Peak inspiratory pressure lacks accuracy to estimate plateau pressure in infants with severe obstructive lower airway disease.

PURPOSE: In children with acute respiratory distress syndrome receiving mechanical ventilation, the peak inspiratory pressure (PIP) is close to plateau pressure (PPLAT) when inspiratory flow approaches zero. We aimed to evaluate the reliability of PIP to estimate PPLAT in infants with severe respiratory viral infection (SRVI), characterized by increased airway resistance, and the accuracy of an equational model to estimates PPLAT (ePPLAT) based on PIP. METHODS: This was a retrospective observational study including mechanically ventilated children (1 to 24 month old) with SRVI, whose respiratory mechanics measurements were performed to evaluate PIP and PPLAT. The measured PPLAT was compared with the result of the equation: ePPLAT = PIP - [5.067 - (0.858 × static compliance) - (0.018 × inspiratory resistance) - (0.390 × pressure above positive-end expiratory pressure) + (4.989 × inspiratory time)]. RESULTS: Thirty-seven patients were included, with a median age of 3 (2-5) months. They presented a high inspiratory and expiratory resistance (136 ± 43 and 168 ± 66 cmH2O/L/s, respectively) and a moderate reduction in static compliance: 0.75 ± 0.3 mL/kg/cmH2O. PIP overestimated PPLAT (33 ± 3 and 26 ± 5 cmH2O, p = 0.01), with a mean difference of 7.3 ± 4 cmH2O. Moreover, the Bland-Altman analysis demonstrated a mean difference between PPLAT and ePPLAT of 1.0 ± 4.0 cmH2O, with 95% limits of agreement of -6.9 and 8.8. CONCLUSIONS: A significant difference between PIP and PPLAT was observed in infants with SRVI. The equation model was inaccurate for estimating PPLAT based on PIP. Any estimation of PPLAT from PIP needs to consider the resistance component of the respiratory system.

Maintenance of joint reduction and allograft incorporation in treating tibial plateau fractures. Retrospective case series using cortico-cancellous, non-irradiated, bone allograft.

Background: Restoring joint congruence and maintaining reduction until healing is imperative in treating tibial plateau fractures (TPF). The main objective of this study was to evaluate the feasibility of augmentation with impacted bone allograft (IBA) to prevent loss of reduction in tibial plateau fractures during healing and to evaluate its incorporation. Methods: We retrospectively analyzed all patients with an acute, closed tibial plateau fracture (Schatzker II, III, IV) treated between 2010 and 2019 with open reduction and internal fixation (ORIF) and impacted bone allograft (IBA), with a minimum follow-up of 24 months. We evaluated the postoperative radiographs by drawing a line along the tibial axis and another perpendicular to the healthy plateau to measure the reduction and subsequent behavior. The incorporation of the allograft was evaluated by radiological analysis assessing its integration, non-union, resorption, or sclerosis. We used the clinical-radiological Rasmussen system and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) to objectify the outcomes. Results: 78 TPFs were included, with a median age of 51.5 (40.7-62.2) years and a median follow-up of 66 (24-89) months. Two (2.5 %) patients presented loss of joint reduction (subsidence) during the follow-up regarding the achieved in the surgery. Seventy-six (94.7 %) patients presented integration, two (2.5 %) resorption, and one (1.3 %) sclerosis. Seventy-two (92.3 %) patients presented excellent and good results in the Rasmussen radiological score, and 72 (92.3 %) patients presented excellent or good clinical scores. The mean WOMAC at two years postoperatively was 15 ± 6.5. Conclusion: Our results demonstrate that allograft is an adjuvant in maintaining a reduction in type II, III, and IV Schatzker's tibial plateau fractures. Low rates of loss of reduction during follow-up can be expected with its use.

3D PRINTING IN COMPLEX TIBIAL FRACTURE CLASSIFICATION & PLANNING.

Objective: Tibial plateau fractures are common intra-articular fractures that pose classification and treatment challenges for orthopedic surgeons. Objective: This study examines the value of 3D printing for classifying and planning surgery for complex tibial plateau fractures. Methods: We reviewed 54 complex tibial plateau fractures treated at our hospital from January 2017 to January 2019. Patients underwent preoperative spiral CT scans, with DICOM data processed using Mimics software. 3D printing technology created accurate 1:1 scale models of the fractures. These models helped subdivide the fractures into seven types based on the tibial plateau's geometric planes. Surgical approaches and simulated operations, including fracture reduction and plate placement, were planned using these models. Results: The 3D models accurately depicted the direction and extent of fracture displacement and plateau collapse. They facilitated the preoperative planning, allowing for precise reconstruction strategies and matching intraoperative details with the pre-printed models. Post-surgery, the anatomical structure of the tibial plateau was significantly improved in all 54 cases. Conclusion: 3D printing effectively aids in the classification and preoperative planning of complex tibial plateau fractures, enhancing surgical outcomes and anatomical restoration. Level of Evidence IV, Prospective Study.

