[Treatment of acute knee dislocations]

A knee dislocation is a serious injury involving at least two of the four major ligamentous stabilizers of the knee. This injury results in multidirectional knee instability. In dislocation of the knee the popliteal artery and the peroneal nerve can also be damaged. Dislocations with vascular involvement are potentially threatening injuries of the lower extremities. The diagnosis of knee dislocation can be difficult due to a high rate of spontaneous reduction at the initial examination. Knee dislocations are rare and mainly occur in young men. They are mostly caused by high-energy trauma; however, they can also be caused by low-energy injuries. Obesity increases the risk of knee dislocations. The classification of a knee dislocation is based on the anatomical structures involved and the direction of dislocation. The acute treatment includes reduction and stabilization measures. Associated injuries, such as vascular, nerve, extensor mechanism and cartilage injuries as well as fractures and meniscal injuries can influence the treatment approach and the outcome. The definitive surgical treatment depends on the severity of the injury and can include ligament reconstruction or repair with bracing. The aftercare should be individually adapted with the aim to restore knee joint stability and function. Complications such as arthrofibrosis, peroneal nerve palsy, compartment syndrome, postoperative infection and recurrent instability can occur. In the long term, patients have an increased risk for the development of symptomatic osteoarthritis.

Cellular Architects at Work: Cells Building their Own Microgel Houses

Microporous annealed particle (MAP) scaffolds are investigated for their application as injectable 3D constructs in the field of regenerative medicine and tissue repair. While available MAP scaffolds provide a stable interlinked matrix of microgels for cell culture, the infiltration depth and space for cells to grow inside the scaffolds is pre-determined by the void fraction during the assembly. In the case of MAP scaffolds fabricated from interlinked spherical microgels, a cellularity gradient can be observed with the highest cell density on the scaffold surface. Additionally, the interlinked microgel network limits the ability of cells to remodel their environment, which contradicts native tissue dynamics. In this work, a cell-induced interlinking method for MAP scaffold formation is established, which avoids the necessity of chemical crosslinkers and pre-engineered pores to achieve micro- or macropores in these 3D frameworks. This method enables cells to self-organize with microgels into dynamic tissue constructs, which can be further controlled by altering the microgel properties, the cell/microgel ratio, and well shape. To form a cell-induced interlinked scaffold, the cells are mixed with dextran-based microgels and function as a glue between the microgels, resulting in a more homogenous cell distribution throughout the scaffold with efficient cell-cell interactions.

Etiology, Classification, Diagnostics, and Conservative Management of Osteochondral Lesions of the Talus. 2023 Recommendations of the Working Group "Clinical Tissue Regeneration" of the German Society of Orthopedics and Traumatology

METHODS

Peer-reviewed literature was analyzed regarding different topics relevant to osteochondral lesions of the talus (OLTs) treatment. This process concluded with a statement for each topic reflecting the best scientific evidence available for a particular diagnostic or therapeutic concept, including the grade of recommendation. Besides the scientific evidence, all group members rated the statements to identify possible gaps between literature and current clinical practice.

CONCLUSION

In patients with minimal symptoms, OLT progression to ankle osteoarthritis is unlikely. Risk factors for progression are the depth of the lesion on MRI, subchondral cyst formation, and the extent of bone marrow edema. Conservative management is the adaptation of activities to the performance of the ankle joint. A follow-up imaging after 12 months helps not to miss any progression. It is impossible to estimate the probability of success of conservative management from initial symptoms and imaging. Cast immobilization is an option in OLTs in children, with a success rate of approximately 50%, although complete healing, estimated from imaging, is rare. In adults, improvement by conservative management ranges between 45% and 59%. Rest and restrictions for sports activities seem to be more successful than immobilization. Intra-articular injections of hyaluronic acid and platelet-rich plasma can improve pain and functional scores for more than 6 months. If 3 months of conservative management does not improve symptoms, surgery can be recommended.

