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Schonhoff M, Beckmann NA, Schwarze M, Eissler M, Kretzer JP, Renkawitz T, Jaeger S. Is TKA femoral implant stability improved by pressure applied cement? a comparison of 2 cementing techniques. BMC Musculoskelet Disord 2023; 24:51. [PMID: 36670400 PMCID: PMC9863212 DOI: 10.1186/s12891-023-06151-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Accepted: 01/09/2023] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND The majority of knee endoprostheses are cemented. In an earlier study the effects of different cementing techniques on cement penetration were evaluated using a Sawbone model. In this study we used a human cadaver model to study the effect of different cementing techniques on relative motion between the implant and the femoral shaft component under dynamic loading. METHODS Two different cementing techniques were tested in a group of 15 pairs of human fresh frozen legs. In one group a conventional cementation technique was used and, in another group, cementation was done using a pressurizing technique. Under dynamic loading that simulated real life conditions relative motion at the bone-implant interface were studied at 20 degrees and 50 degrees flexion. RESULTS In both scenarios, the relative motion anterior was significantly increased by pressure application. Distally, it was the same with higher loads. No significant difference could be measured posteriorly at 20°. At 50° flexion, however, pressurization reduced the posterior relative motion significantly at each load level. CONCLUSION The use of the pressurizer does not improve the overall fixation compared to an adequate manual cement application. The change depends on the loading, flexion angle and varies in its proportion in between the interface zones.
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Affiliation(s)
- Mareike Schonhoff
- grid.5253.10000 0001 0328 4908Laboratory of Biomechanics and Implant Research, Department of Orthopaedics, Heidelberg University Hospital, 69118 Heidelberg, Germany
| | - Nicholas A. Beckmann
- grid.5253.10000 0001 0328 4908Department of Orthopaedics, Heidelberg University Hospital, 69118 Heidelberg, Germany
| | - Martin Schwarze
- grid.5253.10000 0001 0328 4908Laboratory of Biomechanics and Implant Research, Department of Orthopaedics, Heidelberg University Hospital, 69118 Heidelberg, Germany
| | - Marvin Eissler
- grid.5253.10000 0001 0328 4908Department of Diagnostic and Interventional Radiology, Heidelberg University Hospital, Heidelberg, Germany
| | - J. Philippe Kretzer
- grid.5253.10000 0001 0328 4908Laboratory of Biomechanics and Implant Research, Department of Orthopaedics, Heidelberg University Hospital, 69118 Heidelberg, Germany
| | - Tobias Renkawitz
- grid.5253.10000 0001 0328 4908Department of Orthopaedics, Heidelberg University Hospital, 69118 Heidelberg, Germany
| | - Sebastian Jaeger
- grid.5253.10000 0001 0328 4908Laboratory of Biomechanics and Implant Research, Department of Orthopaedics, Heidelberg University Hospital, 69118 Heidelberg, Germany
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Vogel D, Wehmeyer M, Kebbach M, Heyer H, Bader R. Stress and strain distribution in femoral heads for hip resurfacing arthroplasty with different materials: A finite element analysis. J Mech Behav Biomed Mater 2020; 113:104115. [PMID: 33189013 DOI: 10.1016/j.jmbbm.2020.104115] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 09/18/2020] [Accepted: 09/24/2020] [Indexed: 12/28/2022]
Abstract
Femoral bone loss due to stress and strain shielding is a common problem in hip resurfacing arthroplasty (HRA), which arises from the different stiffness of implant materials and the adjacent bone. Usually, the implants used in HRA are made of cobalt-chromium alloy (CoCr). As a novel concept, implants may also be made of ceramics, whose stiffness exceeds that of the adjacent bone by a multiple. Therefore, this computational study aimed to evaluate whether poly (ether-ether-ketone) (PEEK) or a hybrid material with a PEEK body and ceramic surface made of alumina toughened zirconia (ATZ) might be more suitable implant alternatives for HRA, as they can avoid stress and strain shielding. A reconstructed model of a human femur with an HRA implant was simulated, whereby the material of the HRA was varied between CoCr, ATZ, zirconia toughened alumina (ZTA), PEEK, and a hybrid PEEK-ATZ material. The implant fixation method also varied (cemented or cementless). The