scholarly journals Computational Study on Interfacial Interactions between Polymethyl Methacrylate-Based Bone Cement and Hydroxyapatite in Nanoscale

2021 ◽  
Vol 11 (7) ◽  
pp. 2937
Author(s):  
Hongdeok Kim ◽  
Byeonghwa Goh ◽  
Sol Lee ◽  
Kyujo Lee ◽  
Joonmyung Choi
Keyword(s):  
Bone Cement ◽  
Polymethyl Methacrylate ◽  
Load Transfer ◽  
Computational Study ◽  
Thermomechanical Properties ◽  
External Loading ◽  
Crosslinking Reaction ◽  
Mechanical Stiffness ◽  
Joint Replacement Surgery ◽  
Pull Out

Polymethyl methacrylate (PMMA)-based bone cement (BC) is a key material in joint replacement surgery that transfers external forces from the implant to the bone while allowing their robust binding. To quantitatively evaluate the effect of polymerization on the thermomechanical properties of the BC and on the interaction characteristics with the bone ceramic hydroxyapatite (HAp), molecular dynamics simulations were performed. The mechanical stiffness of the BC material under external loading increased gradually with the crosslinking reaction occurrence, indicating increasing load transfer between the constituent molecules. In addition, as the individual Methyl Methacrylate (MMA) segments were interconnected in the system, the freedom of the molecular network was largely suppressed, resulting in more thermally stable structures. Furthermore, the pull-out tests using HAp/BC bilayer models under different constraints (BC at 40% and 85%) revealed the cohesive characteristics of the BC with the bone scaffold in molecular detail. The stiffness and the fracture energy increased by 32% and 98%, respectively, with the crosslink density increasing.

Effect of Tapered Geometry on the Load Transfer of an Idealized Cemented Hip Implant

2002 ◽  
Author(s):  
N. Nun˜o
Keyword(s):  
Residual Stresses ◽  
Bone Cement ◽  
Chemical Bond ◽  
Polymethyl Methacrylate ◽  
Load Transfer ◽  
Hip Implants ◽  
Cement Interface ◽  
Grouting Material ◽  
Surrounding Bone ◽  
Causes Of Failure

Implant looseining of cemented hip implants is one of the major causes of failure of the arthroplasty. In cemented hip implants, the polymethyl methacrylate (PMMA), also called bone cement, is used as grouting material between the stem and the surrounding bone. During polymerisation of the cement, residual stresses are generated in the bulk cement. The bone cement does not have a chemical bond with the stem nor the bone; however, it fills completely the space between the two and serves to distribute the load being transferred from the stem to the bone. Numerical analyses on the load transfer of cemented hip implants usually do not include the residual stresses due to cement curing at the stem-cement interface [1–2].

scholarly journals Theory of the deformation of aligned polyethylene

2015 ◽  
Vol 471 (2180) ◽  
pp. 20150171 ◽  
Author(s):  
A. Hammad ◽  
T. D. Swinburne ◽  
H. Hasan ◽  
S. Del Rosso ◽  
L. Iannucci ◽  
...  
Keyword(s):  
Load Transfer ◽  
Tensile Load ◽  
Equation Of Motion ◽  
Dislocation Dynamics ◽  
Viscoelastic Deformation ◽  
Transfer Length ◽  
Soliton Dynamics ◽  
Fluctuation Dissipation ◽  
Pull Out ◽  
Definition Of

Solitons are proposed as the agents of plastic and viscoelastic deformation in aligned polyethylene. Interactions between straight, parallel molecules are mapped rigorously onto the Frenkel–Kontorova model. It is shown that these molecular interactions distribute an applied load between molecules, with a characteristic transfer length equal to the soliton width. Load transfer leads to the introduction of tensile and compressive solitons at the chain ends to mark the onset of plasticity at a well-defined yield stress, which is much less than the theoretical pull-out stress. Interaction energies between solitons and an equation of motion for solitons are derived. The equation of motion is based on Langevin dynamics and the fluctuation–dissipation theorem and it leads to the rigorous definition of an effective mass for solitons. It forms the basis of a soliton dynamics in direct analogy to dislocation dynamics. Close parallels are drawn between solitons in aligned polymers and dislocations in crystals, including the configurational force on a soliton. The origins of the strain rate and temperature dependencies of the viscoelastic behaviour are discussed in terms of the formation energy of solitons. A failure mechanism is proposed involving soliton condensation under a tensile load.

