Standardized analysis of syndesmosis stability in ankle trauma with an innovative syndesmosis-test-tool: a biomechanical study.

When treating ankle fractures, the question of syndesmosis complex involvement often arises. So far, there is no standardized method to reliably detect syndesmosis injuries in the surgical treatment of ankle fractures. For this reason, an intraoperative syndesmosis-test-tool (STT) was developed and compared to the recommended and established hook-test (HT). Tests were performed on cadaveric lower legs (n = 20) and the diastasis was visualized by 3D camera. Tests were performed at 50, 80, and 100 N in native conditions and four instability levels. Instability was induced from anterior to posterior and the reverse on the opposite side. The impact on diastasis regarding the direction, the force level, the instability level, and the device used was checked using a general linear model for repeated measurement. The direction of the induced instability showed no influence on the diastasis during the stability tests. The diastasis measured with the STT increased from 0.5 to 3.0 mm depending on the instability, while the range was lower with the HT (1.1 to 2.3 mm). The results showed that the differentiation between the instability levels was statistically significantly better for the developed STT. The last level of maximum instability was significantly better differentiable with the STT compared to the HT. An average visualizable diastasis of more than 2 mm could only be achieved at maximum instability. In conclusion, the newly developed STT was superior to the commonly used HT to detect instability.

Helical Plating Compared with Straight Plating and Nailing for Treatment of Proximal Third Humeral Shaft Fractures-A Biomechanical Study.

Background and Objectives: The surgical treatment of proximal humeral shaft fractures usually considers application of either long straight plates or intramedullary nails. By being able to spare the rotator cuff and avoid the radial nerve distally, the implementation of helical plates might overcome the downsides of common fixation methods. The aims of the current study were (1) to explore the biomechanical competence of different plate designs and (2) to compare their performance versus the alternative treatment option of using intramedullary nails. Materials and Methods: Twenty-four artificial humeri were assigned to the following four groups for simulation of an unstable proximal humeral shaft fracture and instrumentation: Group 1 (Straight-PHILOS), Group 2 (MULTILOC-Nail), Group 3 (45°-Helical-PHILOS), and Group 4 (90°-Helical-PHILOS). All specimens underwent non-destructive, quasi-static biomechanical testing under loading in axial compression, torsion in internal/external rotation, and pure bending in four directions, accompanied by motion tracking. Results: Axial stiffness/displacement in Group 2 was significantly higher/smaller than in all other groups (p ≤ 0.010). Torsional displacement in Group 2 was significantly bigger than in all other groups (p ≤ 0.017). Significantly smaller coronal plane displacement was identified in Group 2 versus all other groups (p < 0.001) and in Group 4 versus Group 1 (p = 0.022). Significantly bigger sagittal plane displacement was detected in Group 4 versus all other groups (p ≤ 0.024) and in Group 1 versus Group 2 (p < 0.001). Conclusions: Intramedullary nails demonstrated higher axial stiffness and smaller axial interfragmentary movements compared with all investigated plate designs. However, they were associated with bigger torsional movements at the fracture site. Although 90°-helical plates revealed bigger interfragmentary movements in the sagittal plane, they demonstrated improved resistance against displacements in the coronal plane when compared with straight lateral plates. In addition, 45°-helical plates manifested similar biomechanical competence to straight plates and may be considered a valid alternative to the latter from a biomechanical standpoint.

Biomechanical Comparison of Medio-Plantar and Plantar Plate Fixation for First Tarsometatarsal Joint Arthrodesis.

