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Alimohammadi M, Mirzabozorg H, Farahmand F, Kim S, Baril C, Ploeg HL. Statistical distribution of micro and macro pores in acrylic bone cement- effect of amount of antibiotic content. J Mech Behav Biomed Mater 2024; 150:106297. [PMID: 38100980 DOI: 10.1016/j.jmbbm.2023.106297] [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: 07/10/2023] [Revised: 09/02/2023] [Accepted: 12/02/2023] [Indexed: 12/17/2023]
Abstract
Aseptic loosening due to mechanical failure of bone cement is considered to be a leading cause of revision of joint replacement systems. Detailed quantified information on the number, size and distribution pattern of pores can help to obtain a deeper understanding of the bone cement's fatigue behavior. The objective of this study was to provide statistical descriptions for the pore distribution characteristics of laboratory bone cement specimens with different amounts of antibiotic contents. For four groups of bone cement (Palacos) specimens, containing 0.3, 0.6, 1.2 and 2.4 wt/wt% of telavancin antibiotic, seven samples per group were micro computed tomography scanned (38.97 μm voxel size). The images were first preprocessed in Mimics and then analyzed in Dragonfly, with the level of threshold being set such that single-pixel pores become visible. The normalized pore volume data of the specimens were then used to extract the logarithmic histograms of the pore densities for antibiotic groups, as well as their three-parameter Weibull probability density functions. Statistical comparison of the pore distribution data of the antibiotic groups using the Mann-Whitney non-parametric test revealed a significantly larger porosity (p < 0.05) in groups with larger added antibiotic contents (2.4 and 0.6 wt/wt% vs 0.3 wt/wt%). Further analysis revealed that this effect was associated with the significantly larger frequency of micropores of 0.1-0.5 mm diameter (p < 0.05) in groups with larger antibiotic content (2.4 wt/wt% vs and 0.6 and 0.3 wt/wt%), implying that the elution of the added antibiotic produces micropores in this diameter range mainly. Based on this observation and the fatigue test results in the literature, it was suggested that micropore clusters have a detrimental effect on the mechanical properties of bone cement and play a major role in initiating fatigue cracks in highly antibiotic added specimens.
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Affiliation(s)
- Mahsa Alimohammadi
- Civil Engineering Department, KN Toosi University of Technology, Tehran, Iran; Department of Mechanical and Materials Engineering, Queen's University, Kingston, ON, Canada
| | - Hassan Mirzabozorg
- Civil Engineering Department, KN Toosi University of Technology, Tehran, Iran
| | - Farzam Farahmand
- Mechanical Engineering Department, Sharif University of Technology, Tehran, Iran
| | - Sunjung Kim
- Department of Orthopaedic Surgery, University of Illinois Chicago, Chicago, IL, USA
| | - Caroline Baril
- Department of Mechanical and Materials Engineering, Queen's University, Kingston, ON, Canada
| | - Heidi-Lynn Ploeg
- Department of Mechanical and Materials Engineering, Queen's University, Kingston, ON, Canada.
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Reulbach M, Evers P, Emonde C, Behnsen H, Nürnberger F, Windhagen H, Jakubowitz E. Implications of ageing effects on thermal and mechanical properties of PMMA-based bone cement for THA revision surgery. J Mech Behav Biomed Mater 2023; 148:106218. [PMID: 37931550 DOI: 10.1016/j.jmbbm.2023.106218] [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: 09/15/2023] [Revised: 10/27/2023] [Accepted: 10/30/2023] [Indexed: 11/08/2023]
Abstract
Loosening and infection are the main reasons for revision surgery in total hip arthroplasty (THA). Removing partially detached cemented implant components during revision surgery remains challenging and poses the risk of periprosthetic bone damage. A promising approach for a gentler removal of partially detached prostheses involves softening the PMMA-based bone cement by heating it above its glass transition temperature (TG), thus loosening the implant-cement bond. It is assumed that the TG of PMMA-based bone cement decreases in-vivo due to the gradual absorption of body fluid. Reliable data on TG are essential to develop a heat-based method for removing cemented implant components during revision surgery. The effect of water absorption was investigated in-vitro by ageing PMMA-based bone cement samples for different periods up to 56 days in both Ringer's solution (37 °C) and air (37 °C and 30% humidity). Subsequently, the TG and Vicat softening temperatures of the samples were determined by differential scanning calorimetry and Vicat tests, respectively, according to prescribed methods. Over the entire ageing period, i.e. comparing one day of ageing in air and 56 days in Ringer's solution, the Vicat softening temperature dropped by 16 °C, while the TG dropped by 10 °C for Palacos® R PMMA-based bone cement. Water absorption over time correlated significantly with the Vicat softening temperature until saturation of the PMMA-based bone cement was reached. Based on the TG and Vicat softening temperature measurements, it can be assumed that in body-aged bone cement, an optimal softening can be achieved within a temperature range of 85 °C-93 °C to loosen the bond between the PMMA-based bone cement mantle and the prosthesis stem. These findings may pave the way for a gentler removal of the implant in revision THA.
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Affiliation(s)
- Magnus Reulbach
- Laboratory for Biomechanics and Biomaterials (LBB), Department of Orthopaedic Surgery, Hannover Medical School, Anna-von-Borries-Strasse 1-7, 30625, Hannover, Germany
| | - Patrick Evers
- Institute of Materials Science (Werkstoffkunde), Leibniz University Hannover, An der Universität 2, 30823, Garbsen, Germany
| | - Crystal Emonde
- Laboratory for Biomechanics and Biomaterials (LBB), Department of Orthopaedic Surgery, Hannover Medical School, Anna-von-Borries-Strasse 1-7, 30625, Hannover, Germany
| | - Hannah Behnsen
- Institute of Plastics and Circular Economy, Leibniz University Hannover, An der Universität 2, 30823, Garbsen, Germany
| | - Florian Nürnberger
- Institute of Materials Science (Werkstoffkunde), Leibniz University Hannover, An der Universität 2, 30823, Garbsen, Germany
| | - Henning Windhagen
- Laboratory for Biomechanics and Biomaterials (LBB), Department of Orthopaedic Surgery, Hannover Medical School, Anna-von-Borries-Strasse 1-7, 30625, Hannover, Germany
| | - Eike Jakubowitz
- Laboratory for Biomechanics and Biomaterials (LBB), Department of Orthopaedic Surgery, Hannover Medical School, Anna-von-Borries-Strasse 1-7, 30625, Hannover, Germany.
