Acrylic Bone Cement Research Articles

The chitosan/tri-calcium phosphate bio-composite bone cement promotes better osteo-integration: an in vitro and in vivo study

BackgroundPolymethylmethacrylate bone cement has a variety of applications in orthopedic surgery, but it also has some shortcomings such as high heat generation during polymerization and poor integration with bone tissue. In this study, a bio-composite bone cement composed of tri-calcium phosphate and chitosan as additives to acrylic bone cement was developed. Our hypothesis is that this new bio-composite bone cement has a better osteo-integration than pure polymethyl methacrylate cement.MethodsPhysiological composition, i.e., 65 wt% inorganic and 35 wt% organic components, of tri-calcium phosphate and chitosan contents was selected as degradable additives to replace acrylic bone cement. A series of properties such as exothermic temperature changes, setting time, bio-mechanical characteristics, degradation behaviors, and in vitro cytotoxicity were examined. Preliminary in vivo animal study was also performed.ResultsThe results showed that the bio-composite bone cement exhibited lower curing temperature, longer setting time, higher weight loss and porosity after degradation, lower compressive Young’s modulus, and ultimate compressive strength as compared with those of pure polymethyl methacrylate cement. Cell proliferation tests demonstrated that the bio-composite bone cement was non-cytotoxic, and the in vivo tests revealed that was more osteo-conductive.ConclusionsThe results indicated that the modified chitosan/tri-calcium phosphate/polymethyl methacrylate bio-composites bone cement could be degraded gradually and create rougher surfaces that would be beneficial to cell adherence and growth. This new bio-composite bone cement has potential in clinical application. Our future studies will focus on long-term implantation to investigate the stability of the bio-composite bone cement in long-term implantation.

Surface degradation–enabled osseointegrative, angiogenic and antiinfective properties of magnesium-modified acrylic bone cement

ObjectiveThis work focuses on tackling the inadequate bone/implant interface strength of acrylic bone cements, which is a formidable problem diminishing their clinical performance, especially in percutaneous kyphoplasty surgery. MethodsA new strategy of incorporating magnesium particles into clinically used poly(methylmethacrylate) (PMMA) bone cement to prepare a surface-degradable bone cement (SdBC) is proposed and validated both in vitro and in vivo. ResultsThis surface degradation characteristic enables osseointegrative, angiogenic and antiinfective properties. SdBC showed fast surface degradation and formed porous surfaces as designed, while the desirable high compressive strengths (≥70 MPa) of the cement were preserved. Besides, the SdBC with proper Mg content promoted osteoblast adhesion, spreading, proliferation and endothelial cell angiogenesis capacity compared with PMMA. Also, SdBC demonstrated clear inhibitory effect on Staphylococcus aureus and Escherichia coli. In vivo evaluation on SdBC by the rat femur defect model showed that the bone/implant interface strength was significantly enhanced in SdBC (push-out force of 11.8 ± 1.5 N for SdBC vs 7.0 ± 2.3N for PMMA), suggesting significantly improved osseointegration and bone growth induced by the surface degradation of the cement. The injectability, setting times and compressive strengths of SdBC with proper content of Mg particles (2.8 wt% and 5.4 wt%) were comparable with those of the clinical acrylic bone cement, while the heat release during polymerization was reduced (maximum temperature 78 ± 1 °C for PMMA vs 73.3 ± 1.5 °C for SdBC). ConclusionsThis work validates a new concept of designing bioactive bone/implant interface in PMMA bone cement. And this surface-degradable bone cement possesses great potential for minimally invasive orthopaedic surgeries such as percutaneous kyphoplasty. The translational potential of this articleThis work reports PMMA/Mg surface-degradable acrylic bone cements that possess enhanced osseointegrative, angiogenic and antiinfective properties that are lacking in the clinically used acrylic bone cements. This new kind of bone cements could improve the treatment outcome of many orthopaedic surgeries such as percutaneous kyphoplasty and arthroplasty.

Integrity of Human Mandibular Angle After Block Graft Harvest from Mandibular Body.

