Hydrogel loaded with thiolated chitosan modified taxifolin liposome promotes osteoblast proliferation and regulates Wnt signaling pathway to repair rat skull defects

To alleviate skull defects and enhance the biological activity of taxifolin, this study utilized the thin-film dispersion method to prepare paclitaxel liposomes (TL). Thiolated chitosan (CSSH)-modified TL (CTL) was synthesized through charge interactions. Injectable hydrogels (BLG) were then prepared as hydrogel scaffolds loaded with TAX (TG), TL (TLG), and CTL (CTLG) using a Schiff base reaction involving oxidized dextran and carboxymethyl chitosan. The study investigated the bone reparative properties of CTLG through molecular docking, western blot techniques, and transcriptome analysis. The particle sizes of CTL were measured at 248.90 ± 14.03 nm, respectively, with zeta potentials of +36.68 ± 5.43 mV, respectively. CTLG showed excellent antioxidant capacity in vitro. It also has a good inhibitory effect on Escherichia coli and Staphylococcus aureus, with inhibition rates of 93.88 ± 1.59 % and 88.56 ± 2.83 % respectively. The results of 5-ethynyl-2 '-deoxyuridine staining, alkaline phosphatase staining and alizarin red staining showed that CTLG also had the potential to promote the proliferation and differentiation of mouse embryonic osteoblasts (MC3T3-E1). The study revealed that CTLG enhances the expression of osteogenic proteins by regulating the Wnt signaling pathway, shedding light on the potential application of TAX and bone regeneration mechanisms.

Advances in clinical applications of bioceramics in the new regenerative medicine era

In this editorial, we comment on the hard and soft tissue applications of different ceramic-based scaffolds prepared by different mechanisms such as 3D printing, sol-gel, and electrospinning. The new concept of regenerative medicine relies on biomaterials that can trigger in situ tissue regeneration and stem cell recruitment at the defect site. A large percentage of these biomaterials is ceramic-based as they provide the essential requirements of biomaterial principles such as tailored multisize porosity, antibacterial properties, and angiogenic properties. All these previously mentioned properties put bioceramics on top of the hierarchy of biomaterials utilized to stimulate tissue regeneration in soft and hard tissue wounds. Multiple clinical applications registered the use of these materials in triggering soft tissue regeneration in healthy and diabetic patients such as bioactive glass nanofibers. The results were promising and opened new frontiers for utilizing these materials on a larger scale. The same results were mentioned when using different forms and formulas of bioceramics in hard defect regeneration. Some bioceramics were used in combination with other polymers and biological scaffolds to improve their regenerative and mechanical properties. All this progress will enable a larger scale of patients to receive such services with ease and decrease the financial burden on the government.

3D printed PLGA scaffold with nano-hydroxyapatite carrying linezolid for treatment of infected bone defects

BACKGROUND

Linezolid has been reported to protect against chronic bone and joint infection. In this study, linezolid was loaded into the 3D printed poly (lactic-co-glycolic acid) (PLGA) scaffold with nano-hydroxyapatite (HA) to explore the effect of this composite scaffold on infected bone defect (IBD).

METHODS

PLGA scaffolds were produced using the 3D printing method. Drug release of linezolid was analyzed by elution and high-performance liquid chromatography assay. PLGA, PLGA-HA, and linezolid-loaded PLGA-HA scaffolds, were implanted into the defect site of a rabbit radius defect model. Micro-CT, H&E, and Masson staining, and immunohistochemistry were performed to analyze bone infection and bone healing. Evaluation of viable bacteria was performed. The cytocompatibility of 3D-printed composite scaffolds in vitro was detected using human bone marrow mesenchymal stem cells (BMSCs). Long-term safety of the scaffolds in rabbits was evaluated.

RESULTS

The linezolid-loaded PLGA-HA scaffolds exhibited a sustained release of linezolid and showed significant antibacterial effects. In the IBD rabbit models implanted with the scaffolds, the linezolid-loaded PLGA-HA scaffolds promoted bone healing and attenuated bone infection. The PLGA-HA scaffolds carrying linezolid upregulated the expression of osteogenic genes including collagen I, runt-related transcription factor 2, and osteocalcin. The linezolid-loaded PLGA-HA scaffolds promoted the proliferation and osteogenesis of BMSCs in vitro via the PI3K/AKT pathway. Moreover, the rabbits implanted with the linezolid-loaded scaffolds showed normal biochemical profiles and normal histology, which suggested the safety of the linezolid-loaded scaffolds.

CONCLUSION

Overall, the linezolid-loaded PLGA-HA scaffolds fabricated by 3D printing exerts significant bone repair and anti-infection effects.

Advancements in drug-loaded hydrogel systems for bone defect repair

Bone defects are primarily the result of high-energy trauma, pathological fractures, bone tumor resection, or infection debridement. The treatment of bone defects remains a huge clinical challenge. The current treatment options for bone defects include bone traction, autologous/allogeneic bone transplantation, gene therapy, and bone tissue engineering amongst others. With recent developments in the field, composite scaffolds prepared using tissue engineering techniques to repair bone defects are used more often. Among the various composite scaffolds, hydrogel exhibits the advantages of good biocompatibility, high water content, and degradability. Its three-dimensional structure is similar to that of the extracellular matrix, and as such it is possible to load stem cells, growth factors, metal ions, and small molecule drugs upon these scaffolds. Therefore, the hydrogel-loaded drug system has great potential in bone defect repair. This review summarizes the various natural and synthetic materials used in the preparation of hydrogels, in addition to the latest research status of hydrogel-loaded drug systems.

Injectable ultrasound-powered bone-adhesive nanocomposite hydrogel for electrically accelerated irregular bone defect healing

The treatment of critical-size bone defects with irregular shapes remains a major challenge in the field of orthopedics. Bone implants with adaptability to complex morphological bone defects, bone-adhesive properties, and potent osteogenic capacity are necessary. Here, a shape-adaptive, highly bone-adhesive, and ultrasound-powered injectable nanocomposite hydrogel is developed via dynamic covalent crosslinking of amine-modified piezoelectric nanoparticles and biopolymer hydrogel networks for electrically accelerated bone healing. Depending on the inorganic-organic interaction between the amino-modified piezoelectric nanoparticles and the bio-adhesive hydrogel network, the bone adhesive strength of the prepared hydrogel exhibited an approximately 3-fold increase. In response to ultrasound radiation, the nanocomposite hydrogel could generate a controllable electrical output (-41.16 to 61.82 mV) to enhance the osteogenic effect in vitro and in vivo significantly. Rat critical-size calvarial defect repair validates accelerated bone healing. In addition, bioinformatics analysis reveals that the ultrasound-responsive nanocomposite hydrogel enhanced the osteogenic differentiation of bone mesenchymal stem cells by increasing calcium ion influx and up-regulating the PI3K/AKT and MEK/ERK signaling pathways. Overall, the present work reveals a novel wireless ultrasound-powered bone-adhesive nanocomposite hydrogel that broadens the therapeutic horizons for irregular bone defects.

Dual-functional 3D-printed porous bioactive scaffold enhanced bone repair by promoting osteogenesis and angiogenesis

The treatment of bone defects is a difficult problem in orthopedics. The excessive destruction of local bone tissue at defect sites destroys blood supply and renders bone regeneration insufficient, which further leads to delayed union or even nonunion. To solve this problem, in this study, we incorporated icariin into alginate/mineralized collagen (AMC) hydrogel and then placed the drug-loaded hydrogel into the pores of a 3D-printed porous titanium alloy (AMCI/PTi) scaffold to prepare a bioactive scaffold with the dual functions of promoting angiogenesis and bone regeneration. The experimental results showed that the ACMI/PTi scaffold had suitable mechanical properties, sustained drug release function, and excellent biocompatibility. The released icariin and mineralized collagen (MC) synergistically promoted angiogenesis and osteogenic differentiation in vitro. After implantation into a rabbit radius defect, the composite scaffold showed a satisfactory effect in promoting bone repair. Therefore, this composite dual-functional scaffold could meet the requirements of bone defect treatment and provide a promising strategy for the repair of large segmental bone defects in clinic.

Active components and mechanisms of total flavonoids from Rhizoma Drynariae in enhancing cranial bone regeneration: An investigation employing serum pharmacochemistry and network pharmacology approaches

ETHNOPHARMACOLOGICAL RELEVANCE

Rhizoma Drynariae, as the dried rhizome of Drynaria fortunei (Kunze ex Mett.) J. Sm., is a traditional Chinese medicine for treating the injury and bone broken of falling and beating. Total flavonoids is considered as the major and effective compounds for the therapeutic efficacy of Rhizoma Drynariae.

AIM OF THE STUDY

To explore the effect of total flavonoids from Rhizoma Drynariae (TFRD) on bone regeneration and the underlying mechanisms.

MATERIALS AND METHODS

The effect of TFRD in various doses on bone reconstruction in cranial bone defect rats was explored in vivo. The active ingredients in TFRD-medicated serum were characterized by serum pharmacochemistry and integrated by network pharmacology analysis and target prediction. To elucidate the underlying mechanism of TFRD on bone regeneration, experimental validation in vitro was executed to assess the influence of different concentrations of TFRD-medicated serum on osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs).

RESULTS

Micro-CT, histological examination, immunohistochemical analysis, and ELSA demonstrated that administration of TFRD could promote bone reconstruction in a rat cranial defect model. We identified 27 active components of TFRD using ultra-high-performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS). Results from CCK8, ALP, and Alizarin Red S staining revealed that TFRD-medicated serum notably enhanced BMSCs proliferation and osteogenic differentiation. qRT-PCR and Western blot harvested results consistent with those predicted by network pharmacology, providing further evidence that TFRD activated the TGF-β signaling pathway to benefit bone regeneration.

CONCLUSION

The active components of TFRD modulate the TGF-β signaling pathway to facilitate osteogenesis, thereby repairing cranial bone defects.