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Paul C, Kühn KD. [Chemical and physical properties of PMMA bone cements]. ORTHOPADIE (HEIDELBERG, GERMANY) 2023; 52:943-956. [PMID: 37831091 DOI: 10.1007/s00132-023-04445-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 09/01/2023] [Indexed: 10/14/2023]
Abstract
PMMA-based bone cements are used for anchoring artificial joints. The cements are offered as two-component systems. During mixing, a liquid paste is formed by free-radical polymerization, which completely hardens into a solid cement matrix as polymerization progresses with an increase in viscosity. Polymerization from MMA to PMMA is an exothermic process, energy is released in the form of heat. After fixation of the prosthesis and curing of the cement, the cement fills the space between the prosthesis and the bone. With the filler PMMA, a strong force-locking and interlocking mechanical bond is created. The essential properties of PMMA cements are dictated by the powder component. In vivo, the hard and brittle bone cements absorb body fluids and become more elastic and softer. The properties of various PMMA bone cements differ significantly, although the chemical acrylate base is identical.
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Affiliation(s)
- Christian Paul
- Heraeus Medical GmbH, Philipp-Reis-Straße 8-13, 61273, Wehrheim, Deutschland.
| | - Klaus-Dieter Kühn
- Heraeus Medical GmbH, Philipp-Reis-Straße 8-13, 61273, Wehrheim, Deutschland
- Universitätsklinik für Orthopädie und Traumatologie, Medizinische Universität Graz, Graz, Österreich
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Humez M, Fröschen FS, Wirtz DC, Kühn KD. [The third-generation modern cementing technique in hip and knee arthroplasty]. ORTHOPADIE (HEIDELBERG, GERMANY) 2023; 52:968-980. [PMID: 37828239 DOI: 10.1007/s00132-023-04446-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 09/01/2023] [Indexed: 10/14/2023]
Abstract
BACKGROUND Implant loosening is the most common reason for revision surgery. OBJECTIVES Contribution of modern cementing technique to the long-term stability of an implant. METHODS Evaluation of the available evidence on modern cementing technique. RESULTS Modern cementing technique in hip arthroplasty is considered established and leads to better cementing results. In knee arthroplasty, there are also specific recommendations, including intensive cleaning of the bone bed, mixing of bone cement under vacuum and application of bone cement to the implant and the bone. CONCLUSIONS The use of modern cementing technique in hip and knee arthroplasty facilitates cementing, increases safety, and minimizes the risk of mechanical loosening.
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Affiliation(s)
- Martina Humez
- Heraeus Medical GmbH, Philipp-Reis-Str. 8/13, 61273, Wehrheim, Deutschland.
| | | | | | - Klaus-Dieter Kühn
- Heraeus Medical GmbH, Philipp-Reis-Str. 8/13, 61273, Wehrheim, Deutschland
- Department of Orthopaedics and Trauma, Medizinische Universität Graz, Graz, Österreich
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Toth Z, Roi M, Evans E, Watson JT, Nicolaou D, McBride-Gagyi S. Masquelet Technique: Effects of Spacer Material and Micro-topography on Factor Expression and Bone Regeneration. Ann Biomed Eng 2019; 47:174-189. [PMID: 30259220 PMCID: PMC6318020 DOI: 10.1007/s10439-018-02137-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 09/19/2018] [Indexed: 12/12/2022]
Abstract
We and others have shown that changing surface characteristics of the spacer implanted during the first Masquelet stage alters some aspects of membrane development. Previously we demonstrated that titanium (TI) spacers create membranes that are better barriers to movement of solutes > 70 kDa in size than polymethyl methacrylate (PMMA) induced-membranes, and roughening creates more mechanically compliant membranes. However, it is unclear if these alterations affect the membrane's biochemical environment or bone regeneration during the second stage. Ten-week-old, male Sprague-Dawley rats underwent an initial surgery to create an externally stabilized 6 mm femoral defect. PMMA or TI spacers with smooth (~ 1 μm) or roughened (~ 8 μm) surfaces were implanted. Four weeks later, rats were either euthanized for membrane harvest or underwent the second Masquelet surgery. TI spacers induced thicker membranes that were similar in structure and biochemical expression. All membranes were bilayered with the inner layer having increased factor expression [bone morphogenetic protein 2 (BMP2), transforming growth factor beta (TGFβ), interleukin 6 (IL6), and vascular endothelial growth factor (VEGF)]. Roughening increased overall IL6 levels. Ten-weeks post-engraftment, PMMA-smooth induced membranes better supported bone regeneration (60% union). The other groups only had 1 or 2 that united (9-22%). There were no significant differences in any micro computed tomography or dynamic histology outcome. In conclusion, this study suggests that the membrane's important function in the Masquelet technique is not simply as a barrier. There is likely a critical biochemical, cellular, or vascular component as well.
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Affiliation(s)
- Zacharie Toth
- Department of Orthopaedic Surgery, Saint Louis University School of Medicine, 1402 S. Grand Blvd, Schwitalla Hall M176, St. Louis, MO, 63104, USA
| | - Matt Roi
- Department of Orthopaedic Surgery, Saint Louis University School of Medicine, 1402 S. Grand Blvd, Schwitalla Hall M176, St. Louis, MO, 63104, USA
| | - Emily Evans
- Department of Orthopaedic Surgery, Saint Louis University School of Medicine, 1402 S. Grand Blvd, Schwitalla Hall M176, St. Louis, MO, 63104, USA
| | - J Tracy Watson
- Department of Orthopaedic Surgery, Saint Louis University School of Medicine, 1402 S. Grand Blvd, Schwitalla Hall M176, St. Louis, MO, 63104, USA
| | - Daemeon Nicolaou
- Department of Orthopaedic Surgery, Saint Louis University School of Medicine, 1402 S. Grand Blvd, Schwitalla Hall M176, St. Louis, MO, 63104, USA
| | - Sarah McBride-Gagyi
- Department of Orthopaedic Surgery, Saint Louis University School of Medicine, 1402 S. Grand Blvd, Schwitalla Hall M176, St. Louis, MO, 63104, USA.
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Gaio N, Martino A, Toth Z, Watson JT, Nicolaou D, McBride-Gagyi S. Masquelet technique: The effect of altering implant material and topography on membrane matrix composition, mechanical and barrier properties in a rat defect model. J Biomech 2018; 72:53-62. [PMID: 29510858 PMCID: PMC5895482 DOI: 10.1016/j.jbiomech.2018.02.026] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Revised: 02/12/2018] [Accepted: 02/18/2018] [Indexed: 12/26/2022]
Abstract
The Masquelet technique is a surgical procedure to regenerate segmental bone defects. The two-phase treatment relies on the production of a vascularized foreign-body membrane to support bone grafts over three times larger than the traditional maximum. Historically, the procedure has always utilized a bone cement spacer to evoke membrane production. However, membrane formation can easily be effected by implant surface properties such as material and topology. This study sought to determine if the membrane's mechanical or barrier properties are affected by changing the spacer material to titanium or roughening the surface finish. Ten-week-old, male Sprague Dawley rats were given an externally stabilized, 6 mm femur defect which was filled with a pre-made spacer of bone cement (PMMA) or titanium (TI) with a smooth (∼1 μm) or roughened (∼8 μm) finish. After 4 weeks of implantation, the membranes were harvested, and the matrix composition, tensile mechanics, shrinkage, and barrier function was assessed. Roughening the spacers resulted in significantly more compliant membranes. TI spacers created membranes that inhibited solute transport more. There were no differences between groups in collagen or elastin distribution. This suggests that different membrane characteristics can be created by altering the spacer surface properties. Surgeons may unknowingly effecting membrane formation via bone cement preparation techniques.
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Affiliation(s)
- Natalie Gaio
- Department of Orthopaedic Surgery, Saint Louis University School of Medicine, 1402 S. Grand Blvd, Schwitalla Hall M176, St. Louis, MO 63132, USA
| | - Alice Martino
- Department of Orthopaedic Surgery, Saint Louis University School of Medicine, 1402 S. Grand Blvd, Schwitalla Hall M176, St. Louis, MO 63132, USA
| | - Zacharie Toth
- Department of Orthopaedic Surgery, Saint Louis University School of Medicine, 1402 S. Grand Blvd, Schwitalla Hall M176, St. Louis, MO 63132, USA
| | - J Tracy Watson
- Department of Orthopaedic Surgery, Saint Louis University School of Medicine, 1402 S. Grand Blvd, Schwitalla Hall M176, St. Louis, MO 63132, USA
| | - Daemeon Nicolaou
- Department of Orthopaedic Surgery, Saint Louis University School of Medicine, 1402 S. Grand Blvd, Schwitalla Hall M176, St. Louis, MO 63132, USA
| | - Sarah McBride-Gagyi
- Department of Orthopaedic Surgery, Saint Louis University School of Medicine, 1402 S. Grand Blvd, Schwitalla Hall M176, St. Louis, MO 63132, USA.
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Comparison of Refobacin bone cement and palacos with gentamicin in total hip arthroplasty: an RSA study with two years follow-up. Hip Int 2014; 24:56-62. [PMID: 24062223 DOI: 10.5301/hipint.5000088] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/05/2013] [Indexed: 02/04/2023]
Abstract
Previous experience has demonstrated the importance of testing new bone cement in vivo before widespread clinical use. We performed a consecutive, radiostereometric (RSA) study comparing Refobacin Bone Cement (RBC) to the well proven Palacos with Gentamicin (PWG). According to the manufacturer of RBC it has the equivalent characteristics as PWG, and in vitro tests show good results. The purpose of this study was to evaluate whether RBC is safe to use in clinical practice for total hip arthroplasty (THA). Two consecutive series of patients with primary osteoarthritis received a THA using a highly polished, collarless, tapered stem with a hollow centralizer. The study comprises 21 hips with RBC and 30 with PWG. The patients were followed up for two years with repeated RSA examinations and clinical outcome questionnaires SF-12 and WOMAC. There were no statistically significant migratory differences between the groups. The mean subsidence after two years was 1.28 mm and 1.40 mm, and the mean retroversion was 1.03° and 0.99°, for the RBC and the PWG groups respectively. Almost all migration occurred in the interface between the stem and the cement. The WOMAC and SF12 clinical scores did not reveal any clinical differences between the groups. We conclude that, as previous in vitro tests indicate, RBC performs as well as PWG and seems to be safe to use in clinical practice for THA.
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Zhang H, Blunt L, Jiang X, Brown L, Barrans S. The Significance of the Micropores at the Stem–Cement Interface in Total Hip Replacement. JOURNAL OF BIOMATERIALS SCIENCE-POLYMER EDITION 2012; 22:845-56. [DOI: 10.1163/092050610x540495] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- H. Zhang
- a State Key Laboratory of Tribology, School of Mechanical Engineering, Tsinghua University, Beijing 100084, P. R. China; Centre for Precision Technologies, School of Computing and Engineering, University of Huddersfield, Huddersfield HD1 3DH, UK.
| | - L. Blunt
- b Centre for Precision Technologies, School of Computing and Engineering, University of Huddersfield, Huddersfield HD1 3DH, UK
| | - X. Jiang
- c Centre for Precision Technologies, School of Computing and Engineering, University of Huddersfield, Huddersfield HD1 3DH, UK
| | - L. Brown
- d Centre for Precision Technologies, School of Computing and Engineering, University of Huddersfield, Huddersfield HD1 3DH, UK
| | - S. Barrans
- e Centre for Precision Technologies, School of Computing and Engineering, University of Huddersfield, Huddersfield HD1 3DH, UK
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Oonishi H, Akiyama H, Takemoto M, Kawai T, Yamamoto K, Yamamuro T, Oonishi H, Nakamura T. The long-term in vivo behavior of polymethyl methacrylate bone cement in total hip arthroplasty. Acta Orthop 2011; 82:553-8. [PMID: 22103279 PMCID: PMC3242951 DOI: 10.3109/17453674.2011.625538] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND AND PURPOSE The long-term success of cemented total hip arthroplasty (THA) has been well established. Improved outcomes, both radiographically and clinically, have resulted mainly from advances in stem design and improvements in operating techniques. However, there is concern about the durability of bone cement in vivo. We evaluated the physical and chemical properties of CMW1 bone cements retrieved from patients undergoing revision THA. METHODS CMW1 cements were retrieved from 14 patients who underwent acetabular revision because of aseptic loosening. The time in vivo before revision was 7-30 years. The bending properties of the retrieved bone cement were assessed using the three-point bending method. The molecular weight and chemical structure were analyzed by gel permeation chromatography and Fourier-transform infrared spectroscopy. The porosity of the bone cements was evaluated by 3-D microcomputer tomography. RESULTS The bending strength decreased with increasing time in vivo and depended on the density of the bone cement, which we assume to be determined by the porosity. There was no correlation between molecular weight and time in vivo. The infrared spectra were similar in the retrieved cements and in the control CMW1 cements. INTERPRETATION Our results indicate that polymer chain scission and significant hydrolysis do not occur in CMW1 cement after implantation in vivo, even in the long term. CMW1 cement was stable through long-term implantation and functional loading.
