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Chen N. Embedded 3D printing and pressurized thermo-curing of PMMA for medical implants. J Mech Behav Biomed Mater 2023; 146:106083. [PMID: 37678106 DOI: 10.1016/j.jmbbm.2023.106083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 08/15/2023] [Accepted: 08/20/2023] [Indexed: 09/09/2023]
Abstract
Poly (methyl methacrylate) (PMMA) is a synthetic polymer commonly used for medical implants in cranioplasty and orthopedic surgery owing to its excellent mechanical properties, optical transparency, and minimal inflammatory responses. Recently, the development of 3D printing opens new avenues in the fabrication of patient-specific PMMA implants for personalized medicine. However, challenges are confronted when adapting medical-grade PMMA to the 3D printing process due to its dynamic viscosity and nonself-supporting characteristics before cured. In addition, the intrinsically exothermic polymerization of MMA brings about bubble generation issues that reduce its mechanical performance harshly. Therefore, in this study, an embedded 3D printing methodology followed by pressurized thermo-curing is proposed and developed: a granular alginate microgel is designed for serving as a supporting matrix when jamming formed between the granules to structurally support the extruded precursor filaments of PMMA-MMA ink during both 3D printing and post-curing; moreover, the autoclave reactor enclosing the alginate matrix and as-sculpted PMMA structures is utilized to generate temperature-dependent pressure, which serves for suppressing the bubbles and solidifying the polymerized MMA during the post-curing process. The 3D printed PMMA is comparably matchable to traditional PMMA castings in terms of their microstructures, density, thermal properties, mechanical performance and biocompatibility. In the future, the proposed embedded 3D printing platform combined with the special post-curing method has great potential for a customized and cost-effective fabrication of patient-specific, complex and functional PMMA implants.
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Affiliation(s)
- Na Chen
- Xi'an Children's Hospital, Xi'an, Shaanxi, China.
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Xia X, Shi R, Huang J, Li Y, Zuo Y, Li J. Development of a phase change microcapsule to reduce the setting temperature of PMMA bone cement. J Appl Biomater Funct Mater 2020; 18:2280800020940279. [PMID: 33147094 DOI: 10.1177/2280800020940279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The aim of the current study is to alleviate the adverse effect of the strongly exothermic polymerization of polymethyl methacrylate (PMMA) bone cement in clinical applications. In this study, paraffin/poly(methyl methacrylate-methylene bisacrylamide) (paraffin/P(MMA-MBA)) phase change microcapsules (MPn; n = 1, 2) were developed via the emulsion polymerization method. The reduction of the maximum temperature of polymerization (Tmax) and physicochemical properties were evaluated after doping commercial PMMA cement with MPn in specific proportions (10%, 20%, and 30%). The results reveal that the MPn-doped PMMA exhibited an effective reduction in Tmax, which can help alleviate the adverse effect of the strong exothermic reactions during PMMA setting. After doping with the MPn, the mechanical properties of the PMMA cement decrease and the values are close to that of body cancellous bone. The Tmax of the cement doped with 20 wt% MP1 is 37.6°C, which is close to body temperature. Significantly, the setting and compressive properties of the optimized group can still adhere to clinical requirements. The MPn doping PMMA technique holds much promise in clinical practice.
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Affiliation(s)
- Xue Xia
- Research Center for Nano Biomaterials, Analytical & Testing Center, Sichuan University, Chengdu, Sichuan, People's Republic of China
| | - Rui Shi
- Department of Orthopaedics, West China Hospital, Sichuan University, Chengdu, Sichuan, People's Republic of China
| | - Jinhui Huang
- Research Center for Nano Biomaterials, Analytical & Testing Center, Sichuan University, Chengdu, Sichuan, People's Republic of China
| | - Yubao Li
- Research Center for Nano Biomaterials, Analytical & Testing Center, Sichuan University, Chengdu, Sichuan, People's Republic of China
| | - Yi Zuo
- Research Center for Nano Biomaterials, Analytical & Testing Center, Sichuan University, Chengdu, Sichuan, People's Republic of China
| | - Jidong Li
- Research Center for Nano Biomaterials, Analytical & Testing Center, Sichuan University, Chengdu, Sichuan, People's Republic of China
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Panpisut P, Khan MA, Main K, Arshad M, Xia W, Petridis H, Young AM. Polymerization kinetics stability, volumetric changes, apatite precipitation, strontium release and fatigue of novel bone composites for vertebroplasty. PLoS One 2019; 14:e0207965. [PMID: 30883564 PMCID: PMC6422261 DOI: 10.1371/journal.pone.0207965] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 02/26/2019] [Indexed: 12/19/2022] Open
Abstract