To examine human mandibular angle integrity alterations accompanying a mandibular body block graft harvest surgical procedure. Hemimandibles from 24 human cadavers were resected and sorted into one of three groups by residual dental status. The height of each hemimandible body was obtained and recorded. Acrylic bone cement was utilized to mount the hemimandibles at the mandibular condyle. Using standard surgical instruments and techniques, cortical bone of the mandibular body buccal plate was resected from the right hemimandibles. Left hemimandibles were used as a control. Each hemimandible was secured in an Instron 5565 mechanical unit. With forces placed on and perpendicular to the occlusal plane, each hemimandible underwent sequential loading until osseous fracture occurred. Descriptive statistics between grouped data were compared and discussed in terms of mean, minimum, and maximum. The statistical relationship between the maximal load, gender, and mandibular body height were identified. Donor and control hemimandible maximal load mean values were 423.63 N and 957.90 N, respectively. A statistically significant difference was present between maximal loads of donor and control hemimandibles (P < .0001). Correlations of statistical significance were present between mandibular bone height and maximal load in the control hemimandibles (P = .009). Correlations of statistical significance were not found between mandibular bone height, displacement at maximal load, and maximal load in the grafted hemimandibles (P >.05). No statistically significant correlation between dental status and gender was found in the donor and control hemimandibles (P > .05). After subjected to a typical block graft harvest surgical procedure, the human mandible's integrity is significantly altered. Gender, dental status, and mandibular bone height do not correlate with maximal load,and thus integrity, of donor and control mandibles.

Investigation of Biological Activity, Open Porosity and Water Absorption of Ternary Polymeric Blend (Polymethylmethacrylate / Starch) used for Bone Scaffold

In this study a fabrication of three groups of biological system for bone scaffold, which consist of first group samples (Acrylic bone cement: % X poly methyl meth acrylate ), second group samples (poly methyl meth acrylate: % X Acrylic bone cement), with selected weight percentages of second material are (5, 10,15 and 20 % wt.) and third group, (Acrylic bone cement: 15 % poly methyl meth acrylate : % X starch) with selected weight percentage ratios of starch are (2, 4 and 6 %wt.). In vitro biological activity and water absorption have been studied. The results clarified that the in vitro biological activity test showed that all fabricated samples have no biological influence on the gram positive bacteria Bacillus subtilis and gram negative bacteria Escherichia coli . The results show that the first group of polymer blend have low open porosity and water uptake capacity than a second group. The increasing in starch weight fraction for the third group led to increasing in open porosity and water absorption..

Assessment of the Integrity of Adult Human Mandibular Angle

The purpose of this study was to analyze the integrity of the adult human mandibular angle. The left hemimandibles of 24 human cadavers were selected and divided into three groups based upon remaining dental status. The height of the left mandibular body was measured. Hemimandibles were mounted in acrylic bone cement at the mandibular condyle. The left mounted hemimandibles were secured into an Instron 5565 mechanical unit and the occlusal plane was sequentially loaded until fracture of the mandibular bone occurred. Minimum, maximum, mean, and standard deviations for compressive force as well as displacement of the occlusal plane were derived and compared for descriptive statistics. The correlations between the gender, mandibular body height, and maximal load were examined. The mean mandibular heights among males and females were 22.44 mm and 17.53 mm, respectively. Results portrayed a significant correlation between gender and mandibular height. The mean maximal loads among males and females were 1,174.17 and 828.14 N, respectively. Results portrayed a statistically significant difference between males and females regarding maximum load as well as the height of the mandible ( p=0.0103 and p=0.0067, respectively). No statistically significant association between maximum load and dental status (presence/absence of molar teeth) was found ( p &gt; 0.05). The maximal load of human mandibular angle was found to be higher than that of the heavily investigated polyurethane synthetic mandible replica. The average height of the mandibular body in males was found to be greater than that of females. Mandibular body height showed a direct correlation to maximal load of the hemimandibular angle. In maxillofacial research, biomechanical evaluations of mandibular angle fractures and plating techniques with human cadaveric bone should be considered alongside or in place of conventional synthetic polyurethane mandibles.

