Measurements of the Residual Stresses Due to Cement Polymerization for Cemented Hip Implants

2003 ◽  
Author(s):  
Natalia Nun˜o ◽  
Dominic Plamondon
Keyword(s):  
Residual Stresses ◽  
Bone Cement ◽  
Normal Stresses ◽  
Liquid Form ◽  
Synthetic Bone ◽  
Press Fit ◽  
Grouting Material ◽  
Solidification Phenomenon ◽  
Outside Diameter

In cemented hip implant, the polymethyl methacrylate (PMMA) also called bone cement is used as grouting material between the implant and the bone. During the operation, the bone cement still in a liquid form is inserted between the femoral component and the bone. During polymerisation of the cement, residual stresses are generated in the bulk cement. The process of cement curing is a complex solidification phenomenon where transient stresses are generated and the residual stresses vary with different boundary conditions during curing (Ahmed et al., 1982). In particular, normal stresses are generated at the implant-PMMA interface resulting in a press-fit problem. The 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. An experiment has been devised to measure directly the residual stresses of the bone cement to reproduce the in-vivo behaviour of the prosthesis. An idealized prosthesis (19-mm diameter) is used. A subminiature load cell (9.5-mm diameter) is inserted inside the stem to measure directly the radial residual stresses of the PMMA on the stem. Bone cement polymerizes between the stem and the synthetic bone (40-mm outside diameter). The tests are conducted at body temperature of 37°C.

Measurements of the Residual Stresses due to Cement Polymerization for Cemented Hip Implants

2005 ◽  
Vol 490-491 ◽  
pp. 571-576
Author(s):  
Natalia Nuño ◽  
Dominic Plamondon
Keyword(s):  
Body Temperature ◽  
Residual Stresses ◽  
Bone Cement ◽  
Hip Prosthesis ◽  
Outer Diameter ◽  
Liquid Form ◽  
Synthetic Bone ◽  
Cement Interface ◽  
Initial Fixation

The initial fixation of the cemented hip prosthesis relies on the resistance of the interface between the metallic stem of the implant, the PMMA, and the adjacent bone. During the operation, the bone cement still in a liquid form is inserted between the implant and the bone. During polymerisation of the cement, residual stresses are generated in the bulk cement. An experiment has been devised to reproduce the in vivo behaviour of a cemented hip prosthesis, and to develop a technique to measure the residual stresses of the bone cement at the stem-cement interface. An idealized prosthesis (19-mm diameter) was placed inside a synthetic bone (outer diameter of 40 mm, inside diameter of 30 mm). The bone cement was poured between the stem and the bone. A sub-miniature load cell was inserted inside the idealized stem to measure directly the radial stresses generated by the cement curing on the hip stem. The tests are conducted at body temperature of 37°C to simulate the in-vivo conditions.

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].

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 ◽  
Load Transfer ◽  
Hip Implants ◽  
Implant Loosening ◽  
Cement Interface ◽  
Grouting Material ◽  
Surrounding Bone ◽  
Causes Of Failure

Implant loosening 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].

Calcium Phosphate-Coated Titanium Implants in the Mandible: Limitations of the in vivo Minipig Model

2020 ◽  
Vol 61 (6) ◽  
pp. 177-187
Author(s):  
Till Kämmerer ◽  
Tony Lesmeister ◽  
Victor Palarie ◽  
Eik Schiegnitz ◽  
Andrea Schröter ◽  
...  
Keyword(s):  
Calcium Phosphate ◽  
Statistical Difference ◽  
Surface Modifications ◽  
Titanium Implants ◽  
In Vivo Model ◽  
Implant Surface ◽  
Press Fit ◽  
Endosseous Implant ◽  
Bone To Implant Contact