Plantar plate positioning has been demonstrated as biomechanically superior. However, some operators remain resentful about the morbidity of the surgical approach. To provide improved plate fixation for first tarsometatarsal joint arthrodesis with respect to the tibialis anterior tendon, a medio-plantar plate was developed. The purpose of this biomechanical study was to compare its construct stability to that of a plantar plate construct. Twelve pairs of fresh frozen human specimens were used in a matched pair test. Each pair was fixed with a 4 mm compression screw and either a plantar locking plate or a medio-plantar locking plate. A cantilever beam test was performed in dorsiflexion. Before and after cyclic loading (5000 cycles; 40 N), bending stiffness and relative movements at the joint space were monitored in a quasi-static test including optical motion tracking. Maximum load and bending moment to failure were investigated in a load-to-failure ramp test. The bending stiffness of both groups did not significantly differ before (plantar 49.9 N/mm ± 19.2; medio-plantar 53.9 N/mm ± 25.4, p = 0.43) or after (plantar 24.4 N/mm ± 9.7; medio-plantar 35.3 N/mm ± 22.0, p = 0.08) cyclic loading but decreased significantly in both groups (p < 0.01) after cyclic loading. Relative movement increased significantly during cyclic testing in both groups (p < 0.01) but did not differ significantly between the groups before (p = 0.29) or after (p = 0.16) cyclic loading. Neither load nor bending moment to failure were significantly different (plantar 225 N ± 78, 10.8 Nm; medio-plantar 210 N ± 86, 10.1 Nm, p = 0.61). Both plate constructs provided equivalent construct stability, both being well suited for Lapidus arthrodesis.

Spatio-temporal variability in the abundance and composition of beach litter and microplastics along the Baltic Sea coast of Schleswig-Holstein, Germany.

Abundance and composition of beach litter and microplastics (20-5000 µm, excluding fibres) were assessed in spring and autumn 2018 at various beaches along the Baltic Sea coast of Schleswig-Holstein, Northern Germany. The beach litter survey followed the OSPAR guidelines, while microplastics were extracted from sediment samples using density separation and were then identified with Raman µ-spectroscopy. We observed seasonality in the abundance and composition, but not in the mass of beach litter. The median microplastic abundance was 2 particles per 500 g of dry sediment in spring as well as in autumn, while six different synthetic polymers (PE, PP, PS, PET, PVC, POM) were detected. We found no correlation between the abundances of beach litter and microplastics. Our data represent the first systematic co-assessment of macro- and micro beach litter along the Baltic Sea coast of Schleswig-Holstein.

Rapid shipboard measurement of net-collected marine microplastic polymer types using near-infrared hyperspectral imaging.

Isolation and detection of microplastics (MP) in marine samples is extremely cost- and labor-intensive, limiting the speed and amount of data that can be collected. In the current work, we describe rapid measurement of net-collected MPs (net mesh size 300 µm) using a benchtop near-infrared hyperspectral imaging system during a research expedition to the subtropical North Atlantic gyre. Suspected plastic particles were identified microscopically and mounted on a black adhesive background. Particles were imaged with a Specim FX17 near-infrared linescan camera and a motorized stage. A particle mapping procedure was built on existing edge-finding algorithms and a polymer identification method developed using spectra from virgin polymer reference materials. This preliminary work focused on polyethylene, polypropylene, and polystyrene as they are less dense than seawater and therefore likely to be found floating in the open ocean. A total of 27 net tows sampled 2534 suspected MP particles that were imaged and analyzed at sea. Approximately 77.1% of particles were identified as polyethylene, followed by polypropylene (9.2%). A small fraction of polystyrene was detected only at one station. Approximately 13.6% of particles were either other plastic polymers or were natural materials visually misidentified as plastics. Particle size distributions for PE and PP particles with a length greater than 1 mm followed an approximate power law relationship with abundance. This method allowed at-sea, near real-time identification of MP polymer types and particle dimensions, and shows great promise for rapid field measurements of microplastics in net-collected samples.

Where have all the beads gone? Fate of microplastics in a closed exposure system and their effects on clearance rates in Mytilus spp.

The fate of microplastic particles (MP) in exposure experiments is mostly unclear. We measured the recovery of polystyrene (PS) microbeads, which were applied in various concentrations from 0.07 to 47.47 beads/ml, from the different compartments of an experimental system with mussels (Mytilus spp.). At the end of the experiment, we detected a significant loss of MP indicating that the mussels were exposed to less particles than intended. If such a discrepancy remains un-recognized by the experimenter, observed effects are related to an inaccurate particle concentration. Additionally, we observed reduced clearance rates of the mussels in the presence of MP and the effect size increased with increasing particle concentration. This effect was more pronounced in mussels that had recently spawned than in mussels that still had mature gonads. This is a hint that effects of MP may depend on the reproductive status of an organism.

Effects of artificial light at night on the feeding behaviour of three marine benthic grazers from the Adriatic Sea are species-specific and mostly short-lived.