Objetivo: As fraturas do planalto tibial são fraturas intra-articulares comuns de classificação e tratamento desafiadores aos cirurgiões ortopédicos. Objetivo: Este estudo investiga o uso de impressão 3D para classificar e planejar a cirurgia de fraturas complexas do planalto tibial. Métodos: 54 fraturas complexas do planalto tibial tratadas em nosso hospital de janeiro de 2017 a janeiro de 2019 foram revisadas. Os pacientes foram submetidos a tomografias computadorizadas em espiral pré-operatórias, com dados DICOM processados usando o software Mimics. A tecnologia de impressão 3D gerou modelos precisos em escala 1:1 das fraturas. Estes modelos ajudaram a subdividir as fraturas em sete tipos com base nos planos geométricos do planalto tibial. As abordagens cirúrgicas e as operações simuladas, incluindo a redução da fratura e a colocação de placa, foram planejadas utilizando estes modelos. Resultados: Os modelos 3D representaram com precisão a direção e a extensão da deslocação da fratura e do colapso do planalto. Os modelos facilitaram o planejamento pré-operatório, viabilizando estratégias de reconstrução precisas e a correspondência dos detalhes intraoperatórios com os modelos pré-impressos. Após a cirurgia, a estrutura anatômica do planalto tibial melhorou significativamente em todos os 54 casos. Conclusão: A impressão 3D ajuda na classificação e no planejamento pré-operatório de fraturas complexas do planalto tibial, melhorando os resultados cirúrgicos e a restauração anatômica. Nível de Evidência IV, Estudo Prospectivo.

South America holds the greatest diversity of native daisies (Asteraceae) in the world: an updated catalogue supporting continental-scale conservation.

Asteraceae is the world's richest plant family and is found on all continents, in environments ranging from the coast to the highest mountains. The family shows all growth forms and, as in other angiosperm families, species richness is concentrated in tropical regions. South America has the highest diversity of Asteraceae in the world, yet taxonomic and distributional knowledge gaps remain. This study compiles an updated catalog of Asteraceae native to South America, based on national and regional checklists and ongoing large-scale flora projects. The resulting checklist includes a total of 6,940 species and 564 genera native to South America to date, which represent about a quarter of the family's global diversity. Countries already considered to be megadiverse show the greatest diversity, such as Brazil with 2,095 species, followed by Peru (1,588), Argentina (1,377), and Colombia (1,244), with this diversity mainly focused on the Brazilian Highlands and the Andes. Species endemism also peaks in Brazil, but Sørensen distances reveal the Chilean flora to be eminently different from the rest of the continent. Tribes better represented in the continent are Eupatorieae, Senecioneae and Astereae, also with a remarkably presence of entirely South American subfamilies representing earliest diverging lineages of the Asteraceae, such as Barnadesioideae, Wunderlichioideae, Famatinanthoideae, and Stifftioideae. It is estimated that the discovery and description curves have not yet stabilized, and the number of species is likely to increase by 5 to 10% in the coming years, posing major challenges to continental-scale conservation.

Treatment of Tibial Plateau Fractures with a Circular External Fixator: A Comparative Analysis of Two Assembly Methods.

Objective To compare the functional outcomes of two circular external fixation techniques to treat complex fractures of the proximal end of the tibia. Materials and Methods The present is a retrospective cohort study with 51 patients who underwent surgical treatment for complex fractures of the tibial plateau with a circular external fixator. There were two groups of patients: 12 subjects underwent treatment with the classic assembly technique, and 39 subjects underwent treatment with the simplified technique. The variables analyzed included age, sex, injury mechanism, trauma energy, associated injuries, fixator type, time of fixator use, and clinical-radiographic outcomes. The classic technique mainly uses transfixing Kirschner wires, while the simplified one replaces the Kirschner wires with Schanz pins in the distal block of the circular external fixator. Result There were no statistically significant differences ( p > 0.05) between the two groups concerning the clinical-radiographic outcomes, including fracture consolidation, quality of joint fracture reduction, range of motion, lower limbs residual discrepancy, and postoperative pain. Conclusion We suggest that the simplified technique, using Schanz pins instead of Kirschner wires, can be a viable and effective alternative to treat complex fractures of the proximal end of the tibia with a circular external fixator. This simplified approach can offer benefits, such as a lower infection rate and greater patient comfort, without compromising clinical and radiographic outcomes, thus justifying its use.

