Calcium Phosphate Bone Research Articles

Insights into the Various Cellular Antimicrobial Responses, Biocompatibility, Osteogenesis, Wound Healing, and Angiogenesis of Copper-Doped Nano-Hydroxyapatite Composite Calcium Phosphate Bone Cement In Vitro

Calcium phosphate bone cement (CPC) is a popular material for bone remodeling, and nanohydroxyapatite (nHA) represents a breakthrough that has a wide range of clinical applications. During the early stages of bone repair, antibacterial and angiogenesis effects are essential to remodel new bone tissues. In this study, an antibacterial effect was achieved by incorporating Cu2+-doped nano-hydroxyapatite (Cu–nHA) synthesized through hydrothermal methods into CPC, and the impact of various amounts of Cu–nHA addition on the antibacterial and mechanical properties of CPC hybridization was evaluated. Moreover, the effects of Cu–nHA/CPC composites on the proliferation and mineralization of mouse progenitor osteoblastic cells (D1 cells) were characterized; the cell migration and angiogenesis ability of vascular endothelial cells (HUVECs) were also studied. Results indicated that incorporating 5 wt.% and 10 wt.% Cu–nHA into CPC led to a practical short-term antibacterial effect on S. aureus but not on E. coli. These Cu–nHA/CPC slurries remained injectable, anti-disintegrative, and non-toxic. Furthermore, compared with pure CPC, these Cu–nHA/CPC slurries demonstrated positive effects on D1 cells, resulting in better proliferation and mineralization. In addition, these Cu–nHA/CPC slurries were more effective in promoting the migration and angiogenesis of HUVECs. These findings indicate that 10 wt.% Cu–nHA/CPC has great application potential in bone regeneration.

Navigating the combinations of platelet-rich fibrin with biomaterials used in maxillofacial surgery.

Platelet-rich fibrin (PRF) is a protein matrix with growth factors and immune cells extracted from venous blood via centrifugation. Previous studies proved it a beneficial biomaterial for bone and soft tissue regeneration in dental surgeries. Researchers have combined PRF with a wide range of biomaterials for composite preparation as it is biocompatible and easily acquirable. The results of the studies are difficult to compare due to varied research methods and the fact that researchers focus more on the PRF preparation protocol and less on the interaction of PRF with the chosen material. Here, the literature from 2013 to 2024 is reviewed to help surgeons and researchers navigate the field of commonly used biomaterials in maxillofacial surgeries (calcium phosphate bone grafts, polymers, metal nanoparticles, and novel composites) and their combinations with PRF. The aim is to help the readers select a composite that suits their planned research or medical case. Overall, PRF combined with bone graft materials shows potential for enhancing bone regeneration both in vivo and in vitro. Still, results vary across studies, necessitating standardized protocols and extensive clinical trials. Overviewed methods showed that the biological and mechanical properties of the PRF and material composites can be altered depending on the PRF preparation and incorporation process.

Synthesis and characterization of hydroxyapatite nanowires on tricalcium phosphate bone discs using a hydrothermal reaction

This study reports a hydrothermal process for synthesizing hydroxyapatite (HA) nanowires (NWs). Unlike the conventional hydrothermal process, only β-phase tricalcium phosphate (β-TCP) bone discs and deionized (DI) water, without any additional chemicals or precursor solutions, were used as raw materials. The concept behind this is that β‐TCP can be dissolved in DI water in an autoclave at high temperature and pressure, and the Ca2⁺ and PO43⁻ precursors in the newly formed aqueous solution spontaneously initiate self-assembled nucleation of HA NWs through hydrothermal reaction with the OH⁻ ions. The dissolution of β-TCP in DI water produces all the chemical species involved in the hydrothermal process, including the precursors and ions. The structural and morphological evolution of bone discs were investigated as a function of reaction time. It was found that HA nanoprisms were initially formed, and as the reaction proceeded the HA NWs dominated and formed HA NWs/β‐TCP bone discs with a shell/core structure. The HA NWs had an aspect ratio of approximately 270 with ∼150 μm in length, and a width of ∼0.55 μm. A slightly lower Ca/P molar ratio of ∼1.625, compared to the bulk value of approximately 1.67, indicates that the HA NWs were defective or Ca-deficient. Our findings indicate that the hydrothermal process of β-TCP bone discs is suitable for producing biphasic calcium phosphate bone scaffolds composed of HA NWs/β-TCP crystals with a shell/core structure.

