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Modeling the debonding process of osseointegrated implants due to coupled adhesion and friction. Biomech Model Mechanobiol 2023; 22:133-158. [PMID: 36284076 PMCID: PMC9957925 DOI: 10.1007/s10237-022-01637-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Accepted: 09/06/2022] [Indexed: 11/02/2022]
Abstract
Cementless implants have become widely used for total hip replacement surgery. The long-term stability of these implants is achieved by bone growing around and into the rough surface of the implant, a process called osseointegration. However, debonding of the bone-implant interface can still occur due to aseptic implant loosening and insufficient osseointegration, which may have dramatic consequences. The aim of this work is to describe a new 3D finite element frictional contact formulation for the debonding of partially osseointegrated implants. The contact model is based on a modified Coulomb friction law by Immel et al. (2020), that takes into account the tangential debonding of the bone-implant interface. This model is extended in the direction normal to the bone-implant interface by considering a cohesive zone model, to account for adhesion phenomena in the normal direction and for adhesive friction of partially bonded interfaces. The model is applied to simulate the debonding of an acetabular cup implant. The influence of partial osseointegration and adhesive effects on the long-term stability of the implant is assessed. The influence of different patient- and implant-specific parameters such as the friction coefficient [Formula: see text], the trabecular Young's modulus [Formula: see text], and the interference fit [Formula: see text] is also analyzed, in order to determine the optimal stability for different configurations. Furthermore, this work provides guidelines for future experimental and computational studies that are necessary for further parameter calibration.
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Determinants of the primary stability of cementless acetabular cup implants: A 3D finite element study. Comput Biol Med 2021; 135:104607. [PMID: 34242871 DOI: 10.1016/j.compbiomed.2021.104607] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 05/31/2021] [Accepted: 06/22/2021] [Indexed: 11/20/2022]
Abstract
Primary stability of cementless implants is crucial for the surgical success and long-term stability. However, primary stability is difficult to quantify in vivo and the biomechanical phenomena occurring during the press-fit insertion of an acetabular cup (AC) implant are still poorly understood. The aim of this study is to investigate the influence of the cortical and trabecular bone Young's moduli Ec and Et, the interference fit IF and the sliding friction coefficient of the bone-implant interface μ on the primary stability of an AC implant. For each parameter combination, the insertion of the AC implant into the hip cavity and consequent pull-out are simulated with a 3D finite element model of a human hemi-pelvis. The primary stability is assessed by determining the polar gap and the maximum pull-out force. The polar gap increases along with all considered parameters. The pull-out force shows a continuous increase with Ec and Et and a non-linear variation as a function of μ and IF is obtained. For μ > 0.6 and IF > 1.4 mm the primary stability decreases, and a combination of smaller μ and IF lead to a better fixation. Based on the patient's bone stiffness, optimal combinations of μ and IF can be identified. The results are in good qualitative agreement with previous studies and provide a better understanding of the determinants of the AC implant primary stability. They suggest a guideline for the optimal choice of implant surface roughness and IF based on the patient's bone quality.
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Comparison of Test Setups for the Experimental Evaluation of the Primary Fixation Stability of Acetabular Cups. MATERIALS 2020; 13:ma13183982. [PMID: 32916802 PMCID: PMC7559462 DOI: 10.3390/ma13183982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 08/28/2020] [Accepted: 09/03/2020] [Indexed: 11/22/2022]
Abstract
Sufficient primary fixation stability is the basis for the osseointegration of cementless acetabular cups. Several test methods have been established for determining the tilting moment of acetabular press-fit cups, which is a measure for their primary fixation stability. The central aim of this experimental study was to show the differences between the commonly used lever-out test method (Method 1) and the edge-load test method (Method 2) in which the cup insert is axially loaded (1 kN) during the tilting process with respect to the parameters, tilting moment, and interface stiffness. Therefore, using a biomechanical cup block model, a press-fit cup design with a macro-structured surface was pushed into three cavity types (intact, moderate superior defect, and two-point-pinching cavity) made of 15 pcf and 30 pcf polyurethane foam blocks (n = 3 per cavity and foam density combination), respectively. Subsequently, the acetabular cup was disassembled from the three artificial bone cavities using the lever-out and the edge-load test method. Tilting moments determined with Method 1 ranged from 2.72 ± 0.29 Nm to 49.08 ± 1.50 Nm, and with Method 2, they ranged from 41.40 ± 1.05 Nm to 112.86 ± 5.29 Nm. In Method 2, larger areas of abrasion were observed in the artificial bone cavity compared to Method 1. This indicates increased shear forces at the implant–bone interface in the former method. In conclusion, Method 1 simulates the technique used by orthopedic surgeons to assess the correct fit of the trial cup, while Method 2 simulates the tilting of the cup in the acetabular bone cavity under in situ loading with the hip resultant force.