Manejo de fractura de platillo tibial medial utilizando placas rim anteromedial y posteromedial / Management of Medial Tibial Plateau Fracture using Antero- and Posteromedial Rim Plates

INTRODUCCION En los últimos años, se ha descrito el uso de placas horizontales para la fijación de fracturas que comprometen el reborde articular de los platillos tibiales, lo que se conoce como placa rim. La mayoría de las publicaciones al respecto describen su uso en columnas posteriores y posterolaterales de los platillos tibiales, y a la fecha hay escasos reportes del uso de este tipo de placa en la columna anteromedial y ninguno para la posteromedial. El objetivo de este artículo es presentar dos casos clínicos de fracturas conminutas del platillo tibial medial mostrando su tratamiento con el uso de placas rim. CASOS CLINICOS El primer caso presentaba compromiso anteromedial y posteromedial, y el segundo, compromiso posteromedial. En ambos casos, se logró la reducción mediante un abordaje posteromedial y su fijación con placa bloqueada de 2,7 mm como placa rim. En cada caso, se detalló la estrategia de reducción y el manejo postoperatorio. RESULTADOS Ambos pacientes consiguieron la consolidación ósea entre las semanas 14 y 18 tras la osteosíntesis definitiva, sin presentar pérdidas de reducción. Ambos lograron rango de movilidad articular completo (0°­125°), y retornaron a sus trabajos a los 4 y 6 meses respectivamente. CONCLUSIONES Estas placas ofrecen una buena opción de tratamiento para fracturas articulares conminutas del borde del platillo tibial, tanto en la columna anteromedial como en la posteromedial. A pesar de la ausencia de grandes series de pacientes con uso de placas rim mediales, el resultado de los casos presentados aquí nos permite plantear su utilidad al momento de enfrentarnos a fracturas del reborde articular

INTRODUCTION In recent years, the use of horizontal plates has been described to achieve fixation of fractures that compromise the articular ridge of the tibial plateau; these plates are known as "rim plates." Most publications report their use in the posterior and posterolateral columns of the tibial plateau, and to date there are few reports of its use for the fixation of the anteromedial column and none for the posteromedial column. The objective of the present article is to report two clinical cases of comminuted fractures of the medial tibial plateau, showing their treatment with the use of medial rim plates. CLINICAL CASES The first case presented with an anteromedial and posteromedial tibial plateau fracture, and the second, a posteromedial fracture. In both cases, reduction was achieved through a posteromedial approach, and the fixation was performed with a 2.7-mm locked rim plate. The reduction strategy and postoperative management were detailed in each case. RESULTS Both patients achieved bone consolidation during the 14th and 18th weeks after the definitive osteosynthesis, without presenting loss of reduction. Both patients achieved full range of joint motion (0°­125°) and returned to work after four and six months respectively. CONCLUSION These plates offer a good treatment option for comminuted fractures of the rim of the tibial plateau, for both the anteromedial and posteromedial columns. Despite the absence of large series of patients with the use of medial rim plates, the results of the two cases herein presented enables us to propose it as a useful tool when dealing with fractures of the medial rim of the tibial plateau

INTRODUCTION In recent years, the use of horizontal plates has been described to achieve fixation of fractures that compromise the articular ridge of the tibial plateau; these plates are known as "rim plates." Most publications report their use in the posterior and posterolateral columns of the tibial plateau, and to date there are few reports of its use for the fixation of the anteromedial column and none for the posteromedial column. The objective of the present article is to report two clinical cases of comminuted fractures of the medial tibial plateau, showing their treatment with the use of medial rim plates. CLINICAL CASES The first case presented with an anteromedial and posteromedial tibial plateau fracture, and the second, a posteromedial fracture. In both cases, reduction was achieved through a posteromedial approach, and the fixation was performed with a 2.7-mm locked rim plate. The reduction strategy and postoperative management were detailed in each case. RESULTS Both patients achieved bone consolidation during the 14th and 18th weeks after the definitive osteosynthesis, without presenting loss of reduction. Both patients achieved full range of joint motion (0°­125°) and returned to work after four and six months respectively. CONCLUSION These plates offer a good treatment option for comminuted fractures of the rim of the tibial plateau, for both the anteromedial and posteromedial columns. Despite the absence of large series of patients with the use of medial rim plates, the results of the two cases herein presented enables us to propose it as a useful tool when dealing with fractures of the medial rim of the tibial plateau

Predictive factors for infection after osteosynthesis of tibial plateau fractures: a retrospective study of 314 patients.