Explorating the mechanism of Epimedii folium-Rhizoma drynariae herbal pair promoted bone defects healing through network pharmacology and experimental studies

ETHNOPHARMACOLOGICAL RELEVANCE

Bone defects are difficult to treat and have a high incidence of nonunion. The Epimedii folium-Rhizoma drynariae herbal pair (EDP) is a traditional Chinese medicine (TCM) used for treating bone diseases. However, the mechanisms by which EDP promotes osteogenesis or bone formation remain largely unclear.

AIM OF THE STUDY

This study aimed to investigate the mechanism of EDP promoted bone formation in bone defects using network pharmacology and experiments.

MATERIALS AND METHODS

The chemical components of EDP were analyzed by UHPLC-MS. The hub target and pathway enrichment analysis was conducted using molecular docking or network pharmacology. The pharmacological actions of EDP were determined by μCT and histopathology examination using a bone defect rat model. The effects of EDP on the mRNA expression of Bmp2, Smad2/5, Runx2, and Alp genes were measured by RT-PCR, while changes in the protein expressions of BMP2, COL1A1, SPP1, ALP, and RUNX2in the tibia tissues of the rats in response to EDP were analyzed by immunohistochemical staining or Western blot. We also performed cell viability assays, Alizarin Red and ALP staining assays, and RT-PCR to better understand how EDP affected osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs).

RESULTS

Identified 14 key compounds and 47 hub targets of EDP that may be involved in promoting osteogenesis to repair bone defects. And the BMP/Smad/Runx2 pathway was likely the key pathway through which EDP promoted bone defects repairing. The results of in vivo rat experiments indicated that EDP effectively promoted tibia repair in the model rats and activated the BMP/Smad/Runx2 pathway in the tibia tissue, with upregulating Bmp2, Bmpr1α, Smad2/5, Runx2, and Alp genes, and increased the protein expression of BMP2, COL1A1, RUNX2, and ALP. In vitro, EDP was found to increase the proliferation, differentiation, and mineralization in BMSCs- and also up-regulated the expression of key genes in the BMP/Smad/Runx2 pathway.

CONCLUSION

This study highlighted the ability of EDP to promote the osteogenic differentiation to enable bone repair by activating the BMP/Smad/Runx2 pathway.

[Translated article] Mechanical resistance of polylactic acid bone matrices developed by 3D printing for the reconstruction of bone defects

INTRODUCTION

Bone defects are one of the main limitations in orthopaedic surgery and traumatology. For this reason, multiple bone replacement systems have been developed, either by prosthetic implant or by substitution with osteoforming substances, whose limitations are their survival and lack of structurality, respectively. The objective of this work is the generation of a new material for the creation of biologically active structures that have sufficient tensile strength to maintain the structure during remodelling.

MATERIAL AND METHODS

A new filament based on the fusion of natural polylactide acid (PLA) powder was designed for the generation of pieces by means of fused deposition modelling (FDM) on which to carry out tensile mechanical tests of osteosynthesis material. A total of 13 groups with different cortical thickness, filling and layer height were carried out, with 10 tensile tests in each group, defining the tensile breaking limit for each group. The regression lines for each group and their mechanical resistance to traction on the filament used were determined.

RESULTS

The filament ratio per contact surface unit with the osteosynthesis used was the main determinant of the mechanical resistance to traction, either at the expense of the increase in cortical thickness or by the increase in the percentage of cancellous bone filling. Layer height had a minor effect on tensile strength. The regression value was high for cortical thickness and cancellous filling, being elements with a predictable biomechanical behaviour.

CONCLUSIONS

The new methodology allows the creation of personalised neutral and implantable PLA bone matrices for the reconstruction of large bone defects by means of 3D printing by FDM with a mechanical resistance to traction greater than that of current biological support structures.

Mechanical force increases tooth movement and promotes remodeling of alveolar bone defects augmented with bovine bone mineral

BACKGROUND

Orthodontic tooth movement (OTM) in a region containing alveolar bone defects with insufficient height and width is hard to achieve. Bovine bone mineral (Bio-Oss) is available to restore the alveolar defect; however, whether the region augmented with a bovine bone mineral graft (BG) is feasible for OTM, and the mechanisms by which macrophages remodel the BG material, is uncertain under the mechanical force induced by OTM.

MATERIAL AND METHODS

Rats were divided into three groups: OTM (O), OTM + BG material (O + B), and Control (C). First molars were extracted to create bone defects in the O and O + B groups with bovine bone mineral grafting in the latter. Second molars received OTM towards the bone defects in both groups. After 28 days, maxillae were analyzed using microfocus-computed tomography (μCT) and scanning-electron-microscopy (SEM); and macrophages (M1/M2) were stained using immunofluorescence. THP-1 cell-induced macrophages were cultured under mechanical force (F), BG material (B), or both (F + B). Phagocytosis-related signaling molecules (cAMP/PKA/RAC1) were analyzed, and conditioned media was analyzed for MMP-9 and cytokines (IL-1β, IL-4).

RESULTS

Our study demonstrated that alveolar defects grafted with BG materials are feasible for OTM, with significantly increased OTM distance, bone volume, and trabecular thickness in this region. SEM observation revealed that the grafts served as a scaffold for cells to migrate and remodel the BG materials in the defect during OTM. Moreover, the population of M2 macrophages increased markedly both in vivo and in cell culture, with enhanced phagocytosis via the cAMP/PKA/RAC1 pathway in response to mechanical force in combination with BG particles. By contrast, M1 macrophage populations were decreased under the same circumstances. In addition, M2 macrophage polarization was also indicated by elevated IL-4 levels, reduced IL-1β levels, and less active MMP-9 in cell culture.

CONCLUSION

This study explored the mechanisms of mechanical force-induced alveolar bone remodeling with bovine bone mineral grafts during OTM. The results might provide molecular insights into the related clinical problems of whether we can move teeth into the grafted materials; and how these materials become biologically remodeled and degraded under mechanical force.

Combination effect of Chinese kidney-tonifying granules and platelet-rich plasma gels on enhancing bone healing in rat models with femur defects

BACKGROUND

The traditional Chinese kidney-tonifying granules, known as Bushen Zhongyao Keli (BSZYKL), have been found to stimulate calcium salt deposition, enhance bone formation, and foster bone growth within the bone matrix at sites of bone defects. On the other hand, platelet-rich plasma (PRP) is enriched with various growth factors capable of facilitating the repair of bone defects and enhancing bone strength following fractures. This study is dedicated to investigating the combined efficacy of BSZYKL and PRP gel (PRP-G) in the treatment of bone defects.

METHODS

We established a femur defect model in male Sprague-Dawley (SD) rats and filled the defect areas with autologous coccygeal bone and PRP-G. For 8 consecutive weeks, those rats were given with intragastric administration of BSZYKL. Biomechanical characteristics of the femur were assessed 28 days after intramuscular administration. On day 56, bone formation was examined using X-ray, micro-CT, and transmission electron microscopy. Additionally, we analyzed the expression of bone formation markers, Runx2 and Osterix, in femur tissues through qPCR, Western blotting, and immunohistochemistry.

RESULTS

Rats receiving the combined treatment of BSZYKL and PRP-G exhibited drastically enhanced femoral peak torsion, failure angle, energy absorption capacity, and torsional stiffness as compared to control group. This combination therapy also led to marked improvements in bone volume, mass, and microarchitecture, accompanied by elevated expressions of Runx2 and Osterix when compared to control group. Notably, the synergistic effects of BSZYKL and PRP-G in treating bone defects surpassed the effects of either treatment alone.

CONCLUSIONS

These findings revealed the potential of BSZYKL in combination with PRP-G in improving bone defects.

The effect of periapical bone defects on stress distribution in teeth with periapical periodontitis: a finite element analysis

BACKGROUND

Apical periodontitis directly affects the stress state of the affected tooth owing to the destruction of the periapical bone. Understanding the mechanical of periapical bone defects/tooth is clinically meaningful. In this study, we evaluate the effect of periapical bone defects on the stress distribution in teeth with periapical periodontitis using finite element analysis.

METHODS

Finite element models of normal mandibular second premolars and those with periapical bone defects (spherical defects with diameters of 5, 10, 15, and 20 mm) were created using a digital model design software. The edges of the mandible were fixed and the masticatory cycle was simplified as oblique loading (a 400 N force loaded obliquely at 45° to the long axis of the tooth body) to simulate the tooth stress state in occlusion and analyze the von Mises stress distribution and tooth displacement distribution in each model.

RESULTS

Overall analysis of the models: Compared to that in the normal model, the maximum von Mises stresses in all the different periapical bone defect size models were slightly lower. In contrast, the maximum tooth displacement in the periapical bone defect model increased as the size of the periapical bone defect increased (2.11-120.1% of increase). Internal analysis of tooth: As the size of the periapical bone defect increased, the maximum von Mises stress in the coronal cervix of the tooth gradually increased (2.23-37.22% of increase). while the von Mises stress in the root apical region of the tooth showed a decreasing trend (41.48-99.70% of decrease). The maximum tooth displacement in all parts of the tooth showed an increasing trend as the size of the periapical bone defect increased.

CONCLUSIONS

The presence of periapical bone defects was found to significantly affect the biomechanical response of the tooth, the effects of which became more pronounced as the size of the bone defect increased.

Advances in the Application of Bone Transport Techniques in the Treatment of Bone Nonunion and Bone Defects

Bone nonunion and bone defects frequently occur following high-energy open injuries or debridement surgeries, presenting complex challenges to treatment and significantly affecting patients' quality of life. At present, there are three primary treatment options available for addressing bone nonunion and bone defects: vascularized bone grafts, the Masquelet technique, and the Ilizarov technique. The Ilizarov technique, also known as distraction osteogenesis, is widely favored by orthopedic surgeons because of several advantages, including minimal soft tissue requirements, low infection risk, and short consolidation time. However, in recent years, the application of the Masquelet technique has resulted in novel treatment methods for managing post-traumatic bone infections when bone defects are present. Although these new techniques do not constitute a panacea, they continue to be the most commonly employed options for treating complex large bone nonunion and bone defects. This review evaluates the currently available research on the Ilizarov and Masquelet bone transport techniques applied at various anatomical sites. Additionally, it explores treatment durations and associated complications to establish a theoretical foundation that can guide clinical treatment decisions and surgical procedures for the management of bone nonunion and bone defects.

Excellent mid- to long-term survival of tantalum metal cones in a case series of revision knee arthroplasty with severe bony defects

PURPOSE

Severe metaphyseal bone defects remain a challenge and represent a growing problem in revision total knee arthroplasty (RTKA). The purpose of this study was to examine the survival of first-generation tantalum metal cones (TMC) and to assess clinical and radiographic data obtained from mid- to long-term follow-ups (FU) after RTKA with severe bony defects.

METHODS

This retrospective case series included 100 consecutive patients of the same centre, who underwent RTKA surgery with TMC for tibia and/or femur bone defects between January 2011 and December 2015. Fourteen patients had died and six were lost for FU, leaving a total of eighty patients (one hundred and twelve TMC) for final evaluation. Clinical parameters including the Knee Society Score (KSS), visual analogue scale (VAS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and range of motion (ROM) were determined preoperatively based on the patients' medical charts, and assessed again during the final FU after an average of 6.1 (5-9) years postoperative. Standardised postoperative X-rays were analysed during the final FU visit for osseointegration of the cones, and any signs of implant loosening were assessed with the modified Knee Society Radiographic review criteria. Perioperative and postoperative complications, reoperations, as well as implant and cone re-revisions were analysed. Survivorship analysis was performed with (a) cone-related revision for any reason and (b) implant component revision for any reason.

RESULTS

Previous RTKA had to be performed due to 64 (80%) aseptic and 16 (20%) septic failures. At the final FU, 75 (94%) tibia and 76 (95%) femur TMCs and implants were clinically stable. One patient experienced loosening of cones and implants at the femur and tibia but denied re-revision surgery. There were eight (10%) reoperations including two early wound healing problems, two inlay changes, two periprosthetic fractures, one debridement, antibiotics and implant retention (DAIR), and one secondary patella replacement. The six (7.5%) re-revisions included two aseptic loosening's of the opposite implant without TMC, one arthrodesis for recurrent instability, and three deep infections managed by two two-stage exchanges, and one amputation for persistent infection. At re-revision, all TMC cones were osteointegrated without signs of loosening. The determined clinical parameters showed significant (p < 0.001) postoperative improvement, and objective KSS was rated as excellent in 51%, and as good in 22% of patients at the final FU. The estimated 8-year Kaplan-Meier survival was 95% for TMC and 92.5% for implant components.

CONCLUSION

Tantalum metal cones (TMC) demonstrate a secure fixation for treatment of severe femoral and tibial metaphyseal bone defects during RTKA. This fixation concept showed excellent mid- to long-term clinical and radiographic outcomes with promising 8-year survival rates for cones and implant components.

LEVEL OF EVIDENCE

Retrospective cohort study, Level IV.

Significance of bone morphology and quality on the primary stability of orthodontic mini-implants: in vitro comparison between human bone substitute and artificial bone

AIM

This study evaluated artificial bone models against a human bone substitute to assess the primary stability of orthodontic mini-implants (OMIs) at varying implant sites with different morphologies and qualities.

MATERIALS AND METHODS

A total of 1200 OMI placements of four types were inserted into four artificial bone models of different density (D1, D2, D3, D4) and into a human bone substitute (HB). The implants varied in diameter (2.0 and 2.3 mm) and length (9 and 11 mm). Each specimen had four implant sites: no defect, one-wall defect, three-wall defect, and circular defect. The implant stability quotient (ISQ) values were measured using resonance frequency analysis (RFA) and insertion placement torque values (IPT) were assessed for primary stability. Correlation analysis was performed to evaluate the different models.

RESULTS

The highest IPT value was registered for the 2.0 mm × 11 mm implant inserted into D1 with no defect (37.53 ± 3.02 Ncm). The lowest ISQ value was measured for the 2.3 mm × 9 mm OMI inserted into D3 with a circular defect (12.33 ± 5.88) and the highest for the 2.3 mm × 9 mm implant inserted into HB with no defect (63.23 ± 2.57). A strong correlation (r = 0.64) for IPT values and a very strong correlation (r = 0.8) for ISQ values was found between D2 and HB.

CONCLUSION

Bone defects and bone quality affected the primary stability of implants in terms of ISQ and IPT values. Results for bone model D2 correlated very well with the HB substitution material.

Design and manufacturing of biomimetic scaffolds for bone repair inspired by bone trabeculae

Porous scaffold (PorS) implants, particularly those that mimic the structural features of natural cancellous bone (NCanB), are increasingly essential for the treatment of large-area bone defects. However, the mechanical properties of NCanB-based bionic bone scaffold (BioS) and its performance as a bone repair material have not been fully explored. This study investigates the effect of bionic structure parameters on the mechanical properties and bone reconstruction performance of BioS. Using laser powder bed fusion (L-PBF) technology, different BioS with various structural parameters were created and evaluated using Micro-CT, compression testing, Finite Element (FE) Simulation, and computational fluid dynamics (CFD), and compared to commonly used clinical PorS. Assess the capacity of the BioS scaffold to support and enhance bone reconstruction following implantation through the evaluation of its mechanical properties, permeability, and fluid shear stress (FSS). BioS-85-90 and BioS-80-50 showed suitable mechanical properties, performed well in FE simulation of implantation, demonstrated outstanding abilities for osteoinductive ingrowth and bone tissue differentiation, and proved to be reliable materials for the reconstruction of bone defects. Therefore, BioS shows significant potential for clinical application as a bone reconstruction material, providing a solid foundation for the integration of tissue engineering and bionic design.

Injectable and Cell-Laden Hydrogel in the Contained Bone Defect Animal Model: A Systematic Review

BACKGROUND

Due to its high water content and biomimetic properties simulating extracellular matrix (ECM), hydrogels have been used as preferred cell culture and delivery systems. Similarly, cell-loaded hydrogels can be easily injected into target areas in a minimally invasive manner, minimizing surgical trauma, adapting to irregular shaped defects, and benefiting patients. In this study, we systematically reviewed multiple studies on hydrogel-based bone defect research and briefly summarized the progress of injectable and cell-loaded hydrogels in bone defect repair.

METHODS

A systematic search was conducted in the PubMed and Web of Science databases using selected search terms.

RESULTS

Initially, 185 articles were retrieved from the databases. After full-text screening based on inclusion and exclusion criteria, 26 articles were included in this systematic review. Data collected from each study included culture model, seed cell type and origin, cell concentration, scaffold material, scaffold shape, experimental animal and site, bioactive agents, and binding method. This injectable and cell-loaded hydrogel shows certain feasibility in bone tissue engineering applications.

CONCLUSION

Injectable and cell-loaded hydrogels have been widely applied in bone tissue engineering research. The future direction of bone tissue engineering for bone defect treatment involves the use of new hydrogel materials and biochemical stimulation.

A multifunctional polydopamine/genipin/alendronate nanoparticle licences fibrin hydrogels osteoinductive and immunomodulatory potencies for repairing bone defects

Here, we fabricated a hybrid nanoparticle composed of polydopamine nanoparticles (pNPs), alendronate (Al) and genipin (GP) for cranial bone defect repair. Al was crosslinked into pNPs via GP (Al@pNPs), after which hybrid nanoparticles were obtained. By embedding these Al@pNPs into the fibrin hydrogels, a multifunctional bone repair scaffold was fabricated (Al@pNPs/Fg). The Al@pNPs/Fg exhibited three synergistic effects on the bone microenvironment: i) enhanced ectomesenchymal stem cell (EMSC) osteogenic differentiation by activating the piezo 1 channel; ii) inhibited the formation and function of osteoclasts related to the NF-κB signaling pathways; and iii) promoted M2 polarization and anti-inflammatory factor expression under normal and simulated inflammatory conditions. Al@pNPs/Fg ultimately promoted cranial bone defect regeneration in an SD rat model. This simple and low-cost technology provides a new approach to constructing an efficient delivery system and has desirable biological properties, providing a tissue-committed niche for the repair of bone defects.

GelMA-based bioactive hydrogel scaffolds with multiple bone defect repair functions: therapeutic strategies and recent advances

Currently, the clinical treatment of critical bone defects attributed to various causes remains a great challenge, and repairing these defects with synthetic bone substitutes is the most common strategy. In general, tissue engineering materials that mimic the structural, mechanical and biological properties of natural bone have been extensively applied to fill bone defects and promote in situ bone regeneration. Hydrogels with extracellular matrix (ECM)-like properties are common tissue engineering materials, among which methacrylate-based gelatin (GelMA) hydrogels are widely used because of their tunable mechanical properties, excellent photocrosslinking capability and good biocompatibility. Owing to their lack of osteogenic activity, however, GelMA hydrogels are combined with other types of materials with osteogenic activities to improve the osteogenic capability of the current composites. There are three main aspects to consider when enhancing the bone regenerative performance of composite materials: osteoconductivity, vascularization and osteoinduction. Bioceramics, bioglass, biomimetic scaffolds, inorganic ions, bionic periosteum, growth factors and two-dimensional (2D) nanomaterials have been applied in various combinations to achieve enhanced osteogenic and bone regeneration activities. Three-dimensional (3D)-bioprinted scaffolds are a popular research topic in bone tissue engineering (BTE), and printed and customized scaffolds are suitable for restoring large irregular bone defects due to their shape and structural tunability, enhanced mechanical properties, and good biocompatibility. Herein, the recent progress in research on GelMA-based composite hydrogel scaffolds as multifunctional platforms for restoring critical bone defects in plastic or orthopedic clinics is systematically reviewed and summarized. These strategies pave the way for the design of biomimetic bone substitutes for effective bone reconstruction with good biosafety. This review provides novel insights into the development and current trends of research on GelMA-based hydrogels as effective bone tissue engineering (BTE) scaffolds for correcting bone defects, and these contents are summarized and emphasized from various perspectives (osteoconductivity, vascularization, osteoinduction and 3D-bioprinting). In addition, advantages and deficiencies of GelMA-based bone substitutes used for bone regeneration are put forward, and corresponding improvement measures are presented prior to their clinical application in near future (created with BioRender.com).