PURPOSE The aim was to determine effects of diluent monomer and monocalcium phosphate monohydrate (MCPM) on polymerization kinetics and volumetric stability, apatite precipitation, strontium release and fatigue of novel dual-paste composites for vertebroplasty. MATERIALS AND METHODS Polypropylene (PPGDMA) or triethylene (TEGDMA) glycol dimethacrylates (25 wt%) diluents were combined with urethane dimethacrylate (70 wt%) and hydroxyethyl methacrylate (5 wt%). 70 wt% filler containing glass particles, glass fibers (20 wt%) and polylysine (5 wt%) was added. Benzoyl peroxide and MCPM (10 or 20 wt%) or N-tolyglycine glycidyl methacrylate and tristrontium phosphate (15 wt%) were included to give initiator or activator pastes. Commercial PMMA (Simplex) and bone composite (Cortoss) were used for comparison. ATR-FTIR was used to determine thermal activated polymerization kinetics of initiator pastes at 50-80°C. Paste stability, following storage at 4-37°C, was assessed visually or through mixed paste polymerization kinetics at 25°C. Polymerization shrinkage and heat generation were calculated from final monomer conversions. Subsequent expansion and surface apatite precipitation in simulated body fluid (SBF) were assessed gravimetrically and via SEM. Strontium release into water was assessed using ICP-MS. Biaxial flexural strength (BFS) and fatigue properties were determined at 37°C after 4 weeks in SBF. RESULTS Polymerization profiles all exhibited an inhibition time before polymerization as predicted by free radical polymerization mechanisms. Initiator paste inhibition times and maximum reaction rates were described well by Arrhenius plots. Plot extrapolation, however, underestimated lower temperature paste stability. Replacement of TEGDMA by PPGDMA, enhanced paste stability, final monomer conversion, water-sorption induced expansion and strontium release but reduced polymerization shrinkage and heat generation. Increasing MCPM level enhanced volume expansion, surface apatite precipitation and strontium release. Although the experimental composite flexural strengths were lower compared to those of commercially available Simplex, the extrapolated low load fatigue lives of all materials were comparable. CONCLUSIONS Increased inhibition times at high temperature give longer predicted shelf-life whilst stability of mixed paste inhibition times is important for consistent clinical application. Increased volumetric stability, strontium release and apatite formation should encourage bone integration. Replacing TEGDMA by PPGDMA and increasing MCPM could therefore increase suitability of the above novel bone composites for vertebroplasty. Long fatigue lives of the composites may also ensure long-term durability of the materials.
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Affiliation(s)
- Piyaphong Panpisut
- Department of Biomaterials and Tissue Engineering, UCL Eastman Dental Institute, London, United Kingdom
| | - Muhammad Adnan Khan
- Department of Biomaterials and Tissue Engineering, UCL Eastman Dental Institute, London, United Kingdom
| | - Kirsty Main
- Department of Biomaterials and Tissue Engineering, UCL Eastman Dental Institute, London, United Kingdom
| | - Mayda Arshad
- Department of Biomaterials and Tissue Engineering, UCL Eastman Dental Institute, London, United Kingdom
| | - Wendy Xia
- Department of Biomaterials and Tissue Engineering, UCL Eastman Dental Institute, London, United Kingdom
| | - Haralampos Petridis
- Department of Restorative Dentistry, Unit of Prosthodontics, UCL Eastman Dental Institute, London, United Kingdom
| | - Anne Margaret Young
- Department of Biomaterials and Tissue Engineering, UCL Eastman Dental Institute, London, United Kingdom
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Charlier Q, Fontanier JC, Lortie F, Pascault JP, Gerard JF. Rheokinetic study of acrylic reactive mixtures dedicated to fast processing of fiber-reinforced thermoplastic composites. J Appl Polym Sci 2018. [DOI: 10.1002/app.47391] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Quentin Charlier
- University of Lyon, INSA-Lyon, Ingénierie des Matériaux Polymères, UMR CNRS 5223; F-69621 Villeurbanne France
| | - Jean-Charles Fontanier
- University of Lyon, INSA-Lyon, Ingénierie des Matériaux Polymères, UMR CNRS 5223; F-69621 Villeurbanne France
| | - Frédéric Lortie
- University of Lyon, INSA-Lyon, Ingénierie des Matériaux Polymères, UMR CNRS 5223; F-69621 Villeurbanne France
| | - Jean-Pierre Pascault
- University of Lyon, INSA-Lyon, Ingénierie des Matériaux Polymères, UMR CNRS 5223; F-69621 Villeurbanne France
| | - Jean-François Gerard
- University of Lyon, INSA-Lyon, Ingénierie des Matériaux Polymères, UMR CNRS 5223; F-69621 Villeurbanne France
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Palagummi SV, Landis FA, Chiang MYM. Real-time synchronous measurement of curing characteristics and polymerization stress in bone cements with a cantilever-beam based instrument. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:035102. [PMID: 29604748 PMCID: PMC5834317 DOI: 10.1063/1.5025476] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Accepted: 02/07/2018] [Indexed: 06/08/2023]
Abstract
An instrumentation capable of simultaneously determining degree of conversion (DC), polymerization stress (PS), and polymerization exotherm (PE) in real time was introduced to self-curing bone cements. This comprises the combination of an in situ high-speed near-infrared spectrometer, a cantilever-beam instrument with compliance-variable feature, and a microprobe thermocouple. Two polymethylmethacrylate-based commercial bone cements, containing essentially the same raw materials but differ in their viscosity for orthopedic applications, were used to demonstrate the applicability of the instrumentation. The results show that for both the cements studied the final DC was marginally different, the final PS was different at the low compliance, the peak of the PE was similar, and their polymerization rates were significantly different. Systematic variation of instrumental compliance for testing reveals differences in the characteristics of PS profiles of both the cements. This emphasizes the importance of instrumental compliance in obtaining an accurate understanding of PS evaluation. Finally, the key advantage for the simultaneous measurements is that these polymerization properties can be correlated directly, thus providing higher measurement confidence and enables a more in-depth understanding of the network formation process.
