Calcium Phosphate Bone Cement Research Articles

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 Out of 12 dogs enrolled, 10 were withdrawn before study completion due to deterioration in their general condition.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.

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.

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.

Calcium phosphate cement promotes the stability of osteoporotic lumbar pedicle screw by enhancer-injecters with different number of holes

BackgroundsThis study aimed to compare whether Calcium phosphate cement (CPC) promotes the stability of osteoporotic lumbar pedicle screw by enhancer-injecters with different number of holes.MethodsThrough a self-designed bone cement injection device, the pedicle screw canal was strengthened with calcium phosphate bone cement, and divided into 4-hole group, 6-hole group, 8-hole group, straight pore group and the control group. The screw was inserted into the mechanical test module, the Maximum insertion torque and Maximum axial pull-out strength were recorded, and the distribution of calcium phosphate bone cement was analyzed by CT and X-ray. The data results were analyzed using SPSS19.0 statistical software package.ResultsThe distribution of bone cement in different reinforcement groups was different and showed regularity. The bone cement in the 4-hole group was roughly located in the head 1/3 of the screw, the 6-hole group was located in the middle 1/3 of the screw, and the 8-hole group was located in the caudal 1/3 of the screw. Compared with the control group, the maximum axial pull-out force of screws in the lateral hole and full screw tunnel reinforcement group was significantly increased. There was no significant difference between the 4-hole, 6-hole and straight pore groups. There was no difference in the screw-in torque between the reinforcement groups, and they all increased significantly compared with the control group, and the difference was statistically significant. After the screw was pulled out, the interface between the bone cement and the polyurethane material was fractured, and a tight package was formed with the screw.ConclusionsEnhancer syringes with different hole numbers combined with CPC bone cement injection can significantly increase the maximum screw pull-out force. The 8-hole group has a smaller pull-out force and is relatively prone to leakage of reinforcing material, which lacks safety in use. The local reinforcement of 4-hole and 6-hole sheath can play a similar role to that of total nail tunnel reinforcement.

Highly dense calcium phosphate ceramics prepared by self-hydration with hollow silicon calcium additives

Vertebral compression fractures are common nowadays. The application of calcium phosphate bone cement (CPCs) in the treatment of vertebral compression fractures is the research focus, because of its advantages of good biocompatibility, bone conductivity and injectability. However, it is still limited in the clinical application because of its poor mechanical properties. The main reason for the insufficient strength of CPC is that there are many defects inside the solidified body during the hydration reaction. Therefore, we design a kind of hollow silicon calcium additives to regulate the crystallization behavior of CPC hydration products in the self-curing process to achieve the densification of solidified bodies in the microstructure. Firstly, we plan to increase the nucleation site of hydration products during α-TCP hydration to fill structural defects by introducing hollow bioglass. Secondly, we prepare hollow calcium silicon additive by in situ mineralization which can dissolve calcium and silicon ions efficiently are used to regulate the local hydration microenvironment to reduce the crystal size and increase the number of hydration products to obtain a highly dense solidified body structure. The experimental results show that the initial hydration intensity of CPC increased from 18.36 ± 1.72 MPa to 35.37 ± 1.84 MPa, an increase of about 92.65 %. Also, the toughness of the solidified body has been greatly improved, reaching more than 200 %. After 7 days of hydration, the mechanical strength of CPC was further improved, reaching 89.39 ± 3.65 MPa. With the addition of hollow calcium silica additives, we achieved the conversion from calcium phosphate cement to the calcium phosphate ceramic. Our work provides reference value for the clinical replacement of calcium phosphate ceramic for PMMA in vertebral compression fractures.

Mesoporous Bioactive Glass-Incorporated Injectable Strontium-Containing Calcium Phosphate Cement Enhanced Osteoconductivity in a Critical-Sized Metaphyseal Defect in Osteoporotic Rats.