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O'Rourke D, Taylor M. Patient and surgical variability in the primary stability of cementless acetabular cups: A finite element study. J Orthop Res 2020; 38:1515-1522. [PMID: 32086833 DOI: 10.1002/jor.24636] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 01/23/2020] [Accepted: 02/19/2020] [Indexed: 02/04/2023]
Abstract
Aseptic loosening is the most common indication for revision of cementless acetabular cups and often depends on the primary stability achieved following surgery. Cup designs must be capable of achieving primary stability for a wide variety of individuals and surgical conditions to be successful. Typically, preclinical finite element (FE) testing of cups involves assessing the performance in a single patient and under a limited set of idealized conditions. The aim of this study was to assess the effect of patient and surgical parameters on the primary stability of an acetabular cup design in a set of subject-specific FE models. Interference fit was varied in a representative set of 12 patient-specific models of the implanted hemipelvis. Linear mixed models showed a significant association with micromotion for interference fit (P < .0001), acetabular bone elastic modulus (P < .001), native acetabular diameter (P = .03), and the interference fit-elastic modulus interaction (P = .01). There were no significant associations between the polar gap and any of the parameters considered. The significant interference fit-elastic modulus interaction suggests that increasing the interference fit in patients with low bone quality leads to a greater reduction in micromotion than in patients with higher bone quality. However, the significant association between percentage bone yielding and interference fit (P < .0001) suggests a higher periacetabular fracture risk at higher interference fits. This work supports the development of preclinical testing of cup designs for the broad range patients and surgical conditions a cup may face following surgery.
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Affiliation(s)
- Dermot O'Rourke
- Medical Device Research Institute, College of Science and Engineering, Flinders University, Adelaide, South Australia, Australia
| | - Mark Taylor
- Medical Device Research Institute, College of Science and Engineering, Flinders University, Adelaide, South Australia, Australia
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Al-Saffar AA, Evans SL. Effect of gap outside contact area on lubrication of metal-on-Metal total hip replacement. Comput Methods Biomech Biomed Engin 2020; 23:675-689. [PMID: 32396392 DOI: 10.1080/10255842.2020.1758679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Ball-in-socket metal on metal (MOM) contacts were analysed using the Abaqus Finite Element package to simulate dry contact between the acetabular cup and the femoral head. Different cup thicknesses of 4, 6, 8, and 10 mm were considered using a polyurethane foam block support system. Elastohydrodynamic lubrication (EHL) analyses were developed for the contacts using three different approaches to specify the contact. These were (i) A simple model based on the radii of relative curvature, (ii) An equivalent contact model developed so that its dry contact area and maximum pressure replicated the values obtained from the FE analysis, and (iii) A modified version of (ii) that also ensured equivalence of the gap shape outside the contact area. Published in vivo information for the hip joint contact forces over the walking cycle was used to specify the operating conditions for the EHL analysis. The analysis method was found to be effective for all points of the walking cycle for cases where the cup thickness exceeded 5 mm and modelling approach (ii) was identified as satisfactory. For a cup thickness of 4 mm, membrane action began to emerge in the FE analyses so that such contacts behaved in a different way.