Improvement of fatigue strength and fracture toughness of bone cement by incorporation of aromatic structures to formulations

It has been postulated that the incorporation of cyclic or aromatic groups to the chemical structure of monomers/polymers could improve the mechanical performance of the polymeric materials prepared from them. In this work, N-methacryloyloxyethyl-m-toluidine (MEET) monomer, a compound whose chemical structure is similar to diethylamino ethyl methacrylate (DEAEM) but having an aromatic ring, was synthesized. Acrylic bone cements were prepared using either MEET or DEAEM as co-monomer and a systematic study of the potential influence of adding aromatic structures on the fatigue properties and fracture toughness of such bone cements was performed. Results indicated that the formulations prepared with the aromatic co-monomer (MEET) exhibited a higher fatigue resistance than those containing the aliphatic counterpart (DEAEM), at all co-monomer concentrations. These results confirm the hypothesis that the inclusion of aromatic structures in the bone cement formulations increases the fatigue life of these materials. It was also found that presence of aromatic structures in bone cement formulations improve the fracture toughness of cements.

Enhancing mechanical properties of an injectable two-solution acrylic bone cement using a difunctional crosslinker.

Two-solution bone cements modified with ethylene glycol-dimethacrylate (EG-DMA) as a crosslinker have been developed as an attempt to further improve the mechanical properties of acrylic bone cement. The result of this study shows that EG-DMA can increase the mechanical properties and fractional monomer conversion while preserving the thermal characteristics. The strength and bending modulus increase with EG-DMA concentrations at 5-10 vol % EG-DMA. Substituting the EG-DMA content past 10 vol % decreases the bending properties due to the effects of reduced monomer concentrations. Strengthened EG-DMA samples demonstrated an increase in ductility with noticeably different fracture surface morphologies than the control samples, indicated by microtroughs and ridge formation caused by excessive plastic strain. This work provides insight into the effect of substituting a crosslinker for MMA monomer in an injectable two-solution system and lays out the ideal concentrations of EG-DMA for superior mechanical or fractional monomer conversion properties. © 2018 Wiley Periodicals, Inc. J. Biomed. Mater. Res. Part B, 2018. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 783-790, 2019.

Standardization of Acrylic Bone Cement Mixing Protocols for Total Knee Arthroplasty Results in Cost Savings.

Cost reduction is important in total joint replacement surgery. Bone cement is used to fixate implants in most knee replacement procedures. The authors instituted a 4-pronged approach to reduce the cost of cement. Their approach included reducing the cost of the cement powder, changing the type of mixing method, using less antibiotic cement, and decreasing the amount of cement required for smaller implants. The authors evaluated the implementation of this program and measured the overall costs of cementation during knee replacement. A retrospective review of total knee replacement cementation technique and cost was performed before and after the cost-reduction program was implemented. The type of cement and cement mixing equipment used, the amount of cement used, and the cost of cement and cement mixing equipment were examined. The authors also reported the short-term complication rate including 90-day readmission rate and 30-day revision rate. The program resulted in an overall decrease in cement-related costs from approximately $310 to $105 per case. Reductions in the amount of cement used and the use of antibiotic cement were shown. Among the 3 surgeons, adoption of the program varied. Bone cement is an expense of modern total knee replacement. Implementing a cost-reduction program can reduce cement costs without changing quality of cementation. [Orthopedics. 2018; 41(5):e671-e675.].

Role of antibiotic loaded acrylic bone cement in orthopedic infection

Role of antibiotic loaded acrylic bone cement in orthopedic infection

Pelvic reconstruction with bone cement and total hip prosthesis after resection of chondrosarcoma. Case Report

Abstract Introduction. Chondrosarcoma is a malignant tumor of cartilaginous origin representing approximately 20-30% of all bone malignant tumors and occupying the second place in terms of their incidence. It usually affects adults between 40 and 60 years old, but can be encountered at older ages as well. Materials and methods. We report the case of a 55-year-old male patient who presented to our department with 2 weeks-long right hip pain and partial loss of functionality in right limb. We performed X-rays, magnetic resonance imaging, computed tomography, bone scintigraphy, and angiography, which established the diagnosis of pelvic tumor. Biopsy of the tumor was performed by iliofemoral approach and its result showed moderately differentiated chondrosarcoma. Orthopaedic surgery was performed, with tumoral removal within oncological limits, pelvic reconstruction using acrylic bone cement impregnated with Vancomycin and total hip arthroplasty. Results were assessed using the Musculoskeletal Tumor Rating Scale and a score of 23 out of 35 was obtained (the higher the better). Postoperative complications consisted in flap-skin necrosis that resolved within 2 months after surgery. Conclusion. Bone defects repair using antibiotic impregnated cement drastically reduced the rate of postoperative infections, thus decreasing both morbidity and mortality. In spite of technological advancement, long-term prognosis remains reserved in chondrosarcoma, due to its specific aggressivity, resistance to chemo- and radiotherapy and high rate of recurrence.