scholarly journals Cementing technique for total knee arthroplasty in cadavers using a pastry bone cement

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Hans Bösebeck ◽  
Anna-Maria Holl ◽  
Peter Ochsner ◽  
Manuel Groth ◽  
Kevin Stippich ◽  
...  
Keyword(s):  
Total Knee Arthroplasty ◽  
Bone Cement ◽  
Knee Arthroplasty ◽  
Primary Total Knee Arthroplasty ◽  
Pull Out ◽  
Ensure Patient Safety ◽  
Temperature Development ◽  
Total Knee ◽  
Primary Total Knee ◽  
Rule Out

Abstract Background In cemented primary total knee arthroplasty (TKA), aseptic loosening remains a major cause for failure. Cementing techniques and characteristics of a chosen cement play a key role for good fixation and implant survival. A pastry bone cement was developed to facilitate the cement preparation and to rule out most of preparation-associated application errors. The pastry bone cement was compared to a conventional polymethyl methacrylate cement in a TKA setting. Methods Standardized implantations of total knee endoprostheses were performed in bilateral knee cadavers to investigate handling properties, variables of cement application, working time, and temperature development. Mechanical aspects and cementation quality were assessed by pull-out trials and microscopic interface analysis. Results Both cements expressed similar characteristics during preparation and application, only the curing time of the pastry cement was about 3 min longer and the temperature peak was lower. Fractures of the conventional cement specimens differed from the pastry cement specimens in the tibial part, while no differences were found in the femoral part. Penetration depth of the pastry cement was similar (tibia) or deeper (femur) compared to the conventional cement. Conclusions The pastry cement facilitates the feasibility of cemented TKA. The pre-clinical tests indicate that the pastry bone cement fulfills the requirements for bone cement in the field of knee arthroplasty. A clinical trial is needed to further investigate the approach and ensure patient safety.

N-acetyl cysteine prevents polymethyl methacrylate bone cement extract-induced cell death and functional suppression of rat primary osteoblasts

2010 ◽  
Vol 92A (1) ◽  
pp. 285-296 ◽  
Author(s):  
Hideki Aita ◽  
Naoki Tsukimura ◽  
Masahiro Yamada ◽  
Norio Hori ◽  
Katsutoshi Kubo ◽  
...  
Keyword(s):  
Cell Death ◽  
Bone Cement ◽  
Polymethyl Methacrylate ◽  
Acetyl Cysteine ◽  
Primary Osteoblasts

scholarly journals Experimental study of the antibacterial activity of the lytic Staphylococcus aureus bacteriophage ph20 and lytic Pseudomonas aeruginosa bacteriophage ph57 during modelling of its impregnation into poly(methylmetacrylate) orthopedic implants (bone cement)

2018 ◽  
Vol 73 (1) ◽  
pp. 59-68 ◽  
Author(s):  
A. G. Samokhin ◽  
Ju. N. Kozlova ◽  
D. V. Korneev ◽  
O. S. Taranov ◽  
E. A. Fedorov ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Bone Cement ◽  
Polymethyl Methacrylate ◽  
Bacterial Colonization ◽  
Experimental Studies ◽  
Orthopedic Implants ◽  
Polymerization Process ◽  
Polymerization Reaction ◽  
Chemical Components