In this study, the in vitro and in vivo bone formation behavior of mesoporous bioactive glass (MBG) particles incorporated in a pasty strontium-containing calcium phosphate bone cement (pS100G10) was studied in a metaphyseal fracture-defect model in ovariectomized rats and compared to a plain pasty strontium-containing calcium phosphate bone cement (pS100) and control (empty defect) group, respectively. In vitro testing showed good cytocompatibility on human preosteoblasts and ongoing dissolution of the MBG component. Neither the released strontium nor the BMG particles from the pS100G10 had a negative influence on cell viability. Forty-five female Sprague-Dawley rats were randomly assigned to three different treatment groups: (1) pS100 (n = 15), (2) pS100G10 (n = 15), and (3) empty defect (n = 15). Twelve weeks after bilateral ovariectomy and multi-deficient diet, a 4 mm wedge-shaped fracture-defect was created at the metaphyseal area of the left femur in all animals. The originated fracture-defect was substituted with pS100 or pS100G10 or left empty. After six weeks, histomorphometrical analysis revealed a statistically significant higher bone volume/tissue volume ratio in the pS100G10 group compared to the pS100 (p = 0.03) and empty defect groups (p = 0.0001), indicating enhanced osteoconductivity with the incorporation of MBG. Immunohistochemistry revealed a significant decrease in the RANKL/OPG ratio for pS100 (p = 0.004) and pS100G10 (p = 0.003) compared to the empty defect group. pS100G10 showed a statistically higher expression of BMP-2. In addition, a statistically significant higher gene expression of alkaline phosphatase, osteoprotegerin, collagen1a1, collagen10a1 with a simultaneous decrease in RANKL, and carbonic anhydrase was seen in the pS100 and pS100G10 groups compared to the empty defect group. Mass spectrometric imaging by time-of-flight secondary ion mass spectrometry (ToF-SIMS) showed the release of Sr2+ ions from both pS100 and pS100G10, with a gradient into the interface region. ToF-SIMS imaging also revealed that resorption of the MBG particles allowed for new bone formation in cement pores. In summary, the current work shows better bone formation of the injectable pasty strontium-containing calcium phosphate bone cement with incorporated mesoporous bioactive glass compared to the bioactive-free bone cement and empty defects and can be considered for clinical application for osteopenic fracture defects in the future.

An injectable bioactive poly(γ-glutamic acid) modified magnesium phosphate bone cement for bone regeneration.

As potential alternatives for calcium phosphate bone cements, magnesium phosphate bone cements (MPC) have attracted considerable attention in recent years. However, their several defects, such as rapid setting times, highly hydration temperature and alkaline pH due to the part of the unreacted phosphate, restricted their applications in human body. With aim to overcome these defects, a novel polypeptite poly(γ-glutamic acid) (γ-PGA) modified MPC were developed. Effect of γ-PGA content on the injectability, anti-washout ability, setting times, hydration temperature, mechanical compressive strength, in vitro bioactivity and degradation were investigated. Moreover, in vitro cyto-compatibility was evaluated using MC3T3-E1 cells by CCK-8 and Live/Dead staining. All these results indicated that the 10%PGA-MPC with an improved handling performances, low hydration temperature, high mechanical compressive strength, and good cyto-compatibility hold a great potential for bone repair and regeneration.

Investigation on the size and percentage effects of magnesium nanoparticles on thermophysical properties of reinforced calcium phosphate bone cement by molecular dynamic simulation

In recent years, bone materials and cement innovation have made extraordinary strides. Calcium phosphate cement (CPC) regenerates body tissues and repairs bone and dental defects. Since the presence of nanoparticles (NPs) increased the initial cement strength in terms of the reduction of porosity, magnesium (Mg) NPs were used because of their unique properties. In this study, the effects of various Mg NP percentages and sizes on reinforced cement thermal behavior and mechanical behavior are investigated using the molecular dynamics (MD) simulation method. The changes of Young's modulus (YM), maximum temperature (MT), and ultimate strength (US) were investigated for this reason. The US, YM, and MT of the reinforced cement sample improved from 0.879 to 0.171 MPa to 1.326 and 0.255 MPa, respectively, and from 1321 to 1403 K by raising the NPs percentage to 4%. The radius increase of NPs to 16 Å enhanced the US, YM, and MT to 0.899 MPa, 0.179 MPa, and 1349 K. The MT decreased to 1275 K. The quantity and size of the Mg NPs significantly enhanced the mechanical behavior of the finished cement, according to the findings.

Zn-Doped Calcium Magnesium Phosphate Bone Cement Based on Struvite and Its Antibacterial Properties.

