern diatom communities, i.e. floristic change, using non-metric multi-dimensional scaling and square chord distance. OC AR and BSi fluxes increased over time and were positively correlated with the time period of agricultural intensification in the region (post-1940). Ninety-one percent of the lakes in this study showed evidence for eutrophication based on geochemical proxies, and 88 % of lakes showed major floristic change in the diatom community. Whereas geochemical indicators showed consistent increases in productivity across most lakes, floristic changes reflected more complex interactions between other environmental drivers. The magnitude of floristic change did not directly correlate to nutrient-driven increases in primary production, but was driven by ecological diatom assembly related to lake depth. Transfer functions consistently perform poorly, especially for shallow lakes, and other techniques that combine geochemistry and diatom ecology are recommended for reconstructions of eutrophication.

1. To help meet the requirements of water legislation, palaeolimnology has been widely used to establish ‘reference conditions’ and restoration targets for lakes. However, its potential for assessing the necessity and appropriateness of different lake management activities has been less publicized. 2. With reference to selected case studies covering consultancy projects commissioned by UK conservation agencies, this study highlights the important applied role of palaeolimnology. Using varying combinations of diatom, plant macrofossil and cladoceran analysis, the degree, timing and in many cases the likely drivers of ecological change were inferred for several lake sites. 3. From this basis advice was given on a range of lake management issues, including the need for sediment removal to combat eutrophication and/or the necessity of other nutrient reduction measures (Case study 1), the depth of sediment to be removed to maximize restoration potential through exposure of dormant banks of characean oospores (Case study 2), the requirement for fish management (Case study 3), and advice regarding fish farm expansion and licensing (Case study 4). Where possible management responses to the recommendations are outlined including any major outcomes. 4. All case studies illustrate the advantages, for lake management and conservation decision-making, of placing current lake ecological conditions in the context of long-term change. (Less)

Despite being one of Earth’s major geochemical cycles, the evolution of the silicon cycle has received little attention and changes in oceanic dissolved silica (DSi) concentration through geologic time remain poorly constrained. Silicon isotope ratios (expressed as δ30Si) in marine microfossils are becoming increasingly recognised for their ability to provide insight into silicon cycling. In particular, the δ30Si of siliceous sponge spicules has been demonstrated to be a useful proxy for past DSi concentrations. We analysed δ30Si in radiolarian tests and sponge spicules from the Blake Nose Palaeoceanographic Transect (ODP Leg 171B) spanning the Palaeocene-Eocene (ca. 60 - 30 Ma). Our δ30Si results range from +0.32 to +1.67‰ and -0.48 to +0.63‰ for the radiolarian and sponge records, respectively. Using an established relationship between ambient dissolved Si (DSi) concentrations and the magnitude of silicon isotope fractionation in siliceous sponges, we demonstrate that the Western North Atlantic was DSi deplete during the Palaeocene-Eocene throughout the water column, a conclusion that is robust to a range of assumptions and uncertainties. These data can constitute constraints on reconstructions of past-ocean circulation. Previous work has suggested ocean DSi concentrations were higher than modern ocean concentrations prior to the Cenozoic and has posited a drawdown during the Early Palaeogene due to the evolutionary expansion of diatoms. Our results challenge such an interpretation. We suggest here that if such a global decrease in oceanic DSi concentrations occurred, it must predate 60 Ma.