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Affiliation(s)
- Sri Vikram Palagummi
- Biosystems and Biomaterials Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Forrest A Landis
- Penn State University-York Campus, York, Pennsylvania 17403, USA
| | - Martin Y M Chiang
- Biosystems and Biomaterials Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
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Abstract
Aneurysmal bone cyst (ABC) is a vascular tumor of the spine. Management of spinal ABC still remains controversial because of its location, vascular nature and incidence of recurrence. In this manuscript, we hereby describe two cases of ABC spine treated by curettage, vertebral cement augmentation for control of bleeding and internal stabilization with two years followup. To the best of our knowledge, this is the first case report in the literature describing the role of cement augmentation in spinal ABC in controlling vascular bleeding in curettage of ABC of spine. Case 1: A 22 year old male patient presented with chronic back pain. On radiological investigation, there were multiple, osteolytic septite lesions at L3 vertebral body without neural compression or instability. Percutaneous transpedicular biopsy of L3 from involved pedicle was done. This was followed by cement augmentation through the uninvolved pedicle. Next, transpedicular complete curettage was done through involved pedicle. Case 2: A 15-year-old female presented with nonradiating back pain and progressive myelopathy. On radiological investigation, there was an osteolytic lesion at D9. At surgery, decompression, pedicle screw-rod fixation and posterolateral fusion from D7 to D11 was done. At D9 level, through normal pedicle cement augmentation was added to provide anterior column support and to control the expected bleeding following curettage. Transpedicular complete curettage was done through the involved pedicle with controlled bleeding at the surgical field. Cement augmentation was providing controlled bleeding at surgical field during curettage, internal stabilization and control of pain. On 2 years followup, pain was relieved and there was a stable spinal segment with well filled cement without any sign of recurrence in computed tomography scan. In selected cases of spinal ABC with single vertebral, single pedicle involvement; cement augmentation of vertebra through normal pedicle has an important role in surgery aimed for curettage of vertebra.
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Affiliation(s)
- Saumyajit Basu
- Neuro-Spine Unit, Park Clinic, Minto-park, Kolkata, West-Bengal, India
| | - Dharmesh R Patel
- Neuro-Spine Unit, Park Clinic, Minto-park, Kolkata, West-Bengal, India,Address for correspondence: Dr. Dharmesh R Patel, 6th Floor Reception, Park Clinic, Minto Park, Kolkata - 700 017, West Bengal, India. E-mail:
| | - Gaurav Dhakal
- Neuro-Spine Unit, Park Clinic, Minto-park, Kolkata, West-Bengal, India
| | - T Sarangi
- Neuro-Spine Unit, Park Clinic, Minto-park, Kolkata, West-Bengal, India
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Hagan CP, Orr JF, Mitchell CA, Dunne NJ. Critical evaluation of pulse-echo ultrasonic test method for the determination of setting and mechanical properties of acrylic bone cement: influence of mixing technique. ULTRASONICS 2015; 56:279-286. [PMID: 25260486 DOI: 10.1016/j.ultras.2014.08.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2012] [Revised: 07/24/2014] [Accepted: 08/09/2014] [Indexed: 06/03/2023]
Abstract
Currently there is no reliable objective method to quantify the setting properties of acrylic bone cements within an operating theatre environment. Ultrasonic technology can be used to determine the acoustic properties of the polymerising bone cement, which are linked to material properties and provide indications of the physical and chemical changes occurring within the cement. The focus of this study was the critical evaluation of pulse-echo ultrasonic test method in determining the setting and mechanical properties of three different acrylic bone cement when prepared under atmospheric and vacuum mixing conditions. Results indicated that the ultrasonic pulse-echo technique provided a highly reproducible and accurate method of monitoring the polymerisation reaction and indicating the principal setting parameters when compared to ISO 5833 standard, irrespective of the acrylic bone cement or mixing method used. However, applying the same test method to predict the final mechanical properties of acrylic bone cement did not prove a wholly accurate approach. Inhomogeneities within the cement microstructure and specimen geometry were found to have a significant influence on mechanical property predictions. Consideration of all the results suggests that the non-invasive and non-destructive pulse-echo ultrasonic test method is an effective and reliable method for following the full polymerisation reaction of acrylic bone cement in real-time and then determining the setting properties within a surgical theatre environment. However the application of similar technology for predicting the final mechanical properties of acrylic bone cement on a consistent basis may prove difficult.
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Affiliation(s)
- Christopher P Hagan
- School of Mechanical and Aerospace Engineering, Queen's University Belfast, Stranmillis Road, Belfast BT9 5AH, UK
| | - John F Orr
- School of Mechanical and Aerospace Engineering, Queen's University Belfast, Stranmillis Road, Belfast BT9 5AH, UK
| | - Christina A Mitchell
- School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Grosvenor Road, Belfast BT12 6BP, UK
| | - Nicholas J Dunne
- School of Mechanical and Aerospace Engineering, Queen's University Belfast, Stranmillis Road, Belfast BT9 5AH, UK.