Artificial light at night (ALAN) has the potential to change the day-night activity of marine benthic grazers, and can therefore alter the top-down control they exert on macroalgal communities. In laboratory experiments, we investigated the influence of three realistic ALAN regimes on food consumption and feeding rhythmicity in the sea urchins Arbacia lixula and Paracentrotus lividus as well as in the snail Cerithium spp. from the Adriatic Sea. Food consumption was assessed in assays with algal pellets, while feeding rhythms were documented with 24 h time-lapse photography. Both was done in ALAN-acclimated and in non-acclimated animals. We observed temporary and potential long-term changes in the feeding rhythms of Cerithium spp. and Paracentrotus lividus, respectively, but found no lasting influence of ALAN on consumption rates. Effects were weaker when ALAN was applied only part-night, which suggests a possible mitigation measure to reduce the impact of nighttime lighting on coastal ecosystems.

Nonunions and Their Operative Treatment­a DRG-Based Epidemiological Analysis for the Years 2007-2019 in Germany

BACKGROUND: Nonunions, which arise as a complication of fractures, are an impor - tant medical and socio-economic problem. The goal of this study was to analyze nonunions in Germany with respect to the patients' age and sex, the anatomical site of the lesions, and their operative treatment. METHODS: The study was performed on the basis of DRG (diagnosis-related group) data acquired for billing purposes and collected by the German Federal Statistical Office. The administrative frequencies of nonunions and fractures treated in the inpatient setting, broken down by sex and age group, were calculated from the documentation of ICD codes. An investigation was also made of surgical treatments for nonunion, as they were categorized by the German procedure classification (Operationen- und Prozedurenschlüssel, OPS). RESULTS: The administrative frequency of nonunion was 14.84 per 100 000 persons per year, with a 2% decline in case numbers over the period 2007-2019. Nonunions develop in 2% of fractures. Nonunions affect men more often than women (58% vs. 42%). In men, their incidence as a function of age is highest under age 30; in women, it rises steadily with increasing age. The most common type of surgical treatment is a combination of resection, bone transplantation, and osteosynthesis. CONCLUSION: This is the first detailed nationwide study of diagnoses of nonunions in Germany and their surgical treatment. Despite a slow decline in their incidence, nonunions remain an important problem in the inpatient setting. The risk profile for nonunions is sex-, age-, and site-specific.

Abundance, composition and sources of beach litter on the Cape Verdean island São Vicente.

This study represents the first assessment of beach litter on an island of the west African archipelagic state of Cape Verde. On five beaches of São Vicente, litter was collected along transects and classified according to the OSPAR protocol, with the Matrix Scoring Technique used to allocate it to four sources. Beach litter on São Vicente is highly variable in both amount and composition, while land- and sea-based sources contribute to litter loads to different extents depending on the use and geographic orientation of the beach. Four of the five surveyed beaches exhibited litter loads that were similar to pollution levels previously described for other oceanic islands, while a north-eastern-facing beach featured exceptionally high loads. This was presumably because it receives litter from distant sources due to its exposure to a major ocean surface current.

Blueprint for the ideal microplastic effect study: Critical issues of current experimental approaches and envisioning a path forward.

This article presents a novel conceptual blueprint for an 'ideal', i.e., ecologically relevant, microplastic effect study. The blueprint considers how microplastics should be characterized and applied in laboratory experiments, and how biological responses should be measured to assure unbiased data that reliably reflect the effects of microplastics on aquatic biota. This 'ideal' experiment, although practically unachievable, serves as a backdrop to improve specific aspects of experimental research on microplastic effects. In addition, a systematic and quantitative literature review identified and quantified departures of published experiments from the proposed 'ideal' design. These departures are related mainly to the experimental design of microplastic effect studies failing to mimic natural environments, and experiments with limited potential to be scaled-up to ecosystem level. To produce a valid and generalizable assessment of the effect of microplastics on biota, a quantitative meta-analysis was performed that incorporated the departure of studies from the 'ideal' experiment (a measure of experimental quality) and inverse variance (a measure of the study precision) as weighting coefficients. Greater weights were assigned to experiments with higher quality and/or with lower variance in the response variables. This double-weighting captures jointly the technical quality, ecological relevance and precision of estimates provided in each study. The blueprint and associated meta-analysis provide an improved baseline for the design of ecologically relevant and technically sound experiments to understand the effects of microplastics on single species, populations and, ultimately, entire ecosystems.