Cerium as a crystalline phase stabilizer of α-TCP and its hydration and photothermal properties

Bone cement with photothermal properties can treat bone defects caused by bone tumors while killing residual tumor cells or preventing recurrence. In this study, trace amounts of cerium ions were introduced to enhance the crystal stability of α-TCP, thereby improving the hydration properties of α-TCP and obtaining excellent photothermal properties. The experimental results showed that the content of α-TCP in CON-TCP was 96.05 %, and the content of α-TCP in 1% Ce-TCP was 99.77 %, with an increase of 3.87 %; the compressive strength of 0.5% Ce-CPC hydrated for 5d increased from 16.6 MPa±2.18 MPa to 32.16 MPa±2.77 MPa, with an increase of 93.73 %. The temperature of 0.5% Ce-CPC can be raised to 50.9°C in two minutes under the irradiation of 808 nm laser, which is an increase of 31.5% compared with that of 38.7°C in the blank group. Therefore, trace cerium-doped calcium phosphate bone cement has excellent physicochemical and photothermal properties, and it is a promising composite bone cement material, and the results of the present study are expected to be used to treat bone defects in bone tumors.

Enhancing the mechanical performance of 3D-printed self-hardening calcium phosphate bone scaffolds: PLGA-based strategies

Over the last decade, 3D-printed porous calcium phosphates have emerged in the market for customized bone reconstruction. However, despite their excellent biological properties, the inherent brittleness is an obstacle that limits their clinical applications, as the scaffolds must withstand the surgical procedures and the mechanical stresses once implanted. Low-temperature self-hardening calcium phosphate inks offer unique possibilities to be reinforced with polymers, as they do not require high-temperature treatments. This study compares two routes for incorporating poly (lactic-co-glycolic acid) (PLGA) into 3D-printed calcium phosphate scaffolds: i) the use of a PLGA solution as a binder in an alpha-tricalcium phosphate self-hardening ink; ii) the infiltration of a PLGA solution into previously hardened 3D-printed calcium-deficient hydroxyapatite scaffolds. The influence of the added PLGA on the physical-chemical properties, mechanical performance and in vitro biological properties is assessed using a commercially available biomimetic calcium phosphate scaffold as a control. The addition of PLGA increases the plastic deformation capacity and the strength, both in compression and bending, and significantly improves the work of fracture of the scaffolds, up to an 8-fold in compression when PLGA is incorporated as a binder in the ink. Moreover, screwability tests demonstrate the enhanced fixability of the composite scaffolds in a knife-edge ridge indication with challenging fixation in the jaw. Importantly, the improvement of the mechanical properties by the addition of PLGA does not impair the good cytocompatibility of the material. Regarding the two routes studied, the PLGA incorporation in the ink is the best option in terms of overall improvement of the mechanical performance and osteogenic cell response.

Carvacrol-loaded premixed calcium phosphate bone cements with exceptional osteogenic and antibacterial properties to heal infected bone defects

The healing of infected bone fractures represents a significant clinical challenge in orthopedic surgery. Calcium phosphate cements (CPCs) are attractive materials, highly applicable in bone healing due to their satisfactory biological properties and chemical similarity to bone minerals. However, manual mixing is often required before localized application of conventional CPCs, increasing the risk of infection. Moreover, their antibacterial properties are often insufficient for treating infected fractures. In this study, antimicrobial two-paste premixed CPCs loaded with carvacrol were developed. The influence of the carvacrol on the setting properties and mechanical strength of the cement was studied. In vitro studies demonstrated the biocompatibility, osteogenic potential, and broad-spectrum antimicrobial efficacy of the premixed bone cements, including effectiveness against gram-positive, gram-negative, and drug-resistant bacteria. Notably, in vivo studies revealed exceptional antimicrobial and osteogenic properties of the carvacrol-loaded cements, confirming the promising potential of the premixed cements for the healing of infected bone defects.