INTRODUCTION: The reported incidence of infection related with tibial plateau fractures (IRTPF) ranges from 2 to 23%. This complication can result in catastrophic consequences such as deformity, post-traumatic osteoarthritis, chronic pain, loss of function, and substantial economic burdens on healthcare systems due to extended hospital stays and the resources required for treatment. Consequently, it is imperative to emphasize the identification of infection risk factors. METHODS: A retrospective case-control study was designed, encompassing patients who underwent surgery for tibial plateau fractures between 2015 and 2020. Frequencies and measures of central tendency were compared between infected patients (cases) and non-infected patients (controls) using rank-based statistical tests. Subsequently, two logistic regression models were employed to control for potential confounding variables. RESULTS: A total of 314 patients were included, predominantly male (71.15%). Average age of 44.41 years. IRTPF were observed in 7.64% of the patients. In the univariate inferential statistical analysis, high-energy fractures (OR 6.35, p < 0.001), fractures with compartment syndrome (OR 7.10, p < 0.001), two-stage management with temporary external fixation (OR 8.18, p < 0.001), the use of 2 or more approaches in definitive surgery (OR 2.93, p = 0.011), and the use of two or more plates (OR 9.17, p < 0.001) were identified as risk factors for infection. On average, the duration of surgery in infected patients was 201.2 min, compared to 148.4 min in non-infected patients (p < 0.001). When performing two logistic regression models, the following independent risk factors were identified: high-energy fractures (OR 5.04, p = 0.012), the presence of compartment syndrome (OR 4.53, p = 0.007), and the use of two or more plates in definitive surgery (OR 5.04, p = 0.023). CONCLUSIONS: High-energy tibial plateau fractures (Schatzker IV, V, and VI), the presence of concomitant compartment syndrome, and the use of 2 or more plates in definitive surgery are associated with a higher risk of infection related to fracture following open reduction and osteosynthesis treatment. LEVEL OF EVIDENCE: Case-Control Study.

Measurement of tibial slope using biplanar stereoradiography (EOS®).

OBJECTIVES: Posterior tibial slope (PTS) is an important anatomic parameter of the knee related to anteroposterior instability. Biplanar stereoradiography allows for simultaneous low-dose acquisition of anteroposterior and lateral views with 3D capability, enabling separate lateral and medial plateau analyses. We aimed to evaluate the possibility and compare the reproducibility of measuring medial and lateral PTS on EOS® images with two different patient positionings and compare it with CT of the knees as the gold standard. METHODS: This is a retrospective study including volunteers who underwent lower limb stereoradiography and knee CT from 01/08/2016 to 07/31/2019. Sixty legs from 30 patients were studied. PTS were measured using stereoradiography and CT by two radiologists. Intraclass correlation was used to calculate intrarater and interrater reproducibilities. Pearson's correlation coefficients were used to calculate the correlation between stereoradiography and CT. We also compared the reproducibility of the stereoradiography of volunteers with 2 different positionings. RESULTS: The mean stereoradiography PTS values for right and left knees were as follows: lateral, 12.2° (SD: 4.1) and 10.1° (SD: 3.5); medial,12.2° (SD: 4.4) and 11.6° (SD: 3.9). CT PTS mean values for right and left knee are as follows: lateral, 10.3° (SD:2.5) and 10.6° (SD: 2.8); medial: 8.7° (SD: 3.7) and 10.4° (SD: 3.5). Agreement between CT and EOS for angles between lateral and medial PTS was good (right, 0.874; left, 0.871). Regarding patient positioning on stereoradiography, interrater and intrarater reproducibilities were greater for patients with nonparallel feet (0.738-0.883 and 0.870-0.975). CONCLUSIONS: Stereoradiography allows for appropriate delineation of tibial plateaus, especially in patients with nonparallel feet, for the purpose of measuring PTS. The main advantage is lower radiation doses compared to radiography and CT.

Treatment of Tibial Plateau Fractures with a Circular External Fixator: A Comparative Analysis of Two Assembly Methods / Tratamento de fraturas do planalto tibial com fixador externo circular: Uma análise comparativa de duas formas de montagem

Abstract Objective To compare the functional outcomes of two circular external fixation techniques to treat complex fractures of the proximal end of the tibia. Materials and Methods The present is a retrospective cohort study with 51 patients who underwent surgical treatment for complex fractures of the tibial plateau with a circular external fixator. There were two groups of patients: 12 subjects underwent treatment with the classic assembly technique, and 39 subjects underwent treatment with the simplified technique. The variables analyzed included age, sex, injury mechanism, trauma energy, associated injuries, fixator type, time of fixator use, and clinical-radiographic outcomes. The classic technique mainly uses transfixing Kirschner wires, while the simplified one replaces the Kirschner wires with Schanz pins in the distal block of the circular external fixator. Result There were no statistically significant differences (p> 0.05) between the two groups concerning the clinical-radiographic outcomes, including fracture consolidation, quality of joint fracture reduction, range of motion, lower limbs residual discrepancy, and postoperative pain. Conclusion We suggest that the simplified technique, using Schanz pins instead of Kirschner wires, can be a viable and effective alternative to treat complex fractures of the proximal end of the tibia with a circular external fixator. This simplified approach can offer benefits, such as a lower infection rate and greater patient comfort, without compromising clinical and radiographic outcomes, thus justifying its use.