Amphiphilic Bioactive Filler for Acrylic Bone Cement to Enhance Its Cell Adhesion.

Bioactive amphiphilic raspberry particles (BRPs) were proposed to addressing the challenge in cement-bone interface non-integration that was often taking place when poly(methyl methacrylate) (PMMA) bone cements are used. BRPs were designed to have surface patches with different functions, some of which are bioactive to promote bonding to bone and the rest are hydrophobic to promote well compatibility with PMMA matrix. With Pickering emulsion polymerization plus post-modification on surface, such functional particles have been successfully prepared and the composite cements (BRP-PMMA composite cements) were indeed found to promote bone related cell adhesion, while not to sacrifice any of the virtues of the conventional PMMA bone cements.

In vivo response to a low-modulus PMMA bone cement in an ovine model

Poly(methyl methacrylate) (PMMA) is the most commonly used material for the treatment of osteoporosis-induced vertebral compression fractures. However, its high stiffness may introduce an increased risk of adjacent vertebral fractures post-surgery. One alternative in overcoming this concern is the use of additives. This presents its own challenge in maintaining an adequate biocompatibility when modifying the base cement. The aim of this study was to evaluate the in vivo biocompatibility of linoleic acid (LA)-modified acrylic bone cement using a large animal model for the first time, in order to further advance towards clinical use. A worst-case approach was used, choosing a slow-setting base cement. The in vitro monomer release from the cements was also assessed. Additional material characterization, including mechanical tests, are summarized in Appendix A. Unmodified and LA-modified cements were injected into a total of 56 bone defects created in the femur and humerus of sheep. Histopathologic and histomorphometric analysis indicated that LA-modified cement showed a harmless tissue response similar to that of the unmodified cement. Adjacent bone remodeling was observed microscopically 4 weeks after implantation, suggesting a normal healing process of the bone tissues surrounding the implant. LA-modified cement exhibited lower mechanical properties, with a reduction in the elastic modulus of up to 65%. The handling properties were slightly modified without negatively affecting the injectability of the base cement. LA-modified bone cement showed good biocompatibility as well as bone compliant mechanical properties and may therefore be a promising material for the treatment of osteoporotic vertebral fractures. Statement of SignificanceThe benefits of using linoleic acid to reduce the stiffness of poly(methyl methacrylate) bone cement has been demonstrated previously, with the in vitro and in vivo response of the modified cement in small animals reported as comparable to the base cement. However, biocompatibility evaluation of modified cement in large animal models for future clinical use has yet to be performed. In this study, modified and unmodified cements were injected into bone defects created in sheep. We showed that the inflammatory response of the modified cement was similar to the base cement, allowing remodelling of the bone surrounding the implant. This demonstrates the potential of low-modulus PMMA cement in the field of bone augmentation.

Mechanical Properties and Porosity of Acrylic Cement Bone Loaded with Alendronate Powder

Aseptic loosening is the most common complication of joint replacement. Previous studies showed that acrylic bone cement loaded with a commercially-available alendronate powder (APAC) had good promise against wear debris-mediated osteolysis for prevention of aseptic loosening. The purpose of the present study was to investigate the effect of adding alendronate powder to an acrylic bone cement on quasi-static mechanical properties (namely, compressive strength, compressive modulus, tensile strength, and flexural strength), fatigue life, porosity, and microstructure of the cement. The results showed that adding up to 1 wt./wt.% alendronate powder exerted no detrimental effect on any of the quasi-static mechanical properties. However, the fatigue life of APAC decreased by between ~17% and ~27 % and its porosity increased by between ~ 5-7 times compared with corresponding values for the control cement (no alendronate powder added). Fatigue life was negatively and significantly correlated with porosity. Considering that fatigue life of the cement plays a significant role in joint replacement survival, clinical use of APAC cannot be recommended.