The development of magnesium calcium phosphate bone cements (MCPCs) has garnered substantial attention. MCPCs are bioactive and biodegradable and have appropriate mechanical and antimicrobial properties for use in reconstructive surgery. In this study, the cement powders based on a (Ca + Mg)/P = 2 system doped with Zn2+ at 0.5 and 1.0 wt.% were obtained and investigated. After mixing with a cement liquid, the structural and phase composition, morphology, chemical structure, setting time, compressive strength, degradation behavior, solubility, antibacterial activities, and in vitro behavior of the cement materials were examined. A high compressive strength of 48 ± 5 MPa (mean ± SD) was achieved for the cement made from Zn2+ 1.0 wt.%-substituted powders. Zn2+ introduction led to antibacterial activity against Staphylococcus aureus and Escherichia coli strains, with an inhibition zone diameter of up to 8 mm. Biological assays confirmed that the developed cement is cytocompatible and promising as a potential bone substitute in reconstructive surgery.

Synergistic effect of drug/antibiotic-impregnated micro/nanohybrid mesoporous bioactive glass/calcium phosphate composite bone cement on antibacterial and osteoconductive activities

Calcium phosphate bone cements (CPC) can be used in minimally invasive surgery because of their injectability, and they can also be used to repair small and irregular bone defects. This study aimed to release the antibiotic gentamicin sulfate (Genta) to reduce tissue inflammation and prevent infection in the early stages of bone recovery. Subsequently, the sustained release of the bone-promoting drug ferulic acid (FA) mimicked the response of osteoprogenitor D1 cells interaction, thereby accelerating the healing process of the overall bone repair. Accordingly, the different particle properties of micro-nano hybrid mesoporous bioactive glass (MBG), namely, micro-sized MBG (mMBG) and nano-sized MBG (nMBG), were explored separately to generate different dose releases in MBG/CPC composite bone cement. Results show that nMBG had better sustained-release ability than mMBG when impregnated with the same dose. When 10 wt% of mMBG hybrid nMBG and composite CPC were used, the amount of MBG slightly shortened the working/setting time and lowered the strength but did not hinder the biocompatibility, injectability, anti-disintegration, and phase transformation of the composite bone cement. Furthermore, compared with 2.5wt%Genta@mMBG/7.5 wt% FA@nMBG/CPC, 5wt.%Genta@mMBG/5wt.%FA@nMBG/CPC exhibited better antibacterial activity, better compressive strength, stronger mineralization of osteoprogenitor cell, and similar 14-day slow-release trend of FA. The MBG/CPC composite bone cement developed can be used in clinical surgery to achieve the synergistic sustained release of antibacterial and osteoconductive activities.

Design and fabrication of high-performance injectable self-setting trimagnesium phosphate

Magnesium phosphate bone cement has become a widely used orthopedic implant due to the advantages of fast-setting and high early strength. However, developing magnesium phosphate cement possessing applicable injectability, high strength, and biocompatibility simultaneously remains a significant challenge. Herein, we propose a strategy to develop high-performance bone cement and establish a trimagnesium phosphate cement (TMPC) system. The TMPC exhibits high early strength, low curing temperature, neutral pH, and excellent injectability, overcoming the critical limitations of recently studied magnesium phosphate cement. By monitoring the hydration pH value and electroconductivity, we demonstrate that the magnesium-to-phosphate ratio could manipulate the components of hydration products and their transformation by adjusting the pH of the system, which will influence the hydration speed. Further, the ratio could regulate the hydration network and the properties of TMPC. Moreover, in vitro studies show that TMPC has outstanding biocompatibility and bone-filling capacity. The facile preparation properties and these advantages of TMPC render it a potential clinical alternative to polymethylmethacrylate and calcium phosphate bone cement. This study will contribute to the rational design of high-performance bone cement.

Study on injectable silver-incorporated calcium phosphate composite with enhanced antibacterial and biomechanical properties for fighting bone cement-associated infections

Although commonly used in orthopedic surgery, bone cements often face a high risk of post-operative infection. Developing bone cement with antibacterial capability is an effective path for eliminating implant-associated infections. Herein, the potential of silver ions (Ag+) and silver nanoparticles (AgNPs) in modifying CPC for long-term antibacterial property was investigated. Ag+ ions or AgNPs of various concentrations were incorporated in starch-modified calcium phosphate bone cement (CPB) to obtain Ag+-containing (Ag+@CPB) and AgNPs-containing (AgNP@CPB) bone cements. The results showed that all silver-containing CPBs had setting times of about 25–40 min, compressive strengths of greater than 22 MPa, high cytocompatibility but inhibitory effect on Staphylococcus aureus growth. After soaking for 1 week, the mechanical properties and the cytocompatibility of all cements revealed no significant changes, but only CPB with a relatively high content of Ag+ (H-Ag+@CPB) maintained good antibacterial capability over the tested time period. In addition, all the cements showed high injectability and interdigitating capability in cancellous bone and demonstrated augmentation effect on the cannulated pedicle screws fixation in the Sawbones model. In summary, the sustainable antibacterial capability and enhanced biomechanical properties demonstrated that Ag+ ions were more suitable for the fabrication of antibacterial CPC compared to AgNPs. Also, the H-Ag+@CPB, with good injectability, high cytocompatibility, good interdigitating and biomechanical property in cancellous bone, and sustainable antibacterial effects, bears great potential for the treatments of bone infections or implant-associated infections.