simulated models were compared with an intact model to analyze stress and strain distribution in the femoral head and neck. The strain distribution was evaluated at a total of 30,344 (cemented HRA) and 63,531 (uncemented HRA) nodes in the femoral head and neck region and divided into different strain regions (<400 µm/m: atrophy; 400-3000 μm/m: bone preserving and building; 3000-20,000 μm/m: yielding and >20,000 μm/m fracture). In addition, the mechanical stability of the implants was evaluated. When the material of the HRA implant was simulated as metal or ceramic while evaluating the strains, it was seen that around 22-26% of the analyzed nodes in the femoral head and neck were in an atrophic region, 47-51% were in a preserving or building region, and 27-28% were in a yielding region. In the case of PEEK implant, less than 0.5% of the analyzed nodes were in an atrophic region, 66-69% in a preserving or building region, and 31-34% in a yielding region. The fixation technique also had a small influence. When a hybrid HRA was simulated, the strains at the analyzed nodes depended on the thickness of the ceramic material. In conclusion, the material of the HRA implant was crucial in terms of stress and strain distribution in the adjacent bone. HRA made of PEEK or a hybrid material leads to decisively reduced stress and strain alteration compared to stiffer materials such as CoCr, ATZ, and ZTA. This confirms the potential for reduction in stress and strain shielding in the femoral head with the use of a hybrid material with a PEEK body for HRA.
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Affiliation(s)
- Danny Vogel
- Biomechanics and Implant Technology Research Laboratory, Department of Orthopaedics, Rostock University Medical Center, Doberaner Straße 142, 18057, Rostock, Germany.
| | - Merle Wehmeyer
- Biomechanics and Implant Technology Research Laboratory, Department of Orthopaedics, Rostock University Medical Center, Doberaner Straße 142, 18057, Rostock, Germany.
| | - Maeruan Kebbach
- Biomechanics and Implant Technology Research Laboratory, Department of Orthopaedics, Rostock University Medical Center, Doberaner Straße 142, 18057, Rostock, Germany.
| | - Horst Heyer
- Institute of Structural Mechanics, University of Rostock, Germany.
| | - Rainer Bader
- Biomechanics and Implant Technology Research Laboratory, Department of Orthopaedics, Rostock University Medical Center, Doberaner Straße 142, 18057, Rostock, Germany.
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Influence of the Acetabular Cup Material on the Shell Deformation and Strain Distribution in the Adjacent Bone-A Finite Element Analysis. MATERIALS 2020; 13:ma13061372. [PMID: 32197478 PMCID: PMC7142599 DOI: 10.3390/ma13061372] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 03/06/2020] [Accepted: 03/13/2020] [Indexed: 12/22/2022]
Abstract
In total hip arthroplasty, excessive acetabular cup deformations and altered strain distribution in the adjacent bone are potential risk factors for implant loosening. Materials with reduced stiffness might alter the strain distribution less, whereas shell and liner deformations might increase. The purpose of our current computational study was to evaluate whether carbon fiber-reinforced poly-ether-ether-ketones with a Young´s modulus of 15 GPa (CFR-PEEK-15) and 23 GPa (CFR-PEEK-23) might be an alternative shell material compared to titanium in terms of shell and liner deformation, as well as strain distribution in the adjacent bone. Using a finite element analysis, the press-fit implantation of modular acetabular cups with shells made of titanium, CFR-PEEK-15 and CFR-PEEK-23 in a human hemi-pelvis model was simulated. Liners made of ceramic and polyethylene were simulated. Radial shell and liner deformations as well as strain distributions were analyzed. The shells made of CFR-PEEK-15 were deformed most (266.7 µm), followed by CFR-PEEK-23 (136.5 µm) and titanium (54.0 µm). Subsequently, the ceramic liners were radially deformed by up to 4.4 µm and the polyethylene liners up to 184.7 µm. The shell materials slightly influenced the strain distribution in the adjacent bone with CFR-PEEK, resulting in less strain in critical regions (<400 µm/m or >3000 µm/m) and more strain in bone building or sustaining regions (400 to 3000 µm/m), while the liner material only had a minor impact. The superior biomechanical properties of the acetabular shells made of CFR-PEEK could not be determined in our present study.