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Affiliation(s)
- Hiroyuki Oonishi
- H. Oonishi Memorial Joint Replacement Institute, Tominaga Hospital, Osaka
| | | | | | | | | | - Takao Yamamuro
- Research Institute for Production Development, Kyoto, Japan
| | - Hironobu Oonishi
- H. Oonishi Memorial Joint Replacement Institute, Tominaga Hospital, Osaka
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Abstract
PURPOSE Prosthesis color production and stability as a result of pore entrapment during mixing has not been investigated for maxillofacial silicone prostheses. The purpose of this study was to investigate pore numbers and percentages of a maxillofacial silicone elastomer mixed by two different techniques, using X-ray microfocus computerized tomography (Micro-CT), and to investigate the effect of porosity on color reproducibility and stability after two different aging conditions. MATERIALS AND METHODS Sixty-four disk-shaped specimens were prepared (8-mm diameter, 3-mm thick) by mixing TechSil S25 silicone elastomer (Technovent, Leeds, UK) following two techniques: manual mixing (n = 32) and mechanical mixing under vacuum (n = 32). Half the specimens in each group were intrinsically pigmented, and the other half remained unpigmented. Pore numbers, volumes, and percentages were calculated using the Micro-CT, and then specimens of each subgroup were stored in simulated sebum for 6 months (n = 8), and exposed to accelerated daylight aging for 360 hours (n = 8). Color change (ΔE) was measured at the start and end of conditioning. Pore numbers and percentages were analyzed using one-way Analysis of Variance (ANOVA) and Dunnett's-T3 post-hoc tests (p < 0.05). Independent t-test was used to detect differences (p < 0.05) in ΔE between manually and mechanically mixed specimens, in both unpigmented and pigmented states and to detect differences (p < 0.05) in ΔE before and after conditioning within each mixing method. RESULTS Mechanical mixing under vacuum reduced the number and percentage of pores in comparison to manual mixing, within pigmented and unpigmented silicone specimens (p < 0.05). Perceptible ΔE between manual and mechanical mixing techniques were 5.93 and 5.18 for both unpigmented and pigmented specimens, respectively. Under sebum storage, manually mixed unpigmented specimens showed lower ΔE (p < 0.05) than those that were mechanically mixed; however, pigmented silicone specimens showed the same ΔE (p > 0.05). After light aging, mixing method had no effect on ΔE of unpigmented specimens (p > 0.05). Furthermore, mechanically mixed pigmented specimens showed lower ΔE (p < 0.05). CONCLUSIONS Within silicone elastomers (whether pigmented or unpigmented), mechanical mixing under vacuum reduced pore numbers and percentages in comparison to manual mixing. For selected skin shade, pores affected the resultant color of prosthesis (color reproducibility). Additionally, silicone pores affected silicone color stability upon service. CLINICAL SIGNIFICANCE In fabricating maxillofacial prostheses, mechanically mixing silicone under vacuum produces pore-free prostheses, tending to enhance their color production and stability.
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Affiliation(s)
- Muhanad M Hatamleh
- Department of Allied Dental Science, Faculty of Applied Medical Sciences, Jordan University of Science and Technology, Irbid, Jordan.
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Brock HS, Moodie PG, Hendricks KJ, McIff TE. Compression strength and porosity of single-antibiotic cement vacuum-mixed with vancomycin. J Arthroplasty 2010; 25:990-7. [PMID: 19679443 DOI: 10.1016/j.arth.2009.06.027] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2008] [Accepted: 06/17/2009] [Indexed: 02/01/2023] Open
Abstract
We evaluated the ultimate compression strength (UCS), porosity, and fracture surface roughness of 2 commercially available single-antibiotic bone cements vacuum-mixed with additional amounts of vancomycin (2, 4, 6, and 8 g). At least 8 g could be added to Palacos R + 0.5 g gentamicin (UCS = 75.04 +/- 6.64 MPa) and no more than 6 g to Simplex P + 1 g tobramycin (UCS = 78.93 +/- 4.98 MPa) to maintain a UCS above the International Organization for Standardization minimum standard (70 MPa). Increasing vancomycin concentration correlated with a decrease in porosity but showed a trend towards greater fracture surface roughness.
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Affiliation(s)
- Hugh S Brock
- Department of Orthopedic Surgery, The University of Kansas Medical Center, Kansas City, USA
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12
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Baleani M, Bialoblocka-Juszczyk E, Engels GE, Viceconti M. The effect of vacuum mixing and pre-heating the femoral component on the mechanical properties of the cement mantle. ACTA ACUST UNITED AC 2010; 92:454-60. [PMID: 20190321 DOI: 10.1302/0301-620x.92b3.22579] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
We investigated the effect of pre-heating a femoral component on the porosity and strength of bone cement, with or without vacuum mixing used for total hip replacement. Cement mantles were moulded in a manner simulating clinical practice for cemented hip replacement. During polymerisation, the temperature was monitored. Specimens of cement extracted from the mantles underwent bending or fatigue tests, and were examined for porosity. Pre-heating the stem alone significantly increased the mean temperature values measured within the mantle (+14.2 degrees C) (p < 0.001) and reduced the mean curing time (-1.5 min) (p < 0.001). The addition of vacuum mixing modulated the mean rise in the temperature of polymerisation to 11 degrees C and reduced the mean duration of the process by one minute and 50 seconds (p = 0.01 and p < 0.001, respectively). In all cases, the maximum temperature values measured in the mould simulating the femur were < 50 degrees C. The mixing technique and pre-heating the stem slightly increased the static mechanical strength of bone cement. However, the fatigue life of the cement was improved by both vacuum mixing and pre-heating the stem, but was most marked (+ 280 degrees C) when these methods were combined. Pre-heating the stem appears to be an effective way of improving the quality of the cement mantle, which might enhance the long-term performance of bone cement, especially when combined with vacuum mixing.
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Affiliation(s)
- M Baleani
- Laboratorio di Tecnologia Medica, Istituto Ortopedico Rizzoli, Via Di Barbiano 1/10, 40136, Bologna, Italy.
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Scheerlinck T, Broos J, Janssen D, Verdonschot N. Mechanical implications of interfacial defects between femoral hip implants and cement: A finite element analysis of interfacial gaps and interfacial porosity. Proc Inst Mech Eng H 2008; 222:1037-47. [DOI: 10.1243/09544119jeim362] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Two types of defect between femoral hip implants and cement have been identified. Interfacial porosity arises from cement shrinkage during curing and presents as pores randomly located along the stem. Interfacial gaps are much larger stem—cement separations caused by air introduced during stem insertion. To investigate the mechanical consequences of both types of defect, a finite element analysis model was created on the basis of a computed tomography image of a Charnley—Kerboul stem, and alternating torsional and transverse loads were applied. The propagation of fatigue cracks within the cement and the rotational stability of the stem were assessed in models simulating increasing amounts of interfacial gaps and pores. Anterior gaps covering at least 30 per cent of the implant surface promoted cement cracks and destabilized the stem. Anterolateral gaps were less destabilizing, but had more potential to promote cracks. In both cases, cracks occurred mainly outside gap regions, in areas where the stem contacted the cement during cyclic loading. Although random interfacial pores did not destabilize the implant, they acted as crack initiators even at low fractions (10 per cent). In conclusion, random interfacial pores were more harmful for the cement mantle integrity than were larger regions of interfacial gaps, although gaps were more detrimental for the rotational stability of the stem.