Enhanced Cell Osteogenic Differentiation in Alendronate Acid and Flufenamic Acid Drug-Impregnated Nanoparticles of Mesoporous Bioactive Glass Composite Calcium Phosphate Bone Cement In Vitro.

This study aims to compare the anti-osteoporotic drugs alendronic acid (ALN) and flufenamic acid (FA) alone impregnate into nanoparticles of mesoporous bioactive glass (nMBG), which further composites calcium phosphate cement (CPC) and investigates their in vitro performance. The drug release, physicochemical properties, and biocompatibility of nMBG@CPC composite bone cement are tested, and the effect of the composites on improving the proliferation and differentiation efficiency of mouse precursor osteoblasts (D1 cells) is also investigated. Drug release shows that FA impregnates nMBG@CPC composite, a large amount of FA is released rapidly within 8 h, gradually reaching a stable release within 12 h, followed by a slow and sustained release within 14 days, and then reaches a plateau within 21 days. The release phenomenon confirms that the drug-impregnated nBMG@CPC composite bone cement effectively achieves slow drug delivery. The working time and setting time of each composite are within 4-10 min and 10-20 min, respectively, meeting the operational requirements of clinical applications. The addition of nMBG nanoparticles in the CPC matrix did not prevent the aggregation phenomenon under microstructural observation, thus resulting in a decrease in the strength of the nMBG@CPC composite. However, after 24 h of immersed reaction, the strength of each 5 wt.% nMBG impregnated with different concentrations of FA and ALN is still greater than 30 MPa, which is higher than the general trabecular bone strength. The drug-impregnated nMBG@CPC composites did not hinder the product formation and exhibit biocompatibility. Based on the proliferation and mineralization of D1 cells, the combination of nMBG with abundant FA and ALN in CPC is not conducive to the proliferation of D1 cells. However, when D1 cells are contact cultured for 21 days, alkaline phosphatase (ALP) enzyme activity shows higher ALP secretion from drug-impregnated nMBG@CPC composites than drug-free composites. Accordingly, this study confirms that nMBG can effectively impregnate the anti-osteoporosis drugs FA and ALN, and enhance the mineralization ability of osteoblasts. Furthermore, drug-impregnated nMBG applications can be used alone or in combination with CPC as a new option for osteoporotic bone-filling surgery.

Enhanced bone repair by silver-doped magnesium calcium phosphate bone cements

The aim was to create magnesium calcium phosphate bone cements (MCPCs) based on struvite and newberyite phases and having antibacterial properties due to the presence of Ag+ ions. An increase of Ag+ concentration from 0.5% to 1.0% substantially enhanced mechanical properties of the cements [compressive strength reached 41 ± 2 MPa (mean ± SD)] and increased the inhibition zone up to 8 mm in a disk diffusion test against Escherichia coli and Staphylococcus aureus without toxicity to MG-63 cells in vitro. Analyses of the MCPC samples soaked in Kokubo's simulated body fluid showed the formation of coatings on the cements' surface, corresponding to a merrillite phase and, after 28 days of the soaking, to a bobierrite phase. Histological examination and micro-CT analysis revealed that the newly developed MCPCs are osteoconductive and biodegradable and may be used as a bone substitute.