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Affiliation(s)
- Ali A Al-Saffar
- Department of Mechanical Engineering, Faculty of Engineering, University of Kufa, Kufa, Iraq
| | - Sam L Evans
- School of Engineering, University of Cardiff, Cardiff, UK
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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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Beckmann NA, Bitsch RG, Bormann T, Braun S, Jaeger S. Titanium Acetabular Component Deformation under Cyclic Loading. MATERIALS 2019; 13:ma13010052. [PMID: 31861893 PMCID: PMC6981461 DOI: 10.3390/ma13010052] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 12/15/2019] [Accepted: 12/17/2019] [Indexed: 12/30/2022]
Abstract
Acetabular cup deformation may affect liner/cup congruency, clearance and/or osseointegration. It is unclear, whether deformation of the acetabular components occurs during load and to what extent. To evaluate this, revision multi-hole cups were implanted into six cadaver hemipelvises in two scenarios: without acetabular defect (ND); with a large acetabular defect (LD) that was treated with an augment. In the LD scenario, the cup and augment were attached to the bone and each other with screws. Subsequently, the implanted hemipelvises were loaded under a physiologic partial-weight-bearing modality. The deformation of the acetabular components was determined using a best-fit algorithm. The statistical evaluation involved repeated-measures ANOVA. The mean elastic distension of the ND cup was 292.9 µm (SD 12.2 µm); in the LD scenario, 43.7 µm (SD 11.2 µm); the mean maximal augment distension was 79.6 µm (SD 21.6 µm). A significant difference between the maximal distension of the cups in both scenarios was noted (F(1, 10) = 11.404; p = 0.007). No significant difference was noted between the compression of the ND and LD cups, nor between LD cups and LD augments. The LD cup displayed significantly lower elastic distension than the ND cup, most likely due to increased stiffness from the affixed augment and screw fixation.
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Affiliation(s)
- Nicholas A. Beckmann
- Clinic for Orthopedics and Trauma Surgery, Heidelberg University Hospital, Heidelberg University, 69118 Heidelberg, Germany
- Department of Orthopaedic Surgery and Traumatology, Inselspital, Bern University Hospital, 3010 Bern, Switzerland
- Correspondence: or
| | - Rudi G. Bitsch
- National Joint Center, ATOS Clinics, 69115 Heidelberg, Germany;
| | - Theresa Bormann
- Laboratory of Biomechanics and Implant Research, Clinic for Orthopedics and Trauma Surgery, Heidelberg University Hospital, Heidelberg University, 69118 Heidelberg, Germany; (T.B.); (S.B.); (S.J.)
| | - Steffen Braun
- Laboratory of Biomechanics and Implant Research, Clinic for Orthopedics and Trauma Surgery, Heidelberg University Hospital, Heidelberg University, 69118 Heidelberg, Germany; (T.B.); (S.B.); (S.J.)
| | - Sebastian Jaeger
- Laboratory of Biomechanics and Implant Research, Clinic for Orthopedics and Trauma Surgery, Heidelberg University Hospital, Heidelberg University, 69118 Heidelberg, Germany; (T.B.); (S.B.); (S.J.)
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Raffa ML, Nguyen VH, Tabor E, Immel K, Housset V, Flouzat-Lachaniette CH, Haiat G. Dependence of the primary stability of cementless acetabular cup implants on the biomechanical environment. Proc Inst Mech Eng H 2019; 233:1237-1249. [DOI: 10.1177/0954411919879250] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Biomechanical phenomena occurring at the bone–implant interface during the press-fit insertion of acetabular cup implants are still poorly understood. This article presents a nonlinear geometrical two-dimensional axisymmetric finite element model aiming at describing the biomechanical behavior of the acetabular cup implant as a function of the bone Young’s modulus Eb, the diametric interference fit ( IF), and the friction coefficient µ. The numerical model was compared with experimental results obtained from an in vitro test, which allows to determine a reference configuration with the parameter set: μ* = 0.3, [Formula: see text], and IF* = 1 mm for which the maximal contact pressure tN = 10.7 MPa was found to be localized at the peri-equatorial rim of the acetabular cavity. Parametric studies were carried out, showing that an optimal value of the pull-out force can be defined as a function of μ, Eb, and IF. For the reference configuration, the optimal pull-out force is obtained for μ = 0.6 (respectively, Eb = 0.35 GPa and IF = 1.4 mm). For relatively low value of µ ( µ < 0.2), the optimal value of IF linearly increases as a function of µ independently of Eb, while for µ > 0.2, the optimal value of IF has a nonlinear dependence on µ and decreases as a function of Eb. The results can be used to help surgeons determine the optimal value of IF in a patient specific manner.