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Affiliation(s)
- T Scheerlinck
- Orthopaedic Surgery and Traumatology, Universitair Ziekenhuis Brussel, Brussels, Belgium
| | - J Broos
- Orthopaedic Research Laboratory, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - D Janssen
- Orthopaedic Research Laboratory, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - N Verdonschot
- Orthopaedic Research Laboratory, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
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Brown L, Zhang H, Blunt L, Barrans S. Reproduction of fretting wear at the stem—cement interface in total hip replacement. Proc Inst Mech Eng H 2007; 221:963-71. [DOI: 10.1243/09544119jeim333] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The stem-cement interface experiences fretting wear in vivo due to low-amplitude oscillatory micromotion under physiological loading, as a consequence it is considered to play an important part in the overall wear of cemented total hip replacement. Despite its potential significance, in-vitro simulation to reproduce fretting wear has seldom been attempted and even then with only limited success. In the present study, fretting wear was successfully reproduced at the stem-cement interface through an in-vitro wear simulation, which was performed in part with reference to ISO 7206-4: 2002. The wear locations compared well with the results of retrieval studies. There was no evidence of bone cement transfer films on the stem surface and no fatigue cracks in the cement mantle. The cement surface was severely damaged in those areas in contact with the fretting zones on the stem surface, with retention of cement debris in the micropores. Furthermore, it was suggested that these micropores contributed to initiation and propagation of fretting wear. This study gave scope for further comparative study of the influence of stem geometry, stem surface finish, and bone cement brand on generation of fretting wear.
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Affiliation(s)
- L Brown
- Centre for Precision Technologies, School of Computing and Engineering, University of Huddersfield, Huddersfield, UK
| | - H Zhang
- Centre for Precision Technologies, School of Computing and Engineering, University of Huddersfield, Huddersfield, UK
| | - L Blunt
- Centre for Precision Technologies, School of Computing and Engineering, University of Huddersfield, Huddersfield, UK
| | - S Barrans
- Centre for Precision Technologies, School of Computing and Engineering, University of Huddersfield, Huddersfield, UK
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15
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Heger S, Mumme T, Sellei R, De La Fuente M, Wirtz DC, Radermacher K. A-mode ultrasound-based intra-femoral bone cement detection and 3D reconstruction in RTHR. COMPUTER AIDED SURGERY : OFFICIAL JOURNAL OF THE INTERNATIONAL SOCIETY FOR COMPUTER AIDED SURGERY 2007; 12:168-75. [PMID: 17538789 DOI: 10.3109/10929080701336132] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Due to the difficulty of determining the 3D boundary of the cement-bone interface in Revision Total Hip Replacement (RTHR), the removal of the distal intra-femoral bone cement can be a time-consuming and risky operation. Within the framework of computer- and robot-assisted cement removal, the principles and first results of an automatic detection and 3D surface reconstruction of the cement-bone boundary using A-mode ultrasound are described. Sound propagation time and attenuation of cement were determined considering different techniques for the preparation of bone cement, such as the use of a vacuum system (Optivac, Biomet). A laboratory setup using a rotating, standard 5-MHz transducer was developed. The prototype enables scanning of bisected cement-prepared femur samples in a 90 degrees rotation range along their rotation axis. For system evaluation ex vivo, the distal femur of a human cadaver was prepared with bone cement and drilled (Ø 10 mm) to simulate the prosthesis cavity in a first approximation. The sample was cut in half and CT scanned (0.24 mm resolution; 0.5 mm distance; 0.5 mm thickness), and 3D voxel models of the manually segmented bone cement were reconstructed, providing the ground truth. Afterwards, 90 degrees segments of each ex-vivo sample were scanned by the A-mode ultrasound system. To obtain better ultrasound penetration, we used coded signal excitation and pulse compression filtering. A-mode ultrasound signal detection, filtering and segmentation were accomplished fully automatically. Subsequently, 3D voxel models of each sample were calculated. Accuracy evaluation of the measured ultrasound data was performed by ICP matching of each ultrasound dataset ( approximately 8000 points) to the corresponding CT dataset and calculation of the residual median distance error between the corresponding datasets. Prior to each ICP matching, an initial pre-registration was calculated using prominent landmarks in the corresponding datasets. This method yielded a median distance error in the region of 0.25 mm for the cement-bone interface in both femur halves.
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Affiliation(s)
- Stefan Heger
- Helmholtz-Institute for Biomedical Engineering, RWTH Aachen University, Aachen, Germany.
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16
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Hallan G, Aamodt A, Furnes O, Skredderstuen A, Haugan K, Havelin LI. Palamed G compared with Palacos R with gentamicin in Charnley total hip replacement. A randomised, radiostereometric study of 60 HIPS. ACTA ACUST UNITED AC 2006; 88:1143-8. [PMID: 16943462 DOI: 10.1302/0301-620x.88b9.18008] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
We performed a randomised, radiostereometric study comparing two different bone cements, one of which has been sparsely clinically documented. Randomisation of 60 total hip replacements (57 patients) into two groups of 30 was undertaken. All the patients were operated on using a cemented Charnley total hip replacement, the only difference between groups being the bone cement used to secure the femoral component. The two cements used were Palamed G and Palacos R with gentamicin. The patients were followed up with repeated clinical and radiostereometric examinations for two years to assess the micromovement of the femoral component and the clinical outcome. The mean subsidence was 0.18 mm and 0.21 mm, and the mean internal rotation was 1.7 degrees and 2.0 degrees at two years for the Palamed G and Palacos R with gentamicin bone cements, respectively. We found no statistically significant differences between the groups. Micromovement occurred between the femoral component and the cement, while the cement mantle was stable inside the bone. The Harris hip score improved from a mean of 38 points (14 to 54) and 36 (10 to 57) pre-operatively to a mean of 92 (77 to 100) and 91 (63 to 100) at two years in the Palamed G and Palacos R groups, respectively. No differences were found between the groups. Both bone cements provided good initial fixation of the femoral component and good clinical results at two years.
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Affiliation(s)
- G Hallan
- Department of Orthopaedic Surgery, Haukeland University Hospital, University of Bergen, 5021 Bergen, Norway.
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17
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Kwong FNK, Power RA. A comparison of the shrinkage of commercial bone cements when mixed under vacuum. ACTA ACUST UNITED AC 2006; 88:120-2. [PMID: 16365134 DOI: 10.1302/0301-620x.88b1.16600] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The outcome of a cemented hip arthroplasty is partly dependent on the type of cement which is used. The production of an interface gap between the stem and the cement mantle as a result of shrinkage of the cement, may be a factor involved. Palacos R, Palacos LV (both with gentamicin), CMW 1, CMW 2, CMW Endurance (CMWE) and Simplex were prepared under vacuum and allowed to cure overnight in similar cylinders. The next day this volume was determined by the displacement of water. Shrinkage varied between 3.82% and 7.08% with CMWE having the lowest and Palacos LV the highest. This could be a factor to consider when choosing a cement for a shape-closed stem.
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Affiliation(s)
- F N K Kwong
- Department of Orthopaedics Glenfield Hospital, University Hospitals of Leicester, Groby Road, Leicester LE3 9QP, UK.