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Adhesive strength of total knee endoprostheses to bone cement – analysis of metallic and ceramic femoral components under worst-case conditions. ACTA ACUST UNITED AC 2016; 61:281-9. [DOI: 10.1515/bmt-2014-0090] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Accepted: 02/13/2015] [Indexed: 02/02/2023]
Abstract
Abstract
Evaluation of the adhesive strength of femoral components to the bone cement is a relevant parameter for predicting implant safety. In the present experimental study, three types of cemented femoral components (metallic, ceramic and silica/silane-layered ceramic) of the bicondylar Multigen Plus knee system, implanted on composite femora were analysed. A pull-off test with the femoral components was performed after different load and several cementing conditions (four groups and n=3 components of each metallic, ceramic and silica/silane-layered ceramic in each group). Pull-off forces were comparable for the metallic and the silica/silane-layered ceramic femoral components (mean 4769 N and 4298 N) under standard test condition, whereas uncoated ceramic femoral components showed reduced pull-off forces (mean 2322 N). Loading under worst-case conditions led to decreased adhesive strength by loosening of the interface implant and bone cement using uncoated metallic and ceramic femoral components, respectively. Silica/silane-coated ceramic components were stably fixed even under worst-case conditions. Loading under high flexion angles can induce interfacial tensile stress, which could promote early implant loosening. In conclusion, a silica/silane-coating layer on the femoral component increased their adhesive strength to bone cement. Thicker cement mantles (>2 mm) reduce adhesive strength of the femoral component and can increase the risk of cement break-off.
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Faisal TR, Luo Y. Study of stress variations in single-stance and sideways fall using image-based finite element analysis. Biomed Mater Eng 2016; 27:1-14. [PMID: 27175463 DOI: 10.3233/bme-161563] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Image-based finite element analysis (FEA) has been considered an effective computational tool to predict hip fracture risk. The patient specific FEA gives an insight into the inclusive effect of three-dimensional (3D) complex bone geometry, and the distribution of inhomogeneous isotropic material properties in conjunction with loading conditions. The neck region of a femur is primarily the weakest in which fracture is likely to happen, when someone falls. A sideways fall results in the development of greater tensile and compressive stresses, respectively, in the inferior and superior aspects of the femoral neck, whereas the state of stress is reversed in usual gait or stance configuration. Herein, the variations of stresses have been investigated at the femoral neck region considering both single-stance and sideways fall. Finite element models of ten human femora have been generated using Quantitative Computed Tomography (QCT) scan datasets and have been simulated with an equal magnitude of load applied to the aforementioned configurations. Fracture risk indicator, defined as the ratio of the maximum compressive or tensile stress computed at the superior and inferior surfaces to the corresponding yield stress, has been used in this work to measure the variations of fracture risk between single-stance and sideways fall. The average variations of the fracture risk indicators between the fall and stance are at least 24.3% and 8% at the superior and inferior surfaces, respectively. The differences may interpret why sideways fall is more dangerous for the elderly people, causing hip fracture.
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Affiliation(s)
- Tanvir R Faisal
- Department of Mechanical Engineering, Faculty of Engineering, University of Manitoba, Winnipeg, MB R3T 2N2, Canada. E-mails: ,
| | - Yunhua Luo
- Department of Mechanical Engineering, Faculty of Engineering, University of Manitoba, Winnipeg, MB R3T 2N2, Canada. E-mails: ,
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Krueger AP, Singh G, Beil FT, Feuerstein B, Ruether W, Lohmann CH. Ceramic femoral component fracture in total knee arthroplasty: an analysis using fractography, fourier-transform infrared microscopy, contact radiography and histology. J Arthroplasty 2014; 29:1001-4. [PMID: 24360338 DOI: 10.1016/j.arth.2013.11.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Revised: 10/21/2013] [Accepted: 11/02/2013] [Indexed: 02/01/2023] Open
Abstract
Ceramic components in total knee arthroplasty (TKA) are evolving. We analyze the first case of BIOLOX delta ceramic femoral component fracture. A longitudinal midline fracture in the patellar groove was present, with an intact cement mantle and no bony defects. Fractographic analysis with laser scanning microscopy and white light interferometry showed no evidence of arrest lines, hackles, wake hackles, material flaws, fatigue or crack propagation. Analysis of periprosthetic tissues with Fourier-transform infrared (FT-IR) microscopy, contact radiography, histology, and subsequent digestion and high-speed centrifugation did not show ceramic debris. A macrophage-dominated response was present around polyethylene debris. We conclude that ceramic femoral component failure in this case was related to a traumatic event. Further research is needed to determine the suitability of ceramic components in TKA.