Injectable Biomimetic Hydrogel Guided Functional Bone Regeneration by Adapting Material Degradation to Tissue Healing

AbstractThe treatment of irregular bone defects remains a clinical challenge since the current biomaterials (e.g., calcium phosphate bone cement (CPC)) mainly act as inert substitutes, which are incapable of transforming into a regenerated host bone (termed functional bone regeneration). Ideally, the implant degradation rate should adapt to that of bone regeneration, therefore providing sufficient physicochemical support and giving space for bone growth. This study aims to develop an injectable biomaterial with bone regeneration‐adapted degradability, to reconstruct a biomimetic bone‐like structure that can timely transform into new bone, facilitating functional bone regeneration. To achieve this goal, a hybrid (LP‐CPC@gelatin, LC) hydrogel is synthesized via one‐step incorporation of laponite (LP) and CPC into gelatin hydrogel, and the LC gel degradation rate is controlled by adjusting the LP/CPC ratio to match the bone regeneration rate. Such an LC hydrogel shows good osteoinduction, osteoconduction, and angiogenesis effects, with complete implant‐to‐new bone transformation capacity. This 2D nanoclay‐based bionic hydrogel can induce ectopic bone regeneration and promote ligament graft osseointegration in vivo by inducing functional bone regeneration. Therefore, this study provides an advanced strategy for functional bone regeneration and an injectable biomimetic biomaterial for functional skeletal muscle repair in a minimally invasive therapy.

Egg white improves the biological properties of an alginate-methylcellulose bioink for 3D bioprinting of volumetric bone constructs

Three-dimensional microextrusion bioprinting has attracted great interest for fabrication of hierarchically structured, functional tissue substitutes with spatially defined cell distribution. Despite considerable progress, several significant limitations remain such as a lack of suitable bioinks which combine favorable cell response with high shape fidelity. Therefore, in this work a novel bioink of alginate-methylcellulose (AlgMC) blend functionalized with egg white (EW) was developed with the aim of solving this limitation. In this regard, a stepwise strategy was proposed to improve and examine the cell response in low-viscosity alginate inks (3%, w/v) with different EW concentrations, and in high-viscosity inks after gradual methylcellulose addition for enhancing printability. The rheological properties and printability of these cell-responsive bioinks were characterized to obtain an optimized formulation eliciting balanced physicochemical and biological properties for fabrication of volumetric scaffolds. The bioprinted AlgMC + EW constructs exhibited excellent shape fidelity while encapsulated human mesenchymal stem cells showed high post-printing viability as well as adhesion and spreading within the matrix. In a proof-of-concept experiment, the impact of these EW-mediated effects on osteogenesis of bioprinted primary human pre-osteoblasts (hOB) was evaluated. Results confirmed a high viability of hOB (93.7 ± 0.15%) post-fabrication in an EW-supported AlgMC bioink allowing cell adhesion, proliferation and migration. EW even promoted the expression of osteogenic genes, coding for bone sialoprotein (integrin binding sialoprotein/bone sialoprotein precursor (IBSP)) and osteocalcin (BGLAP) on mRNA level. To demonstrate the suitability of the novel ink for future fabrication of multi-zonal bone substitutes, AlgMC + EW was successfully co-printed together with a pasty calcium phosphate bone cement biomaterial ink to achieve a partly mineralized 3D volumetric environment with good cell viability and spreading. Along with the EW-mediated positive effects within bioprinted AlgMC-based scaffolds, this highlighted the promising potential of this novel ink for biofabrication of bone tissue substitutes in clinically relevant dimensions.

Analysis of the epidemiological status, microbiology, treatment methods and financial burden of hematogenous osteomyelitis based on 259 patients in Northwest China.

The incidence of hematogenous osteomyelitis is on the rise, and the prognosis is poor. There has been no large-scale epidemiological analysis of hematogenous osteomyelitis in the world, and the treatment method is still controversial. A retrospective case study method was used to collect and analyze clinical data obtained from patients with hematogenous osteomyelitis in a tertiary hospital in Northwest China from January 1, 2011, to December 31, 2020. The aim of this study was to investigate the epidemiological status, microbiological characteristics, treatment and financial burden of hematogenous osteomyelitis in Northwest China to explore the therapeutic effects of different treatment methods, elucidate the epidemiological characteristics of hematogenous osteomyelitis and to provide a basis for the choice of treatment. We included 259 patients with hematogenous osteomyelitis, including 96 patients with acute hematogenous osteomyelitis and 163 patients with chronic hematogenous osteomyelitis. The cause of the disease was not obvious in most patients, the sex ratio of males to females was 1.98, and the three most common infected sites were the tibia, femur and phalanx. Regarding preoperative serum inflammatory markers, the rate of positivity for ESR was the highest at 67.58%. Among pathogenic microorganisms, Staphylococcus aureus was the most common. Regarding the financial burden, the median total cost per patient was 25,754 RMB, and medications accounted for the largest proportion of the main costs. The most common pathogen associated with HO infection was MSSA. Oxacillin has good PK and PD and is recommended as the first-line drug. Some blood-borne bone infections may lead to complications, such as pulmonary infection through bacteremia, which requires early detection to avoid a missed diagnosis. Regarding surgical intervention, debridement plus absorbable calcium sulfate bone cement and calcium sulfate calcium phosphate bone cement exclusion have achieved good therapeutic effects, but they are worthy of further in-depth research. Regarding the financial burden, the median total cost per patient was 25,754 RMB. The financial burden of blood-borne osteomyelitis was lower than that of traumatic osteomyelitis. Among the main costs, drugs accounted for the largest proportion.