Endoplasmic reticulum stress: a novel targeted approach to repair bone defects by regulating osteogenesis and angiogenesis

Bone regeneration therapy is clinically important, and targeted regulation of endoplasmic reticulum (ER) stress is important in regenerative medicine. The processing of proteins in the ER controls cell fate. The accumulation of misfolded and unfolded proteins occurs in pathological states, triggering ER stress. ER stress restores homeostasis through three main mechanisms, including protein kinase-R-like ER kinase (PERK), inositol-requiring enzyme 1ɑ (IRE1ɑ) and activating transcription factor 6 (ATF6), collectively known as the unfolded protein response (UPR). However, the UPR has both adaptive and apoptotic effects. Modulation of ER stress has therapeutic potential for numerous diseases. Repair of bone defects involves both angiogenesis and bone regeneration. Here, we review the effects of ER stress on osteogenesis and angiogenesis, with emphasis on ER stress under high glucose (HG) and inflammatory conditions, and the use of ER stress inducers or inhibitors to regulate osteogenesis and angiogenesis. In addition, we highlight the ability for exosomes to regulate ER stress. Recent advances in the regulation of ER stress mediated osteogenesis and angiogenesis suggest novel therapeutic options for bone defects.

Antimicrobial and Biodegradable 3D Printed Scaffolds for Orthopedic Infections

In bone tissue engineering, the performance of scaffolds underpins the success of the healing of bone. Microbial infection is the most challenging issue for orthopedists. The application of scaffolds for healing bone defects is prone to microbial infection. To address this challenge, scaffolds with a desirable shape and significant mechanical, physical, and biological characteristics are crucial. 3D printing of antibacterial scaffolds with suitable mechanical strength and excellent biocompatibility is an appealing strategy to surmount issues of microbial infection. The spectacular progress in developing antimicrobial scaffolds, along with beneficial mechanical and biological properties, has sparked further research for possible clinical applications. Herein, the significance of antibacterial scaffolds designed by 3D, 4D, and 5D printing technologies for bone tissue engineering is critically investigated. Materials such as antibiotics, polymers, peptides, graphene, metals/ceramics/glass, and antibacterial coatings are used to impart the antimicrobial features for the 3D scaffolds. Polymeric or metallic biodegradable and antibacterial 3D-printed scaffolds in orthopedics disclose exceptional mechanical and degradation behavior, biocompatibility, osteogenesis, and long-term antibacterial efficiency. The commercialization aspect of antibacterial 3D-printed scaffolds and technical challenges are also discussed briefly. Finally, the discussion on the unmet demands and prevailing challenges for ideal scaffold materials for fighting against bone infections is included along with a highlight of emerging strategies in this field.

A review of the Masquelet technique in the treatment of lower limb critical-size bone defects

The need for bone tissue to heal effectively is paramount given its role in the mechanical support of tissues. Bone has a very good natural healing potential in comparison with most other tissue types, largely regenerating to its pre-injury state in the vast majority of cases. Certain factors such as high energy trauma, tumour resection, revision surgery, developmental deformities and infection can lead to the formation of bone defects, where the intrinsic healing potential of bone is diminished owing to bone loss. Various approaches to resolving bone defects exist in current practice, each with their respective benefits and drawbacks. These include bone grafting, free tissue transfer, Ilizarov bone transport and the Masquelet induced membrane technique. This review focuses on evaluating the Masquelet technique, discussing its method and underlying mechanisms, the effectiveness of certain modifications, and its potential future directions.

Complications associated with single-level bone transport for the treatment of tibial bone defects caused by fracture-related infection

BACKGROUND

The purpose of this study was to report the outcomes of single-level bone transport with a unilateral external fixator for treatment of proximal, intermediate and distal tibial bone defects caused by fracture-related infection (FRI) and compare their complications.

METHODS

The clinical records and consecutive X-ray photographs of patients with tibial bone defects treated by single-level bone transport using a unilateral external fixator (Orthofix Limb Reconstruction System) were analyzed retrospectively, from January 2012 to December 2018. Patients were divided into the proximal group (P, n = 19), intermediate group (I, n = 25), and distal group (D, n = 18) according to the location of the tibial bone defect. The Association for the Study and Application of the Method of Ilizarov (ASAMI) standard was applied to assess the bone and functional outcomes and postoperative complications evaluated by the Paley classification.

RESULTS

A total of 62 participants were included in this study, with a median age of 36 ± 7.14 years. Sixty patients with tibial bone defects caused by FRI were successfully treated by single-level bone transport using a unilateral external fixator, with a mean bone union time (BUT) of 7.3 ± 1.71 months. According to the ASAMI criteria, there were statistical differences in bone and function results between the three groups (P vs. I vs. D, P < 0.001). The excellent and good rate of bone result in the intermediate group was higher than the other (P vs. I vs. D, 73.6% vs. 84% vs. 66.7%), and the excellent and good rate of function result in the proximal group was the highest (P vs. I vs. D, 84.2% vs. 80% vs. 73.3%). Complications were observed in 29 out of 62 patients (46.7%), with pin tract infection being the most common (14.8%), followed by axial deviation (14.8%), muscle contractures (12.7%), joint stiffness (12.7%), and soft tissue incarceration (12.7%). Other complications included delayed consolidation (12.7%), delayed union (6.3%), nonunion (4.2%), and neurological injury (8.5%). Two patients (3.2%) required below-knee amputation due to uncontrollable infection and previous surgery failure.

CONCLUSIONS

Pin tract infection was the most common complication in tibial bone transport using an external fixator. Complications of distal tibial bone transport are more severe and occur at a higher rate than in other parts. Axial deviation mostly occurred in the intermediate tibial bone transport.

Incorporation of synthetic water-soluble curcumin polymeric drug within calcium phosphate cements for bone defect repairing

Modified macroporous structures and active osteogenic substances are necessary to overcome the limited bone regeneration capacity and low degradability of self-curing calcium phosphate cement (CPC). Curcumin (CUR), which possesses strong osteogenic activity and poor aqueous solubility/bioavailability, esterifies the side chains in hyaluronic acid (HA) to form a water-soluble CUR-HA macromolecule. In this study, we incorporated the CUR-HA and glucose microparticles (GMPs) into the CPC powder to fabricate the CUR-HA/GMP/CPC composite, which not only retained the good injectability and mechanical strength of bone cements, but also significantly increased the cement porosity and sustained release property of CUR-HA in vitro. CUR-HA incorporation greatly improved the differentiation ability of bone marrow mesenchymal stem cells (BMSCs) to osteoblasts by activating the RUNX family transcription factor 2/fibroblast growth factor 18 (RUNX2/FGF18) signaling pathway, increasing the expression of osteocalcin and enhancing the alkaline phosphatase activity. In addition, in vivo implantation of CUR-HA/GMP/CPC into femoral condyle defects dramatically accelerated the degradation rate of cement and boosted local vascularization and osteopontin protein expression, and consequently promoted rapid bone regeneration. Therefore, macroporous CPC based composite cement with CUR-HA shows a remarkable ability to repair bone defects and is a promising translational application of modified CPC in clinical practice.

Repair of critical-sized rat cranial defects with RADA16-W9 self-assembled peptide hydrogel

Bone defects are common in orthopaedics and there is an urgent need to explore effective bone repair materials with osteoinductive activity. Peptide self-assembled nanomaterials have a fibrous structure like that of the extracellular matrix and are ideal bionic scaffold materials. In this study, a short peptide WP9QY (W9) with strong osteoinductive effect was tagged to a self-assembled peptide RADA16 molecule through solid phase synthesis to design a RADA16-W9 peptide gel scaffold. A rat cranial defect was used as a research model to explore the effect of this peptide material on the repair of bone defects in vivo. The structure characteristic of the functional self-assembling peptide nanofiber hydrogel scaffold RADA16-W9 was evaluated by atomic force microscopy (AFM). Then adipose stem cells (ASCs) were isolated from Sprague-Dawley (SD) rat and cultured. the cellular compatibility of scaffold was evaluated through Live/Dead assay. Furthermore, we explore the effects of hydrogels in vivo with the critical-sized mouse calvarial defect model. Micro-CT analysis showed that the RADA16-W9 group had higher levels of bone volume/total volume (BV/TV) (P < 0.05)，Trabecular number(TB.N) (P < 0.05)，bone mineral density (BMD)(P < 0.05) and trabecular thickness (Tb. Th) (P < 0.05) compared with the RADA16 and PBS groups. Hematoxylin and eosin (H&E) staining showed that RADA16-W9 group had the highest bone regeneration level. Histochemical staining showed significantly higher expression levels of osteogenic factors such as alkaline phosphatase (ALP) and osteocalcin (OCN) in the RADA16-W9 group than in the other two groups (P < 0.05). Reverse transcription polymerase chain reaction (RT-PCR) quantification showed higher mRNA expression levels of osteogenic-related genes ALP, Runt-related transcription factor 2(Runx2), OCN, Osteopontin (OPN) in the RADA16-W9 group than in the RADA16 and PBS groups (P < 0.05). The live/dead staining results showed that RADA16-W9 is not toxic to rASCs and has good biocompatibility. In vivo experiments show that it accelerates the process of bone reconstruction, significantly promoting bone regeneration and can be used to develop a molecular drug for bone defect repair.

FLIM imaging revealed spontaneous osteogenic differentiation of stem cells on gradient pore size tissue-engineered constructs

BACKGROUND

There is an urgent clinical need for targeted strategies aimed at the treatment of bone defects resulting from fractures, infections or tumors. 3D scaffolds represent an alternative to allogeneic MSC transplantation, due to their mimicry of the cell niche and the preservation of tissue structure. The actual structure of the scaffold itself can affect both effective cell adhesion and its osteoinductive properties. Currently, the effects of the structural heterogeneity of scaffolds on the behavior of cells and tissues at the site of damage have not been extensively studied.

METHODS

Both homogeneous and heterogeneous scaffolds were generated from poly(L-lactic acid) methacrylated in supercritical carbon dioxide medium and were fabricated by two-photon polymerization. The homogeneous scaffolds consist of three layers of cylinders of the same diameter, whereas the heterogeneous (gradient pore sizes) scaffolds contain the middle layer of cylinders of increased diameter, imitating the native structure of spongy bone. To evaluate the osteoinductive properties of both types of scaffold, we performed in vitro and in vivo experiments. Multiphoton microscopy with fluorescence lifetime imaging microscopy was used for determining the metabolic states of MSCs, as a sensitive marker of cell differentiation. The results obtained from this approach were verified using standard markers of osteogenic differentiation and based on data from morphological analysis.

RESULTS

The heterogeneous scaffolds showed improved osteoinductive properties, accelerated the metabolic rearrangements associated with osteogenic differentiation, and enhanced the efficiency of bone tissue recovery, thereby providing for both the development of appropriate morphology and mineralization.

CONCLUSIONS

The authors suggest that the heterogeneous tissue constructs are a promising tool for the restoration of bone defects. And, furthermore, that our results demonstrate that the use of label-free bioimaging methods can be considered as an effective approach for intravital assessment of the efficiency of differentiation of MSCs on scaffolds.

TGM2 accelerates migration and differentiation of BMSCs by activating Wnt/β-catenin signaling

BACKGROUND

Transglutaminase 2 (TGM2) is a gene previously reported to be associated with the differentiation of bone marrow mesenchymal stem cells (BMSCs). The study was developed to reveal the impact of TGM2 on the migration and differentiation of BMSCs.

METHODS

Cells were isolated from bone marrow of mice and then the surface antigens were identified by flow cytometry. Wound healing assays were conducted to assess the migratory ability of BMSCs. The mRNA levels of TGM2 and osteoblast-associated genes (ALP, OCN, and RUNX2) were subjected to RT-qPCR analysis, and protein levels of these genes as well as β-catenin were quantitated by western blotting. Alizarin red staining was conducted for detection of osteogenic ability. The activation of Wnt signaling was assessed by TOP/FOP flash assays.

RESULTS

Surface antigens were positively identified in MSCs, indicating good multidirectional differentiation ability of cells. TGM2 silencing suppressed BMSC migration while weakening mRNA and protein levels of osteoblast-associated genes. While TGM2 overexpression exerts the opposite impact on cell migration and expression levels of osteoblast-associated genes. Additionally, overexpressed TGM2 promotes the mineralization of BMSCs according to results of Alizarin red staining. Moreover, TGM2 activated the Wnt/β-catenin signaling, and DKK1 (an inhibitor of Wnt signaling) reversed the promoting influence of TGM2 on cell migration and differentiation.

CONCLUSION

TGM2 promotes the migration and differentiation of BMSCs via activation of the Wnt/β-catenin signaling.

Development of a novel regenerative therapy for malignant bone tumors using an autograft containing tumor inactivated by high hydrostatic pressurization (HHP)

Surgical resection of malignant bone tumors leads to significant defects in the normal surrounding tissues that should be reconstructed to avoid amputation. Our research aimed to inactivate osteosarcoma (OS)-affected bone to obtain autologous bone grafts for bone defect reconstruction using a novel therapy called high hydrostatic pressurization (HHP) therapy. The key points are complete tumor death and preservation of the non-denatured native extracellular matrix (ECM) and bone tissue by HHP. Previously, we found that HHP at 200 MPa for 10 min can completely inactivate cells in normal skin and skin tumors, including malignant melanoma and squamous cell carcinoma while maintaining their original biochemical properties and biological components. Based on our previous research, this study used HHP at 200 MPa for 10 min to eradicate OS. We prepared an OS cell line (LM8), pressurized it at 200 MPa for 10 min, and confirmed its inactivation through morphological observation, WST-8 assay, and live/dead assay. We then injected OS cells with or without HHP into the bone marrow of the murine tibia, after which we implanted tumor tissues with or without HHP into the anterior surface of the tibia. After HHP, OS cells did not proliferate and were assessed using a live/dead assay. The pressurized cells and tumors did not grow after implantation. The pressurized bone was well prepared as tumor-free autologous bone tissues, resulting in the complete eradication of OS. This straightforward and short-pressing treatment was proven to process the tumor-affected bone to make a transplantable and tumor-free autologous bone substitute.

Bifocal versus trifocal bone transport for the management of tibial bone defects caused by fracture-related infection: a meta-analysis

BACKGROUND

The purpose of this meta-analysis was to compare the efficacy and outcomes of bifocal bone transport (BFT) and trifocal bone transport (TFT) for the treatment of tibial bone defects caused by fracture-related infection (FRI).

METHODS

The literature searches of Cochrane Library, Embase, Google Scholar databases, PubMed/Medline, and Web of Science for literature published up to September 20, 2022, were performed. The quality of the included studies was evaluated according to the MINORS scale. Patients were divided into the BFT group and the TFT group, depending on the site of the osteotomy. The demographic data, defect size (DS), external fixation time (EFT), external fixation index (EFI), bone and functional results, complications, and autologous bone grafting (ABG) were extracted and analyzed using the Review Manager software (version 5.3).

RESULTS

Five studies included 484 patients with tibial bone defects treated by bone transport investigated in this meta-analysis, with a mean bone defect of 9.3 cm. There were statistical differences in DS (MD =  - 2.38, 95% CI - 3.45 to - 1.32, P < 0.0001), EFT (MD = 103.44, 95% CI 60.11 to 146.77, P < 0.00001), and EFI (MD = 26.02, 95% CI 14.38 to 37.65, P < 0.00001) between BFT group and TFT group. There was no statistical difference in bone results (RR = 0.98, 95% CI 0.91 to 1.06, P = 0.67), functional results (RR = 0.94, 95% CI 0.82 to 1.07, P = 0.37), complications (OR = 1.57, 95% CI 0.59 to 4.14, P = 0.36), and ABG (RR = 1.2, 95% CI 0.78 to 1.84, P = 0.42) between two groups.

CONCLUSIONS

TFT was a feasible and practical method in the treatment of massive tibial bone defects caused by FRI to receive shorter EFT and satisfactory bone and functional results.

Mechanical resistance of polylactic acid bone matrices developed by 3D printing for the reconstruction of bone defects

INTRODUCTION

Bone defects are one of the main limitations in orthopedic surgery and traumatology. For this reason, multiple bone replacement systems have been developed, either by prosthetic implant or by substitution with osteoforming substances, whose limitations are their survival and lack of structurality, respectively. The objective of this work is the generation of a new material for the creation of biologically active structures that have sufficient tensile strength to maintain the structure during remodeling.

MATERIAL AND METHODS

A new filament based on the fusion of natural polylactide acid (PLA) powder was designed for the generation of pieces by means of fused deposition modeling (FDM) on which to carry out tensile mechanical tests of osteosynthesis material. A total of 13 groups with different cortical thickness, filling and layer height were carried out, with 10 tensile tests in each group, defining the tensile breaking limit for each group. The regression lines for each group and their mechanical resistance to traction on the filament used were determined.

RESULTS

The filament ratio per contact surface unit with the osteosynthesis used was the main determinant of the mechanical resistance to traction, either at the expense of the increase in cortical thickness or by the increase in the percentage of cancellous bone filling. Layer height had a minor effect on tensile strength. The regression value was high for cortical thickness and cancellous filling, being elements with a predictable biomechanical behavior.

CONCLUSIONS

The new methodology allows the creation of personalized neutral and implantable PLA bone matrices for the reconstruction of large bone defects by means of 3D printing by FDM with a mechanical resistance to traction greater than that of current biological support structures.

Outcomes of free vascularised fibular graft reconstruction in upper limb trauma-a systematic review

PURPOSE

To evaluate existing literature describing the use of free fibular flaps in upper extremity trauma and summarise flap outcomes. Secondary objectives are to evaluate patient demographics and flap characteristics.

METHODS

EMBASE, PubMed, MEDLINE and the Cochrane Database were searched for eligible studies published from 1975 to January 2019. Primary outcome measures collected were rate of union, graft survival rate, and complication rates. Patient demographics and flap characteristics were also collected. Statistical analysis was performed using SPSS software (SPSS version 25; IBM, Chicago, USA). Pooled data were presented as mean and standard deviation or median and range. Categorical variables were assessed by chi-squared test. Quality of studies were assessed using the National Institutes of Health (NIH) Quality Assessment Tool for case series studies.

RESULTS

Initial search yielded 1070 articles. A total of 25 studies (151 cases) met the inclusion criteria. Flap survival was 97% (147/151) at time of follow-up, with first union rate of 95% (142/151) and second union rate of 97% (147/151) following bone graft or further procedure. Overall complication rate was 33% (47/140). There was a statistically significant association between recipient flap site and rates of flap fracture (p = 0.049). There was no statistically significant association between flap type, evidence of infection at donor or defect site, or method of flap fixation on outcomes.

CONCLUSIONS

Vascularised fibular flaps are a safe and efficacious reconstructive option for upper limb trauma. Further research is required to enable better understanding of the impact of patient and clinical factors on flap outcome measures.

High porosity 3D printed titanium mesh allows better bone regeneration

BACKGROUND

Most patients with insufficient bone mass suffer from severe horizontal or vertical bone defects in oral implant surgery. The purpose of this study was to compare the bone regeneration effects of titanium meshes with different porosity in the treatment of bone defects.

METHODS

Nine beagle dogs were equally divided into three groups based on execution time. Three months after the extraction of the first to fourth premolars of the mandible, three bone defects were randomly made in the mandible. Bone particles and three kinds of three-dimensional (3D) printed titanium nets with different porosities (low porosity group (LP), 55%; medium porosity group (MP), 62%; and high porosity group (HP), 68%) were replanted in situ. The beagles were killed 4, 8, and 12 weeks after surgery. Formalin-fixed specimens were embedded in acrylic resin. The specimens were stained with micro-CT, basic fuchsin staining, and toluidine blue staining.

RESULTS

Micro-CT analysis showed that the trabecular thickness, trabecular number, and bone volume fraction of the HP group were higher than those of the other two groups. Moreover, the trabecular separation of the HP group decreased slightly and was lower than that of the MP and LP groups. Histological staining analysis showed that the trabecular number in the HP group was higher than in the other two groups at 8 and 12 weeks, and the bone volume fraction of the HP was higher than that in the other two groups at 12 weeks. Moreover, the trabecular thickness of the MP was higher than that of the LP group at 12 weeks and the trabecular separation was lower in the HP group at 4 and 8 weeks. The differences were statistically significant (p < 0.05).

CONCLUSION

A 3D printed titanium mesh with HP in a certain range may have more advantages than a titanium mesh with LP in repairing large bone defects.

Bone defect classifications in revision total knee arthroplasty, their reliability and utility: a systematic review

BACKGROUND

There are various classification systems described in the literature for managing bone defects in revision knee arthroplasty (RTKA). We analysed the reliability and usefulness of these classification systems.

QUESTIONS/PURPOSES

(1) To review and critique the various classification systems proposed for bone loss in RTKA. (2) Among all the proposed classifications which one is the most commonly used by surgeons to report their results. (3) What is the reliability of various bone defect classification systems for RTKA. In this review, we have assessed the studies validating those classifications with a detailed description of the limitations and the proposed modifications.

METHODS

This systematic review was conducted following PRISMA guidelines. Pubmed/Medline, CINAHL, EMBASE, Scopus, Cochrane databases and Web of Science databases were searched using multiple search terms and MeSH terms where possible. Studies meeting inclusion criteria were assessed for statistical parameters of reliability of a classification system.

RESULTS

We found 16 classification systems for bone defects in RTKA. Six studies were found evaluating a classification system with reporting their reliability parameters. Fifty-four studies were found which classified bone loss using AORI classification in their series. AORI classification is most commonly reported for classifying bone defects. Type T2B and F2B are the most common bone defects in RTKA. The average kappa value for AORI classification for femoral bone loss was 0.38 (0.27-0.50) and 0.76 (0.63-1) for tibial bone loss assessment.

CONCLUSION

None of the available classification systems is reliably established in determining the bone loss and treatment plans in RTKA. Among all, AORI classification is the most widely used system in clinical practice. The reliability of AORI Classification is fair for femoral bone loss and substantial for tibial bone loss.

Platelet-rich fibrin as a tissue engineering material in accelerate bone healing in rat bone defects: A systematic review and meta-analysis

Introduction

Various techniques for tissue engineering have been introduced to help regenerate damaged or lost bone tissue. This study aimed to see the potential implication of platelet-rich fibrin (PRF) to accelerate the bone healing process in rat bone defects.

Methods

A systematic literature search was conducted from several electronic databases on subjects looking at the use of PRF in rat bone defects and their results in bone regeneration. Specific results compared PRF vs. other methods, PRF vs. control, and PRV vs. combination PRF and other methods. Science Direct, PubMed, and Cochrane Library were the main information sources. The Cochrane Collaboration method is employed to assess the risk of bias.

Results

A total of 483 rats were used in the twelve studies, and this meta-analysis showed that the PRF vs. other methods pooled odds ratio (OR) obtained was 0.92 (95% CI 0.42-2.04; p = 0.29; I² = 18%), PRF versus control OR obtained 9.45 (95% CI 4.68-19.08; P = 0.01; I² = 0%), the combination of PRF compared to PRF alone OR obtained 0.12 (95% CI 0.03-0.41; p = 0.01; I² = 0%).

Discussion

Platelet-rich fibrin accelerates the bone healing process in rat bone defects compared to physiologically. Platelet-rich fibrin combined with other methods can stimulate rat bone defects than utilization of platelet-rich fibrin only. The small number of articles assessed may cause limitations in sensitivity tests. This study was registered in the research registry (reviewregistry1341).

Pre-operative planning and templating with 3-D printed models for complex primary and revision total hip arthroplasty

Background

Complex primary and revision THR requires comprehensive understanding of abnormal bony anatomy. Evaluation and classification of acetabular bone defects is essential to manage them appropriately. It is difficult to appreciate complex defects using conventional 2-Dimensional radiological modalities. 3D printed models can provide both visual and tactile reproduction of the bony anatomy, with potential for better pre-operative planning and making these complex surgeries more precise and accurate.

Materials and methods

Anatomical 3D models of pelvis and femur were made based on CT scans of 27 patients undergoing complex primary THR/Revision THR by FDM (Fusion Deposition Modeling) technology using Flash Forge-Dreamer 3D printer with ABS (plastic) material. Models were used for pre-operative planning and simulation of surgery. Aims of the study were to study the accuracy of 3D models in predicting the implant sizes, accuracy in evaluation of acetabular bone defects and validating the utility of 3 D models through surgeon feedback.

Results

The acetabular cup size and placement was accurate in 25 (92.6%) patients. Preoperative acetabular bone defect was accurately estimated in all the patients. There were no neurovascular complications at early and 1-year follow-up in this case series. Model realism and reliability survey response from five surgeons was graded, with average overall usefulness of 3D models of 4.86/5, average model realism was 4.9/5, average usefulness for planning was 4.74/5 and usefulness for teaching was 5/5.

Conclusion

3D models are accurate and help in assessing acetabular bone deficiencies reliably in complex and revision THR. Anatomical models help in surgical planning and simulation, enabling surgeons in predicting the correct implant sizes and importantly placement of acetabular cup and for management of bone defects. The safe trajectory of acetabular screws can be simulated and determined, thereby avoiding penetration into pelvis and neuro-vascular injuries.

Risk factors of transport gap bending deformity in the treatment of critical-size bone defect after bone transport

Background

The purpose of this study was to investigate the risk factors of transport gap bending deformity (TGBD) in the treatment of critical-size bone defect (CSBD) after the removal of the external fixator.

Methods

From January 2008 to December 2019, 178 patients with bone defects of the lower extremity caused by infection were treated by bone transport using a unilateral external fixator in our medical institution. TGBD was defined as the bone callus in the distraction area with a deviation to the force line of the femur (> 10°) or tibia (> 12°) after removal of the external fixator. The Association for the Study and Application of the Method of Ilizarov (ASAMI) standard was applied to assess the bone and functional outcomes. After the data were significant by the T-test or Pearson’s Chi-square test was analyzed, odds ratios were calculated using logistic regression tests to describe factors associated with the diagnosis of TGBD.

Results

A total of 178 patients were enrolled in the study, with a mean follow-up time of 28.6 ± 3.82 months. The positive result of the bacteria isolated test was observed in 144 cases (80.9%). The rate of excellent and good in the bone outcomes (excellent/good/fair/poor/failure, 41/108/15/14/0) was 83.7%, and 92.3% in the functional results (excellent/good/fair/poor/failure, 50/98/16/14/0) according to the ASAMI criteria. TGBD after removal of external fixator occurred in twenty-two patients (12.3%), including 6 tibias, and 16 femurs. Age > 45 years, BMI > 25 kg/m², femoral defect, diabetes, osteoporosis, glucocorticoid intake, duration of infection > 24 months, EFT > 9 months, EFI > 1.8 month/cm were associated significantly with a higher incidence of TGBD in the binary logistic regression analysis (P < 0.05). The incidence more than 50% was found in patients with femoral defect (76.1%), osteoporosis (72.7%), BMI > 25 kg/m² (69.0%), diabetes (59.5%), glucocorticoid intake (54.7%). In the multivariate logistic regression analyses, the following factors were associated independently with TGBD, including age > 45 years, BMI > 25 kg/m², femoral defect, diabetes, and osteoporosis.

Conclusions

Bone transport using a unilateral external fixator was a safe and practical method in the treatment of CSBD caused by infection. The top five risk factors of TGBD included femoral defect, BMI > 25 kg/m², duration of bone infection > 24 months, age > 45 years, and diabetes. Age > 45 years, BMI > 25 kg/m², femoral defect, osteoporosis, and diabetes were the independent risk factors. The higher incidence of TGBD may be associated with more risk factors.

Validation of a proposed radiographic bone defect classification system

OBJECTIVES

To clinically validate a recently proposed classification scheme of post-traumatic bone defects.

METHODS AND MATERIALS

Open fractures were classified utilising a newly introduced classification system. This classification system is based on plain radiographs, assessing the extent and local geometry of bone loss, including: D1 - Incomplete Defects; D2 - Minor/Sub-Critical (Complete) Defects (<2 cm); and D3 - Segmental/Critical Sized Defects (≥2 cm). Reliability was assessed among six independent assessors (three trauma orthopaedic surgeons and three orthopaedic training surgeons) using Fleiss' kappa tests. 43 open fractures from a tertiary referral trauma centre and their radiographic series were analysed.

RESULTS

Interobserver reliability testing demonstrated the proposed classification system had substantial agreement between the 6 observers, κ = 0.623 (z = 33.8), p < 0.001. Intraobserver variability showed a range of substantial to almost perfect agreement of each observer following a three-week interval between repeat assessments, κ range 0.69-0.914, p < 0.001.

CONCLUSIONS

In this representative validation cohort there was substantial agreement between observers when assessing a diverse range of bone defects following long bone open trauma, with highly reproducible assessments by both orthopaedic surgeons and trainee orthopaedic surgeons alike on an internal level. The classification scheme is based on conventional orthogonal radiographs and requires no sophisticated technology, and is therefore pragmatic and applicable to secondary, tertiary and quaternary levels of care for trauma patients.

LEVEL OF EVIDENCE

III.

Bone defect development in experimental canine peri-implantitis models: a systematic review

PURPOSE

To provide a systematic overview of preclinical research regarding bone defect formation around different implant surfaces after ligature-induced peri-implantitis models in dogs. Two focused questions were formulated: 'How much bone loss can be expected after a certain time of ligature induced peri-implantitis?' and 'Do different implant types, dog breeds and study protocols differ in their extent of bone loss?'

MATERIALS AND METHODS

A systematic literature search was conducted on four databases (MEDLINE, Web of Science, EMBASE and Scopus). Observations, which consisted of bone defects measured directly after ligature removal in canine models, were included and analysed. Two approaches were used to analyse the relatively heterogeneous studies that fulfilled the inclusion criteria. First, separate simple linear regressions were calculated for each study and implant surface, for which observations were available across multiple time points. Second, a linear mixed model was specified for the observations at 12 weeks after ligature initiation, and assessing the potential influencing factors on defect depth was explored using lasso regularisation.

RESULTS

Thirty-six studies with a total of 1082 implants were included after. Bone loss was determined at different time points, either with clinical measurements radiographically or histologically. Different implant groups [e.g. turned, sand-blasted-acid-etched (SLA), titanium-plasma-sprayed (TPS) and other rough surfaces] were assessed and described in the studies. A mean incremental defect depth increase of 0.08 mm (SD: -0.01-0.28 mm) per week was observed. After 12 weeks, the defect depths ranged between 0.7 and 5 mm. Based on the current data set, implant surface could not be statistically identified as an essential factor in defect depth after 12 weeks of ligature-induced peri-implantitis.

CONCLUSION

Expectable defect depth after a specific time of ligature-induced peri-implantitis can vary robustly. It is currently impossible to delineate apparent differences in bone loss around different implant surfaces.

3D printed scaffold design for bone defects with improved mechanical and biological properties

Bone defect treatment is still a challenge in clinics, and synthetic bone scaffolds with adequate mechanical and biological properties are highly needed. Adequate waste and nutrient exchange of the implanted scaffold with the surrounded tissue is a major concern. Moreover, the risk of mechanical instability in the defect area during regular activity increases as the defect size increases. Thus, scaffolds with better mass transportation and mechanical properties are desired. This study introduces 3D printed polymeric scaffolds with a continuous pattern, ZigZag-Spiral pattern, for bone defects treatments. This pattern has a uniform distribution of pore size, which leads to uniform distribution of wall shear stress which is crucial for uniform differentiation of cells attached to the scaffolds. The mechanical, mass transportation, and biological properties of the 3D printed scaffolds are evaluated. The results show that the presented scaffolds have permeability similar to natural bone and, with the same porosity level, have higher mechanical properties than scaffolds with conventional lay-down patterns 0-90° and 0-45°. Finally, human mesenchymal stem cells are seeded on the scaffolds to determine the effects of geometrical microstructure on cell attachment and morphology. The results show that cells in scaffold with ZigZag-Spiral pattern infilled pores gradually, while the other patterns need more time to fill the pores. Considering mechanical, transportation, and biological properties of the considered patterns, scaffolds with ZigZag-Spiral patterns can mimic the properties of cancellous bones and be a better choice for treatments of bone defects.

Dynamic transcriptome analysis of NFAT family in guided bone regeneration with occlusive periosteum in swine model

OBJECTIVE

To investigate the dynamic expression of NFAT family of periosteum in guided bone regeneration process.

MATERIAL AND METHODS

The swine ribs on one side were used as the trauma group and the contralateral side as the control group. After rib segment was removed, periosteum was sutured to form a closed cavity mimicking guided bone regeneration. The periosteum and regenerated bone tissue were collected at nine time points for gene sequencing and hematoxylin-eosin staining. The expression data of each member were extracted for analysis. Expression correlations among various members were analyzed.

RESULTS

Staining showed the guided bone regeneration was almost completed 1 month after the operation with later stage for bone remodeling. The expression levels of each member in both groups changed greatly, especially within postoperative 1.5 months. The expression of NFATc1 and NFATC2IP in trauma group was significantly correlated with those of control group. The foldchange of each member also had large fluctuations especially within 1.5 months. In the trauma group, NFATc2 and NFATc4 were significantly upregulated, and there was a significant aggregation correlation of NFAT family expression between the various time points within one month, similar to the "pattern-block" phenomenon.

CONCLUSION

This study revealed the dynamic expression of NFAT family in guided bone regeneration, and provided a reference for the specific mechanism. The first 1.5 months is a critical period and should be paid attention to. The significant high-expression of NFATc2 and NFATc4 may role importantly in this process, which needs further research to verify it.

A quantitative study of bone defects in displaced femoral neck fractures based on virtual reduction techniques

BACKGROUND

Bone defects in femoral neck fractures are strongly associated with the prognosis after internal fixation. However, qualitative analysis of bone defects in femoral neck fractures has already been performed, quantitative studies have not been reported. In this study, we aimed to systematically analyse the morphological characteristics of bone defects in patients with femoral neck fractures using computed tomography (CT) images combined with computer image analysis techniques.

METHODS

Four hundred and sixty-nine patients with femoral neck fractures from January 2014 to December 2018 at two grade A tertiary hospitals were included. Models were created in Mimics software based on CT images collected within 1 week after injury and then imported into 3-matic software for virtual reduction. The volume of the bone defect (VBD), maximum defect thickness (MDT), extent of the bone defect region (EBDR) , main defect quadrant (MDQ), collapse type and fracture classification were calculated and recorded.

RESULTS

The EBDR, collapse type and MDT all had a significant positive effect on the VBD (P <0.05), with a more significant effect at higher quantiles. Age also had a significant positive effect on the VBD (P < 0.05), but its effect was more pronounced at lower quantiles. Compared to non-subcapital fractures, subcapital fractures had a positive effect on the VBD only at the 50 and 75% quantiles (P < 0.01). The female sex had a significant negative effect on the VBD compared to the male sex (P < 0.05).

CONCLUSION

This study established a reliable computer image processing method for quantitative analysis of the VBD in femoral neck fractures and revealed that all patients with femoral neck fractures had bone defects, which can occur at any part of the femoral neck. The EBDR, MDT, collapse type, and patient age and sex were all important risk factors for the extent of the defect and should be taken into account in surgical planning.

Treatment of bone defects with bovine hydroxyapatite xenograft and platelet rich fibrin (PRF) to accelerate bone healing

INTRODUCTION

The autograft treatment has become a gold standard therapy for bone defects, although it has its drawbacks and a side effect of donor site morbidity. Furthermore, the bovine hydroxyapatite xenograft due to its excellent osteoconduction characteristic combined with platelet-rich fibrin (PRF), which is a source of growth factor, makes both utilized as therapeutic measures. Therefore, this study examines the potential use of bovine hydroxyapatite xenograft and platelet-rich fibrin in the treatment of bone defects.

METHOD

The report on three cases of bone defects that were treated using a combination of bovine hydroxyapatite xenograft and platelet-rich fibrin (PRF) for internal fixation and grafting was used for this investigation. The study showed that delayed and non-union fractures of the femur, humerus, and tibia may cause bone deformities.

RESULT

The outcome revealed a positive clinical and radiological finding about using the combination of bovine hydroxyapatite xenograft and platelet-rich fibrin (PRF) in the repair of bone defects and acceleration of healing processes.

CONCLUSION

The use of a combination of bovine hydroxyapatite xenograft and platelet-rich fibrin (PRF) in the repair of bone defects shows more effective and accelerated healing. Future studies with a bigger sample size may be carried out and are expected to yield optimal results.

Biodegradable open-porous scaffolds made of sintered magnesium W4 and WZ21 short fibres show biocompatibility in vitro and in long-term in vivo evaluation

Open-porous scaffolds made of W4 and WZ21 fibres were evaluated to analyse their potential as an implant material. WZ21 scaffolds without any surface modification or coating, showed promising mechanical properties which were comparable to the W4 scaffolds tested in previous studies. Eudiometric testing results were dependent on the experimental setup, with corrosion rates differing by a factor of 3. Cytotoxicity testing of WZ21 showed sufficient cytocompatibility. The corrosion behavior of the WZ21 scaffolds in different cell culture media are indicating a selective dealloying of elements from the magnesium scaffold by different solutions. Long term in-vivo studies were using 24 W4 scaffolds and 12 WZ21 scaffolds, both implanted in rabbit femoral condyles. The condyles and important inner organs were explanted after 6, 12 and 24 weeks and analyzed. The in-vivo corrosion rate of the WZ21 scaffolds calculated by microCT-based volume loss was up to 49 times slower than the in-vitro corrosion rate based on weight loss. Intramembranous bone formation within the scaffolds of both alloys was revealed, however a low corrosion rate and formation of gas cavities at initial time points were also detected. No systemic or local toxicity could be observed. Investigations by μ-XRF did not reveal accumulation of yttrium in the neighboring tissue. In summary, the magnesium scaffold´s performance is biocompatible, but would benefit from a surface modification, such as a coating to obtain lower the initial corrosion rates, and hereby establish a promising open-porous implant material for load-bearing applications. STATEMENT OF SIGNIFICANCE: Magnesium is an ideal temporary implant material for non-load bearing applications like bigger bone defects, since it degrades in the body over time. Here we developed and tested in vitro and in a rabbit model in vivo degradable open porous scaffolds made of sintered magnesium W4 and WZ21 short fibres. These scaffolds allow the ingrowth of cells and blood vessels to promote bone healing and regeneration. Both fibre types showed in vitro sufficient cytocompatibility and proliferation rates and in vivo, no systemic toxicity could be detected. At the implantation site, intramembranous bone formation accompanied by ingrowth of supplying blood vessels within the scaffolds of both alloys could be detected.