Preparation of composite calcium phosphate cement scaffold loaded with Hedysarum polysaccharides and its efficacy in repairing bone defects

It’s imperative to create a more ideal biological scaffold for bone defect repair. Calcium phosphate bone cements (CPC) could be used as a scaffold. Some ingredients and osteogenic factors could be added to improve its poor mechanical properties and biological activity. As a macromolecule extracted from traditional Chinese medicine, Hedysarum polysaccharides (HPS) would significantly promote the osteogenic activity of bone biomaterials. Zirconium oxide and starch were added to the solid phase and citric acid was added to the liquid phase to optimize CPC. HPS was loaded onto the scaffold as an osteogenic factor, and the prepared CPS + HPS was characterized. Further, the cytocompatibility of CPS + HPS was assessed according to activity, differentiation, and calcification in neonatal rat calvarial osteoblasts, and the biosafety of CPS + HPS was evaluated according to acute toxicity, pyrogen, sensitization, and hemolysis. The success of CPS + HPS in repairing bone defects was evaluated by using a rabbit femur implantation experiment. After optimization, CPS-20-CA-5 containing 10% starch and 5% citric acid displayed the highest mechanical strength of 28.96 ± 0.03 MPa. HPS-50 was demonstrated to exert the best osteogenic effect. The combination of CPS + HPS achieved HPS-loaded CPC. Material characterization, cytocompatibility, biosafety, and femoral implantation experiments indicated that CPS + HPS possessed better pressure resistance and improved osteogenic ability in bone defect repair.CPS + HPS demonstrated effective pressure resistance and superior osteogenic ability, which may be of great significance for bone defects and bone tissue engineering to promote bone regeneration and repair.Graphical The composite CPS loaded with HPS-50 is an excellent scaffold with fine load-bearing ability and sustained release of osteogenic factors to repair bone defects.

A ternary calcium silicate bone cement with high mechanical properties and good operability

The treatment of vertebral compression fractures of the spinal necessitates the use of injectable bone repair materials with the adaptive modulus of elasticity. Currently, newly developed injectable self-curing materials for minimally invasive surgery are primarily categorized into calcium phosphate and calcium silicate systems, both of which exhibit excellent biocompatibility. However, calcium phosphate bone cement lacks adequate mechanical properties and the stress does not match between bone and material. Calcium silicate cement has a long curing time, low mechanical strength, and high alkalinity. These deficiencies render them inadequate for meeting clinical requirements. Therefore, we incorporated inorganic disodium phosphate, organic polyvinyl alcohol, and solid component cerium oxide into the matrix phase of tricalcium silicate bone cement to establish a ternary self-curing hydration reinforcement system and produced an organic-inorganic composite injectable bone cement. Even though the composite bone cement has a longer setting time, it exhibited high compressive strength (61.9Mpa) and fracture strain (7.88 %), demonstrating excellent mechanical properties. Furthermore, it also demonstrates good injectable properties (86 %), anti-collapse properties, good biological activity, and outstanding antibacterial properties. The composite bone cement has great potential to develop a new injectable self-curing material to replace PMMA bone cement in clinical vertebral compression fractures.

Mechanical Properties, Drug Release, Biocompatibility, and Antibacterial Activities of Modified Emulsified Gelatin Microsphere Loaded with Gentamicin Composite Calcium Phosphate Bone Cement In Vitro.

