456 research outputs found

    Prothèse totale de genou et lésion des tissus mous : quelles options pour la reconstruction ?

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    Wound healing issues are not rare after total knee arthroplasty. While most patients heal with local wound care, a minority is susceptible to develop serious complications such as peri-prosthetic joint infection. If direct closure is not feasible, we recommend a multidisciplinary approach based on the ortho-plastic model to determine the optimal wound closure strategy. Negative pressure wound therapy can be used while waiting for definitive coverage to optimise wound environment. Medial gastrocnemius flap is considered as the gold standard procedure for peri-prosthetic substance loss around the knee.Les problèmes de cicatrisation ne sont pas rares après l’implantation d’une prothèse totale de genou. La plupart des patients guérissent avec des soins locaux mais une minorité d’entre eux peut développer des complications redoutables allant jusqu’à l’infection périprothétique. Hormis les situations pour lesquelles une fermeture directe de la cicatrice chirurgicale peut être réalisée, nous recommandons une approche multidisciplinaire basée sur le modèle de l’ortho-plastique afin de déterminer la stratégie de reconstruction la plus adaptée. La thérapie par pression négative peut être utilisée pour conditionner la plaie en vue d’un geste de couverture définitive. Le lambeau gastrocnémien médial est considéré comme la procédure de référence pour les pertes de substance périprothétique du genou

    Luxations de prothèse de hanche : comment les éviter ?

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    Dislocation after hip replacement is a complication that can have dramatic consequences for the patient. The purpose of this article is to review the different parameters influencing stability and how to reduce this risk. The approach, the diameter of the femoral head, and the use of dual-mobility acetabular cups have led to a drastic reduction in the rate of dislocation, particularly in patients at risk, in cases of imbalance of the spino-pelvic complex, or in cases of revision surgery. The inclusion of patients in dedicated clinical pathways and participation in preoperative education sessions also contribute to the reduction of dislocation risk.La luxation après prothèse de hanche est une complication qui peut avoir des conséquences dramatiques pour le patient. Cet article a pour but de revoir les différents paramètres influençant la stabilité prothétique et pouvant diminuer ce risque. La voie d’abord, le diamètre de la tête fémorale et l’usage de cotyles à double mobilité ont permis une diminution drastique du taux de luxation, en particulier chez les patients à risque, en cas de déséquilibre du complexe spino-pelvien ou en cas de reprise chirurgicale. L’inclusion des patients dans des itinéraires cliniques dédiés et la participation à des séances d’information préopératoire participent également à la réduction du risque de luxation

    Extensive skin necrosis following total hip arthroplasty performed through the direct anterior approach

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    Abstract Background Total hip arthroplasty is a widely performed surgical procedure, which enables patients to regain mobility, alleviates pain, and improves overall quality of life. Periarticular multimodal drug infiltration (PAI) is increasingly being used as an effective postoperative pain management, decreasing the systemic consumption of opioids. Extensive postoperative skin necrosis without a deep joint infection as a complication of total hip arthroplasty with PAI has not yet been described. Case presentation A 71-year-old patient who underwent total hip arthroplasty of the right hip for primary osteoarthritis through the Direct Anterior Approach presented postoperatively a large area of necrotic skin at the incision. Joint infection was excluded. An extensive debridement was performed and the tissue defect was reconstructed by a pedicled anterolateral thigh flap. The skin maintained a satisfactory appearance at 1 year postoperatively, and the hip was pain-free with restored ranges of motion. The patient was able to walk with no support and without limitation. Conclusion We address the possible risk factors, discuss the use of epinephrine in PAI and explore possible treatment options for such a complication

    Cell type- and time-dependent biological responses in ex vivo perfused lung grafts

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    International audienceIn response to the increasing demand for lung transplantation, ex vivo lung perfusion (EVLP) has extended the number of suitable donor lungs by rehabilitating marginal organs. However despite an expanding use in clinical practice, the responses of the different lung cell types to EVLP are not known. In order to advance our mechanistic understanding and establish a refine tool for improvement of EVLP, we conducted a pioneer study involving single cell RNA-seq on human lungs declined for transplantation. Functional enrichment analyses were performed upon integration of data sets generated at 4 h (clinical duration) and 10 h (prolonged duration) from two human lungs processed to EVLP. Pathways related to inflammation were predicted activated in epithelial and blood endothelial cells, in monocyte-derived macrophages and temporally at 4 h in alveolar macrophages. Pathways related to cytoskeleton signaling/organization were predicted reduced in most cell types mainly at 10 h. We identified a division of labor between cell types for the selected expression of cytokine and chemokine genes that varied according to time. Immune cells including CD4+ and CD8+ T cells, NK cells, mast cells and conventional dendritic cells displayed gene expression patterns indicating blunted activation, already at 4 h in several instances and further more at 10 h. Therefore despite inducing inflammatory responses, EVLP appears to dampen the activation of major lung immune cell types, what may be beneficial to the outcome of transplantation. Our results also support that therapeutics approaches aiming at reducing inflammation upon EVLP should target both the alveolar and vascular compartments