Background: The problem of bacterial colonization of implants used in medical practice continues to be relevant regardless of the material of the implant. Particular attention deserves polymeric implants, which are prepared ex tempore from polymethyl methacrylate, for example - duting orthopedic surgical interventions (so-called "bone cement"). The protection of such implants by antibiotic impregnation is subjected to multiple criticisms, therefore, as an alternative to antibiotics, lytic bacteriophages with a number of unique advantages can be used - however, no experimental studies have been published on the possibility of impregnating bacteriophages into polymethyl methacrylate and their antibacterial activity assessment under such conditions.Aims: to evaluate the possibility of physical placement of bacteriophages in polymethylmethacrylate and to characterize the lytic antibacterial effect of two different strains of bacteriophages when impregnated into polymer carrier ex tempore during the polymerization process in in vitro model.Materials and methods:  First stage - Atomic force microscopy (AFM) of polymethyl methacrylate samples for medical purposes was used to determine the presence and size of caverns in polymethyl methacrylate after completion of its polymerization at various reaction  temperatures (+6…+25°C and +18…+50°C).The second stage was performed in vitro and included an impregnation of two different bacteriophage strains (phage ph20 active against S. aureus and ph57 active against Ps. aeruginosa) into polymethyl methacrylate during the polymerization process, followed by determination of their antibacterial activity.Results: ACM showed the possibility of bacteriophages placement in the cavities of polymethyl methacrylate - the median of the section and the depth of cavities on the outer surface of the polymer sample polymerized at +18…+50°C were 100.0 and 40.0 nm, respectively, and on the surface of the transverse cleavage of the sample - 120.0 and 100.0 nm, respectively, which statistically did not differ from the geometric dimensions of the caverns of the sample polymerized at a temperature of +6…+25°C.The study of antibacterial activity showed that the ph20 bacteriophage impregnated in polymethyl methacrylate at +6…+25°C lost its effective titer within the first six days after the start of the experiment, while the phage ph57 retained an effective titer for at least 13 days.Conclusion: the study confirmed the possibility of bacteriophages impregnation into medical grade polymethyl methacrylate, maintaining the effective titer of the bacteriophage during phage emission into the external environment, which opens the way for the possible application of this method of bacteriophage delivery in clinical practice. It is also assumed that certain bacteriophages are susceptible to aggressive influences from the chemical components of "bone cement" and / or polymerization reaction products, which requires strict selection of bacteriophage strains that could be suitable for this method of delivery.

Laboratory-scale pull-out tests on a geothermal energy pile in dry sand subjected to heating cycles

2020 ◽  
Vol 57 (11) ◽  
pp. 1754-1766
Author(s):  
Rehab Elzeiny ◽  
Muhannad T. Suleiman ◽  
Suguang Xiao ◽  
Mu’ath Abu Qamar ◽  
Mohammed Al-Khawaja
Keyword(s):  
Load Transfer ◽  
Pressure Sensors ◽  
Temperature Sensors ◽  
Heat Pumps ◽  
Laboratory Model ◽  
Ground Source Heat Pumps ◽  
Energy Pile ◽  
Pull Out ◽  
Energy Piles ◽  
Dry Sand

Ground source heat pumps coupled with energy piles operate intermittently, subjecting the piles to temperature cycles throughout their lifetime. The research presented in this paper focuses on studying the thermomechanical behavior of energy piles subjected to heating cycles. Laboratory model tests were performed at the soil-structure interaction (SSI) facility at Lehigh University. A fully instrumented model energy pile, embedded in dry sand, was subjected to different number of heating cycles followed by axial pull-out loading. Baseline (room temperature), five heating cycles (5HC), and 100 heating cycles (100HC) tests are reported in this paper. The soil was instrumented with temperature sensors and pressure sensors, while the pile was instrumented with temperature sensors, strain gauges, and pressure sensors. The test results showed that the peak pull-out loads for the baseline, 5HC, and 100HC were 2794 N, 3633 N (30% higher than baseline), and 3559 N (27% higher than baseline), respectively. It was also found that subjecting the pile to large number of daily heating cycles induced small degradation in the load transfer or the peak pull-out load in dry sand.

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