Bone defects are commonly addressed with bone graft substitutes; however, surgical procedures, particularly for open and complex fractures, may pose a risk of infection. As such, a course of antibiotics combined with a drug carrier is often administered to mitigate potential exacerbations. This study involved the preparation and modification of emulsified (Em) crosslinking-gelatin (gel) microspheres (m-Em) to reduce their toxicity. The antibiotic gentamicin was impregnated into gel microspheres (m-EmG), which were incorporated into calcium phosphate bone cement (CPC). The study investigated the effects of m-EmG@CPC on antibacterial activity, mechanical properties, biocompatibility, and proliferation and mineralization of mouse progenitor osteoblasts (D1 cells). The average size of the gel microspheres ranged from 22.5 to 16.1 μm, with no significant difference between the groups (p > 0.05). Most of the oil content within the microspheres was transferred through modification, resulting in reduced cytotoxicity. Furthermore, antibiotic-impregnated m-EmG did not compromise the intrinsic properties of the microspheres and exhibited remarkably antibacterial effects. After combining with CPC (m-EmG@CPC), the microspheres did not significantly hinder the CPC reaction and produced the main product, hydroxyapatite (HA). However, the compressive strength of the largest microsphere content of 0.5 wt.% m-EmG in CPC decreased significantly from 59.8 MPa of CPC alone to 38.7 MPa of 0.5m-EmG@CPC (p < 0.05). The 0.5m-EmG@CPC composite was effective against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) in drug release and antibacterial tests. Compared with m-EmG alone, the 0.5m-EmG@CPC composite showed no toxicity to mouse fibroblast cells (L929). Additionally, the proliferation and mineralization of mouse osteoblastic osteoprogenitor cells (D1 cells) did not have a negative impact on the 0.5m-EmG@CPC composite over time in culture compared with CPC alone. Results suggest that the newly developed antibacterial 0.5m-EmG@CPC composite bone cement did not negatively affect the performance of osteoprogenitor cells and could be a new option for bone graft replacement in surgeries.

A Janus Microsphere Delivery System Orchestrates Immunomodulation and Osteoinduction by Fine-tuning Release Profiles.

Bone regeneration is a well-orchestrated process synergistically involving inflammation, angiogenesis, and osteogenesis. Therefore, an effective bone graft should be designed to target multiple molecular events and biological demands during the bone healing process. In this study, a biodegradable gelatin methacryloyl (GelMA)-based Janus microsphere delivery system containing calcium phosphate oligomer (CPO) and bone morphogenetic protein-2 (BMP-2) is developed based on natural biological events. The exceptional adjustability of GelMA facilitates the controlled release and on-demand application of biomolecules, and optimized delivery profiles of CPO and BMP-2 are explored. The sustained release of CPO during the initial healing stages contributes to early immunomodulation and promotes mineralization in the late stage. Meanwhile, the administration of BMP-2 at a relatively high concentration within the therapeutic range enhances the osteoinductive property. This delivery system, with fine-tuned release patterns, induces M2 macrophage polarization and creates a conducive immuno-microenvironment, which in turn facilitates effective bone regeneration in vivo. Collectively, this study proposes a bottom-up concept, aiming to develop a user-friendly and easily controlled delivery system targeting individual biological events, which may offer a new perspective on developing function-optimized biomaterials for clinical use.

Preliminary osteogenic and antibacterial investigations of wood derived antibiotic-loaded bone substitute for the treatment of infected bone defects.