Influence of the Resin System and Sand Type on the Infiltration of 3D-Printed Sand Tools

Binder jetting is a highly productive additive manufacturing (AM) method for porous parts. Due to its cost-effectiveness, it is used for large components and quantities ranging from prototyping to series production. Post-processing steps like sintering or infiltration are common in several applications to achieve high density and strength. This work investigates how 3D-printed sand molds can be infiltrated with epoxy resins without vacuum assistance to produce high-strength molds for thermoforming applications. Specimens 3D-printed from different sand types are infiltrated with resins of different viscosity and analyzed for infiltration velocity and depth. The infiltration velocities corresponded well with the correlation described in Washburn's equation: The resins' viscosities and the saturation level were decisive. Amongst the investigated sand types commonly used in foundries, sand type GS19 was found most suitable for infiltration. However, the sand type proved to be a less relevant influencing factor than the resins' viscosities and quantities applied. Infiltration of topology-optimized 3D-printed sand tools up to a wall thickness of 20 mm for thermoforming applications was found to be feasible.

Transformative Materials to Create 3D Functional Human Tissue Models In Vitro in a Reproducible Manner

Recreating human tissues and organs in the petri dish to establish models as tools in biomedical sciences has gained momentum. These models can provide insight into mechanisms of human physiology, disease onset, and progression, and improve drug target validation, as well as the development of new medical therapeutics. Transformative materials play an important role in this evolution, as they can be programmed to direct cell behavior and fate by controlling the activity of bioactive molecules and material properties. Using nature as an inspiration, scientists are creating materials that incorporate specific biological processes observed during human organogenesis and tissue regeneration. This article presents the reader with state-of-the-art developments in the field of in vitro tissue engineering and the challenges related to the design, production, and translation of these transformative materials. Advances regarding (stem) cell sources, expansion, and differentiation, and how novel responsive materials, automated and large-scale fabrication processes, culture conditions, in situ monitoring systems, and computer simulations are required to create functional human tissue models that are relevant and efficient for drug discovery, are described. This paper illustrates how these different technologies need to converge to generate in vitro life-like human tissue models that provide a platform to answer health-based scientific questions.

Oxonium diimidotriphosphate from the hydrolysis of trimetaphosphimic acid

Trimetaphosphimates decompose not only upon heating but also in water. Hydrolysis of trimetaphosphimic acid leads to the formation of diimidotriphosphoric acid by ring opening. Single-crystal structure determination using synchrotron radiation revealed the oxonium salt of the latter acid with double stacks of rod-shaped anions along [001]. Anharmonic displacement parameters were used to model slight disorder of part of the anions. These are interconnected by hydrogen bonds within and between the stacks. Powder X-ray diffraction confirmed phase purity. At temperatures above 120 °C, diimidotriphosphoric acid decomposes into unknown crystalline compounds. It thus seems a promising precursor for the synthesis of oxonitridophosphates at moderate temperatures.

Graphical abstract

Modular Principle for Complex Disordered Tetrahedral Frameworks in Quenched High-Pressure Phases of Phosphorus Oxide Nitrides

Invited for the cover of this issue are the groups of Oliver Oeckler at Leipzig University and Wolfgang Schnick at University of Munich (LMU). The image background depicts a diffraction pattern of an intergrown crystal containing P₄₀ O₃₁ N₄₆ as a night sky. P₄₀ O₃₁ N₄₆ and P₇₄ O₅₉ N₈₄ form complex disordered frameworks, a cutout of which symbolizes the earth's surface (which mainly contains silicates with related building blocks). The structures are built up from chain-like building units, which fall like rain, symbolizing the modular building scheme. Read the full text of the article at 10.1002/chem.202203892.

Descriptive analysis and short-term follow-up clinical results of osteochondral lesions of the distal tibia based on data of the German Cartilage Register (Knorpelregister® DGOU)

INTRODUCTION

An increasing number of ankle injuries with osteochondral lesions (OCL) also include lesions of the distal tibia. Therefore, the German Cartilage Society database is used to describe and examine the characteristics of these lesions and, early on, the results of different surgical therapies on the clinical outcome.

MATERIALS AND METHODS

Forty-seven patients out of 844 registered in the German Cartilage Society database met the inclusion criteria showing an OCL of the distal tibia (OLDT). Sixteen of them also presented a 1-year follow-up regarding the Foot and Ankle Ability Measure (FAAM). Further evaluations were included in the follow-up, such as the Foot and Ankle Outcome Score (FAOS) and the Visual Analogue Scale for pain (VAS).

RESULTS

The patients' mean age was 35 ± 11 with a mean BMI in the range of overweight (26/27 ± 5 kg/m²). The lesions were equally distributed on the articular surface of the distal tibia. Most patients were operated using anterior ankle arthroscopy [n_T 34 (72%); n_S 13 (81%)], while some (n_T 9; n_S 4) converted to open procedures. Almost 90% staged III and IV in the ICRS classification. Debridement, bone marrow stimulation, solid scaffolds, and liquid filler were the treatment choices among the subgroup. All therapies led to a clinical improvement between pre-op and 1-year follow-up but not to a significant level.

CONCLUSION

This study presents baseline data of OLDT based on data from a large database. BMS and scaffolds were the treatment of choice but did not present significant improvement after a 1-year follow-up.

Modular Principle for Complex Disordered Tetrahedral Frameworks in Quenched High-Pressure Phases of Phosphorus Oxide Nitrides

The crystal structures of the new phosphorus oxide nitrides P₄₀ O₃₁ N₄₆ and P₇₄ O₅₉ N₈₄ , which were synthesized from amorphous phosphorus oxide nitride imide, exhibit complex frameworks built up from P(O,N)₄ tetrahedra. The latter form various chain-like building units with various degrees of branching. These modular units can be combined and arranged in different ways, which leads to closely related structures and several disordered configurations in each compound. As the material was obtained by high-pressure high-temperature synthesis, the disorder is most likely a consequence of quenching a high-pressure phase with P(O,N)₅ trigonal bipyramids. Under ambient conditions, P atoms are expected to relax by moving to the centers of the face-sharing tetrahedra that constitute the bipyramid. Diffraction patterns acquired with microfocused synchrotron radiation reveal that domains of both compounds are intergrown with H₃ P₈ O₈ N₉ , whose tetrahedral framework represents a cutout of the structures of both P₄₀ O₃₁ N₄₆ and P₇₄ O₅₉ N₈₄ . Powder diffraction patterns do not indicate any further phases.

Removal of Stair-Step Effects in Binder Jetting Additive Manufacturing Using Grayscale and Dithering-Based Droplet Distribution

Binder jetting is a layer-based additive manufacturing process for three-dimensional parts in which a print head selectively deposits binder onto a thin layer of powder. After the deposition of the binder, a new layer of powder is applied. This process repeats to create three-dimensional parts. The binder jetting principle can be adapted to many different materials. Its advantages are the high productivity and the high degree of freedom of design without the need for support structures. In this work, the combination of binder jetting and casting is utilized to fabricate metal parts. However, the achieved properties of binder jetting parts limit the potential of this technology, specifically regarding surface quality. The most apparent surface phenomenon is the so-called stair-step effect. It is considered an inherent feature of the process and only treatable by post-processing. This paper presents a method to remove the stair-step effect entirely in a binder jetting process. The result is achieved by controlling the binder saturation of the individual voxel volumes by either over or underfilling them. The saturation is controlled by droplet size variation as well as dithering, creating a controlled migration of the binder between powder particles. This work applies the approach to silica sand particle material with an organic binder for casting molds and cores. The results prove the effectiveness of this approach and outline a field of research not identified previously.

Linarite from Cap Garonne

Linarite, PbCuSO4(OH)2, crystallizes as secondary mineral in form of clusters of crystals in Mine du Pradet at Cap Garonne in France. A tiny single crystal was isolated and its structure was refined from synchrotron diffraction data (λ = 0.049592 nm): P121/m1, a = 467.75(2), b = 563.48(4), c = 967.64(5) pm, β = 102.647(5)°, wR = 0.0544, 819 F 2 values and 56 variables. The proton positions were also refined. The Cu2+ cations are located within Cu(OH)2 ribbons and exhibit pronounced Jahn-Teller distortion (d(Cu–O): 2 × 191.9, 2 × 197.3 and 2 × 252.8 pm). The Cu(OH)2 ribbons are condensed with the sulfate tetrahedra and the lead cations. The latter are coordinated to eight oxygen atoms in a slightly anisotropic manner. Calculations of the electron localization function (ELF) of PbO (litharge), PbSO4 (anglesite) and PbCuSO4(OH)2 (linarite) show pronounced lone-pair character for PbO but rather isotropic ELF values around the lead cations in PbSO4 and PbCuSO4(OH)2.

Characterization of Slurry-Cast Layer Compounds for 3D Printing of High Strength Casting Cores

Additive manufacturing of casting cores and molds is state of the art in industrial application today. However, improving the properties of chemically bonded casting cores regarding temperature stability, bending strength, and surface quality is still a major challenge. The process of slurry-based 3D printing allows the fabrication of dense structures and therefore sinterable casting cores. This paper presents a study of the slurry-based fabrication of ceramic layer compounds focusing on the drying process and the achievable properties in slurry-based 3D printing of casting cores. This study aims at contributing to a better understanding of the interrelations between the drying conditions in the 3D printing process and the properties of sintered specimens relating thereto. The drying intensity influenced by an IR heater as well as the drying periods are varied for layer thicknesses of 50, 75, and 100 µm. Within this study, a process window applicable for 3D printing of sinterable casting cores is identified and further indications are given for optimization potentials. At layer heights of 75 µm, bending strengths between ~8 and 11 MPa as well as densities of around 50% of the theoretical density were achieved. Since the mean roughness depth Rz is determined to be <30 µm in plane, an application of slurry-based 3D printing in investment casting is conceivable.

3D Printed Sand Tools for Thermoforming Applications of Carbon Fiber Reinforced Composites-A Perspective

Tooling, especially for prototyping or small series, may prove to be very costly. Further, prototyping of fiber reinforced thermoplastic shell structures may rely on time-consuming manual efforts. This perspective paper discusses the idea of fabricating tools at reduced time and cost compared to conventional machining-based methods. The targeted tools are manufactured out of sand using the Binder Jetting process. These molds should fulfill the demands regarding flexural and compressive behavior while allowing for vacuum thermoforming of fiber reinforced thermoplastic sheets. The paper discusses the requirements and the challenges and presents a perspective study addressing this innovative idea. The authors present the idea for discussion in the additive manufacturing and FRP producing communities.

Herausforderungen von Evidenzlevel-1-Studien in der Unfallchirurgie und Orthopädie

Randomisierte kontrollierte klinische Studien stellen für chirurgische Fachdisziplinen eine Herausforderung dar. Dieser Artikel beschreibt die Besonderheiten und Schwierigkeiten solcher Studien. Wann immer möglich, sollte das höchste Evidenzlevel angestrebt werden. Ist ein hohes Evidenzlevel allerdings methodisch nicht korrekt erreichbar, sollte das bestmögliche nächste Evidenzlevel erzielt werden. Die Bewertung, auch im Hinblick auf die Kostenerstattung, sollte daher gerade in chirurgischen Disziplinen nicht ausschließlich am Evidenzlevel festgemacht werden. Vielmehr sollte im Rahmen von Expertengremien und unter Zuhilfenahme der besten, verfügbaren Evidenz beurteilt werden.

Heading in Soccer: Does Kinematics of the Head-Neck-Torso Alignment Influence Head Acceleration?

There is little scientific evidence regarding the cumulative effect of purposeful heading. The head-neck-torso alignment is considered to be of great importance when it comes to minimizing potential risks when heading. Therefore, this study determined the relationship between head-neck-torso alignment (cervical spine, head, thoracic spine) and the acceleration of the head, the relationship between head acceleration and maximum ball speed after head impact and differences between head accelerations throughout different heading approaches (standing, jumping, running). A total of 60 male soccer players (18.9 ± 4.0 years, 177.6 ± 14.9 cm, 73.1 ± 8.6 kg) participated in the study. Head accelerations were measured by a telemetric Noraxon DTS 3D Sensor, whereas angles for the head-neck-torso alignment and ball speed were analyzed with a Qualisys Track Manager program. No relationship at all was found for the standing, jumping and running approaches. Concerning the relationship between head acceleration and maximum ball speed after head impact only for the standing header a significant result was calculated (p = 0.024, R2 = .085). A significant difference in head acceleration (p < .001) was identified between standing, jumping and running headers. To sum up, the relationship between head acceleration and head-neck-torso alignment is more complex than initially assumed and could not be proven in this study. Furthermore first data were generated to check whether the acceleration of the head is a predictor for the resulting maximum ball speed after head impact, but further investigations have to follow. Lastly, we confirmed the results that the head acceleration differs with the approach.

Nitridophosphate-Based Ultra-Narrow-Band Blue-Emitters: Luminescence Properties of AEP8 N14 :Eu2+ (AE=Ca, Sr, Ba)

The nitridophosphates AEP₈N₁₄ (AE=Ca, Sr, Ba) were synthesized at 4–5 GPa and 1050–1150 °C applying a 1000 t press with multianvil apparatus, following the azide route. The crystal structures of CaP₈N₁₄ and SrP₈N₁₄ are isotypic. The space group Cmcm was confirmed by powder X‐ray diffraction. The structure of BaP₈N₁₄ (space group Amm2) was elucidated by a combination of transmission electron microscopy and diffraction of microfocused synchrotron radiation. Phase purity was confirmed by Rietveld refinement. IR spectra are consistent with the structure models and the chemical compositions were confirmed by X‐ray spectroscopy. Luminescence properties of Eu²⁺‐doped samples were investigated upon excitation with UV to blue light. CaP₈N₁₄ (λ_em=470 nm; fwhm=1380 cm⁻¹) and SrP₈N₁₄ (λ_em=440 nm; fwhm=1350 cm⁻¹) can be classified as the first ultra‐narrow‐band blue‐emitting Eu²⁺‐doped nitridophosphates. BaP₈N₁₄ shows a notably broader blue emission (λ_em=417/457 nm; fwhm=2075/3550 cm⁻¹).

BaP6 N10 NH:Eu2+ as a Case Study-An Imidonitridophosphate Showing Luminescence

Barium imidonitridophosphate BaP6 N10 NH was synthesized at 5 GPa and 1000 °C with a high-pressure high-temperature approach using the multianvil technique. Ba(N3 )2 , P3 N5 and NH4 Cl were used as starting materials, applying a combination of azide and mineralizer routes. The structure elucidation of BaP6 N10 NH (P63 , a=7.5633(11), c=8.512(2) Å, Z=2) was performed by a combination of transmission electron microscopy and single-crystal diffraction with microfocused synchrotron radiation. Phase purity was verified by Rietveld refinement. 1 H and 31 P solid-state NMR and FTIR spectroscopy are consistent with the structure model. The chemical composition was confirmed by energy-dispersive X-ray spectroscopy and CHNS analyses. Eu2+ -doped samples of BaP6 N10 NH show blue emission upon excitation with UV to blue light (λem =460 nm, fwhm=2423 cm-1 ) representing unprecedented Eu2+ -luminescence of an imidonitride.

Targeting Vacancies in Nitridosilicates: Aliovalent Substitution of M2+ (M=Ca, Sr) by Sc3+ and U3

Based on the known linking options of their fundamental building unit, that is the SiN₄ tetrahedron, nitridosilicates belong to the inorganic compound classes with the greatest structural variability. Although facilitating the discovery of novel Si-N networks, this variability represents a challenge when targeting non-stoichometric compounds. Meeting this challenge, a strategy for targeted creation of vacancies in highly condensed nitridosilicates by exchanging divalent M²⁺ for trivalent M³⁺ using the ion exchange approach is reported. As proof of concept, the first Sc and U nitridosilicates were prepared from α-Ca₂ Si₅ N₈ and Sr₂ Si₅ N₈ . Powder X-ray diffraction (XRD) and synchrotron single-crystal XRD showed random vacancy distribution in Sc_0.2 Ca_1.7 Si₅ N₈ , and partial vacancy ordering in U_0.5x Sr_2-0.75x Si₅ N₈ with x≈1.05. The high chemical stability of U nitridosilicates makes them interesting candidates for immobilization of actinides.