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Thermal Isotherms in PMMA and Cell Necrosis during Total Hip Arthroplasty. J Appl Biomater Funct Mater 2014; 12:193-202. [DOI: 10.5301/jabfm.5000196] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/31/2013] [Indexed: 11/20/2022] Open
Abstract
Background Polymethylmethacrylate (PMMA), also known as bone cement, is a commonly used adhesive material to fix implants in Total Hip Arthroplasty (THA). During implantation, bone cement undergoes a polymerization reaction which is an exothermic reaction and results in the release of heat to the surrounding bone tissue, which ultimately leads to thermal necrosis. Necrosis in the bony tissue results in early loosening of the implant, which causes pain and reduces the life of the implant. Purpose The main objective of the present study was to understand the thermal isotherms in PMMA and to determine the optimal cement mantle thickness to prevent cell necrosis during THA. Methods In this study, the environment in the bony tissue during implantation was simulated by constructing 3D solid models to observe the temperature distribution in the bony tissue at different cement mantle thicknesses (1 mm, 3 mm and 5 mm), by applying the temperature conditions that exist during the surgery. Stems made with Co-Cr-Mo, 316L stainless steel and Ti6Al4V were used, which acted as heat sinks, and a thermal damage equation was used to measure the bone damage. FEA was conducted based on temperature conditions and thermal isotherms at different cement mantle thicknesses were obtained. Results Thermal isotherms derived with respect to distance in the bony tissue from the center of the cement mantle, and cell necrosis was determined at different mantle thicknesses. Based on the deduced results, cement mantle thickness of 1-5 mm does not cause thermal damage in the bony tissue. Conclusion Considering the long term stability of the implant, cement mantle thickness range from 3 mm-5 mm was found to be optimal in THA to prevent cell necrosis.
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Lai PL, Tai CL, Chu IM, Fu TS, Chen LH, Chen WJ. Hypothermic manipulation of bone cement can extend the handling time during vertebroplasty. BMC Musculoskelet Disord 2012; 13:198. [PMID: 23072273 PMCID: PMC3524464 DOI: 10.1186/1471-2474-13-198] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Accepted: 10/12/2012] [Indexed: 11/12/2022] Open
Abstract
Background Polymethylmethacrylate (PMMA) is commonly used for clinical applications. However, the short handling time increases the probability of a surgeon missing the crucial period in which the cement maintains its ideal viscosity for a successful injection. The aim of this article was to illustrate the effects a reduction in temperature would have on the cement handling time during percutaneous vertebroplasty. Methods The injectability of bone cement was assessed using a cement compressor. By twisting the compressor, the piston transmits its axial load to the plunger, which then pumps the bone cement out. The experiments were categorized based on the different types of hypothermic manipulation that were used. In group I (room temperature, sham group), the syringes were kept at 22°C after mixing the bone cement. In group 2 (precooling the bone cement and the container), the PMMA powder and liquid, as well as the beaker, spatula, and syringe, were stored in the refrigerator (4°C) overnight before mixing. In group 3 (ice bath cooling), the syringes were immediately submerged in ice water after mixing the bone cement at room temperature. Results The average liquid time, paste time, and handling time were 5.1 ± 0.7, 3.4 ± 0.3, and 8.5 ± 0.8 min, respectively, for group 1; 9.4 ± 1.1, 5.8 ± 0.5, and 15.2 ± 1.2 min, respectively, for group 2; and 83.8 ± 5.2, 28.8 ± 6.9, and 112.5 ± 11.3 min, respectively, for group 3. The liquid and paste times could be increased through different cooling methods. In addition, the liquid time (i.e. waiting time) for ice bath cooling was longer than for that of the precooling method (p < 0.05). Conclusions Both precooling (i.e. lowering the initial temperature) and ice bath cooling (i.e. lowering the surrounding temperature) can effectively slow polymerization. Precooling is easy for clinical applications, while ice bath cooling might be more suitable for multiple-level vertebroplasty. Clinicians can take advantage of the improved injectability without any increased cost.
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Affiliation(s)
- Po-Liang Lai
- Graduate Institute of Medical Mechatronics, Department of Mechanical Engineering, Chang Gung University, Taoyuan, Taiwan
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10
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The effect of N-acetylcysteine addition on the polymerization behavior of PMMA bone cement. Macromol Res 2012. [DOI: 10.1007/s13233-012-0132-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Qiu XS, Wang F, Yao C, Chen DY, Xu ZH, Jiang Q. Association between deep vein thrombosis and the temperature at the popliteal fossa during cement curing in total knee arthroplasty. J Arthroplasty 2011; 26:414-8. [PMID: 20347257 DOI: 10.1016/j.arth.2010.01.099] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2009] [Accepted: 01/27/2010] [Indexed: 02/01/2023] Open
Abstract
The temperature at the popliteal fossa during cement curing and its relationship with deep vein thrombosis (DVT) in total knee arthroplasty (TKA) has not been investigated. Fifty-six consecutive patients who underwent primary TKA were recruited. The temperatures at the popliteal fossa were measured during bone cement exothermic polymerization. Postoperative operated leg ascending venographies were performed 5 days after TKA for screening of DVT. The maximum temperatures were 32.5°C ± 1.0°C at the popliteal fossa during cement curing. No significant difference was found of the maximum temperatures in the popliteal fossa between the non-DVT and DVT groups. The present study indicated that the heat resulting from polymerization of the cement may not be a possible cause of damage to the veins surrounding the knee, and it may have no relationship with DVT.
