Use of allograft bone matrix in clinical orthopedics

Osteogenic Potential and Bone Matrix Maturity: Comparison of Demineralized Bone Matrix and P15 Polypeptide iFactor® in an In Vitro Study

Background and Objectives: Demineralized bone matrix (DBM) is a widely used bone graft substitute due to its osteoconductive and osteoinductive properties. However, its efficacy varies due to differences in donor, processing, and storage conditions. Synthetic alternatives, such as iFactor®, combine non-organic bone mineral and a small peptide (P-15) to enhance the cellular attachment and osteogenesis. To compare the osteogenic potential and bone matrix maturity of iFactor® and a commercial DBM scaffold through calcium nodule formation and Fourier transform infrared spectroscopy (FTIR) analysis. Materials and Methods: Human mesenchymal stem cells (hMSCs) were cultured and exposed to iFactor® or DBM in paracrine culture conditions for 21 days. Calcium nodule formation was assessed using alizarin red staining and quantified spectrophotometrically. The FTIR analysis of hMSCs exposed to the scaffolds for three months evaluated the biomolecular composition and bone matrix maturity. Results: Calcium nodules formed in both groups but in smaller quantities than in the positive control (p < 0.05). The biomolecular components of the DBM were similar to healthy bone (p > 0.05) than those of the iFactor® group (p < 0.005). A different rate of bone regeneration was observed through the formation of a greater number of calcium nodule aggregates identified in the extracellular matrix of mesenchymal stem cell cultures exposed to iFactor® compared to those cultures enriched with DBM. Conclusions: Both experimental matrices demonstrated similar osteogenic potential at the 3-month follow-up. Although DBM has a closer biomolecular composition and carbonate substitution compared to healthy bone, iFactor® showed faster matrix maturity expressed through the formation of a greater number of calcium nodule aggregates and higher hMSCs proliferation.

Research Progress of Bone Grafting: A Comprehensive Review

Bone tissue, the second most transplanted tissue after blood, is utilized in over 2.2 million bone grafts annually to address various bone-related conditions including fractures, tumors, bone infections, scoliosis, congenital defects, osteoporosis, osteoarthritis, and osteogenesis imperfecta. According to incomplete statistics, $4.3 billion was spent on bone graft materials in 2015 alone, with projections suggesting this figure may reach $66 billion by 2026. The limited availability of autogenous bone graft considered the gold standard due to their three critical biological properties: osteoconduction, osteoinduction, and osteogenesis-alongside the increasing global aging population, may be contributing to this rising expenditure. Furthermore, advancements in biomaterials and engineering technologies have created opportunities for the exploration of new bone graft substitutes. In this review, we will examine the fundamental structure of natural bone and the characteristics of ideal bone graft, highlighting common bone graft materials currently available, such as true bone ceramics, decalcified bone matrix, freeze-dried bone and demineralized freeze-dried bone, bioactive glasses, bone marrow aspirate concentrate, polymer nanocomposites, which have different characteristics in osteogenic, osteoconductivity, osteoinductivity, biocompatibility, mechanical properties, and resorption. How to utilize its advantages to maximize the osteogenic effect will be the focus of this review, and some of the current challenges in the field of bone grafting will be identified, outlining potential directions for future development. In conclusion, the choice of bone graft is critical to bone repair and regeneration, and a comprehensive understanding of the advantages and disadvantages of bone graft materials can improve the effectiveness of related surgical interventions.

Immunology in Osseointegration After Implantation

Bone tissue is renowned for its regenerative capabilities, yet handling extensive defects and complex fractures presents considerable medical challenges. Osteoimmunology, studying the complex mechanism of the mutual influence within the range of immunity and skeletal systems, has highlighted the indispensable function of immune reactions in the process of bone integration. This procedure, primarily immune-driven, fosters new bone formation around implants instead of relying solely on osteogenic mechanisms. Traditionally, implant research has emphasized bone bonding and osteoinduction, often overlooking the significant influence of immune interactions. Implants pose risks including donor site morbidity, decreased bioactivity, and pathogen transmission risks. To mitigate these, implant surfaces are modified through altering local factors such as electrical fields and applying physical treatments to change roughness, hydrophilicity, and nanotopography. These modifications aim to regulate immune reactions at the surface of the bone implant, improving osseointegration and the repair of bone. This review examines the types of immune cells in osseointegration, especially the pivotal function that macrophages serve in the regeneration of bone tissue, and investigates key implant features-morphology, wettability, cytokine interaction, and metal ion and bioactive molecule adsorption-that impact immune responses. These insights underscore the immune system's importance in bone repair and advance osteoimmunology as essential for developing strategies to control bone immune responses, enhancing implant integration and bone regeneration.