[Significance of Matrix-augmented Bone Marrow Stimulation for Treatment of Cartilage Defects of the Knee: A Consensus Statement of the DGOU Working Group on Tissue Regeneration]

Surgical principles for treatment of full-thickness cartilage defects of the knee include bone marrow stimulation techniques (i.e. arthroscopic microfracturing) and transplantation techniques (i.e. autologous chondrocyte implantation and osteochondral transplantation). On the basis of increasing scientific evidence, indications for these established therapeutical concepts have been specified and clear recommendations for practical use have been given. Within recent years, matrix-augmented bone marrow stimulation has been established as a new treatment concept for chondral lesions. To date, scientific evidence is limited and specific indications are still unclear. The present paper gives an overview of available products as well as preclinical and clinical scientific evidence. On the basis of the present evidence and an expert consensus from the "Working Group on Tissue Regeneration" of the German Orthopaedic and Trauma Society (DGOU), indications are specified and recommendations for the use of matrix-augmented bone marrow stimulation are given. In principle, it can be stated that the various products offered in this field differ considerably in terms of the number and quality of related studies (evidence level). Against the background of the current data situation, their application is currently seen in the border area between cell transplantation and bone marrow stimulation techniques, but also as an improvement on traditional bone marrow stimulation within the indication range of microfracturing. The recommendations of the Working Group have preliminary character and require re-evaluation after improvement of the study situation.

[Debridement in Focal Cartilage Damage of the knee. Systematical review of the literature and recommendations of the working group "clinical tissue regeneration" of the German Society of Orthopaedics and Trauma (DGOU)]

BACKGROUND

In clinical practice, there is still no definite treatment algorithm for focal, partial thickness cartilage lesions (grade II - III). It is well-established that debridement (shaving/lavage) of large degenerative cartilage lesions is not recommended, but there is no such recommendation in the case of focal, partial thickness cartilage defects.

MATERIALS AND METHODS

The scientific rationale of cartilage shaving and joint lavage was investigated and a systematic analysis was performed of the literature on the clinical effect of cartilage debridement. Furthermore, a consensus statement on this issue was developed by the working group on Clinical Tissue Regeneration of the German Society of Orthopaedics and Trauma (DGOU).

RESULTS

The therapeutic approach is different for asymptomatic lesions with biomechanical stable residual cartilage tissue and clinically symptomatic defects with unstable fragments. The benefit of a joint lavage or surface smoothening of focal partial thickness has not been proved. Even more importantly, the mechanical or thermal resection of cartilage tissue even induces a zone of necrosis in adjacent cartilage, and thus leads to additional injury. Therefore, large scale smoothening (shaving) of clinically asymptomatic, fibrillated or irregular cartilage defects should not be performed. However, if there are clinical symptoms, resection of unstable and delaminated cartilage fragments may be reasonable, as it can reduce harmful shear tension in residual tissue. This can help to brake the progression of the damage and avoid formation of free bodies.

CONCLUSION

The decision criteria for debridement of partial thickness focal cartilage lesions are multifactorial and include the clinical symptoms, the size and the degree of the defect, the stability of remaining cartilage, localisation of the defect, and individual patient-specific parameters. Debridement is not recommended for asymptomatic lesions, but may be reasonable for symptomatic cases with unstable tissue.

Autologous chondrocyte implantation (ACI) for cartilage defects of the knee: A guideline by the working group "Clinical Tissue Regeneration" of the German Society of Orthopaedics and Trauma (DGOU)

BACKGROUND

Autologous chondrocyte implantation (ACI) is an established and well-accepted procedure for the treatment of localised full-thickness cartilage defects of the knee.

METHODS

The present review of the working group "Clinical Tissue Regeneration" of the German Society of Orthopaedics and Trauma (DGOU) describes the biology and function of healthy articular cartilage, the present state of knowledge concerning therapeutic consequences of primary cartilage lesions and the suitable indication for ACI.

RESULTS

Based on best available scientific evidence, an indication for ACI is given for symptomatic cartilage defects starting from defect sizes of more than three to four square centimetres; in the case of young and active sports patients at 2.5cm(2), while advanced degenerative joint disease needs to be considered as the most important contraindication.

CONCLUSION

The present review gives a concise overview on important scientific background and the results of clinical studies and discusses the advantages and disadvantages of ACI.