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Affiliation(s)
- Xu-sheng Qiu
- Department of Orthopedics, Drum Tower Hospital, NanjingUniversity Medical School, China
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Madrala A, Nuño N, Bureau MN. Does stem preheating have a beneficial effect on PMMA bulk porosity in cemented THA? J Biomed Mater Res B Appl Biomater 2010; 95:1-8. [DOI: 10.1002/jbm.b.31673] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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13
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Pore distribution and material properties of bone cement cured at different temperatures. Acta Biomater 2010; 6:886-91. [PMID: 19800995 DOI: 10.1016/j.actbio.2009.09.016] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2009] [Revised: 09/12/2009] [Accepted: 09/23/2009] [Indexed: 11/24/2022]
Abstract
Implant heating has been advocated as a means to alter the porosity of the bone cement/implant interface; however, little is known about the influence on cement properties. This study investigates the mechanical properties and pore distribution of 10 commercially available cements cured in molds at 20, 37, 40 and 50 degrees Celsius. Although each cement reacted differently to the curing environments, the most prevalent trend was increased mechanical properties when cured at 50 degrees Celsius vs. room temperature. Pores were shown to gather near the surface of cooler molds and near the center in warmer molds for all cement brands. Pore size was also influenced. Small pores were more often present in cements cured at cooler temperatures, with higher-temperature molds producing more large pores. The mechanical properties of all cements were above the minimum regulatory standards. This work shows the influence of curing temperature on cement properties and porosity characteristics, and supports the practice of heating cemented implants to influence interfacial porosity.
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Madrala A, Nuño N. Effect of stem preheating and precooling on residual stress formation at stem/cement interface for cemented hip implants. J Biomed Mater Res B Appl Biomater 2010; 93:258-65. [DOI: 10.1002/jbm.b.31583] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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15
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Boner V, Kuhn P, Mendel T, Gisep A. Temperature evaluation during PMMA screw augmentation in osteoporotic bone--an in vitro study about the risk of thermal necrosis in human femoral heads. J Biomed Mater Res B Appl Biomater 2009; 90:842-8. [PMID: 19353575 DOI: 10.1002/jbm.b.31353] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The use of polymethylmethacrylate (PMMA) bone cement to augment hip screws reduces cut-out risk but is associated with an exothermic reaction. This in vitro investigation evaluated the risk of thermal necrosis when augmenting the implant purchase with PMMA. A pilot study analyzed the effects of different PMMA layer thicknesses on temperatures around an implant. The main study used either 3.0 or 6.0 cc PMMA for hip screw augmentation in human femoral heads. The risk of thermal necrosis was estimated according to critical values reported in literature. Highest temperatures were measured inside the PMMA with a significant drop of average maximum temperatures from the center of the PMMA to the PMMA/bone interface. Risk of thermal necrosis exists with PMMA layer thicknesses greater than 5.0 mm. In the main study, we found no risk of thermal necrosis at the PMMA/bone interface or in the surrounding bone, neither with 3.0 nor 6.0 cc PMMA. The results of the two studies were consistent regarding average peak temperatures related to associated cement layer thicknesses. The results of this in vitro study reduce objections concerning the risk of thermal necrosis when augmenting cancellous bone around hip screws with up to 6.0 cc PMMA.
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Mucci V, Cook WD, Vallo C. Impact of radiation attenuation and temperature evolution on monomer conversion of dimethacrylate-based resins with a photobleaching photoinitiator. POLYM ENG SCI 2009. [DOI: 10.1002/pen.21460] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Pérez MA, Nuño N, Madrala A, García-Aznar JM, Doblaré M. Computational modelling of bone cement polymerization: temperature and residual stresses. Comput Biol Med 2009; 39:751-9. [PMID: 19615676 DOI: 10.1016/j.compbiomed.2009.06.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2008] [Revised: 04/17/2009] [Accepted: 06/12/2009] [Indexed: 11/26/2022]
Abstract
The two major concerns associated with the use of bone cement are the generation of residual stresses and possible thermal necrosis of surrounding bone. An accurate modelling of these two factors could be a helpful tool to improve cemented hip designs. Therefore, a computational methodology based on previous published works is presented in this paper combining a kinetic and an energy balance equation. New assumptions are that both the elasticity modulus and the thermal expansion coefficient depend on the bone cement polymerization fraction. This model allows to estimate the thermal distribution in the cement which is later used to predict the stress-locking effect, and to also estimate the cement residual stresses. In order to validate the model, computational results are compared with experiments performed on an idealized cemented femoral implant. It will be shown that the use of the standard finite element approach cannot predict the exact temporal evolution of the temperature nor the residual stresses, underestimating and overestimating their value, respectively. However, this standard approach can estimate the peak and long-term values of temperature and residual stresses within acceptable limits of measured values. Therefore, this approach is adequate to evaluate residual stresses for the mechanical design of cemented implants. In conclusion, new numerical techniques should be proposed in order to achieve accurate simulations of the problem involved in cemented hip replacements.