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18
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Merkhan IK, Hasenwinkel JM, Gilbert JL. Gentamicin release from two-solution and powder-liquid poly(methyl methacrylate)-based bone cements by using novel pH method. J Biomed Mater Res A 2005; 69:577-83. [PMID: 15127405 DOI: 10.1002/jbm.a.30033] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The release of gentamicin as a function of time was measured for Palacos and two-solution bone cements by using a novel pH technique. The pH of an aqueous solution of gentamicin is a function of the gentamicin concentration and it decreases linearly over concentrations of 0.0-0.1 wt %. Therefore, a new, direct, and inexpensive in vitro technique was developed based on continuous readings of the pH in phosphate-buffered saline (PBS) at 37 degrees C to determine the release kinetics of gentamicin from poly(methyl methacrylate) (PMMA)-based bone cement. In addition, this method was used to compare the release profiles of Palacos R-40 bone cement with a two-solution bone cement developed in our laboratory and loaded with two different concentrations of gentamicin sulfate. Finally, the pH-based method was used to track the elution of gentamicin in both mixed and static conditions to determine the effect of mixing on the diffusion of gentamicin out of the cement. It was found that Palacos R-40 released 4.95 +/- 0.22 wt % of its gentamicin after 24 h in PBS solution. This data compares favorably with previously reported values of gentamicin elution from Palacos R-40, which ranged from 3 to 8 wt % of the total amount of incorporated gentamicin, depending on the size and the surface area of the samples. The results show that Palacos samples released 4.84 +/- 0.27 mg after 24 h, a two-solution cement loaded with an equivalent concentration of gentamicin sulfate released 3.81 +/- 0.52 mg, and two-solution cement loaded with twice the concentration of Palacos released 5.53 +/- 0.26 mg of gentamicin. A higher percentage of release was recorded from Palacos than from the two-solution bone cement, and the effect of PBS mixing conditions on the release kinetics was only significant in the early stages of release and not at 24 h. It was concluded that monitoring the pH is an effective technique to measure gentamicin release from PMMA-based bone cements in PBS solution.
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Affiliation(s)
- Imad K Merkhan
- Department of Bioengineering and Neuroscience, 373 Link Hall, Syracuse University, Syracuse, New York 13244-5290, USA.
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19
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Abstract
Mechanical and physical properties are of particular significance for the performance of acrylic bone cement. Several mechanical test methods are described in the literature to characterize the mechanical performance of bone cements. The simulation of the in vivo situation is extremely difficult, however, because of the complex mechanism of loading in the bone. The usefulness of the different mechanical and physical test methods, several results of commercial acrylic bone cements, and the influence of different parameters, such as temperature, test environment, and preparation of specimens on these results are discussed in this article.
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Affiliation(s)
- Klaus-Dieter Kuehn
- Heraeus Kulzer GmbH & Co. KG, Endomedicine Division, Philipp-Reis-Strasse 8/13, D-61273 Wehrheim, Germany.
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20
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Macaulay W, DiGiovanni CW, Restrepo A, Saleh KJ, Walsh H, Crossett LS, Peterson MGE, Li S, Salvati EA. Differences in bone-cement porosity by vacuum mixing, centrifugation, and hand mixing. J Arthroplasty 2002; 17:569-75. [PMID: 12168171 DOI: 10.1054/arth.2002.32693] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The mean pore size and percent porosity of vacuum-mixed cement were compared with centrifuged cement and cement hand mixed by skilled specialized operating room technicians. Centrifuged cement samples had the smallest mean pore size when compared with vacuum-mixed specimens. The mean pore size for the hand-mixed specimens was intermediate and not significantly different from the other 2 mixing techniques. Results were reversed, however, for mean percent porosity. Centrifuged cement had the highest percent porosity; vacuum-mixed cement, the lowest; and hand-mixed cement, intermediate. The porosity of vacuum-mixed Simplex P (Howmedica, Rutherford, NJ) bone-cement was similar from the initial to the remnant cement extruded from the cement gun. There was no reduced cement porosity with vacuum mixing or centrifugation as anticipated. Reversion to hand mixing by highly skilled technicians could result in a significant cost savings without negative effects on cement porosity.
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Affiliation(s)
- William Macaulay
- Department of Orthopaedic Surgery, Columbia University, New York, USA.
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21
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Abstract
Palacos R bone cement was prepared using three commercially available mixing techniques, first generation, second generation and third generation, to determine the mechanical properties and porosity contents of the bone cement. The compressive strengths, bending strengths and flexural moduli were expressed as a function of void content. The volume of pores within the cement structure was found to be a contributing factor to the physical properties of acrylic bone cement. The lower the volume of voids in the cement the better the compressive and flexural properties, hence stronger bone cement. It was found that the best results were obtained from cement that had been mixed using the Mitab Optivac or Summit HiVac Syringe systems at a reduced pressure level of between -72 and -86 kPa below atmospheric pressure, resulting in cement of porosity 1.44-3.17%; compressive strength 74-81 MPa; flexural modulus 2.54-2.60 GPa; and flexural strength 65-73 MPa.
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Affiliation(s)
- N J Dunne
- School of Mechanical and Manufacturing Engineering, Dublin City University, Glasnevin, Republic of Ireland.
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22
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Graham J, Pruitt L, Ries M, Gundiah N. Fracture and fatigue properties of acrylic bone cement: the effects of mixing method, sterilization treatment, and molecular weight. J Arthroplasty 2000; 15:1028-35. [PMID: 11112200 DOI: 10.1054/arth.2000.8188] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The purpose of this study was to characterize the relative and combined effects of sterilization, molecular weight, and mixing method on the fracture and fatigue performance of acrylic bone cement. Palacos R brand bone cement powder was sterilized using ethylene oxide gas (EtO) or gamma irradiation. Nonsterile material was used as a control. Molecular weights of the bone-cement powders and cured cements were measured using gel permeation chromatography. Hand and vacuum mixing were employed to mold single edge-notched bend specimens for fracture toughness testing. Molded dog-bone specimens were used for fatigue tests. Electron microscopy was used to study fracture mechanisms. Analysis of variance and Student t-tests were used to compare fracture and fatigue performance between sterilization and mixing groups. Our results indicate that vacuum mixing improved significantly the fracture and fatigue resistance (P<.05, P<.07) over hand mixing in radiation-sterilized and EtO-sterilized groups. In vacuum-mixed cement, the degradation in molecular weight resulting from gamma irradiation decreased fracture resistance significantly when compared with EtO sterilization and control (P<.05). A corresponding decrease in fatigue resistance was observed in the cement that was degraded severely by a radiation dose of 10 MRad (P<.05). In contrast, EtO sterilization did not result in a significantly different fracture resistance when compared with unsterilized controls for vacuum-mixed cement (P>.1). For hand-mixed cement, fracture and fatigue resistance appeared to be independent of sterilization method. This independence is believed to be the result of higher porosity that compromised the mechanical properties and obscures any effect of sterilization. Our results indicate that a combination of nonionizing sterilization and vacuum mixing resulted in the best mechanical performance and is most likely to contribute to enhanced longevity in vivo.