Introduction: The development of reliable treatments for infected or potentially infected bone loss resulting from open fractures and non-unions is extremely urgent, especially to reduce the prolonged courses of antimicrobial therapy to which affected patients are subjected. Numerous bone graft substitutes have been used over the years, but there are currently no effective solutions to treat critical bone loss, especially in the presence of infection. The present study evaluated the use of the biomorphic calcium phosphate bone scaffold b. Bone™, based on a next-generation resorbable biomimetic biomaterial, in bone reconstruction surgery in cases of infection. Methods: Using an "in vitro 3D bone fracture model" to predict the behavior of this drug delivery system during critical bone loss at an infected (or potentially infected) site, the effects of scaffolds loaded with gentamicin or vancomycin on the viability and differentiation capacity of human mesenchymal stem cells (hMSCs) were evaluated. Results: This scaffold, when loaded with gentamicin or vancomycin, exhibits a typical drug release curve that determines the inhibitory effects on the growth of Staphylococcus aureus, Enterococcus faecalis, and Escherichia coli, as well as relative biofilm formation. Discussion: The study demonstrates that b.bone scaffolds can effectively address key challenges in orthopedic surgery and patient care by inhibiting bacterial growth and biofilm formation through rapid, potent antibiotic release, reducing the risk of treatment failure due to resistance, and providing a promising solution for bone infections and improved patient outcomes. Future studies could explore the combination of different antibiotics on these scaffolds for more tailored and effective treatments against post-traumatic osteomyelitis pathogens.

Magnesium malate-modified calcium phosphate bone cement promotes the repair of vertebral bone defects in minipigs via regulating CGRP

Active artificial bone substitutes are crucial in bone repair and reconstruction. Calcium phosphate bone cement (CPC) is known for its biocompatibility, degradability, and ability to fill various shaped bone defects. However, its low osteoinductive capacity limits bone regeneration applications. Effectively integrating osteoinductive magnesium ions with CPC remains a challenge. Herein, we developed magnesium malate-modified CPC (MCPC). Incorporating 5% magnesium malate significantly enhances the compressive strength of CPC to (6.18 ± 0.49) MPa, reduces setting time and improves disintegration resistance. In vitro, MCPC steadily releases magnesium ions, promoting the proliferation of MC3T3-E1 cells without causing significant apoptosis, proving its biocompatibility. Molecularly, magnesium malate prompts macrophages to release prostaglandin E2 (PGE2) and synergistically stimulates dorsal root ganglion (DRG) neurons to synthesize and release calcitonin gene-related peptide (CGRP). The CGRP released by DRG neurons enhances the expression of the key osteogenic transcription factor Runt-related transcription factor-2 (RUNX2) in MC3T3-E1 cells, promoting osteogenesis. In vivo experiments using minipig vertebral bone defect model showed MCPC significantly increases the bone volume fraction, bone density, new bone formation, and proportion of mature bone in the defect area compared to CPC. Additionally, MCPC group exhibited significantly higher levels of osteogenesis and angiogenesis markers compared to CPC group, with no inflammation or necrosis observed in the hearts, livers, or kidneys, indicating its good biocompatibility. In conclusion, MCPC participates in the repair of bone defects in the complex post-fracture microenvironment through interactions among macrophages, DRG neurons, and osteoblasts. This demonstrates its significant potential for clinical application in bone defect repair.

Sodium fusidate loaded apatitic calcium phosphates: Adsorption behavior, release kinetics, antibacterial efficacy, and cytotoxicity assessment

The present work reports the adsorption, release, antibacterial properties, and in vitro cytotoxicity of sodium fusidate (SF) associated with a carbonated calcium phosphate bone cement. The adsorption study of SF on cement powder compared to stoichiometric hydroxyapatite and nanocrystalline carbonated apatite was investigated to understand the interaction between this antibiotic and the calcium phosphate phases involved in the cement formulation and setting reaction. The adsorption data revealed a fast kinetic process. However, the evolution of the amount of adsorbed SF was well described by a Freundlich-type isotherm characterized by a low adsorption capacity of the materials toward the SF molecule. The in vitro release results indicated a prolonged and controlled SF release for up to 34 days. The SF amounts eluted daily were at a therapeutic level (0.5–2 mg/L) and close to the antibiotic minimum inhibitory concentration (0.1–0.9 mg/L). Furthermore, the release data fitting and modeling suggested that the drug release occurred mainly by a diffusion mechanism. The antibacterial activity showed the effectiveness of SF released from the formulated cements against Staphylococcus aureus. Furthermore, the biological in vitro study demonstrated that the tested cements didn’t show any cytotoxicity towards human peripheral blood mononuclear cells and did not significantly induce inflammation markers like IL-8.