Resumo Objetivo Comparar os resultados funcionais entre duas técnicas de fixação externa circular utilizadas no tratamento de fraturas complexas da extremidade proximal da tíbia. Materiais e Métodos Trata-se de um estudo de coorte retrospectivo, com 51 pacientes submetidos ao tratamento cirúrgico de fraturas complexas do planalto tibial com fixador externo circular. Os pacientes foram divididos em dois grupos: 12 pacientes tratados com a técnica clássica e 39 pacientes tratados com a técnica simplificada. As variáveis analisadas incluíram idade, sexo, mecanismo da lesão, energia do trauma, lesões associadas, tipo de fixador, tempo de uso do fixador e resultados clínico-radiográficos. A técnica clássica lança mão principalmente de fios de Kirschner transfixantes, e a simplificada substitui os fios de Kirschner por pinos de Schanz no bloco distal do fixador externo circular. Resultados A partir da comparação das montagens, não encontramos diferenças estatisticamente significativas (p> 00,5) entre os dois grupos em relação aos resultados clínico-radiográficos, incluindo a consolidação da fratura, a qualidade da redução da fratura articular, a amplitude de movimento, a discrepância residual na medida dos membros inferiores e a dor do paciente no pós-operatório. Conclusão Sugerimos que a técnica simplificada, utilizando pinos de Schanz no lugar dos fios de Kirschner, pode ser uma alternativa viável e eficaz no tratamento de fraturas complexas da extremidade proximal da tíbia com fixador externo circular. Essa abordagem simplificada pode oferecer benefícios, como menor taxa de infecção e maior conforto para o paciente, sem comprometer os resultados clínicos e radiográficos, o que justifica, o seu uso.

3D PRINTING IN COMPLEX TIBIAL FRACTURE CLASSIFICATION & PLANNING / Impressão 3d para a classificação e planejamento de fraturas tibiais complexas

ABSTRACT Objective: Tibial plateau fractures are common intra-articular fractures that pose classification and treatment challenges for orthopedic surgeons. Objective: This study examines the value of 3D printing for classifying and planning surgery for complex tibial plateau fractures. Methods: We reviewed 54 complex tibial plateau fractures treated at our hospital from January 2017 to January 2019. Patients underwent preoperative spiral CT scans, with DICOM data processed using Mimics software. 3D printing technology created accurate 1:1 scale models of the fractures. These models helped subdivide the fractures into seven types based on the tibial plateau's geometric planes. Surgical approaches and simulated operations, including fracture reduction and plate placement, were planned using these models. Results: The 3D models accurately depicted the direction and extent of fracture displacement and plateau collapse. They facilitated the preoperative planning, allowing for precise reconstruction strategies and matching intraoperative details with the pre-printed models. Post-surgery, the anatomical structure of the tibial plateau was significantly improved in all 54 cases. Conclusion: 3D printing effectively aids in the classification and preoperative planning of complex tibial plateau fractures, enhancing surgical outcomes and anatomical restoration. Level of Evidence IV, Prospective Study.

RESUMO Objetivo: As fraturas do planalto tibial são fraturas intra-articulares comuns de classificação e tratamento desafiadores aos cirurgiões ortopédicos. Objetivo: Este estudo investiga o uso de impressão 3D para classificar e planejar a cirurgia de fraturas complexas do planalto tibial. Métodos: 54 fraturas complexas do planalto tibial tratadas em nosso hospital de janeiro de 2017 a janeiro de 2019 foram revisadas. Os pacientes foram submetidos a tomografias computadorizadas em espiral pré-operatórias, com dados DICOM processados usando o software Mimics. A tecnologia de impressão 3D gerou modelos precisos em escala 1:1 das fraturas. Estes modelos ajudaram a subdividir as fraturas em sete tipos com base nos planos geométricos do planalto tibial. As abordagens cirúrgicas e as operações simuladas, incluindo a redução da fratura e a colocação de placa, foram planejadas utilizando estes modelos. Resultados: Os modelos 3D representaram com precisão a direção e a extensão da deslocação da fratura e do colapso do planalto. Os modelos facilitaram o planejamento pré-operatório, viabilizando estratégias de reconstrução precisas e a correspondência dos detalhes intraoperatórios com os modelos pré-impressos. Após a cirurgia, a estrutura anatômica do planalto tibial melhorou significativamente em todos os 54 casos. Conclusão: A impressão 3D ajuda na classificação e no planejamento pré-operatório de fraturas complexas do planalto tibial, melhorando os resultados cirúrgicos e a restauração anatômica. Nível de Evidência IV, Estudo Prospectivo.

Plateau iris syndrome: Epidemiology, diagnosis, and treatment: A narrative review.

Plateau iris syndrome (PIS) was first coined in 1958 to describe the iris configuration of a patient, 2 years later; the concept of plateau iris was published. In 1992, the anatomic aspects of plateau iris were studied using ultrasound biomicroscopy (UBM) determining it as a form of primary angle-closure glaucoma caused by a large or anteriorly positioned ciliary body that leads to mechanical obstruction of the trabecular meshwork, this condition is most often found in young patients. We aim to review the current literature and knowledge on the diagnosis and treatment options of PIS; the search was conducted in PubMed, LILACS, and BIREME internet search sites using keywords and snowball search strategy of articles published until 2022, focusing on PIS history, epidemiology, clinical diagnosis, UBM feature, and treatment.