Complications Following Intraosseous Injections of Calcium Phosphate Bone Cement in Subchondroplasty.

An alternative approach to the major problem of osteoarthritis that has begun to pique the interest of researchers focuses on the pathology of the subchondral bone, its constant cross-talk with the articular cartilage, and its interaction with the joint. The presence of bone marrow lesions, detectable on MRI scans, has proven to be a cause of pain as well as a predictor of the progression of degenerative changes. Subchondroplasty is a relatively new surgical procedure for the treatment of these lesions, in which injectable calcium phosphate bone cement is infused into the affected area percutaneously, under fluoroscopic guidance. In its use as a synthetic scaffold, calcium phosphate bone cement exhibits considerable osteoconductivity, bioabsorbability, and low toxicity, thus showing great potential for restoring subchondral biomechanical properties through structural remodeling. Although published results appear quite promising, there are certain complications that the surgeon should be aware of. We reviewed the published data regarding complications of the procedure, highlighting possible causes according to these data, and suggesting safety measures. Avascular necrosis of the talus is the most reported concern. Postsurgical pain, infection, and continuous wound drainage due to bone substitute material extravasation to the joint or soft tissue are also mentioned, necessitating further standardization of the procedure. There are no reports of permanent postoperative disability or fatal outcomes.

Multifunctional magnetocaloric bone cement with a time-varying alkaline microenvironment for sequential bacterial inhibition, angiogenesis and osteogenesis.

Repairing infected bone defects remains a severe challenge due to antibiotic abuse and recurrence. Hence, we modified magnetocaloric Fe3O4 nanoparticles and added them to magnesium calcium phosphate bone cement (MCPC) to fabricate multifunctional magnetic composites for sequential bacterial inhibition, angiogenesis and osteogenesis. Nevertheless, high doses of Mg ions and Fe ions were released from MCPC, which adversely affected osteogenesis. Thus, Fe3O4 was modified using gelatin according to the emulsification crosslinking method, which exhibited a controllable magnetocaloric effect and degradation behavior, and favorable anti-bacterial ability under the action of an alternating magnetic field (AMF). In the early stage, the residual MgO created a local strong alkaline microenvironment by hydrolysis, which inhibited the function and activity of S. aureus and E. coli. At the later stage, the MCPC composites were controllably degraded under the function of gelatin and maintained a long-term local slight alkaline microenvironment that promoted the osteogenic differentiation and mineralization of BMSCs. In vivo subcutaneous implantation experiments further indicated that MCPC composites showed good biocompatibility and facilitated angiogenesis, presenting a promising future in magnetic materials design and infectious bone defect repair.

Biosurfactants as foaming agents in calcium phosphate bone cements

The idea of using biosurfactants to obtain highly porous, foamed calcium phosphate cements (fCPCs) is novel. The popularity of these compounds is mainly attributed to their biological activity such as anticancer or antibacterial properties. In our study, it was investigated how the functionalization of cements, based on α-tricalcium phosphate (α-TCP), with non-ionic biosurfactants such as sucrose ester S0112 and saponin from Quillaja bark affected the physicochemical as well as biological properties of cement-type materials. Foaming with these selected surface active agents led to highly porous fCPCs (open porosity >60 vol%) with compressive strength values ranging from 0.2 to 3.3 MPa and did not influence negatively the bioactive potential of the cements. Results showed that the sucrose ester had a positive effect on all studied cell types (osteosarcoma cell line MG-63 and preosteoblasts MC3T3-E1), while the effect of the saponin differed depending on the origin of the cells (cancerous or non-cancerous). The obtained results shed new light on the use of biosurfactants as additives to CPCs and pave the way for further studies, especially in vivo.