The Correction Potential of the Lateral Release of the Hallux Valgus: A Comparative Anatomical Study of Minimally Invasive Versus Open Surgical Technique Using a Dorsal Approach.

Background: Lateral release (LR) is an integral part of surgical correction of hallux valgus. A comparison was made between the open and minimally invasive LR techniques using a dorsal approach. The reliability and safety of the two methods were compared. Besides, the release of specific structures was investigated with special emphasis on ascertaining if the release was partial or a total one. Methods: In this study on cadavers, LR was performed on nine pairs of foot and ankle specimens. The group assignments were randomized for each case. The operations were followed by anatomical preparation, data collection, photo documentation, and statistical analysis. Results: A statistically significant advantage was observed with the open dorsal approach as there was a complete release of the adductor hallucis muscle from the lateral sesamoid and the lateral metatarsosesamoid ligament (p = 0.015 in each case). In terms of releasing the adductor hallucis muscle from the proximal phalanx, the lateral joint capsule, and the lateral collateral ligament, none of the investigated procedures showed better performance. However, open dorsal access tends to show a higher degree of release more frequently. Conclusions: Splitting of the lateral joint capsule, including the lateral collateral ligament and lateral metatarsosesamoid ligament via the dorsal approach can be performed reliably and completely using the open surgical technique. The open dorsal technique shows better rates of detachment when the adductor hallucis muscle is released from the lateral sesamoid. Both techniques resulted in incomplete release of the adductor hallucis muscle from the proximal phalanx. Study Type: Therapeutic-investigating the results of a treatment. Level of Evidence: II (Prospective cohort study). Supplementary Information: The online version contains supplementary material available at 10.1007/s43465-021-00575-3.

[Cement augmentation and bone graft substitutes-Materials and biomechanics]. / Zementaugmentation und Knochenersatz ­ Materialien und Biomechanik.

BACKGROUND: Materials with different characteristics are used for cement augmentation and as bone graft substitutes. OBJECTIVE: Cement augmentation and bone graft substitutes are the subject of current research. The evaluation of new knowledge allows its specific application. MATERIAL AND METHODS: Selective literature search and outline of experimental research results on cement augmentation and bone graft substitutes. RESULTS: Augmentation and bone graft substitutes are essential components of current trauma surgical procedures. Despite intensive research all materials have specific disadvantages. Cement augmentation of implants enhances not only the anchorage but also influences the failure mode. CONCLUSION: Cement augmentation has large potential especially in osteoporotic bone. In load-bearing regions acrylic-based cements remain the standard of choice. Ceramic cements are preferred in non-load-bearing areas. Their combination with resorbable metals offers still largely unexplored potential. Virtual biomechanics can help improve the targeted application of cement augmentation.

Effects of microplastics (PVC, PMMA) on the mussel Semimytilus algosus differ only at high concentrations from those of natural microparticles (clay, celite).

Laboratory exposure studies allow to investigate the impact of microplastics on marine biota, but commonly lack a procedural control, i.e. assessing the effects of natural microparticles. In two experiments with the mussel Semimytilus algosus, we compared the effects of clay vs. polyvinyl chloride (PVC) and celite vs. polymethyl-methacrylate (PMMA), respectively, at concentrations of 1.5, 15 and 150 mg l-1. After more than 60 days, no effects on respiration and clearance rates, mortality and byssus strength were observed. However, in mussels exposed to PVC the Body Condition Index was 34% lower at 150 mg l-1 than at 1.5 mg l-1. Furthermore, at 15 mg l-1, mussels exposed to microplastics produced over 40% less byssus than those exposed to natural microparticles. This suggests that mussels react differently to natural microparticles and to microplastics, but only at high particle loads that exceed current environmental microplastic concentrations by orders of magnitude.

Anatomical Study of Sinus Tarsi-Based Lateral Lengthening Calcaneal Osteotomy.