LEVEL OF EVIDENCE

Non-systematic Review.

Skin edema in first trimester fetuses

PURPOSE

The aim of this study was to prove an association between generalized skin edema and nuchal translucency (NT) thickness and its predictive value for aneuploidy and structural anomalies.

MATERIALS AND METHODS

In this retrospective study fetuses with and without skin edema in the first trimester with an NT above 2.2 mm were compared. Statistical significance was calculated with the Chi-square test (p < 0.05).

RESULTS

237 fetuses were included in this study (median NT of 3.0; IQR: 2.5 - 3.9 mm, median CRL 68.8; IQR: 58.9 - 74.9 mm). 17.3 % presented with skin edema. The rate of skin edema was 1.3 % in the group with an NT < 95th percentile, 2.7 % in the group with an NT between the 95th and 99th percentile, 17.5 % with an NT of 3.5 - 4.4 mm, 36.4 % with an NT of 4.5 - 5.4 mm, 54.5 % with an NT of 5.5 - 6.4 mm and 95.5 % with an NT above 6.5 mm. 19 % had chromosomal disorders. The rate of aneuploidy was 61.0 % (25/41) in the group with skin edema which was significantly higher than the rate of 10.2 % (20/196) in those without skin edema (p < 0.0001). 12 % had structural anomalies in euploid fetuses. The rate of anomalies was 43.8 % (7/16) in the group with skin edema and significantly higher compared to 9.1 % (16/176) in those without skin edema (p < 0.0005).

CONCLUSION

Our data show a clear association between the thickness of NT and the rate of skin edema. Skin edema has a high predictive value for aneuploidy or structural malformations. Therefore, fetuses with skin edema should have early malformation scans in case of normal karyotype.

Evaluation strategies for isotope ratio measurements of single particles by LA-MC-ICPMS

Data evaluation is a crucial step when it comes to the determination of accurate and precise isotope ratios computed from transient signals measured by multi-collector-inductively coupled plasma mass spectrometry (MC-ICPMS) coupled to, for example, laser ablation (LA). In the present study, the applicability of different data evaluation strategies (i.e. 'point-by-point', 'integration' and 'linear regression slope' method) for the computation of (235)U/(238)U isotope ratios measured in single particles by LA-MC-ICPMS was investigated. The analyzed uranium oxide particles (i.e. 9073-01-B, CRM U010 and NUSIMEP-7 test samples), having sizes down to the sub-micrometre range, are certified with respect to their (235)U/(238)U isotopic signature, which enabled evaluation of the applied strategies with respect to precision and accuracy. The different strategies were also compared with respect to their expanded uncertainties. Even though the 'point-by-point' method proved to be superior, the other methods are advantageous, as they take weighted signal intensities into account. For the first time, the use of a 'finite mixture model' is presented for the determination of an unknown number of different U isotopic compositions of single particles present on the same planchet. The model uses an algorithm that determines the number of isotopic signatures by attributing individual data points to computed clusters. The (235)U/(238)U isotope ratios are then determined by means of the slopes of linear regressions estimated for each cluster. The model was successfully applied for the accurate determination of different (235)U/(238)U isotope ratios of particles deposited on the NUSIMEP-7 test samples.

[Autologous chondrocyte implantation (ACI) for cartilage defects of the knee: a guideline by the working group "Tissue Regeneration" of the German Society of Orthopaedic Surgery and Traumatology (DGOU)]

Autologous chondrocyte transplantation/implantation (ACT/ACI) is an established and recognised procedure for the treatment of localised full-thickness cartilage defects of the knee. The present review of the working group "Clinical Tissue Regeneration" of the German Society of Orthopaedics and Traumatology (DGOU) describes the biology and function of healthy articular cartilage, the present state of knowledge concerning potential consequences of primary cartilage lesions and the suitable indication for ACI. Based on current evidence, an indication for ACI is given for symptomatic cartilage defects starting from defect sizes of more than 3-4 cm2; in the case of young and active sports patients at 2.5 cm2. Advanced degenerative joint disease is the single most important contraindication. The review gives a concise overview on important scientific background, the results of clinical studies and discusses advantages and disadvantages of ACI.