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Affiliation(s)
- J Graham
- Department of Bioengineering, University of California, San Francisco, California, USA
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23
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Abstract
Acrylic bone cement occupies a distinctive place in the hierarchy of synthetic biomaterials, because it is the only material currently used for anchoring the prosthesis to the contiguous bone in a cemented arthroplasty. However, the cement is not without its drawbacks. The main one is the role that it has been postulated to play in the aseptic loosening and, hence, clinical life of the arthroplasty. In turn, this role is directly related to the mechanical properties of the cement, especially the resistance to fracture of the cement in the mantle at the cement-prosthesis interface or the cement-bone interface. The present work is a detailed critical review of the recent literature on the properties of bone cement that are considered germane to its use in the stated application. The relevant properties are identified and a case is made for including each of them. Compilations of the values of these properties, obtained under clearly identified conditions, are presented for the six commercial formulations of bone cement in current popular orthopedic use. The gaps and unresolved questions in the current data base, efforts that should be made to address these issues, and research directions are covered.
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Affiliation(s)
- G Lewis
- Department of Mechanical Engineering, The University of Memphis, Tennessee 38152, USA
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24
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Müller-Wille P, Wang JS, Lidgren L. Integrated system for preparation of bone cement and effects on cement quality and environment. JOURNAL OF BIOMEDICAL MATERIALS RESEARCH 2000; 38:135-42. [PMID: 9178741 DOI: 10.1002/(sici)1097-4636(199722)38:2<135::aid-jbm8>3.0.co;2-r] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We developed a prepacked mixing system for the preparation of bone cement. The system is based on mixing and collection of bone cement under a vacuum and serves as both the storage and mixing device for the cement components, thereby minimizing the exposure of the operating staff to the monomer and the risk for contamination of the cement during preparation. We evaluated the system using Palacos R and Simplex P. The cement produced was compared with cement obtained from a commercially available mixing system. Temperature evolution during curing, handling characteristics, density, and porosity of the cement obtained were analyzed. The results showed that the experimental system produces cement with physical properties (i.e., setting times and temperature, porosity, and density) equal to or better than those obtained with commercially available systems. Reducing the amount of monomer in the experimental system led to a reduction of the curing temperature without compromising the physical properties of the cements.
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Affiliation(s)
- P Müller-Wille
- Department of Orthopedics, Lund University Hospital, Sweden
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25
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Hasenwinkel JM, Lautenschlager EP, Wixson RL, Gilbert JL. A novel high-viscosity, two-solution acrylic bone cement: effect of chemical composition on properties. JOURNAL OF BIOMEDICAL MATERIALS RESEARCH 1999; 47:36-45. [PMID: 10400878 DOI: 10.1002/(sici)1097-4636(199910)47:1<36::aid-jbm5>3.0.co;2-r] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Solutions of poly(methyl methacrylate) (PMMA) powder predissolved in methyl methacrylate (MMA) have been developed as an alternative to current powder/liquid bone cements. They utilize the same addition polymerization chemistry as commercial cements, but in mixing and delivering via a closed system, porosity is eliminated and the dependence of material properties on the surgical technique is decreased. Twelve different sets of compositions were prepared, with two solutions of constant polymer-to-monomer ratio (80 g of PMMA/100 mL of MMA) and all combinations of four benzoyl peroxide (BPO) initiator levels added to the first solution and three N, N-dimethyl-p-toluidine (DMPT) activator levels added to the second. These compositions were tested, along with Simplex-P bone cement, for effects of BPO and DMPT concentrations on polymerization exotherm, setting time, flexural strength, modulus, and maximum strain. The results show that each of these dependent variables was affected significantly by the individual concentrations of BPO and DMPT and their interactions. The flexural strength, modulus, and polymerization exotherm reached their maximums at about a 1:1 molar ratio of BPO to DMPT. Most compositions had exotherms, setting times, and maximum strains within the range of commercial cements and flexural strengths and moduli up to 54 and 43% higher than Simplex-P, respectively.
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Affiliation(s)
- J M Hasenwinkel
- Division of Biological Materials, Northwestern University Dental School, 311 E. Chicago Avenue, Chicago, Illinois 60611-3008, USA
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26
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Wang JS, Franzén H, Lidgren L. Interface gap after implantation of a cemented femoral stem in pigs. ACTA ORTHOPAEDICA SCANDINAVICA 1999; 70:234-9. [PMID: 10429597 DOI: 10.3109/17453679908997799] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
We studied the interface gap around cemented femoral stems. Fresh pig femora were used. Bone cement mixed under vacuum or at atmospheric pressure was injected into the femoral canal and a cobalt chrome stem was then implanted. The femora were sectioned transversely from the minor trochanter and distally by using a high-pressure water cutter. Most of the interfaces had intimate contact. However, in all specimens, small gaps were found at the bone-cement and cement-stem interfaces. The gaps at the interfaces between the bone and cement and the cement and stem were measured, using a computerized video digital system. They occupied about 10% of the circumference at the bone-cement interface and about 15% of the circumference at the cement-stem interface, irrespective of the mixing procedures. Most gaps were less than 100 mu at the interfaces. In conclusion, cemented implants in the animal model showed that small gaps are found at the interfaces directly after implantation. These gaps may be weak points and initiate debonding when loading the prostheses.
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Affiliation(s)
- J S Wang
- Department of Orthopedics, Lund University Hospital, Sweden.
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27
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Ioannidis TT, Kavadias C, Sdrenias C, Nakopoulou L, Prassianakis J. Detrimental effect of aging on the endurance of bone cement. An in vivo and in vitro study in rabbits. ACTA ORTHOPAEDICA SCANDINAVICA. SUPPLEMENTUM 1997; 275:115-8. [PMID: 9385284 DOI: 10.1080/17453674.1997.11744762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We investigated the effect of aging on the compressive strength of bone cement under in vivo and in vitro conditions. Cement molds were implanted in the dorsum of rabbits and other molds were kept under stable conditions and in darkness. Comparative measures taken at 15 days and 1, 3, 6, 12 and 24 months showed lower endurance of the implanted molds (p < 0.001). A reactive capsule surrounded the bone cement in vivo up to the 3rd month, its cellularity increased, and then almost disappeared by 1 year. Macrophages and foreign body cells reappeared at 2 years, indicating a "chemical aging" effect in the in vivo environment. Our findings suggest that aging may play an important role in the amelioration of the mechanical properties of bone cement.