Modified gastrocnemius splitting anatomic approach to the tibial plateau. Medium-term evaluation.

BACKGROUND: Posterior tibial plateau fractures, including avulsion fractures of the posterior cruciate ligament (PCL) insertion, represent a challenge for the orthopedic trauma surgeon. These injuries have gained a new perspective both diagnostically and therapeutically after the regular use of multiplanar computed tomography. In the herein study, we describe the outcome of patients sustaining a tibial plateau fracture with posterior articular involvement treated by open reduction and internal fixation (ORIF) using our modified gastrocnemius splitting anatomic approach. METHODS: This observational retrospective descriptive study was conducted at Complejo Medico de la Policia Federal Argentina Churruca-Visca. All patients were treated by ORIF by our team through our modified gastrocnemius splitting anatomic approach, and followed-up for a minimum of 12 months. RESULTS: A total of 18 patients sustaining plateau fracture were treated by this approach. Satisfactory tomographic reduction with articular gap and/or step-off <2 mm was achieved in 16. The mean time to the return to activities of daily living was 192.2 days. CONCLUSION: The modified gastrocnemius splitting anatomic approach represents a good alternative for the management of tibial plateau fractures involving the posterior quadrants.

The AO classification system for tibial plateau fractures: An independent inter and intraobserver agreement study.

PURPOSE: Classifying tibial plateau fractures is paramount in determining treatment regimens and systemizing decision making. The original AO classification described by Müller in 1996 and the Schatzker classification of 1970 are the most cited classifications for tibial plateau fractures, demonstrating substantial to almost perfect agreement. The main problem with these classifications schemes is that they lack the detail required to convey the variety of fracture patterns encountered. In 2018, the AO foundation published a new classification system for proximal tibia fractures, highlighting a more complete and detailed number of categories and subcategories. We sought to independently determine inter and intraobserver agreement of the AO classification system, compared to the previous systems described by Müller and Schatzker. METHODS: One hundred seven consecutive tibial plateau fractures were screened, and a representative data set of 69 was created. Six independent evaluators (three knee surgeons, three senior orthopedic residents) classified the fractures using the original AO, the Schatzker and the new AO classifications. After six weeks, the 69 cases were randomized and reclassified by all evaluators. The Kappa coefficient (k) was calculated for inter- and intraobserver correlation and is expressed with 95% confidence intervals. RESULTS: interobserver agreement was moderate for all three classifications. k = 0.464 (0.383-0.560) for the original AO; k = 0.404 (0.337-0.489) for Schatzker; and k = 0.457 (0.371-0.545) for the base categories of the new AO classification. The inclusion of subcategories and letter modifiers to the new classification worsened agreement to k = 0.358 (0.302-0.423) and k = 0.174 (0.134-0.222), respectively. There were no significant differences between knee surgeons and residents for the new classification. Intra-observer correlation was also moderate for each of the scores: k = 0.630 (0.578-0.682) for the original AO; k = 0.623 (0.569-0.674) for Schatzker; and k = 0.621 (0.566-0.678) for the new AO base categories; without differences between knee surgeons or residents. CONCLUSIONS: This study demonstrated an adequate inter and intra-observer agreement for the new AO tibial plateau fractures classification system for its base categories, but not at the subcategory or letter modifier levels.

Miocene surface uplift and orogenic evolution of the southern Andean Plateau (central Puna), northwestern Argentina.

We present stable hydrogen-isotope analyses of volcanic glass ([Formula: see text]Dg) and radiometric ages (U-Pb zircon, U-Th calcite, AMS14C) from deformed sedimentary deposits in the vicinity of the intermontane Pocitos Basin in the central Puna of the Andean Plateau at about 24.5°S. Our results demonstrate 2-km surface uplift since the middle to late Miocene and protracted shortening that persists until the present day, while other sectors of the Puna show evidence for tectonically neutral and/or extensional settings. These findings are at odds with previous studies suggesting near-modern elevations (4 km) of the Puna Plateau since the late Eocene and formation of the intermontane Miocene Arizaro-Pocitos Basin associated with gravitational foundering of a dense lithosphere. Geophysical and geochemical data support the removal of continental lithosphere beneath the Puna, but the timing and mechanisms by which this removal occurs have remained controversial. We hypothesize that intermontane basin formation in the central Puna is the result of crustal shortening since about 20 Ma, followed by rapid surface uplift, likely related to lithospheric delamination.

A new species of Rhynchospora section Pluriflorae (Cyperaceae) from the southwestern edge of the Brazilian Amazon

ABSTRACT A new species of Rhynchospora (Cyperaceae) only known from the Parecis plateau, on the southwestern edge of the Brazilian Amazon, is described here. Rhynchospora parecisensis was found growing only in open environments of deciduous seasonal forest and savanna enclaves in the midst of seasonal evergreen forest, in the state of Mato Grosso, western Brazil. Rhynchospora parecisensis differs from the other species of Rhynchospora sect. Pluriflorae subsect. Subebracteatae by the distally puberulent to pubescent glumes. The new species resembles Rhynchospora acanthoma, but differs from it by the subtriangular to quadrangular scapes in cross-section and the distally puberulent to pubescent glumes, with ciliate to ciliolate margins. Taxonomic comments, illustrations and a distribution map are also provided.