BACKGROUND: Lateral lengthening calcaneal osteotomy (LL-CO) is commonly performed as a treatment for an abducted midfoot in pes planovalgus deformity. The purpose of this study is to investigate potential damage to medial structures with a sinus tarsi LL-CO. METHODS: Sixteen cadaver feet were used. Eight feet had an extended lateral approach, and 8 had a limited lateral (sinus tarsi) approach. All underwent a sinus tarsi LL-CO. Specimens were then dissected to identify inadvertent injury to medial structures. RESULTS: Sinus tarsi LL-CO was associated with damage to the sustentaculum tali and medial articular facets in 56% and 62.5% of specimens, respectively. No anterior or posterior facet injuries were found, although 56% of specimens had a confluent medial and anterior facet. CONCLUSION: Damage to the medial articular facet and sustentaculum is possible with a flat cut sinus tarsi LL-CO due to the curved nature of the relevant sinus tarsi and canal anatomy. CLINICAL RELEVANCE: Sinus tarsi LL-CO needs to be performed with caution since damage to the subtalar joint is possible. LEVEL OF EVIDENCE: Level II, prospective cohort study.

Iatrogenic Damage to Neurovascular and Soft Tissue Structures During Lateral Release of Hallux Valgus: A Comparative Anatomical Study of Minimally Invasive Versus Open Surgical Techniques.

Lateral release is often an integral step in surgical correction of hallux valgus and can be performed using open or minimally invasive techniques. We investigated whether these techniques cause iatrogenic damage to arteries, nerves, tendons, or joint capsules. In this cadaver study, lateral release was performed on 9 pairs of specimens by a specialized foot surgeon. The specimens were randomly assigned to each group. The operations were followed by anatomical preparation, data collection, photo documentation, and statistical analysis. Iatrogenic damage to arteries, nerves, tendons, or joint capsules was rare, regardless of the surgical technique used. However, with the minimally invasive technique, the tendon of the extensor hallucis longus muscle and the sensitive terminal branches of the fibular nerve were at risk due to their anatomical proximity to the access portal. The deep transverse metatarsal ligament was potentially at risk if the adductor hallucis muscle was completely detached from the lateral sesamoid. When the deep transverse metatarsal ligament was transected there was risk of damaging the underlying plantar neurovascular structures. Both surgical techniques are safe in terms of the risk of injury to neighboring neurovascular and soft tissue structures.

Plastic and natural inorganic microparticles do not differ in their effects on adult mussels (Mytilidae) from different geographic regions.

Microplastics are ubiquitous in the marine environment and studies on their effects on benthic filter feeders at least partly revealed a negative influence. However, it is still unclear whether the effects of microplastics differ from those of natural suspended microparticles, which constitute a common stressor in many coastal environments. We present a series of experiments that compared the effects of six-week exposures of marine mussels to two types of natural particles (red clay and diatom shells) to two types of plastic particles (Polymethyl Methacrylate and Polyvinyl Chloride). Mussels of the family Mytilidae from temperate regions (Japan, Chile, Tasmania) through subtropical (Israel) to tropical environments (Cabo Verde) were exposed to concentrations of 1.5 mg/L, 15 mg/L and 150 mg/L of the respective microparticles. At the end of this period, we found significant effects of suspended particles on respiration rate, byssus production and condition index of the animals. There was no significant effect on clearance rate and survival. Surprisingly, we observed only small differences between the effects of the different types of particles, which suggests that the mussels were generally equally robust towards exposure to variable concentrations of suspended solids regardless of whether they were natural or plastic. We conclude, that microplastics and suspended solids elicit similar effects on the tested response variables, and that both types of microparticles mainly cause acute responses rather than more persistent carry-over effects.

Biogeography rather than substrate type determines bacterial colonization dynamics of marine plastics.