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Affiliation(s)
- M A Pérez
- Group of Structural Mechanics and Material Modelling, Aragón Institute of Engineering Research (I3A), Mechanical Engineering, University of Zaragoza, Zaragoza, Spain.
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Radev BR, Kase JA, Askew MJ, Weiner SD. Potential for thermal damage to articular cartilage by PMMA reconstruction of a bone cavity following tumor excision: A finite element study. J Biomech 2009; 42:1120-6. [PMID: 19344902 DOI: 10.1016/j.jbiomech.2009.02.005] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2008] [Revised: 01/23/2009] [Accepted: 02/04/2009] [Indexed: 10/20/2022]
Abstract
Benign, giant cell tumors are often treated by intralesional excision and reconstruction with polymethylmethacrylate (PMMA) bone cement. The exothermic reaction of the in-situ polymerizing PMMA is believed to beneficially kill remaining tumor cells. However, at issue is the extent of this necrotic effect into the surrounding normal bone and the adjacent articular cartilage. Finite element analysis (ABAQUS 6.4-1) was used to determine the extent of possible thermal necrosis around prismatically shaped, PMMA implants (8-24cc in volume), placed into a peripheral, sagittally symmetric, metaphyseal defect in the proximal tibia. Temperature/exposure time conditions indicating necrotic potential during the exotherm of the polymerizing bone cement were found in regions of the cancellous bone within 3mm of the superior surface of the PMMA implant. If less than 3mm of cancellous bone existed between the PMMA implant and the subchondral bone layer, regions of the subchondral bone were also exposed to thermally necrotic conditions. However, as long as there were at least 2mm of uniform subchondral bone above the PMMA implant, the necrotic regions did not extend into the overlying articular cartilage. This was the case even when the PMMA was in direct contact with the subchondral bone. If the subchondral bone is not of sufficient thickness, or is not continuous, then care should be taken to protect the articular cartilage from thermal damage as a result of the reconstruction of the tumor cavity with PMMA bone cement.
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Affiliation(s)
- Boyko R Radev
- Department of Orthopaedic Surgery, Summa Health System, Akron, OH 44309-2090, United States
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Nuño N, Madrala A, Plamondon D. Measurement of transient and residual stresses during polymerization of bone cement for cemented hip implants. J Biomech 2008; 41:2605-11. [PMID: 18692188 DOI: 10.1016/j.jbiomech.2008.06.030] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2008] [Revised: 05/24/2008] [Accepted: 06/19/2008] [Indexed: 10/21/2022]
Abstract
The initial fixation of a cemented hip implant relies on the strength of the interface between the stem, bone cement and adjacent bone. Bone cement is used as grouting material to fix the prosthesis to the bone. The curing process of bone cement is an exothermic reaction where bone cement undergoes volumetric changes that will generate transient stresses resulting in residual stresses once polymerization is completed. However, the precise magnitude of these stresses is still not well documented in the literature. The objective of this study is to develop an experiment for the direct measurement of the transient and residual radial stresses at the stem-cement interface generated during cement polymerization. The idealized femoral-cemented implant consists of a stem placed inside a hollow cylindrical bone filled with bone cement. A sub-miniature load cell is inserted inside the stem to make a direct measurement of the radial compressive forces at the stem-cement interface, which are then converted to radial stresses. A thermocouple measures the temperature evolution during the polymerization process. The results show the evolution of stress generation corresponding to volumetric changes in the cement. The effect of initial temperature of the stem and bone as well as the cement-bone interface condition (adhesion or no adhesion) on residual radial stresses is investigated. A maximum peak temperature of 70 degrees C corresponds to a peak in transient stress during cement curing. Maximum radial residual stresses of 0.6 MPa in compression are measured for the preheated stem.
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Affiliation(s)
- N Nuño
- Ecole de technologie supérieure, Laboratoire de recherche en imagerie et orthopédie, Département de génie de la production automatisée, Université du Québec, 1100 rue Notre-Dame Ouest, Montréal, Québec, Canada H3C 1K3.
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20
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Schroeder WF, Cook WD, Vallo CI. Photopolymerization of N,N-dimethylaminobenzyl alcohol as amine co-initiator for light-cured dental resins. Dent Mater 2008; 24:686-93. [PMID: 17804051 DOI: 10.1016/j.dental.2007.06.035] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2006] [Revised: 06/12/2007] [Accepted: 06/18/2007] [Indexed: 11/17/2022]
Abstract
OBJECTIVE The present study was carried out in order to assess the suitability of N,N-dimethylaminobenzyl alcohol (DMOH) as co-initiator of camphorquinone (CQ) and 1-phenyl-1,2-propanedione (PPD) in light-cured dental resins. METHODS DMOH was synthesized and used as co-initiator for the photopolymerization of a model resin based on {2,2-bis[4-(2-hydroxy-3-methacryloxyprop-1-oxy)phenyl]propane} (Bis-GMA)/triethylene glycol dimethacrylate (TEGDMA). Experimental formulations containing CQ or PPD in combination with DMOH at different concentrations were studied. The photopolymerization was carried out by means of a commercial light-emitting diode (LED) curing unit. The evolution of double bonds consumption versus irradiation time was followed by near-infrared spectroscopy (NIR). The photon absorption efficiency (PAE) of the photopolymerization process was calculated from the spectral distribution of the LED unit and the molar absorption coefficient distributions of PPD and CQ. RESULTS DMOH is an efficient photoreducer of CQ and PPD resulting in higher polymerization rate and higher double bond conversion compared with dimethylaminoethylmethacrylate. The PAE for PPD was higher than that for CQ. However, the polymerization initiated by PPD progressed at a lower rate and exhibited lower values of final conversion compared with the resins containing CQ. This observation indicates that the lower polymerization rate of the PPD/amine system should be explained in terms of the mechanism of generating primary radicals by PPD, which is less efficient compared with CQ. SIGNIFICANCE The DMOH/benzoyl peroxide redox system, has recently been proposed as a more biocompatible accelerator for the polymerization of bone cements based on poly(methyl methacrylate), because cytotoxity tests have demonstrated that DMOH possesses better biocompatibility properties compared with traditional tertiary amines. The results obtained in the present study reveal the suitability of the CQ/DMOH initiator system for the polymerization of light-cured dental composites.