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Affiliation(s)
- Alexander P Krueger
- Department of Orthopaedic Surgery, Otto-von-Guericke University, Magdeburg, Germany
| | - Gurpal Singh
- Department of Orthopaedic Surgery, Otto-von-Guericke University, Magdeburg, Germany; University Orthopaedics, Hand and Reconstructive Microsurgery Cluster, National, University Health System, Singapore, Singapore
| | - Frank Timo Beil
- Department of Orthopaedics, University of Hamburg, Hamburg, Germany
| | - Bernd Feuerstein
- Department of Mechanical Engineering, Magdeburg-Stendal University of Applied Sciences, Magdeburg, Germany
| | - Wolfgang Ruether
- Department of Orthopaedics, University of Hamburg, Hamburg, Germany
| | - Christoph H Lohmann
- Department of Orthopaedic Surgery, Otto-von-Guericke University, Magdeburg, Germany
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Woiczinski M, Tollrian C, Schröder C, Steinbrück A, Müller PE, Jansson V. Calculation of the elastic properties of prosthetic knee components with an iterative finite element-based modal analysis: quantitative comparison of different measuring techniques. ACTA ACUST UNITED AC 2014; 58:369-76. [PMID: 23729597 DOI: 10.1515/bmt-2013-0003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Accepted: 05/13/2013] [Indexed: 11/15/2022]
Abstract
With the aging but still active population, research on total joint replacements relies increasingly on numerical methods, such as finite element analysis, to improve wear resistance of components. However, the validity of finite element models largely depends on the accuracy of their material behavior and geometrical representation. In particular, material properties are often based on manufacturer data or literature reports, but can alternatively be estimated by matching experimental measurements and structural predictions through modal analyses and identification of eigenfrequencies. The aim of the present study was to compare the accuracy of common setups used for estimating the eigenfrequencies of typical components often used in prosthetized joints. Eigenfrequencies of cobalt-chrome and ultra-high-molecular weight polyethylene components were therefore measured with four different setups, and used in modal analyses of corresponding finite element models for an iterative adjustment of their material properties. Results show that for the low-damped cobalt chromium endoprosthesis components, all common measuring setups provided accurate measurements. In the case of high-damped structures, measurements were only possible with setups including a continuously excitation system such as electrodynamic shakers. This study demonstrates that the iterative back-calculation of eigenfrequencies can be a reliable method to estimate the elastic properties for finite element models.
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Affiliation(s)
- Matthias Woiczinski
- Department of Orthopaedic Surgery, University Hospital of Munich LMU, Campus Grosshadern, 81377 Munich, Germany.
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Kluess D, Bergschmidt P, Mueller I, Mittelmeier W, Bader R. Influence of the distal femoral resection angle on the principal stresses in ceramic total knee components. Knee 2012; 19:846-50. [PMID: 22542212 DOI: 10.1016/j.knee.2012.03.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2011] [Revised: 03/23/2012] [Accepted: 03/26/2012] [Indexed: 02/02/2023]
Abstract
PURPOSE A certain failure mode using a newly developed cemented ceramic femoral component in total knee replacement was observed in clinical application, i.e. fracture of the femoral component during intraoperative impaction. This may be caused by unintentional deflection of the saw blades during cutting with consecutive higher resection angle of the distal femur than desired, leading to bending of the femoral component during implantation. A finite-element-analysis was carried out to simulate implantation of the femoral component and to evaluate the influence of distal femur preparation on implant stress. SCOPE We developed and validated a numerical model of the ceramic femoral component including a contact formulation which allowed calculating the principal stresses of the implant during implantation onto the resected femur. The analysis considered different anterior and posterior resection angles with a total of 17 variations. By increasing the femoral resection angle in the finite-element-model it could be shown that a deviation of three degrees from the intended resection angle can cause critical stress amounts during implantation. CONCLUSIONS When implanting the ceramic component in total knee arthroplasty, the femoral resection angles should be prepared very precisely, in particular anterior saw blade deflection has to be avoided. The implant manufacturer increased implant safety through an additional resection template. Moreover, the impaction of the ceramic femoral component during cementing was not further recommended by using a hammer.