RESUMO Uma nova espécie de Rhynchospora (Cyperaceae), conhecida apenas para o Planalto dos Parecis, no sudoeste da Amazônia brasileira é descrita. Rhynchospora parecisensis foi encontrada apenas em ambientes abertos de floresta sazonal decídua e enclaves de savana, em meio a áreas de floresta estacional sempre verde, estado do Mato Grosso, centro-oeste do Brasil. Rhynchospora parecisensis difere das outras espécies de Rhynchospora sect. Pluriflorae subsect. Subebracteatae pelas suas glumas puberulentas a pubescentes distalmente. A nova espécie é semelhante a Rhynchospora acanthoma, porém difere pelos escapos subtriangulares a quadrangulares em secção transversal, e pelas glumas puberulentas a pubescentes distalmente, com margens ciliadas a cilioladas. Comentários taxonômicos, ilustrações e mapa de distribuição são apresentados.

Amanoacondorensis (Phyllanthaceae), a new shrubby species from the Cordillera del Condor in southern Ecuador.

A new species of Amanoa (Phyllanthaceae) is described from the sandstone Nangaritza Plateau in the Cordillera del Cóndor Region in southern Ecuador. Amanoacondorensis J.L.Clark & D.A.Neill is a small tree, 4 m tall that is only known from the type collection. The new species is distinct by a shrub habit, presence of coriaceous leaves with an acuminate apex, and congested inflorescences. The relatively high elevation of the type locality, presence of an androphore, and the habit as shrub or low tree are an unusual combination for Amanoa. The conservation status of A.condorensis is assessed as Critically Endangered (CR), based on IUCN Criteria.

ResumenSe describe una nueva especie de Amanoa (Phyllanthaceae) de la meseta de arenisca de Nangaritza en la región de la Cordillera del Cóndor en el sur de Ecuador. Amanoacondorensis J.L.Clark & D.A.Neill es un pequeño árbol de 4 metros de altura que sólo se conoce de la colección tipo. La nueva especie se distingue por la presencia de inflorescencias congestionadas, hojas coriáceas con ápice acuminado, y porte arbustivo. La elevación relativamente más alta de la localidad tipo, la presencia de un andróforo, y el hábito de arbusto o árbol pequeño son una combinación inusual para Amanoa. El estado de conservación de A.condorensis se evalúa como En Peligro Crítico (CR) según los Criterios de la UICN.

Abordaje posterior en fracturas de meseta tibial complejas en pacientes tratados quirúrgicamente en el IAHULA / Posterior approach in complex tibial plateau fractures IAHUL A Surgically treated patients

Las fracturas de meseta tibial compleja se asocian a traumatismo de alta energía, principalmente en accidentes de motocicleta, siendo un desafío para el cirujano ortopedista. En la década de 1970, Schatzker propuso una clasificación radiológica para las fracturas de la meseta tibial, que destacaba la morfología de los seis tipos principales. Las imágenes de tomografía computarizada y tridimensional, han cambiado la comprensión y el tratamiento de las fracturas de la meseta tibial. Recientemente, esa clasificación original se complementó con una más amplia; puesto que, se introdujo el fragmento en cuña dividida y la continuidad de la columna posterior como determinantes de la estabilidad articular y el papel fundamental que desempeña en el tratamiento de las fracturas de la meseta tibial, con ellos también la importancia de abordajes quirúrgicos que permitan la visualización posterior para una adecuada reducción. El estudio documenta las técnicas de fijación interna y abordajes posteriores realizadas en el IAHULA, valorando los resultados clínicos en cuanto a dolor y satisfacción del paciente, como consolidación, pseudoartrosis o falla en la técnica de osteosíntesis realizada. El resultado a partir de las escalas de evaluación de la AO y KOOS, arrojaron que, con un efecto excelentes se agrupa un 28,6% y bueno a un 42,9%, indicando la importancia de la fijación de la columna posterior, para prevenir artrosis postraumática temprana e inestabilidad articular(AU)

A complex fracture of the posterior tibial plateau are related to high energy traumatisms, mainly during motorcycle accidents, becoming a challenge to the ortopedic surgen. During the seventies, Stchatzker proposed a radiologic classification for the tibial plateau fractures that pointed the morphology of six main types. The computarized and tridimensional tomographic images have changed the comprehension and treatment of these fractures. Recently, the original classification was complemented with a more broaded approach due to the introduction of the fragment in divided crib and the continuity of the posterior column as factors determining the articular stability and the fundamental roll played in the treatment of fractures of the tibial plateau, as well as the important roll of surgical approaches that allow the posterior visualization for a correct reduction. This research documents the technics of internal fixation and posterior approach developed in the IAHULA, evaluating the clinic results about patients' pain level and comfort, as well as the radiologic findings of consolidation, pseudoarthrosis, or fail in the technic of osteosynthesis developed. The results from a point of view of the evaluation scales of the AO and KOOS, show 28.6% with excellent outcomes, and 42.9% with good outcomes, indicating the importance of the fixation of the posterior column to prevent early start of posttraumatic arthrosis and articular instability(AU)