An accelerated and accurate process for the initial guess calculation in Digital Image Correlation algorithm

The Digital Image Correlation (DIC) is now an effective method for measuring displacement in engineering fields. DIC includes a coarse search scheme with pixel-size accuracy for finding an initial guess (IG) followed by an iteration procedure to successively find the accurate/true displacements. The closer IG to the true displacement values, the higher the likelihood of convergence and the more efficient the convergence of the subsequent Newton-Raphson (NR) iteration procedure. This study introduced and verified a novel fuzzy-logic based approximation scheme intending to provide more accurate IG values after the standard full-field IG search scheme. The results based on numerical experiments showed that the novel step of IG searching scheme provided considerably more accurate IG values and reduced the computational costs of finding IG values by up to 88.5% compared to the standard scheme. Furthermore, the overall computational costs including the subsequent NR iteration procedure were reduced by 31.5%, which is substantial. To further test and demonstrate the robustness, accuracy and effectiveness of the novel DIC procedure, a large number of numerical experiments using images simulating a wide range of rigid body motions (rotation, translation) and tensile testing conditions was utilized. The results had a 98.8% accuracy rate and a 99% precision rate. The DIC procedure provided therefore efficient and accurate displacement/deformation measurements in different types of loading conditions which are used for studying the mechanics of acrylic medical bone cements that are of interest in our research laboratory.

The role of microconstituents on the fatigue failure of bone cement

Implant fixation via the use of acrylic bone cement is now a well-established practice in orthopaedics. Excellent long-term clinical results are evidenced in national joint registers based on over 5 decades of clinical experience. Increased life expectancies, patient BMI, together with the need to remain active in later life, are expected to put greater demands on the materials used in load bearing joint arthroplasty. Failure of bone cement and its interfaces with the implant and bone often leads to loosening, requiring revision surgery. This is a particularly invasive procedure, with lower long-term success rates compared to the primary procedure. To reduce the incidence of bone cement failure, it is necessary to understand the origins of failure in vivo. In the past, bulk failure of bone cement has been attributed to damage accumulation originating at pores. Advances in imaging technology now mean that we are able to observe cement microconstituents readily and identify crack-initiating defects more precisely as we attempt to understand origins of failure. The role of radiopacifier particles within the bone cement has not been examined extensively to date, and the present study demonstrates that this microconstituent could be in crack formation due in part to its ability to agglomerate and not bond with the surrounding matrix. To verify this hypothesis, explanted bone cement and laboratory tested bone cement are compared and correlations in failure mechanisms are discussed.

Therapy for Chronic Recurrent Osteomyelitis with Multi-Resistant Pseudomonas aeruginosa Using Local Antibiotic Release by a Polymethylmethacrylate Custom-Made Tibia Nail

Background: The treatment of chronic osteomyelitis by antibiotics administered intravenously is limited by the blood supply that is not present in bone sequestra. Local delivery of antibiotics using acrylic bone cement has been reported with favorable results for treatment of chronic osteomyelitis. Case Presentation: Treatment of a patient with recurrent osteomyelitis after a third- degree open tibia fracture at our hospital failed several times because of recurrent infection with Pseudomonas aeruginosa that later became multi-resistant. Suitable antibiotic treatment was limited to colistin that was mixed with polymethylmethacrylate (PMMA) matrix (Copal® G+C Plus, Heraeus, Hanau, Germany) and used to cover an Ender nail. The PMMA–tibia nail construct was placed intra-medullary for two weeks under appropriate antibiotics applied intravenously. The patient has been pain free for 18 months without any signs of infection and with normal blood tests. Conclusion: We provide evidence that colistin can be applied locally with Copal G+C providing appropriate concentration because of elution over a period of at least two weeks. This technique demonstrates a custom-made solution for patients with multi-resistant osteomyelitis for P. aeruginosa when conventional treatment fails.

Caracterizarea reologica a cimenturilor acrilice osoase utilizate in inlocuirea totala a soldului

The paper presents the results of rheological tests for three commercial acrylic bone cements currently used in total hip replacement . Moreover, twelve experimental formulations of acrylic bone cements were realized, by partially replacing the methyl methacrylate (MMA) from the classical liquid monomer phase with a new monomer and their rheological properties were evaluated and compared with the commercial bone cements. Thus, the efficacy of acrylic bone cements as anchoring materials as well as their handling and curing properties were estimated. The new formulations exhibited higher elasticity, lower dynamic moduli and clear shear-thinning behavior proving to be potential replacements for classical acrylic based bone cements.