Fabrication and enhanced degradation behavior of sinterless porous apatite scaffolds with centrosymmetric structure

The primary component of natural bone minerals, hydroxyapatite (HA), has been the subject of research on materials for bone implants. Sintered HA scaffolds, on the other hand, degrade slowly after implantation and exhibit a high degree of crystallization at high temperatures, making it challenging to match the rate at which new bone grows. In this study, the benefit of self-curing calcium phosphate bone cement was employed to create porous apatite scaffolds without sintering. The lamellar pore structure was created by directional freeze-casting, and the enhanced specific surface area aided the in-situ hydration process. The crystallinity of sinterless porous apatite scaffolds diminishes when the TTCP and DCPD molar ratios drop. When the molar ratio is adjusted to 1:2.25, the crystallinity of the fabricated scaffold is reduced to 63.99 %, and 10.21 % can be degraded in 30 days. The degradation of porous scaffolds in simulated body fluids mainly depends on the rapid dissolution and transformation of solid phase powders in the early hydration reaction and the slow diffusion of the apatite in the later stage. The compressive strength of the porous scaffold is 5.3 MPa and its elastic modulus is 0.68 GPa. After 14 days of degradation, the compressive strength was 4.0 MPa and the elastic modulus was 0.64 GPa, which was still within the applicable range of cancellous bone repair. It has a promising application prospect as a substitute scaffold for absorbable cancellous bone.

Pilot Clinical Trial to Evaluate In Situ Calcium Phosphate Cement Injection for Conservative Surgical Management of Appendicular Osteosarcoma in Dogs.

Cementoplasty is a minimally invasive procedure that consists of injecting a bone substitute into the tumor lesion to provide bone reinforcement and alleviate pain. This study aimed to demonstrate the feasibility, safety, and efficacy of cementoplasty with a calcium phosphate cement in osteosarcoma to reduce pain and preserve limb function. Throughout the 6-month study, dogs received no adjuvant therapy, and dogs' evaluations included a clinical examination, monitoring of postoperative complications, radiographic follow-up, and assessment of limb function and pain scores. Out of 12 dogs enrolled, 10 were withdrawn before study completion due to deterioration in their general condition. Nine (9) dogs were followed until D28, six until D56, and two until D183. Compared to D0, more than 50% of the dogs showed improvement in both veterinarian and owner scores at their final visit. Throughout the study, 10 major and 4 minor complications were reported, all unrelated to the procedure. This open non-controlled study provides first evidence of the feasibility, safety, and efficacy of cementoplasty procedure using a calcium phosphate bone cement to relieve pain and preserve limb function in dogs suffering from appendicular osteosarcoma.

Biphasic Calcium Phosphate Bone Graft With a Unique Surface Topography: A Single-Center Ambispective Study for Degenerative Disease of the Lumbar Spine.

This study is an ambispective evaluation and analysis of a single-center cohort. This study aimed to evaluate the performance of a novel biphasic calcium phosphate (BCP) bone graft with submicron-sized needle-shaped surface topography (BCP<µm) in interbody arthrodesis of the lumbar spine. This study was a single-center ambispective assessment of adult patients receiving BCP<µm as part of their lumbar interbody fusion surgery. The primary outcome was a fusion status on computed tomography (CT) 12months postoperative. The secondary outcomes included postoperative changes in the visual analogscale (VAS), Oswestry Disability Index (ODI), Short Form 12 (SF-12), and length of stay (LOS). Sixty-three patients with one- to three-level anterior (48, 76%) and lateral (15, 24%) interbody fusions with posterior instrumentation were analyzed. Thirty-one participants (49%) had three or more comorbidities, including heart disease (43 participants, 68%), obesity (31 participants, 49%), and previous lumbar surgery (23 participants, 37%). The mean ODI decreased by 24. The mean SF-12 physical health and SF-12 mental health improved by a mean of 11.5 and 6.3, respectively. The mean VAS for the left leg, right leg, and back improved by a mean of 25.75, 22.07, and 37.87, respectively. Of 101 levels, 91 (90%) demonstrated complete bridging trabecular bone fusion with no evidence of supplemental fixation failure. The data of BCP<µm in interbody fusions for degenerative disease of the lumbar spine provides evidence of fusion in a complicated cohort of patients.