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Affiliation(s)
- Maria Letizia Raffa
- CNRS, Laboratoire Modélisation et Simulation Multi Echelle, MSME UMR 8208 CNRS, Créteil, France
| | - Vu-Hieu Nguyen
- Université Paris-Est, Laboratoire Modélisation et Simulation Multi Echelle, MSME UMR 8208 CNRS, Créteil, France
| | - Elisabeth Tabor
- CNRS, Laboratoire Modélisation et Simulation Multi Echelle, MSME UMR 8208 CNRS, Créteil, France
| | - Katharina Immel
- CNRS, Laboratoire Modélisation et Simulation Multi Echelle, MSME UMR 8208 CNRS, Créteil, France
- Aachen Institute for Advanced Study in Computational Engineering Science (AICES), RWTH Aachen University, Aachen, Germany
| | - Victor Housset
- Service de Chirurgie Orthopédique et Traumatologique du Centre Hospitalier Universitaire Henri Mondor, Créteil, France
- Équipe 10, Groupe 5, IMRB U955, INSERM/UPEC, Créteil, France
| | - Charles-Henri Flouzat-Lachaniette
- Service de Chirurgie Orthopédique et Traumatologique du Centre Hospitalier Universitaire Henri Mondor, Créteil, France
- Équipe 10, Groupe 5, IMRB U955, INSERM/UPEC, Créteil, France
| | - Guillaume Haiat
- CNRS, Laboratoire Modélisation et Simulation Multi Echelle, MSME UMR 8208 CNRS, Créteil, France
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Jahnke A, Bott CC, Fonseca Ulloa CA, Jahnke GW, Rickert M, Ishaque BA, Ahmed GA. In vitro examination of the primary stability of three press-fit acetabular cups under consideration of two different bearing couples. Med Eng Phys 2019; 67:49-54. [PMID: 30902521 DOI: 10.1016/j.medengphy.2019.03.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 01/09/2019] [Accepted: 03/10/2019] [Indexed: 12/21/2022]
Abstract
BACKROUND For preclinical statements about the anchoring behavior of prostheses, the primary stability of the prosthesis is of special importance. It was the aim of this study to examine and compare the relevant relative micromotions of three different acetabulum prostheses by introducing three-dimensional torques. METHODS The cups were implanted under standard conditions into an anatomical artificial bone model. Three-dimensional torques were applied to the acetabular cups. Taking into account the resulting frictional moments of two different bearing couples, ceramic-on-ceramic and ceramic-on-polyethylene, the relative micromotions of the cups were recorded as maximum total micromotion, translational and rotational micromotion, and the primary stability values of the three cups were compared. RESULTS Relative micromotion of all cup models was always significantly smaller with the CoC bearing couples than with the CoP bearing couples (p < 0.001). The rotational micromotion was always lower (p < 0.001) than the translational micromotion, and the rotational as well as the translational micromotions were each always lower than the maximum total micromotion (p < 0.001, p < 0.010). The thinnest-walled cup system always showed the largest relative micromotions. CONCLUSION The results of our study can be interpreted as indicating that the low relative micromotions of all cups - irrespective of the use of CoC or CoP bearing couples - are within an acceptable range favoring secondary osseointegration of the implants. Furthermore, we were able to show that the cup wall thickness and the surface quality of the cup systems have an influence on the primary stability and the elastic deformability of the examined cup systems.
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Affiliation(s)
- Alexander Jahnke
- Laboratory of Biomechanics, Justus-Liebig-University Giessen, Klinikstrasse 29, 35392 Giessen, Germany.
| | - Catharina Chiara Bott
- Laboratory of Biomechanics, Justus-Liebig-University Giessen, Klinikstrasse 29, 35392 Giessen, Germany
| | | | - Gerhard Walter Jahnke
- Laboratory of Biomechanics, Justus-Liebig-University Giessen, Klinikstrasse 29, 35392 Giessen, Germany
| | - Markus Rickert
- Laboratory of Biomechanics, Justus-Liebig-University Giessen, Klinikstrasse 29, 35392 Giessen, Germany; Department of Orthopaedics and Orthopaedic Surgery, University Hospital Giessen and Marburg (UKGM), Klinikstrasse 33, 35392 Giessen, Germany
| | - Bernd Alexander Ishaque
- Laboratory of Biomechanics, Justus-Liebig-University Giessen, Klinikstrasse 29, 35392 Giessen, Germany; Department of Orthopaedics and Orthopaedic Surgery, University Hospital Giessen and Marburg (UKGM), Klinikstrasse 33, 35392 Giessen, Germany
| | - Gafar Adam Ahmed
- Laboratory of Biomechanics, Justus-Liebig-University Giessen, Klinikstrasse 29, 35392 Giessen, Germany; Department of Orthopaedics and Orthopaedic Surgery, University Hospital Giessen and Marburg (UKGM), Klinikstrasse 33, 35392 Giessen, Germany
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Schulze C, