1,628 research outputs found

    Functional performance of a bi-layered chitosan-nano-hydroxyapatite osteochondral scaffold: a pre-clinical <i>in vitro</i> tribological study

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    Osteochondral grafts are used for repair of focal osteochondral lesions. Autologous grafts are the gold standard treatment; however, limited graft availability and donor site morbidity restrict use. Therefore, there is a clinical need for different graft sources/materials which replicate natural cartilage function. Chitosan has been proposed for this application. The aim of this study was to assess the biomechanics and biotribology of a bioresorbable chitosan/chitosan-nano-hydroxyapatite osteochondral construct (OCC), implanted in an in vitro porcine knee experimental simulation model. The OCC implanted in different surgical positions (flush, proud and inverted) was compared to predicate grafts in current clinical use and a positive control consisting of a stainless steel graft implanted proud of the cartilage surface. After 3 h (10 800 cycles) wear simulation under a walking gait, subsidence occurred in all OCC samples irrespective of surgical positioning, but with no apparent loss of material and low meniscus wear. Half the predicate grafts exhibited delamination and scratching of the cartilage surfaces. No graft subsidence occurred in the positive controls but wear and deformation of the meniscus were apparent. Implanting a new chitosan-based OCC either optimally (flush), inverted or proud of the cartilage surface resulted in minimal wear, damage and deformation of the meniscus

    The application of custom 3D-printed prostheses with ultra-short stems in the reconstruction of bone defects: a single center analysis

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    Objective: Considering the advantages and widespread presence of 3D-printing technology in surgical treatments, 3D-printed porous structure prostheses have been applied in a wide range of the treatments of bone tumor. In this research, we aimed to assess the application values of the 3D-printed custom prostheses with ultra-short stems for restoring bone defects and maintaining arthrosis in malignant bone tumors of lower extremities in children.Methods: Seven cases of pediatric patients were included in this study. In all cases, the prostheses were porous titanium alloy with ultra-short stems. MSTS 93 (Musculoskeletal Tumor Society) scores were recorded for the functional recovery of the limbs. VAS (Visual analogue scale) scores were utilized to assess the degree of painfulness for the patients. X-ray and MRI (magnetic resonance imaging) were applied to evaluate the bone integration, prostheses aseptic loosening, prostheses fracture, wound healing, and tumor recurrence during follow-up.Results: During follow-up, none of the patients developed any postoperative complications, including prostheses aseptic loosening, prostheses fracture, or tumor recurrence. Radiological examinations during the follow-up showed that prostheses implanted into the residual bone were stably fitted and bone defects were effectively reconstructed. The MSTS 93 scores were 24.9 ± 2.9 (20–28). VAS scores were decreased to 5.8 ± 1.2 (4.0–7.0). No statistically significant differences in leg length discrepancy were observed at the time of the last follow-up.Conclusion: 3D-printing technology can be effectively applied throughout the entire surgical treatment procedures of malignant bone tumors, offering stable foundations for the initial stability of 3D-printed prostheses with ultra-short stems through preoperative design, intraoperative precision operation, and personalized prosthesis matching. With meticulous postoperative follow-up, close monitoring of postoperative complications was ensured. These favorable outcomes indicate that the utilization of 3D-printed custom prostheses with ultra-short stems is a viable alternative for reconstructing bone defects. However, further investigation is warranted to determine the long-term effectiveness of the 3D-printing technique

    Die Segmentspaltverknöcherung nach Unterkieferrekonstruktion mit dem Fibulatransplantat unter Berücksichtigung biomechanischer Eigenschaften verschiedener Osteosynthesen

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    Die Studien der vorliegenden Arbeit analysierten Untersuchungsmethoden für die Segmentspaltverknöcherung nach Unterkieferrekonstruktionen mit Fibulatransplantaten, sowie die biomechanischen Eigenschaften von etablierten und alternativen Osteosynthesen. Mit der volumetrischen Messung der Segmentspaltverknöcherung konnte eine zuverlässige und objektive Methodik neu eingeführt werden; eine mit dieser Bewertungsmethode durchgeführte retrospektive Untersuchung an Patienten identifizierte den anterioren Segmentspalt bei Unterkieferrekonstruktionen mit einem Fibulatransplantat und der Osteosynthese mit einer CAD/CAM Rekonstruktionsplatte als unabhängigen Risikofaktor für eine Pseudarthrose. Hierdurch wurde ein klarer Hinweis auf die Relevanz der Biomechanik für die Verknöcherung nach Unterkieferrekonstruktionen geliefert, was zusätzlich durch FEA dieser Arbeit untermauert werden konnte. Klinisch sollte der anteriore Spalt daher zukünftig bei Fragen rund um eine mögliche dentale Rehabilitation inklusive Materialentfernung besonders intensiv betrachtet werden. Mittels biomechanischer Untersuchungen an einem Unterkieferrekonstruktionsmodell konnte eine erhöhte IOM von konventionellen und CAD/CAM Miniplatten im Vergleich zu einer CAD/CAM Rekonstruktionsplatte zur Osteosynthese von Fibulatransplantaten nachgewiesen werden. Vor dem Hintergrund von postoperativ reduzierten Kaukräften, der Notwendigkeit einer gewissen axialen Belastung des Segmentspaltkallus und klinisch erhöhten Pseudarthroseraten bei CAD/CAM Rekonstruktionsplatten scheint eine mäßige IOM wie bei Osteosynthesen mit Miniplatten vorteilhaft zu sein. Weitere FEA zeigten, dass der kombinierte Einsatz von CAD/CAM Miniplatten im anterioren Bereich und einer kleinen posterioren CAD/CAM Rekonstruktionsplatte sowohl aus biomechanischer als auch aus klinischer Sicht günstig sein dürfte. Hingegen beeinflusst offenbar eine Veränderung des Schraubensystems die IOM nicht maßgeblich. Osteosynthesen mit alternativen Materialien wie PEEK oder PLA scheinen allgemein nicht für Unterkieferrekonstruktionen geeignet zu sein, sodass weitere Materialalternativen wie Magnesium, Zink oder Seide von Interesse sind. Für eine zukünftige biomechanische Optimierung der Osteosynthese mit dem Ziel der Verringerung der Pseudarthroserate sind weitere Studien auf biomechanischer und klinischer Ebene erforderlich, insbesondere weil sich die Biomechanik im Segmentspalt durch die Osteosyntheseart, Kaukräfte, und die Anatomie der Rekonstruktion maßgeblich verändert

    3D Innovations in Personalized Surgery

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    Current practice involves the use of 3D surgical planning and patient-specific solutions in multiple surgical areas of expertise. Patient-specific solutions have been endorsed for several years in numerous publications due to their associated benefits around accuracy, safety, and predictability of surgical outcome. The basis of 3D surgical planning is the use of high-quality medical images (e.g., CT, MRI, or PET-scans). The translation from 3D digital planning toward surgical applications was developed hand in hand with a rise in 3D printing applications of multiple biocompatible materials. These technical aspects of medical care require engineers’ or technical physicians’ expertise for optimal safe and effective implementation in daily clinical routines.The aim and scope of this Special Issue is high-tech solutions in personalized surgery, based on 3D technology and, more specifically, bone-related surgery. Full-papers or highly innovative technical notes or (systematic) reviews that relate to innovative personalized surgery are invited. This can include optimization of imaging for 3D VSP, optimization of 3D VSP workflow and its translation toward the surgical procedure, or optimization of personalized implants or devices in relation to bone surgery

    Translational Models for Advancement of Regenerative Medicine and Tissue Engineering

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    At the root of each regenerative medicine or tissue engineering breakthrough is a simple goal, to improve quality of healing, thus improving a patient’s quality of life. Each tissue presents its own complexities and limitations to healing, whether it is the scarring nature of tendon healing or the mechanical complexity driving bone regeneration. Preclinical, translational models aim to reflect these complexities and limitations, allowing for effective development and refinement of tissue engineered therapeutics for human use. The following body of work explores several of these translational models, both utilizing them for tissue regenerative therapy development and evaluating the benefits and complications incurred with each model. This work begins with a discussion of the complexity of bone healing and how dysfunction in the mechanical, surgical, and systemic fracture environment can lead to delayed healing and nonunion. A comprehensive review of the advances in preventative and corrective therapeutics for bone nonunion is included next, with specific focuses on mechanical and tissue-engineered technology. Then, this work presents a tissue-engineered application of mesenchymal stem cells in acute tendon injury, highlighting experimentation in cell fate direction in vitro and intralesional mesenchymal stem cell implantation in vivo. Next, this work presents a series of experiments that evaluated and refined a commonly utilized preclinical model of delayed bone healing, the caprine segmental tibial defect stabilized using single locking plate fixation. First, the biomechanical stability of the model was evaluated in vivo using plantar-pressure analysis of gait. Then, the surgical technique was refined through a retrospective analysis of the effects of plate length and position on fixation stability in vitro and in vivo. Finally, the comorbidities of this preclinical model were explored via an analysis of the effect of long-term tibial locking plate fixation on cortical dimensions and density

    Complex geometry and integrated macro-porosity: Clinical applications of electron beam melting to fabricate bespoke bone-anchored implants

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    The last decade has witnessed rapid advancements in manufacturing technologies for biomedical implants. Additive manufacturing (or 3D printing) has broken down major barriers in the way of producing complex 3D geometries. Electron beam melting (EBM) is one such 3D printing process applicable to metals and alloys. EBM offers build rates up to two orders of magnitude greater than comparable laser-based technologies and a high vacuum environment to prevent accumulation of trace elements. These features make EBM particularly advantageous for materials susceptible to spontaneous oxidation and nitrogen pick-up when exposed to air (e.g., titanium and titanium-based alloys). For skeletal reconstruction(s), anatomical mimickry and integrated macro-porous architecture to facilitate bone ingrowth are undoubtedly the key features of EBM manufactured implants. Using finite element modelling of physiological loading conditions, the design of a prosthesis may be further personalised. This review looks at the many unique clinical applications of EBM in skeletal repair and the ground-breaking innovations in prosthetic rehabilitation. From a simple acetabular cup to the fifth toe, from the hand-wrist complex to the shoulder, and from vertebral replacement to cranio-maxillofacial reconstruction, EBM has experienced it all. While sternocostal reconstructions might be rare, the repair of long bones using EBM manufactured implants is becoming exceedingly frequent. Despite the various merits, several challenges remain yet untackled. Nevertheless, with the capability to produce osseointegrating implants of any conceivable shape/size, and permissive of bone ingrowth and functional loading, EBM can pave the way for numerous fascinating and novel applications in skeletal repair, regeneration, and rehabilitation. Statement of significance: Electron beam melting (EBM) offers unparalleled possibilities in producing contaminant-free, complex and intricate geometries from alloys of biomedical interest, including Ti6Al4V and CoCr. We review the diverse range of clinical applications of EBM in skeletal repair, both as mass produced off-the-shelf implants and personalised, patient-specific prostheses. From replacing large volumes of disease-affected bone to complex, multi-material reconstructions, almost every part of the human skeleton has been replaced with an EBM manufactured analog to achieve macroscopic anatomical-mimickry. However, various questions regarding long-term performance of patient-specific implants remain unaddressed. Directions for further development include designing personalised implants and prostheses based on simulated loading conditions and accounting for trabecular bone microstructure with respect to physiological factors such as patient\u27s age and disease status

    Biomaterials for Bone Tissue Engineering 2020

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    This book presents recent advances in the field of bone tissue engineering, including molecular insights, innovative biomaterials with regenerative properties (e.g., osteoinduction and osteoconduction), and physical stimuli to enhance bone regeneration

    The antibiotic bead pouch – a useful technique for temporary soft tissue coverage, infection prevention and therapy in trauma surgery

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    Soft tissue defects resulting from trauma and musculoskeletal infections can complicate surgical treatment. Appropriate temporary coverage of these defects is essential to achieve the best outcomes for necessary plastic soft tissue defect reconstruction. The antibiotic bead pouch technique is a reasonable surgical approach for managing temporary soft tissue defects following adequate surgical debridement. This technique involves the use of small diameter antibiotic-loaded bone cement beads to fill the dead space created by debridement. By applying antibiotics to the bone cement and covering the beads with an artificial skin graft, high local dosages of antibiotics can be achieved, resulting in the creation of a sterile wound that offers the best starting position for soft tissue and bone defect reconstruction. This narrative review describes the rationale for using this technique, including its advantages and disadvantages, as well as pearls and pitfalls associated with its use in daily practice. In addition, the article provides a comprehensive overview of the literature that has been published since the technique was introduced in surgical practice

    Non-osteopenic Bone Pathology After Allo-hematopoietic Stem Cell Transplantation in Patients with Inborn Errors of Immunity

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    PURPOSE: There is a lack of data on post-HSCT non-osteopenic bone pathology specifically for children with inborn errors of immunity (IEI). We collected data on non-osteopenic bone pathology in children with IEI post-HSCT over two decades in a large tertiary pediatric immunology center. METHODS: Descriptive study with data analysis of bone pathology in allo-HSCT for IEI was performed between 1/1/2000 to 31/12/2018 including patients alive at follow-up to July 2022. Records were analyzed for bone pathology and risk factors. Exclusion criteria included isolated reduced bone density, fractures, and skeletal anomalies due to underlying IEI and short stature without other bone pathology. Bone pathologies were divided into 5 categories: bone tumors; skeletal dysplasia; avascular necrosis; evolving bone deformities; slipped upper femoral epiphysis. RESULTS: A total of 429 children received HSCT between 2000 and 2018; 340 are alive at last assessment. Non-osteopenic bone pathology was observed post-HSCT in 9.4% of patients (32/340, mean 7.8 years post-HSCT). Eleven patients (34%) had > 1 category of bone pathology. Seventeen patients (17/32; 53%) presented with bilateral bone pathology. The majority of patients received treosulfan-based conditioning (26/32; 81.2%). Totally, 65.6% (21/32) of patients had a history of prolonged steroid use (> 6 months). Pain was the presenting symptom in 66% of patients, and surgical intervention was required in 43.7%. The highest incidence of bone pathologies was seen in Wiskott-Aldrich syndrome (WAS) (n = 8/34; 23.5%) followed by hemophagocytic lymphohistiocytosis patients (n = 3/16; 18.8%). CONCLUSION: Non-osteopenic bone pathology in long-term survivors of allo-HSCT for IEI is not rare. Most patients did not present with complaints until at least 5 years post-HSCT highlighting the need for ongoing bone health assessment for patients with IEI. Children presenting with stunted growth and bone pathology post-HSCT should undergo skeletal survey to rule out development of post-HSCT skeletal dysplasia. Increased rates and complexity of bone pathology were seen amongst patients with Wiskott-Aldrich syndrome

    Ceramic Materials for 3D Printing of Biomimetic Bone Scaffolds – Current state–of–the–art &amp; Future Perspectives

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    Ceramic bone implants have potential properties ideal for long-term implantation applications. On comparison with other materials, ceramic biomaterials have advantages such as biocompatibility, low cost, osteoconductivity, osteoinductivity, corrosion resistance, and can be made into various shapes with desired surface properties. Among transplantation surgeries, bone transplantation is the second largest in the globe after blood transfusion which is an indication for rising hope on the potential treatment options for bone. 3D printing is one of the most advanced fabrication techniques to create customized bone implants using materials such as ceramics and their composites. Developing bone scaffolds that precisely recapitulate the mechanical properties and other biological functions of bone remains a major challenge. However, extensive research on ceramic biomaterials have resulted in the successful 3D printing of complex bony designs with >50% porosity with cortical bone mechanical properties. This review critically analyses the use of various 3D printing techniques to fabricate ceramic bone scaffolds. Further, various natural and synthetic ceramic materials for producing customized ceramic implants are discussed along with potential clinical applications. Finally, a list of companies that offer customized 3D printed implants and the future on clinical translation of 3D printed ceramic bone implants are outlined
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