407 Results of Biphasic Calcium Phosphate Bone Graft With Submicron-Sized Needle-Shaped Surface Topography as Standalone Alternative to Autograft Are Favorable in a Prospective, Multi-center, Randomized, Intra-patient Controlled Trial

INTRODUCTION: Pseudoarthrosis after spinal fusion is an important complication leading to revision spine surgeries. Iliac Crest Bone Graft is considered the gold standard, but with limited availability and associated co-morbidities, spine surgeons often utilize alternative bone grafts. METHODS: Adult patients indicated for instrumented PLF of one to six levels from T10-S2 were enrolled at five participating centers. After preparation of the bone bed, one side was grafted with 10 cc of autograft per level containing a minimum of 50% iliac crest bone. The other side was grafted with 10 cc of BCP &lt; µm granules standalone. In total, 71 levels were treated. Prospective follow-up included a fine-cut (&lt;1 mm) Computerized Tomography (CT) at one year. Fusion was systematically scored as fused or not fused per level per side by two spine surgeons blinded for the procedure. RESULTS: The first fifty patients enrolled are included in this analysis. Average age was 57 years old, with 60% female and 40% male. The diagnoses included deformity (56%), structural instability (28%), and instability from decompression (20%). The fusion rate determined by fine-cut CT for BCP &lt; μm was 76.1% (54/71 levels), which compared favorably to the autograft fusion rate of 43.7% (31/71 levels). Fusion of the BCP &lt; μm side was not contingent upon fusion of the autograft side, as 36.6% (26/71) of levels fused on the BCP &lt; μm side but did not fuse on the autograft side. Binomial modeling revealed that the odds of fusion of BCP &lt; μm was 2.54 times higher than that of autograft. CONCLUSIONS: These data, aiming to determine non-inferiority of standalone BCP &lt; μm as compared to autograft for PLF, are promising. Ongoing studies with additional patients are forthcoming.

Application value of bone cement containing rhbFGF and RHBMP-2 in PKP treatment of osteoporotic lumbar compression fracture

To investigate the effect of bone cement containing recombinant human basic fibroblast growth factor (rhbFGF) and recombinant human bone morphogenetic protein-2 (rhBMP-2) in percutaneous kyphoplasty(PKP)treatment of osteoporotic vertebral compression fracture(OVCF). A total of 103 OVCF patients who underwent PKP from January 2018 to January 2021 were retrospectively analyzed, including 40 males and 63 females, aged from 61 to 78 years old with an average of (65.72±3.29) years old. The injury mechanism included slipping 33 patients, falling 42 patients, and lifting injury 28 patients. The patients were divided into three groups according to the filling of bone cement. Calcium phosphate consisted of 34 patients, aged(65.1±3.3) years old, 14 males and 20 females, who were filled with calcium phosphate bone cement. rhBMP-2 consisted of 34 patients, aged (64.8±3.2) years old, 12 males and 22 females, who were filled with bone cement containing rhBMP-2. And rhbFGF+rhBMP-2 consisted of 35 patients, aged (65.1±3.6) years old, 14 males and 21 females, who were filled with bone cement containing rhbFGF and rhBMP-2. Oswestry disability index (ODI), bone mineral density, anterior edge loss height, anterior edge compression rate of injured vertebra, visual analog scale (VAS) of pain, and the incidence of refracture were compared between groups. All patients were followed for 12 months. Postoperative ODI and VAS score of the three groups decreased (P<0.001), while bone mineral density increased (P<0.001), anterior edge loss height, anterior edge compression rate of injured vertebra decreased first and then slowly increased (P<0.001). ODI and VAS of group calcium phosphate after 1 months, 6 months, 12 months were lower than that of rhBMP-2 and group rhbFGF+rhBMP-2(P<0.05), bone mineral density after 6 months, 12 months was higher than that of rhBMP-2 and group calcium phosphate(P<0.05), and anterior edge loss height, anterior edge compression rate of injured vertebra of group rhbFGF+rhBMP-2 after 6 months and 12 months were lower than that of group rhBMP-2 and group calcium phosphate(P<0.05). There was no statistical difference in the incidence of re-fracture among the three groups (P>0.05). Bone cement containing rhbFGF and rhBMP-2 could more effectively increase bone mineral density in patients with OVCF, obtain satisfactory clinical and radiological effects after operation, and significantly improve clinical symptoms.