Antibiotic elution from acrylic bone cement loaded with high doses of tobramycin and vancomycin.

Two-stage revision treatment of prosthetic joint infection (PJI) frequently employs the use of a temporary bone cement spacer loaded with multiple antibiotic types. Tobramycin and vancomycin are commonly used antibiotics in cement spacers, however, there is no consensus on the relative concentrations and combinations that should be used. Therefore, the purpose of this study was to investigate the influence of dual antibiotic loading on the total antibiotic elution and compressive mechanical properties of acrylic bone cement. Varying concentrations of tobramycin (0-3 g) and vancomycin (0-3 g) were added either alone or in combination to acrylic cement (Palacos R), resulting in 12 experimental groups. Samples were submerged in 37°C saline for 28 d and sampled at specific time points. The collected eluent was analyzed to determine the cumulative antibiotic release. In addition, the cement's compressive mechanical properties and porosity were characterized. Interestingly, the cement with the highest concentration of antibiotics did not possess the best elution properties. Cement samples containing both 3 g of tobramycin and 2 g vancomycin demonstrated the highest cumulative antibiotic release after 28 d, which was coupled with a significant decrease in the mechanical properties and an increased porosity. The collected data also suggests that tobramycin elutes more effectively than vancomycin from cement. In conclusion, this study demonstrates that high antibiotic loading in cement does not necessarily lead to enhanced antibiotic elution. Clinically this information may be used to optimize cement spacer antibiotic loading so that both duration and amount of antibiotics eluted are optimized. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1078-1085, 2018.

Synthesis of imidazolium-containing mono-methacrylates as polymerizable antibacterial agents for acrylic bone cements

With the aim to prepare antibacterial acrylic bone cements, a series of imidazolium-containg mono-methacrylates with N-alkyl chain length varied from 10 to 18 (MEIM-x) were synthesized as polymerizable antibacterial agents through a two-step reaction. The structures of the monomers were confirmed by 1H NMR. Methyl methacrylate in the liquid compoent of cements was partially replaced by MEIM-x to prepare bone cements with 5wt% of MEIM-x. Properties of prepared cements like antibacterial activity, doughing time, curing parameters including maximum temperature (Tmax) and setting time (tset), flexual strength (FS) and modulus (FM), compressive strength (CS) and fluid uptake (FU) in Ringer's solution were investigated. Acrylic bone cement without any MEIM-x was used as control. Compared with the control cement, MEIM-x-containing cements had shorter doughing time, lower Tmax, same or longer tset, and higher FU. Though MEIM-x could endow cements with strong antibacterial activity, it could reduce mechanical properties of bone cements. Therefore, further study should be taken to optimize the content of MEIM-x in cement which could supply sufficient antibacterial activity and maintain mechanical performance.

Levofloxacin-loaded bone cement delivery system: Highly effective against intracellular bacteria and Staphylococcus aureus biofilms

Staphylococcus aureus is a major pathogen in bone associated infections due to its ability to adhere and form biofilms on bone and/or implants. Moreover, recrudescent and chronic infections have been associated with S. aureus capacity to invade and persist within osteoblast cells. With the growing need of novel therapeutic tools, this research aimed to evaluate some important key biological properties of a novel carrier system composed of acrylic bone cement (polymethylmethacrylate – PMMA), loaded with a release modulator (lactose) and an antibiotic (levofloxacin).Levofloxacin-loaded bone cement (BC) exhibited antimicrobial effects against planktonic and biofilm forms of S. aureus (evaluated by a flow chamber system). Moreover, novel BC formulation showed high anti-bacterial intraosteoblast activity. This fact led to the conclusion that levofloxacin released from BC matrices could penetrate the cell membrane of osteoblasts and be active against S. aureus strains in the intracellular environment. Furthermore, levofloxacin-BC formulations showed no significant in vitro cytotoxicity and no allergic potential (measured by the in vivo chorioallantoic membrane assay). Our results indicate that levofloxacin-loaded BC has potential as a local antibiotic delivery system for treating S. aureus associated bone infections.