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Affiliation(s)
- Daniel Kluess
- Department of Orthopaedics, University of Rostock, 18057 Rostock, Germany.
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Bergschmidt P, Bader R, Kluess D, Zietz C, Mittelmeier W. The All-Ceramic Knee Endoprosthesis—The Gap Between Expectation and Experience with Ceramic Implants. ACTA ACUST UNITED AC 2012. [DOI: 10.1053/j.sart.2013.01.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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10
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Bergschmidt P, Bader R, Ganzer D, Hauzeur C, Lohmann C, Rüther W, Tigani D, Rani N, Prats FL, Zorzi C, Madonna V, Rigotti S, Benazzo F, Rossi SMP, Kundt G, Bloch HR, Mittelmeier W. Ceramic femoral components in total knee arthroplasty - two year follow-up results of an international prospective multi-centre study. Open Orthop J 2012; 6:172-8. [PMID: 22582104 PMCID: PMC3349949 DOI: 10.2174/1874325001206010172] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Revised: 03/28/2012] [Accepted: 03/29/2012] [Indexed: 12/31/2022] Open
Abstract
Background:
Total knee arthroplasty can be considered as a reliable surgical procedure with a good long-term clinical result. However, implant failure due to particle induced aseptic loosening as well as the aspect of hypersensitivity to metal ions still remains an emerging issue. Methods:
The purpose of this prospective international multi-centre study was to evaluate the clinical and radiological outcomes and the reliability of the unconstrained Multigen Plus Total Knee System with a new BIOLOX® delta ceramic femoral component. Cemented total knee arthroplasty was performed on 108 patients (110 knees) at seven hospitals in three countries. Clinical and radiological evaluations were performed preoperatively, and after 3, 12 and 24 months postoperatively using the HSS-, WOMAC-, SF-36-score and standardised X-rays. Results:
The mean preoperative HSS-Score amounted to 55.5 ± 11.5 points and improved significantly in all postoperative evaluations (85.7 ± 11.7 points at 24 months). Furthermore, improvements in WOMAC- and SF-36-score were evaluated as significant at all points of evaluation. Radiolucent lines around the femoral ceramic component at 24 months were found in four cases. Progression of radiolucent lines was not seen and no implant loosening was observed. During the 24 month follow-up eight patients underwent subsequent surgery due to reasons unrelated to the implant material. Conclusions:
The observed clinical and radiological results are encouraging for a long-term survival of the ceramic femoral component. Therefore, ceramic implants could be a promising solution not only for patients with allergies against metallic implant materials, but also for the osteoarthritic knee joint. Long-term follow-up is necessary to draw conclusions regarding the superiority of the ceramic knee implants concerning in vivo wear and long-term survivorship.