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Affiliation(s)
- Walter F Schroeder
- Institute of Materials Science and Technology (INTEMA), Universidad Nacional de Mar del Plata-National Research Council (CONICET), Av. Juan B. Justo 4302, 7600 Mar del Plata, Argentina
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21
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Gilbert JL. Complexity in modeling of residual stresses and strains during polymerization of bone cement: effects of conversion, constraint, heat transfer, and viscoelastic property changes. J Biomed Mater Res A 2007; 79:999-1014. [PMID: 16958044 DOI: 10.1002/jbm.a.30852] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Aseptic loosening of cemented joint prostheses remains a significant concern in orthopedic biomaterials. One possible contributor to cement loosening is the development of porosity, residual stresses, and local fracture of the cement that may arise from the in-situ polymerization of the cement. In-situ polymerization of acrylic bone cement is a complex set of interacting processes that involve polymerization reactions, heat generation and transfer, full or partial mechanical constraint, evolution of conversion- and temperature-dependent viscoelastic material properties, and thermal and conversion-driven changes in the density of the cement. Interactions between heat transfer and polymerization can lead to polymerization fronts moving through the material. Density changes during polymerization can, in the presence of mechanical constraint, lead to the development of locally high residual strain energy and residual stresses. This study models the interactions during bone cement polymerization and determines how residual stresses develop in cement and incorporates temperature and conversion-dependent viscoelastic behavior. The results show that the presence of polymerization fronts in bone cement result in locally high residual strain energies. A novel heredity integral approach is presented to track residual stresses incorporating conversion and temperature dependent material property changes. Finally, the relative contribution of thermal- and conversion-dependent strains to residual stresses is evaluated and it is found that the conversion-based strains are the major contributor to the overall behavior. This framework provides the basis for understanding the complex development of residual stresses and can be used as the basis for developing more complex models of cement behavior.
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Affiliation(s)
- Jeremy L Gilbert
- Department of Biomedical and Chemical Engineering, College of Engineering and Computer Science, Syracuse University, Syracuse, New York 13244, USA.
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Schroeder W, Arenas G, Vallo C. Monomer conversion in a light-cured dental resin containing 1-phenyl-1,2- propanedione photosensitizer. POLYM INT 2007. [DOI: 10.1002/pi.2239] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Vallo CI, Schroeder WF. Properties of acrylic bone cements formulated with Bis-GMA. J Biomed Mater Res B Appl Biomater 2006; 74:676-85. [PMID: 15954119 DOI: 10.1002/jbm.b.30211] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Experimental cement formulations were prepared by replacing part of the methylmethacrylate (MMA) liquid phase of a conventional surgical cement with an equivalent weight of 2,2-bis [4(2-hydroxy-3-methacryloxypropoxy) phenyl] propane (Bis-GMA), which is the reaction product of diglycidyl ether of bisphenol A and methacrylic acid. It was found that up to 50 wt % of the MMA could be replaced by Bis-GMA without reductions in flow characteristics of the precured polymers. Cements containing 20, 30, 40, and 50 wt % of Bis-GMA in the liquid component were prepared. Over this range of Bis-GMA wt %, it was found that, relative to the unmodified cement, the volumetric shrinkage (DV), the peak temperature reached during the polymerization reaction (Tp), and the flexural strength (obtained in three-point bend tests) were each significantly reduced, the flexural modulus (obtained in three-point bend tests) increased significantly, the compressive strength increased slightly, while there were no significant effects on any of the other properties determined, namely, degree of conversion of the monomer during the polymerization reaction and the glass transition temperature. The drops in D(V) and Tp indicate that cements whose liquid monomers are modified using Bis-GMA hold promise for use in anchoring total joint replacements. The increase in the crosslinking density with increasing amount of Bis-GMA renders the polymer matrix more brittle. This feature was considered responsible for the reduced flexural strength.
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Affiliation(s)
- Claudia I Vallo
- Institute of Materials Science and Technology (INTEMA), Universidad Nacional de Mar del Plata-National Research Council (CONICET), Av. Juan B. Justo 4302, (7600) Mar del Plata, Argentina.
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Quarini GL, Learmonth ID, Gheduzzi S. Numerical Predictions of the Thermal Behaviour and Resultant Effects of Grouting Cements While Setting Prosthetic Components in Bone. Proc Inst Mech Eng H 2006; 220:625-34. [PMID: 16898219 DOI: 10.1243/09544119jeim118] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Acrylic cements are commonly used to attach prosthetic components in joint replacement surgery. The cements set in short periods of time by a complex polymerization of initially liquid monomer compounds into solid structures with accompanying significant heat release. Two main problems arise from this form of fixation: the first is the potential damage caused by the temperature excursion, and the second is incomplete reaction leaving active monomer compounds, which can potentially be slowly released into the patient. This paper presents a numerical model predicting the temperature-time history in an idealized prosthetic-cement-bone system. Using polymerization kinetics equations from the literature, the degree of polymerization is predicted, which is found to be very dependent on the thermal history of the setting process. Using medical literature, predictions for the degree of thermal bone necrosis are also made. The model is used to identify the critical parameters controlling thermal and unreacted monomer distributions.
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Affiliation(s)
- G L Quarini
- Department of Mechanical Engineering, University of Bristol, UK.
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Vallo CI, Abraham GA, Cuadrado TR, San Román J. Influence of cross-linked PMMA beads on the mechanical behavior of self-curing acrylic cements. J Biomed Mater Res B Appl Biomater 2004; 70:407-16. [PMID: 15264326 DOI: 10.1002/jbm.b.30054] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Cross-linked PMMA beads were prepared with the use of two cross-linking agents with different chain lengths: triethylene glycol dimethacrylate (TEGDMA) and poly(ethylene glycol) dimethacrylate (PEGDMA). Beads containing 10 wt % TEGDMA and 2, 5, and 10 wt % PEGDMA were synthesized by suspension polymerization. Experimental cement formulations were prepared by replacing part of the PMMA powder phase by an equivalent weight of the cross-linked beads. The mechanical behavior of the modified cements was carried out by testing the cements in flexure and compression. All cements displayed a higher flexural modulus, which was accompanied with a slight decrease in the flexural strength. The two-parameter Weibull model, which was used to analyze the flexural strength data, gave a good representation of the fracture load distribution. In cements prepared with beads containing 2 and 5 wt % PEGDMA and 10 wt % TEGDMA, no improvement in the flexural strength was observed. Debonding of the particles from the matrix was considered responsible for the decreased flexural strength. On the contrary, cements prepared with different proportions of beads containing 10 wt % PEGDMA resulted in a markedly increased flexural strength compared with the unmodified cement. An improved reinforcing effect of the cross-linked beads and a significant degree of bonding with the matrix in these cements account for the superior flexural strength compared with the other composite cements tested.
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Affiliation(s)
- C I Vallo
- Instituto de Investigaciones en Ciencia y Tecnología de Materiales (INTEMA) (UNMdP-CONICET), J. B. Justo 4302, B7608FDQ Mar del Plata, Argentina
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Li C, Wang Y, Mason J. The effects of curing history on residual stresses in bone cement during hip arthroplasty. ACTA ACUST UNITED AC 2004; 70:30-6. [PMID: 15199580 DOI: 10.1002/jbm.b.30016] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
During cement curing in total hip arthroplasty, residual stresses are introduced in the cement mantle as a result of curing shrinkage, thermal shrinkage, and geometrical constraints. These high residual stresses are capable of initiating cracks in the mantle of cemented hip replacements. The purpose of this study was to determine the residual stresses in the cemented hip replacements. The finite element method was developed to predict the residual stresses built up in joint arthroplasties. Experimental tests were then performed to validate the numerical methodology. Then the effects of curing history on the residual stress distribution were investigated with finite element simulations. Results showed that the predictions of the thermal shrinkage residual stresses by the developed method agreed with the experimental tests very well. The residual stress buildup was shown to depend on the curing history. By preheating the prosthesis stem prior to implantation, a desired low-level residual stress at the critical prosthesis-cement interface was obtained. As a result, this article provides a numerical tool for the quantitative simulation of residual stress and for examining and refining new designs computationally.
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Affiliation(s)
- Chaodi Li
- Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, Indiana 46556, USA
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Abstract
The heat transfer in a general bone-cement-prosthesis system was modelled. A quantitative understanding of the heat transfer and the polymerization kinetics in the system is necessary because injury of the bone tissue and the mechanical properties of the cement have been suggested to be effected by the thermal and chemical history of the system. The mathematical model of the heat transfer was based on first principles from polymerization kinetics and heat transfer, rather than certain in vitro observed properties, which has been the common approach. Our model was valid for general three-dimensional geometries and an arbitrary bone cement consisting of an initiator and monomer. The model was simulated for a cross-section of a hip with a potential femoral stem prosthesis and for a cement similar to Palacos R. The simulations were conducted by using the finite element method. These simulations showed that this general model described an auto accelerating heat production and a residual monomer concentration, which are two phenomena suggested to cause bone tissue damage and effect the mechanical properties of the cement.
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Affiliation(s)
- Eskil Hansen
- Numerical Analysis, Centre for Mathematical Sciences, Lund University, Box 118, Lund S-221 00, Sweden.
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