Rendimiento Biomecánico de las Placas de Tibia Proximal Utilizadas en Fracturas de Platillos Tibiales evaluado a través de Modelos de Elementos Finitos: Protocolo de Revisión Sistemática / A systematic Review Protocol Examining the Biomechanical Performance of Proximal Tibial Plates used in Tibial Plate Fractures assessed by Finite Element Analysis

Objetivo. Analizar el rendimiento biomecánico de las placas de tibia proximal utilizadas en fracturas de platillos tibiales evaluado a través de modelos de elementos finitos. Métodos. Se realizará una búsqueda exhaustiva en PubMed/Medline, Embase, Lilacs, Web of Science y Google Scholar. No se utilizará ninguna restricción de idioma o estado de publicación. Dos revisores examinarán de forma independiente los posibles artículos elegibles, de acuerdo con los criterios de selección predefinidos. Se incluirán los estudios que evalúen el rendimiento de los platillos tibiales proximales utilizados en las fracturas del platillo tibial evaluadas mediante el análisis de elementos finitos. La extracción de datos sobre las características del estudio, los métodos, los resultados y la evaluación del riesgo de sesgo se realizará mediante un formulario estandarizado. Considerando el diseño de estudio no se requiere evaluación por comité de ética. Los resultados de esta revisión se difundirán a través de la publicación en revistas revisadas por pares, redes sociales y congresos de la especialidad. Se espera que los resultados de esta revisión permitan optimizar los resultados del manejo quirúrgico de las fracturas de platillos tibiales. Número de registro PROSPERO: CRD42023396015.

Objetive. To analyze the biomechanical performance of proximal tibial plates used in tibial plate fractures evaluated through finite element modeling. Methods. A comprehensive search will be conducted in PubMed/Medline, Embase, Lilacs, Web of Science, and Google Scholar. No language or publication status restrictions will be used. Two reviewers will independently review potential eligible articles according to predefined selection criteria. Studies evaluating the performance of proximal tibial splints used in tibial splint fractures assessed by finite element analysis will be included. Data extraction on study characteristics, methods, results, and risk of bias assessment will be performed using a standardized form. Considering the study design, evaluation by an ethics committee is not required. The results of this review will be disseminated through publication in peer-reviewed journals, social networks and specialty congresses. It is expected that the results of this review will allow optimizing the results of the surgical management of tibial plate fractures. PROSPERO registration number: CRD42023396015.

Phylogenomics and Biogeography of the Mammilloid Clade Revealed an Intricate Evolutionary History Arose in the Mexican Plateau.

Mexico harbors ~45% of world's cacti species richness. Their biogeography and phylogenomics were integrated to elucidate the evolutionary history of the genera Coryphantha, Escobaria, Mammillaria, Mammilloydia, Neolloydia, Ortegocactus, and Pelecyphora (Mammilloid Clade). We analyzed 52 orthologous loci from 142 complete genomes of chloroplast (103 taxa) to generate a cladogram and a chronogram; in the latter, the ancestral distribution was reconstructed with the Dispersal-Extinction-Cladogenesis model. The ancestor of these genera arose ~7 Mya on the Mexican Plateau, from which nine evolutionary lineages evolved. This region was the site of 52% of all the biogeographical processes. The lineages 2, 3 and 6 were responsible for the colonization of the arid southern territories. In the last 4 Mya, the Baja California Peninsula has been a region of prolific evolution, particularly for lineages 8 and 9. Dispersal was the most frequent process and vicariance had relevance in the isolation of cacti distributed in the south of Mexico. The 70 taxa sampled as Mammillaria were distributed in six distinct lineages; one of these presumably corresponded to this genus, which likely had its center of origin in the southern part of the Mexican Plateau. We recommend detailed studies to further determine the taxonomic circumscription of the seven genera.

Joint depression in tibial plateau fractures: To bone graft or not to bone graft?

Tibial plateau fractures with significant joint depression and metaphyseal comminution pose a challenge. In order to prevent the collapse of the articular surface, some authors propose filling the subchondral void created during reduction with bone graft/substitute, which can add further complications. We present two cases of tibial plateau fractures with severe joint depression of the lateral condyle; both treated with a periarticular rafting construct, in one caseadditional bone substitute was used and in the other case no bone graft/substitute was used; their final outcomes were reported. The treatment of joint depression in tibial plateau fractures using periarticular rafting constructs without bone graft, may be also a valid option, to achieve good final results without the morbidity associated with the use of bone graft/substitutes.