Since the middle of the 20th century, plastics have been incorporated into our everyday lives at an exponential rate. In recent years, the negative impacts of plastics, especially as environmental pollutants, have become evident. Marine plastic debris represents a relatively new and increasingly abundant substrate for colonization by microbial organisms, although the full functional potential of these organisms is yet to be uncovered. In the present study, we investigated plastic type and incubation location as drivers of marine bacterial community structure development on plastics, i.e., the Plastisphere, via 16S rRNA amplicon analysis. Four distinct plastic types: high-density polyethylene (HDPE), linear low-density polyethylene (LDPE), polyamide (PA), polymethyl methacrylate (PMMA), and glass-slide controls were incubated for five weeks in the coastal waters of four different biogeographic locations (Cape Verde, Chile, Japan, South Africa) during July and August of 2019. The primary driver of the coastal Plastisphere composition was identified as incubation location, i.e., biogeography, while substrate type did not have a significant effect on bacterial community composition. The bacterial communities were consistently dominated by the classes Alphaproteobacteria, Gammaproteobacteria, and Bacteroidia, irrespective of sampling location or substrate type, however a core bacterial Plastisphere community was not observable at lower taxonomic levels. Overall, this study sheds light on the question of whether bacterial communities on plastic debris are shaped by the physicochemical properties of the substrate they grow on or by the marine environment in which the plastics are immersed. This study enhances the current understanding of biogeographic variability in the Plastisphere by including biofilms from plastics incubated in the previously uncharted Southern Hemisphere.

Wound Closure After Port Implantation-A Randomized Controlled Trial Comparing Tissue Adhesive and Intracutaneous Suturing.

BACKGROUND: Wound healing after pectoral port implantation is a major factor determining the success or failure of the procedure. Infection and wound dehiscence can endanger the functionality of the port system and impede chemotherapy. The cosmetic result is important for patient satisfaction as well. METHODS: From August 2015 to July 2017, adult patients with an indication for port implantation were entered into a prospective, randomized and controlled single-center study. The skin incision was closed either with tissue adhesive or with an intracutaneous suture. The primary endpoints were the total score of the scar evaluated by the patient and the investigator on the POSAS scale (Patient and Observer Scar Assessment Scale: 6 [normal skin] to 60 points), blinded assessment of photographic documentation by ten evaluating physicians, and the patient's reported quality of life. The calculation of case numbers was based only on the patients' overall POSAS assessment, which was tested for non-inferiority. The secondary endpoints were other complications (infection, dehiscence) and the duration of wound closure (trial registration number NCT02551510). RESULTS: 156 patients (60 ± 13 years, 64% women) participated in the study. The patient-assessed total POSAS score of tissue adhesive revealed non-inferiority to suturing (adhesive 11.7 ± 5.8 vs. suture 10.1 ± 4.0, p for non-inferiority <0.001). Both the investigators in their POSAS assessments and the blinded physician evaluators in their assessment of photographically documented wounds rated wound closure by suturing better than closure with tissue adhesive. No significant differences were found between groups with respect to quality of life or the frequency of wound infection or dehiscence. CONCLUSION: Closure of the upper cutaneous layer with tissue adhesive is a suitable and safe method of wound closure after port implantation.

Negative impacts of realistic doses of spherical and irregular microplastics emerged late during a 42 weeks-long exposure experiment with blue mussels.

Microplastics have been found in all compartments of the environment, and numerous life forms are known to take up the anthropogenic particles. Marine filter feeders are particularly susceptible to ingest suspended microplastics, but long-term studies on the potential effects of this uptake are scarce. We exposed juvenile Mytilus spp. to environmentally realistic doses of irregularly shaped polyvinylchloride (PVC) particles (15, 1500, 15,000, 150,000, 1,500,000 particles/individual/week calibrated in the size range 11-60 µm) and regularly shaped polystyrene (PS) beads (15, 1500, 15,000 particles/individual/week, 40 µm) over 42 weeks. During this period, we monitored physiological traits such as clearance rate, byssus production, growth rate, superoxide dismutase (SOD) activity, malondialdehyde (MDA) concentrations, and the condition index (CI). Negative effects of the tested microplastics on mussel performance emerged late in the experiment and were rather weak. Interestingly, even after having received the lowest particle dose of PS, SOD activity in the gill was significantly lower in mussels exposed to microplastics compared to a group of conspecifics that were kept in clean water. However, growth and CI, which are both closely related to the fitness of the mussels, were not found to be impaired at the end of the exposure phase. This is the so far longest laboratory microplastic exposure study on mussels and we worked with particle doses that reflect todays pollution levels. The small effect sizes we observed for the response variables assessed suggest that these specific microplastics pose only a minor threat to blue mussel populations.