[Application of RUNX2 gene over expression vector modified exosomes from BMSC combined with calcium carbonate scaffold system in bone defect]

OBJECTIVE

To investigate the effect of RUNX2 gene overexpression vector modified exosomes derived from bone marrow mesenchymal stem cells (BMSCs) combined with calcium carbonate scaffold system in bone defect.

METHODS

Rabbit BMSCs were used as the research object, and BMSCs were identified by flow cytometry. Construct RUNX2 gene overexpression vector, transfect BMSCs with lentivirus, and collect exosomes by ultracentrifugation. The morphology of exosomes was observed by transmission electron microscope, the expression of exosome marker CD63 was detected by Western blot, and the calcium carbonate scaffold was constructed by three chamber parallel automatic temperature control reaction system. According to whether the RUNX2 gene overexpression vector was transfected or not, the complex of BMSCs and calcium carbonate scaffold was divided into three groups, namely BMSCs group, RUNX2 overexpression group and exosome group. The osteogenic differentiation of BMSCs was detected by oil red O staining and RT-PCR. There were 9 clean adult healthy male New Zealand white rabbits, aged (12.97±1.21) months, with a body weight of (19.3±3.6) kg, with 3 rabbits in each group. The animal model of skull defect was constructed by surgical method, and the repair of bone defect was evaluated by imaging, he staining and Masson staining.

RESULTS

The results of flow cytometry showed that the expression of CD29 protein, CD44 protein, CD11b protein and CD45 protein on the surface of BMSCs were 99.5%, 100%, 0.1% and 0.1%, respectively. Transmission electron microscopy showed that the exosomes were bilayer vesicles with a diameter of 50 to 150 nm. Western blot showed that the molecular marker CD63 of exosomes was positive. Oil red O staining showed that the osteogenic differentiation of BMSCs in exosome group was significantly higher than that in RUNX2 overexpression group and BMSCs group. The results of RT-PCR showed that the relative expressions of RUNX2, BMP-2 and ALP mRNA in BMSCs in exosome group were significantly higher than those in RUNX2 overexpression group and BMSCs group (P<0.05). The imaging results showed that the repair effect of skull defect in exosome group was better than that in RUNX2 overexpression group. HE staining and Masson staining showed that the repair effect of skull defect in exosome group was better than that in RUNX2 overexpression group (P<0.05). MSCs in exosome group was significantly higher than that in RUNX2 overexpression group and BMSCs group. The results of RT-PCR showed that the relative expressions of RUNX2, BMP-2 and ALP mRNA in BMSCs in exosome group were significantly higher than those in RUNX2 overexpression group and BMSCs group(P<0.05). The imaging results showed that the repair effect of skull defect in exosome group was better than that in RUNX2 overexpression group. HE staining and Masson staining showed that the repair effect of skull defect in exosome group was better than that in RUNX2 overexpression group(P<0.05).

CONCLUSION

Compared with RUNX2 gene overexpression vector transfection, extraction of exosomes directly can promote the differentiation of BMSCs into osteoblasts more efficiently, and the combination with calcium carbonate scaffold can better promote the healing of bone defects. So as to provide new ideas and methods for the clinical treatment of bone defects.

Two-stage strategy in end-stage hip periprosthetic joint infection: utility of industrially prefabricated custom-made antibiotic spacers

PURPOSE

Use of prefabricated mobile spacers in end-stage cases of hip periprosthetic joint infection (HPJI) is hindered when large bone defects exist. In such cases, prefabricated custom-made antibiotic spacers (P-CMAS) offer an alternative. Such spacers are individually designed according to the size and anatomical characteristics of the bone defect. The purpose of this study is to describe and evaluate the use of such patient-specific spacers in a two-stage strategy to treat end-stage HPJI cases, and to report on clinical outcomes.

METHODS

A retrospective study identified all patients with end-stage HPJIs from January 2015 through December 2019, treated using a P-CMAS. Primary outcome: infection eradication rate. Secondary outcomes: spacer-related complications and patient satisfaction. Minimum follow-up: 12 months after the second-stage surgery.

RESULTS

A total of 7 end-stage cases (mean of 6.7 previous surgical procedures) were included. Mean bone defect size was 191.57 (range 47-304) mm. Polymicrobial infection was detected in 42.86% of these cases. During the spacer stage there were no periprosthetic fractures, spacer dislocations or breakages, nor spacer-drug-related complications. All patients proceeded with the second stage uneventfully, with an average time between stages of 178 (range 119-326) days. In 5 cases a total femur arthroplasty was the reconstructive procedure performed. After a mean follow-up of 27.29 (range 14-49) months the infection was clinically eradicated in all patients, despite their difficult-to-treat scenarios.

CONCLUSIONS

Industrially custom-made spacers offer an effective and safe option in performing 2-stage exchange arthroplasty in cases of end-stage HPJI with extensive bone defects.

Does the incorporation of strontium into calcium phosphate improve bone repair? A meta-analysis

Background

The application of calcium phosphate (CaP)-based bone substitutes plays an important role in periodontal regeneration, implant dentistry and alveolar bone reconstruction. The incorporation of strontium (Sr) into CaP-based bone substitutes appears to improve their biological properties, but the reported in vivo bone repair performance is inconsistent among studies. Herein, we conducted a systematic review and meta-analysis to investigate the in vivo performance of Sr-doped materials.

Methods

We searched PubMed, EMBASE (via OVIDSP), and reference lists to identify relevant animal studies. The search, study selection, and data extraction were performed independently by two investigators. Meta-analyses and sub-group analyses were conducted using Revman version 5.4.1. The heterogeneity between studies were assessed by I². Publication bias was investigated through a funnel plot.

Results

Thirty-five studies were finally enrolled, of which 16 articles that reported on new bone formation (NBF) were included in the meta-analysis, covering 31 comparisons and 445 defects. The overall effect for NBF was 2.25 (95% CI 1.61–2.90, p < 0.00001, I² = 80%). Eight comparisons from 6 studies reported the outcomes of bone volume/tissue volume (BV/TV), with an overall effect of 1.42 (95% CI 0.65–2.18, p = 0.0003, I² = 75%). Fourteen comparisons reported on the material remaining (RM), with the overall effect being -2.26 (95% CI − 4.02 to − 0.50, p = 0.0009, I² = 86%).

Conclusions

Our study revealed that Sr-doped calcium phosphate bone substitutes improved in vivo performance of bone repair. However, more studies are also recommended to further verify this conclusion.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12903-022-02092-7.

Evaluation of complications associated with bifocal bone transport as treatment for either proximal, intermediate or distal femoral defects caused by infection: outcome analysis of 76 patients

Background

The purpose of this study was to evaluate the outcomes of bifocal bone transport in the treatment of femoral bone defects caused by infections.

Methods

Clinical and radiographic data of patients with infected femoral nonunion treated by the bifocal bone transport at our hospital were analyzed retrospectively, from January 2008 to December 2019. Depending on the location of bone defects, the patients were divided into three groups (proximal, intermediate, and distal). The Association for the Study and Application of the Method of Ilizarov (ASAMI) criteria was applied to assess the bone and functional outcomes. Postoperative complications of three groups were documented and compared.

Results

Seventy-six cases of infected femoral bone defects (31 cases of proximal, 19 cases of intermediate, and 26 cases of distal) were managed by bifocal bone transport successfully with a mean follow-up time of 30.8 months (range, 23 to 41 months). There were 58 men (76.3%) and 18 women (23.6%), with a mean age of 38.8 years (range, 23 to 60 years). The bone union was received in 76 cases with a mean of 6.9 months (range, 5 to 8 months). Pin tract infection was observed in twenty-nine cases (38.1%), 7 cases (9.2%) of muscle contractures, 3 cases (7.9%) of joint stiffness, 13 cases (17.1%) of axial deviation, 2 cases (2.6%) of delayed union, one case (1.3%) of nonunion, and none (0%) of transport gap re-fracture. One patient (1.3%) was scheduled for knee arthroplasty when bone transport treatment ended.

Conclusions

Bone transport using an external rail fixator was a practical method to treat the femoral bone defects, since the satisfactory rate of bone union and limb function recovery. Complications of distal femoral bone transport were more severe than the proximal and intermedia, but the rate of complication was the least of the three groups. Soft-tissue-related complications were more likely to occur in the intermediate bone transport.

Fibular strut allograft or bone cement for reconstruction after curettage of a giant cell tumour of the proximal femur : a retrospective cohort study

AIMS

Giant cell tumours (GCTs) of the proximal femur are rare, and there is no consensus about the best method of filling the defect left by curettage. In this study, we compared the outcome of using a fibular strut allograft and bone cement to reconstruct the bone defect after extended curettage of a GCT of the proximal femur.

METHODS

In a retrospective study, we reviewed 26 patients with a GCT of the proximal femur in whom the bone defect had been filled with either a fibular strut allograft (n = 12) or bone cement (n = 14). Their demographic details and oncological and nononcological complications were retrieved from their medical records. Limb function was assessed using the Musculoskeletal Tumor Society (MSTS) score.

RESULTS

Mean follow-up was 116 months (SD 59.2; 48 to 240) for the fibular strut allograft group and 113 months (SD 43.7; 60 to 192) for the bone cement group (p = 0.391). The rate of recurrence was not significantly different between the two groups (25% vs 21.4%). The rate of nononcological complications was 16.7% in the strut allograft group and 42.8% in the bone cement group. Degenerative joint disease was the most frequent nononcological complication in the cement group. The mean MSTS score of the patients was 92.4% (SD 11.5%; 73.3% to 100.0%) in the fibular strut allograft group and 74.2% (SD 10.5%; 66.7% to 96.7%) in the bone cement group (p < 0.001).

CONCLUSION

Given the similar rate of recurrence and a lower rate of nononcological complications, fibular strut grafting could be recommended as a method of reconstructing the bone defect left by curettage of a GCT of the proximal femur. Cite this article: Bone Joint J 2022;104-B(2):297-301.