Improving bone defect healing using magnesium phosphate granules with tailored degradation characteristics

ObjectivesDental implant placement frequently requires preceding bone augmentation, for example, with hydroxyapatite (HA) or β-tricalcium phosphate (β-TCP) granules. However, HA is degraded very slowly in vivo and for β-TCP inconsistent degradation profiles from too rapid to rather slow are reported. To shorten the healing time before implant placement, rapidly resorbing synthetic materials are of great interest. In this study, we investigated the potential of magnesium phosphates in granular form as bone replacement materials. MethodsSpherical granules of four different materials were prepared via an emulsion process and investigated in trabecular bone defects in sheep: struvite (MgNH4PO4·6H2O), K-struvite (MgKPO4·6H2O), farringtonite (Mg3(PO4)2) and β-TCP. ResultsAll materials except K-struvite exhibited promising support of bone regeneration, biomechanical properties and degradation. Struvite and β-TCP granules degraded at a similar rate, with a relative granules area of 29% and 30% of the defect area 4 months after implantation, respectively, whereas 18% was found for farringtonite. Only the K-struvite granules degraded too rapidly, with a relative granules area of 2% remaining, resulting in initial fibrous tissue formation and intermediate impairment of biomechanical properties. Significance:We demonstrated that the magnesium phosphates struvite and farringtonite have a comparable or even improved degradation behavior in vivo compared to β-TCP. This emphasizes that magnesium phosphates may be a promising alternative to established calcium phosphate bone substitute materials.

Octacalcium phosphate phase forming cements as an injectable bone substitute materials: Preparation and in vitro structural study

In the realm of regenerating damaged or degenerated bones through minimally invasive techniques, injectable materials have emerged as exceptionally promising. Among these, calcium phosphate bone cements (CPCs) have garnered significant interest due to their remarkable bioactivity, setting it apart from non-degradable alternatives such as polymethyl methacrylate cements. α-Tricalcium phosphate (α-TCP) is a widely used solid phase component in CPCs. It can transform into calcium-deficient hydroxyapatite (CDHAp) when it comes in contact with water. In this study, we aimed to create an injectable, self-setting bone cement using low-temperature synthesized α-TCP powder as a single precursor of the powder phase. We found that changes in the pH of the liquid phase (pH 6.0, pH 6.2, pH 7.0 and pH 7.4) significantly altered the cement's setting, handling, and mechanical properties. The formation of the octacalcium phosphate (OCP) phase was identified in our study, which positively affects the osteoblastic cell response. Hardened OCP-forming bone cements prepared using a liquid phase with pH 7.0 and 7.4 showed better osteogenic cell attachment and proliferation than those prepared with pH 6.0 and 6.2. Our study suggests that changes in the pH of the liquid phase can significantly affect the properties of α-TCP-based bone cement, and the presence of the OCP phase is crucial for optimal cement performance.