Biomimetic Fabrication and Osteogenic Effects of E7BMP-2 Peptide Coassembly Microspheres Based α-Tricalcium Phosphate with Silk Fibroin

The repair and reconstruction of bone defects remain a challenge in orthopedics. Inadequate mechanical qualities, poor biocompatibility, and insufficient osteoconductivity are some of the issues facing current bone healing materials. Better materials that can replicate the composition and functionality of natural bone, promote quick and full healing, and reduce the likelihood of rejection and infection are desperately needed. Bone tissue engineering, combining biomaterial scaffolds and pro-osteogenic drugs, provides support in the repair and regeneration of bone defects. The development of an effective scaffold for bone defect repair is an urgent clinical need. The present study investigates the feasibility of using microspheres based on α-tricalcium phosphate and fibroin as an osteoconductive matrix and a carrier for controlled local delivery of the E7BMP-2 peptide, in which the E7 domain confers a calcium chelation property, while the BMP-2 mimicking peptide induces bone formation. We prepared α-tricalcium phosphate/silk fibroin (α-TCP/SF) microspheres through a high voltage electric field based on the protocol of α-TCP/SF bone cement slurry. This α-TCP/SF microspheres-based system was designed for delivery vehicles of the modified BMP-2 peptide by the E7 domain to realize sustainable and steady release of the peptide. In vitro cell tests and the experimental model of cranial bone defects in rats were used to investigate the pro-osteogenic benefits. The results demonstrated that the E7BMP-2 peptide-bound microspheres functioned as a sustained release system for the peptide and enhanced osteogenic differentiation of bone marrow mesenchymal stem cells in rat calvarial defects. Additionally, toxicity studies showed that microspheres have good biocompatibility and safety. Thus, these E7BMP-2 peptide-bound α-TCP/SF microspheres provide a promising therapeutic strategy for the treatment of bone defects.

Bone Regeneration: A Review of Current Treatment Strategies

Bone regeneration has emerged as a critical research and clinical advancement field, fueled by the growing demand for effective treatments in orthopedics and oncology. Over the past two decades, significant progress in biomaterials and surgical techniques has led to the development of novel solutions for treating bone defects, surpassing the use of traditional autologous grafts. This review aims to assess the latest approaches in bone regeneration, including autologous, allogenic, and xenogenic grafts, naturally derived biomaterials, and innovative synthetic substitutes such as bioceramics, bioactive glasses, metals, polymers, composite materials, and other specialized applications. A comprehensive literature search was conducted on PubMed, focusing on studies published between 2019 and 2024, including meta-analyses, reviews, and systematic reviews. The review evaluated a range of bone regeneration strategies, examining the clinical outcomes, materials used, surgical techniques, and the effectiveness of various approaches in treating bone defects. The search identified numerous studies, with the inclusion criteria focused on those exploring innovative bone regeneration strategies. These studies provided valuable insights into the clinical and biological outcomes of different biomaterials and graft types. Results indicated that while advancements in synthetic and naturally derived biomaterials show promising potential, challenges remain in optimizing therapeutic strategies across diverse patient populations and clinical settings. The findings emphasize the need for an integrated approach that combines scientific research, clinical practice, and technological innovation to improve bone regeneration therapies. Further research is required to establish standardized protocols and determine the optimal application of various materials and techniques to enhance patient outcomes and the quality of care.

[Research progress in repair and reconstruction of tumor-related bone defects in proximal femur]

Objective

To review the repair and reconstruction methods for large segmental femoral proximal bone defects caused by tumors, and to explore their clinical application effects, advantages, and disadvantages, and future research directions.

Methods

A comprehensive search of Chinese and foreign databases was conducted to select basic and clinical research literature related to the repair and reconstruction of femoral proximal bone defects caused by tumors. The studies were classified and analyzed based on two main strategies: hip-preserving reconstruction and non-hip-preserving reconstruction.

Results

In hip-preserving reconstruction, traditional methods such as allograft transplantation and vascularized autograft transplantation are common but have risks of poor bone integration and bone resorption. The clinical application of inactivated tumor segment reimplantation and distraction osteogenesis techniques is limited. In recent years, three-dimensional printing technology has become increasingly mature, with personalized prostheses and precise surgeries becoming development trends. Non-hip-preserving reconstruction primarily includes allograft prosthesis composite and total femoral replacement. The former focuses on improving the survival rate and bone integration efficiency of the allograft, while the latter requires the simultaneous reconstruction of hip and knee joint stability.

Conclusion

Significant progress has been made in repairing and reconstructing proximal femoral bone defects caused by tumors, but many challenges remain. The integration of three-dimensional printing technology and digital design offers potential for precise bone defect repair. Future efforts should focus on new concepts, technologies, and materials through multidisciplinary approaches to provide personalized and precise solutions, thereby improving patient quality of life.