    Articular cartilage repair after implantation of hyaline cartilage beads engineered from adult dedifferentiated chondrocytes: cartibeads preclinical efficacy study in a large animal model

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    Background: Chondrocyte-based cell therapy to repair cartilage has been used for &gt;25 years despite current limitations. This work presents a new treatment option for cartilage lesions. Hypothesis: High-quality hyaline cartilage microtissues called Cartibeads are capable of treating focal chondral lesions once implanted in the defect, by complete fusion of Cartibeads among themselves and their integration with the surrounding native cartilage and subchondral bone. Study design: Controlled laboratory study. Methods: Cartibeads were first produced from human donors and characterized using histology (safranin O staining of glycosaminoglycan [GAG] and immunohistochemistry of collagen I and II) and GAG dosage. Cartibeads from 6 Göttingen minipigs were engineered and implanted in an autologous condition in the knee (4 or 5 lesions per knee). One group was followed up for 3 months and the other for 6 months. Feasibility and efficacy were measured using histological analysis and macroscopic and microscopic scores. Results: Cartibeads revealed hyaline features with strong staining of GAG and collagen II. High GAG content was obtained: 24.6-µg/mg tissue (wet weight), 15.52-µg/mg tissue (dry weight), and 35 ± 3-µg GAG/bead (mean ± SD). Histological analysis of Göttingen minipigs showed good integration of Cartibeads grafts at 3 and 6 months after implantation. The Bern Score of the histological assay comparing grafted versus empty lesions was significant at 3 months (grafted, n = 10; nongrafted, n = 4; score, 3.3 and 5.3, respectively) and 6 months (grafted, n = 11; nongrafted, n = 3; score, 1.6 and 5.1). Conclusion: We developed an innovative 3-step method allowing, for the first time, the use of fully dedifferentiated adult chondrocytes with a high number of cell passage (owing to the extensive amplification in culture). Cartibeads engineered from chondrocytes hold potential as an advanced therapy medicinal product for treating cartilage lesions with established efficacy. Clinical relevance: This successful preclinical study, combined with standardized manufacturing of Cartibeads according to good manufacturing practice guidelines, led to the approval of first-in-human clinical trial by the ethics committee and local medical authority. The generated data highlighted a promising therapy to treat cartilage lesions from a small amount of starting biopsy specimen. With our innovative cell amplification technology, very large lesions can be treated, and older active patients can benefit from it.</p

    In vitro-generated human muscle reserve cells are heterogeneous for Pax7 with distinct molecular states and metabolic profiles

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    Abstract Background The capacity of skeletal muscles to regenerate relies on Pax7+ muscle stem cells (MuSC). While in vitro-amplified MuSC are activated and lose part of their regenerative capacity, in vitro-generated human muscle reserve cells (MuRC) are very similar to quiescent MuSC with properties required for their use in cell-based therapies. Methods In the present study, we investigated the heterogeneity of human MuRC and characterized their molecular signature and metabolic profile. Results We observed that Notch signaling is active and essential for the generation of quiescent human Pax7+ MuRC in vitro. We also revealed, by immunofluorescence and flow cytometry, two distinct subpopulations of MuRC distinguished by their relative Pax7 expression. After 48 h in differentiation medium (DM), the Pax7High subpopulation represented 35% of the total MuRC pool and this percentage increased to 61% after 96 h in DM. Transcriptomic analysis revealed that Pax7High MuRC were less primed for myogenic differentiation as compared to Pax7Low MuRC and displayed a metabolic shift from glycolysis toward fatty acid oxidation. The bioenergetic profile of human MuRC displayed a 1.5-fold decrease in glycolysis, basal respiration and ATP-linked respiration as compared to myoblasts. We also observed that AMPKα1 expression was significantly upregulated in human MuRC that correlated with an increased phosphorylation of acetyl-CoA carboxylase (ACC). Finally, we showed that fatty acid uptake was increased in MuRC as compared to myoblasts, whereas no changes were observed for glucose uptake. Conclusions Overall, these data reveal that the quiescent MuRC pool is heterogeneous for Pax7 with a Pax7High subpopulation being in a deeper quiescent state, less committed to differentiation and displaying a reduced metabolic activity. Altogether, our data suggest that human Pax7High MuRC may constitute an appropriate stem cell source for potential therapeutic applications in skeletal muscle diseases

    Single-cell analysis of megakaryopoiesis in peripheral CD34+ cells: insights into ETV6-related thrombocytopenia

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    ETV6-related thrombocytopenia mechanisms remain poorly understood Megakaryopoiesis was studied by single-cell RNA sequencing and defects were confirmed ex-vivo ETV6 deficiency led to the development of aberrant haemopoietic cells as early as the MEP stage Upregulation of ribosome biogenesis were documented in patient megakaryocytes and platelet
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