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Affiliation(s)
- Philipp Bergschmidt
- Department of Orthopaedics, University of Rostock, Doberaner Strasse 142, 18057 Rostock, Germany
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Zietz C, Bergschmidt P, Fritsche A, Kluess D, Mittelmeier W, Bader R. Comparison of cross-sections of different femoral components for revision total knee replacement. J Orthop Surg (Hong Kong) 2012; 20:32-6. [PMID: 22535808 DOI: 10.1177/230949901202000107] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED PURPOSE. To compare the inner contour of the femoral component of 10 total knee replacement (TKR) designs for possible exchange in use. METHODS Inner contours of the femoral components of 10 cemented, cruciate-retaining TKR designs (e.motion, Genesis, Genia, Innex, LCS, Multigen Plus, NexGen, PFC, Scorpio, Vanguard) were scanned and reconstructed to 2-dimensional contours. Their cross-sections were compared by superimposition and aligning at the distal and anterior cuts. The patellar notch and outer contour were not analysed. RESULTS The maximum deviation was 5 mm in the posterior and posterior oblique cuts and 10 mm in the anterior oblique cut. Based on similarity of the inner contour, LCS and Innex was classified as group I, e.motion, Genesis, Scorpio, Vanguard, and Multigen Plus as group II, and Genia, NexGen, and PFC as group III. All 2 designs in group I were not compatible with the other 8 designs. Four of the 5 designs in group II showed good compatibility. All 3 designs in group III significantly differed in the posterior and oblique cuts. CONCLUSION A standardised inner contour of the femoral component can increase compatibility of different TKR systems in revision surgery and reduces the extent of bone resection.
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Affiliation(s)
- Carmen Zietz
- Department of Orthopaedics, University of Rostock, Rostock, Germany.
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Bergschmidt P, Kluess D, Zietz C, Finze S, Bader R, Mittelmeier W. Composite Ceramics in Total Knee Arthroplasty: Two-Year Experience in Clinical Application. ACTA ACUST UNITED AC 2011. [DOI: 10.1053/j.sart.2011.10.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Kluess D, Souffrant R, Mittelmeier W, Wree A, Schmitz KP, Bader R. A convenient approach for finite-element-analyses of orthopaedic implants in bone contact: modeling and experimental validation. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2009; 95:23-30. [PMID: 19231021 DOI: 10.1016/j.cmpb.2009.01.004] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2008] [Revised: 10/21/2008] [Accepted: 01/06/2009] [Indexed: 05/27/2023]
Abstract
With regard to the growing potential of finite-element-analysis (FEA) in the field of orthopaedic biomechanics, we present an approach helping in the development of appropriate models of the implant-bone compound. The algorithm is based on computed-tomography data of the bone and accordant computer-aided-design (CAD) data of the implant and aims at predicting the bone strains and interface mechanics of the included parts. The developed algorithm was validated exemplary using an acetabular cup in combination with a left and a right fresh-frozen human hemipelvis. The strains under maximum loads during the gait cycle as well as the micromotion in the bone-implant interface were measured and compared to results from equivalent finite-element-analyses. Thereby, we found strong correlation between the calculated and measured principal strains with correlation coefficients of r(2)=0.94 (left side) and r(2)=0.86 (right side). A validation of micromotion was not possible due to limited accuracy of the motion tracking system.
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Affiliation(s)
- Daniel Kluess
- Department of Orthopaedics, University of Rostock, Rostock, Germany.
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Bader R, Bergschmidt P, Fritsche A, Ansorge S, Thomas P, Mittelmeier W. [Alternative materials and solutions in total knee arthroplasty for patients with metal allergy]. DER ORTHOPADE 2009; 37:136-42. [PMID: 18210089 DOI: 10.1007/s00132-007-1189-x] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The annual number of total knee replacement implantations is rising continuously. A progressive cutaneous hypersensitivity rate against metallic materials in the population has been registered which can lead to an increase of allergy-induced reactions associated with implant loosening in the future although the correlation with an allergic cutaneous sensitisation has not been proven in all cases. On apparent allergy against metallic implant components different alternative solutions to standard endoprostheses should be taken into account for primary implantation or revision of total knee replacement, for example the application of implant components without metallic elements (e.g. ceramics), the use of non-allergic metallic implants, such as titanium or ZrNb alloys, or potential allergy-inducing metallic materials after masking the implant surface using a suitable coating. In the case of primary or revision surgery most patients with metal allergy are treated with a Ti(Nb)N-coated knee implant made of cobalt-chrome or titanium alloys in our hospital. Within an international multi-centre study we are currently implanting a newly developed knee endoprosthesis system with a ceramic femoral component as an alternative.
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Affiliation(s)
- R Bader
- Orthopädische Klinik und Poliklinik, Universität Rostock, Doberaner Strasse 142, 18057, Rostock, Deutschland.
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