Introduction: We aimed to compare implant osseointegration with calcium phosphate (CaP) surfaces and rough subtractive-treated sandblasted/acid etched surfaces (SA) in an in vivo minipig mandible model. Materials and Methods: A total of 36 cylindrical press-fit implants with two different surfaces (CaP, n = 18; SA, n = 18) were inserted bilaterally into the mandible of 9 adult female minipigs. After 2, 4, and 8 weeks, we analyzed the cortical bone-to-implant contact (cBIC; %) and area coverage of bone-to-implant contact within representative bone chambers (aBIC; %). Results: After 2 weeks, CaP implants showed no significant increase in cBIC and aBIC compared to SA (cBIC: mean 38 ± 5 vs. 16 ± 11%; aBIC: mean 21 ± 1 vs. 6 ± 9%). Two CaP implants failed to achieve osseointegration. After 4 weeks, no statistical difference between CaP and SA was seen for cBIC (mean 54 ± 15 vs. 43 ± 16%) and aBIC (mean 43 ± 28 vs. 32 ± 6). However, we excluded two implants in each group due to failure of osseointegration. After 8 weeks, we observed no significant intergroup differences (cBIC: 18 ± 9 vs. 18 ± 20%; aBIC: 13 ± 8 vs. 16 ± 9%). Again, three CaP implants and two SA implants had to be excluded due to failure of osseointegration. Conclusion: Due to multiple implant losses, we cannot recommend the oral mandibular minipig in vivo model for future endosseous implant research. Considering the higher rate of osseointegration failure, CaP coatings may provide an alternative to common subtractive implant surface modifications in the early phase post-insertion.

Mechanical Performance and In Vivo Tests of an Acrylic Bone Cement Filled with Bioactive Sepia Officinalis Cuttlebone

2010 ◽  
Vol 21 (1) ◽  
pp. 113-125 ◽  
Author(s):  
S. García-Enriquez ◽  
H. E. R. Guadarrama ◽  
I. Reyes-González ◽  
E. Mendizábal ◽  
C. F. Jasso-Gastinel ◽  
...  
Keyword(s):  
Bone Cement ◽  
Mechanical Performance ◽  
Sepia Officinalis ◽  
Acrylic Bone Cement ◽  
In Vivo Tests

Development of Novel Bioactive PMMA-Based Bone Cement and its In Vitro and In Vivo Evaluation

2006 ◽  
Vol 309-311 ◽  
pp. 801-804 ◽  
Author(s):  
S.B. Cho ◽  
Akari Takeuchi ◽  
Ill Yong Kim ◽  
Sang Bae Kim ◽  
Chikara Ohtsuki ◽  
...  
Keyword(s):  
Mechanical Property ◽  
Compressive Strength ◽  
Bone Cement ◽  
The Novel ◽  
In Vivo Evaluation ◽  
Natural Bone ◽  
Pmma Bone Cement ◽  
Rabbit Tibia

In order to overcome the disadvantage of commercialized PMMA bone cement, we have developed novel PMMA-based bone cement(7P3S) reinforced by 30 wt.% of bioactive CaO-SiO2 gel powders to induce the bioactivity as well as to increase mechanical property for the PMMA bone cement. The novel 7P3S bone cement hardened after mixing for about 7 minutes. For in vitro evaluation, apatite forming ability of it was investigated using SBF. When the novel 7P3S bone cement was soaked into SBF, it formed apatite on its surfaces within 1 week Furthermore; there is no decrease in its compressive strength within 9 weeks soaking in SBF. It is though that hardly decrease in compressive strength of 7P3S bone cement in SBF is due to the relative small amount of gel powder or its spherical shape and monosize. In vivo evaluation of the novel 7P3S bone cement was carried out using rabbit. After implantion into rabbit tibia for several periods, the interface between novel bone cement and natural bone was evaluated by CT images. According to the results, the novel bone cement directly contact to the natural bone without fibrous tissue after implantation for 4 weeks. This results indicates that the newly developed 7P3S bone cement can bond to the living bone and also be effectively used as bioactive bone cement without decrease in mechanical property.

scholarly journals Preliminary in Vivo Evaluation of Bone Healing in Critical Size Bone Defects Implanted with an Injectable Calcium Phosphate Bone Cement (Osteopaste)