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Affiliation(s)
- T T Ioannidis
- Department of Orthopaedic Surgery, Th. Garofallidis Research Center, Athens, Greece
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28
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Abstract
The effects of hand mixing with two different mechanical mixing systems (fixed versus rotating central axis) on unmixed powder content, macroporosity, density, and bending strength of acrylic bone-cement are compared. The effects of voids and unmixed powder on cement bending strength are also evaluated. In acrylic cement, both unmixed powder monomer and voids 1 mm and larger can be easily visualized and analyzed on radiographs of 3-mm-thick samples. Image analysis allowed demonstration of a significant increase in unmixed powder content (P < .0001), in cement prepared using a vacuum mixing system with a fixed central axis compared with both the rotating axis system and hand mixing. The rotating-axis system produced cement of higher density compared with hand mixing only (P = .004). There was a significant correlation between the number of voids measured per square centimeter and cement bending strength (P < .0001), as well as an independent and significant correlation between unmixed powder content and cement bending strength (P < .0001). Mechanical mixing using a fixed central axis produced significantly weaker cement compared with both hand mixing (P < .015) and the rotating-central-axis system (P < .0001). A 15% drop in strength between the two mechanical mixing systems was observed. It is therefore concluded that the use of different rotating systems in mechanical mixers can influence void and unmixed powder content and, consequently, the mechanical properties of acrylic cement, and that unmixed powder is an independent factor affecting the bending strength of the cement.
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Affiliation(s)
- N M Kurdy
- Orthopaedic Department, Hope Hospital, Salford, United Kingdom
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29
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Fritsch EW. Static and fatigue properties of two new low-viscosity PMMA bone cements improved by vacuum mixing. JOURNAL OF BIOMEDICAL MATERIALS RESEARCH 1996; 31:451-6. [PMID: 8836840 DOI: 10.1002/(sici)1097-4636(199608)31:4<451::aid-jbm3>3.0.co;2-k] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
With the objectives of reducing toxicity and improving the mechanical properties of the prior Sulfix-6 cement, a new low-viscosity bone cement with a new catalyst (Sulfix-60), and a gentamycin containing cement (Allofix-G) were developed. Although static strength could be improved in comparison with the older Sulfix-6 cement, investigations regarding improved fatigue strength and the influence of vacuum mixing on the mechanical properties were missing. Dynamic weakness was the major disadvantage of the older Sulfix-6 cement. To investigate fatigue strength specimens of the new bone cements were tested with load guiding until breakage or 20 million cycles. In the three series, hand mixing, vacuum mixing, and vacuum mixing with additional pressurization were performed, respectively. Vacuum mixing led to increased fatigue stability from 6.3 to 9.1 MPa for Sulfix-60, and from 6.3 to 8.2 MPa for Allofix-G. Additional compression had no significant effect. A 200% increased fatigue strength was detectable in comparison with the older cement. In the four-point bending test, similar results were found. It could be proved that an increased polymerization rate achieved with the use of the new catalyst was responsible for the improved mechanical properties of the new bone cement Sulfix-60.
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Affiliation(s)
- E W Fritsch
- Orthopaedic University Hospital Homburg/Saar, Germany
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30
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Wang JS, Toksvig-Larsen S, Müller-Wille P, Franźen H. Is there any difference between vacuum mixing systems in reducing bone cement porosity? JOURNAL OF BIOMEDICAL MATERIALS RESEARCH 1996; 33:115-9. [PMID: 8736030 DOI: 10.1002/(sici)1097-4636(199622)33:2<115::aid-jbm8>3.0.co;2-u] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Six vacuum mixing systems, Cemvac, Merck, Mitvac, Optivac, Osteobond, and Stryker, were tested using prechilled Palacos R bone cement to investigate the reduction of porosity compared to mixing at atmospheric pressure. In addition the Optivac, Osteobond, and Stryker were tested using Simplex P bone cement to find out if they were effective in reducing the porosity of a middle viscosity bone cement. All vacuum mixing systems reduced the number of macropores (> 1 mm) and micropores (0.1 mm < voids < 1 mm) and increased the density of both Palacos R and Simplex P. But only the Optivac, Stryker, and Merck systems reduced the area percentage of macropores with more than 50% compared to the control. When using Simplex P bone cement, all three mixing systems tested reduced the numbers and the area percentage of macropores compared to the control. The results show that vacuum mixing is effective in reducing the porosity in both a high viscosity cement such as Palacos R and a middle viscosity cement such as Simplex P. Not all systems tested were effective in reducing the number and size of large voids.
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Affiliation(s)
- J S Wang
- Department of Orthopedics, Lund University Hospital, Sweden
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31
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Kindt-Larsen T, Smith DB, Jensen JS. Innovations in acrylic bone cement and application equipment. JOURNAL OF APPLIED BIOMATERIALS : AN OFFICIAL JOURNAL OF THE SOCIETY FOR BIOMATERIALS 1995; 6:75-83. [PMID: 7703541 DOI: 10.1002/jab.770060111] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A new bone cement was developed with the purpose of reducing the adverse biological effects during cementation of implants. This bone cement is characterized by lower exotherm, low release of monomer, low residual content of monomer, and retained physical properties. The essential innovation was substitution of half of the methylmethacrylate (MMA) in the monomer with long chain, high molecular weight, less volatile, and less soluble methacrylates (n-decylmethacrylate, isobornyl-methacrylate), as well as alteration of the accelerator system to a mix of dihydroxypropyl-p-toluidine and N,N-dimethyl-p-toluidine. The powder contains butylmethacrylate-MMA copolymers. These measures lower the glass-transition temperature, and permit more complete mixing in an integrated package, mixing, and delivery system consisting of a vacuum packed, double chamber pouch. The porosity was reduced to about 2% and the largest voids measured 0.1 mm. The polymerization exotherm was reduced to 58 degrees C. The compressive strength was 82 MPa, the four-point bending strength 55 MPa, the flexural modulus 2.24 GPa, the tensile strength 32 MPa, and the shear strength 36 MPa. The fracture toughness was 0.89 MPa square root of cm. These mechanical properties together with the fatigue life were on level with manually mixed, conventional PMMA bone cements.
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Wang JS, Franzén H, Toksvig-Larsen S, Lidgren L. Does vacuum mixing of bone cement affect heat generation? Analysis of four cement brands. JOURNAL OF APPLIED BIOMATERIALS : AN OFFICIAL JOURNAL OF THE SOCIETY FOR BIOMATERIALS 1995; 6:105-8. [PMID: 7640436 DOI: 10.1002/jab.770060204] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Four different brands of bone cement (Palacos R, Simplex P, Sulfix, CMW 1) were tested for exothermic changes during polymerization at atmospheric pressure and under partial vacuum of 0.2 bar. Palacos R was also mixed at four pressure levels (1.0, 0.2, 0.12, and 0.05 bar). The peak temperature in the bone cement was 46 to 124 degrees C, depending on the measuring point. There was no difference in peak temperature or duration of temperature increase above 50 degrees C during the curing of cement whether mixed at atmospheric pressure or under partial vacuum at different pressure levels.
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Affiliation(s)
- J S Wang
- Department of Orthopaedics, Lund University Hospital, Sweden
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