2017 ◽  
Vol 16 (1) ◽  
Author(s):  
Che Nor Zarida Che Seman ◽  
Zamzuri Zakaria ◽  
Zunariah Buyong ◽  
Mohd Shukrimi Awang ◽  
Ahmad Razali Md Ralib @ Md Raghib
Keyword(s):  
Calcium Phosphate ◽  
Bone Cement ◽  
Bone Tissue ◽  
Bone Repair ◽  
Critical Size ◽  
Healing Process ◽  
Bone Defects ◽  
Calcium Phosphate Bone Cement ◽  
Rabbit Tibia

Introduction: A novel injectable calcium phosphate bone cement (osteopaste) has been developed. Its potential application in orthopaedics as a filler of bone defects has been studied. The biomaterial was composed of tetra-calcium phosphate (TTCP) and tricalcium phosphate (TCP) powder. The aim of the present study was to evaluate the healing process of osteopaste in rabbit tibia. Materials and method: The implantation procedure was carried out on thirty-nine of New Zealand white rabbits. The in vivo bone formation was investigated by either implanting the Osteopaste, Jectos or MIIG – X3 into a critical size defect (CSD) model in the proximal tibial metaphysis. CSD without treatment served as negative control. After 1 day, 6 and 12 weeks, the rabbits were euthanized, the bone were harvested and subjected for analysis. Results: Radiological images and histological sections revealed integration of implants with bone tissue with no signs of graft rejection. There was direct contact between osteopaste material and host bone. The new bone was seen bridging the defect. Conclusion: The result showed that Osteopaste could be a new promising biomaterial for bone repair and has a potential in bone tissue engineering.

Tibial tray debonding from the cement mantle is associated with deformation of the backside of polyethylene tibial inserts

2021 ◽  
pp. 1-11
Author(s):  
Rohan M. Bhalekar ◽  
Matthew E. Nargol ◽  
Nish Shyam ◽  
Antoni V. F. Nargol ◽  
Stephen R. Wells ◽  
...  
Keyword(s):  
Light Microscopy ◽  
Manufacturing Process ◽  
Cement Mantle ◽  
Frictional Torque ◽  
Total Knee Arthroplasties ◽  
Fixed Bearing ◽  
Regression Modelling ◽  
Press Fit ◽  
Total Knee

Aims The aim of this study was to investigate whether wear and backside deformation of polyethylene (PE) tibial inserts may influence the cement cover of tibial trays of explanted total knee arthroplasties (TKAs). Methods At our retrieval centre, we measured changes in the wear and deformation of PE inserts using coordinate measuring machines and light microscopy. The amount of cement cover on the backside of tibial trays was quantified as a percentage of the total surface. The study involved data from the explanted fixed-bearing components of four widely used contemporary designs of TKA (Attune, NexGen, Press Fit Condylar (PFC), and Triathlon), revised for any indication, and we compared them with components that used previous generations of PE. Regression modelling was used to identify variables related to the amount of cement cover on the retrieved trays. Results A total of 114 explanted fixed-bearing TKAs were examined. This included 76 used with contemporary PE inserts which were compared with 15 used with older generation PEs. The Attune and NexGen (central locking) trays were found to have significantly less cement cover than Triathlon and PFC trays (peripheral locking group) (p = 0.001). The median planicity values of the PE inserts used with central locking trays were significantly greater than of those with peripheral locking inserts (205 vs 85 microns; p < 0.001). Attune and NexGen inserts had a characteristic pattern of backside deformation, with the outer edges of the PE deviating inferiorly, leaving the PE margins as the primary areas of articulation. Conclusion Explanted TKAs with central locking mechanisms were significantly more likely to debond from the cement mantle. The PE inserts of these designs showed characteristic patterns of deformation, which appeared to relate to the manufacturing process and may be exacerbated in vivo. This pattern of deformation was associated with PE wear occurring at the outer edges of the articulation, potentially increasing the frictional torque generated at this interface.

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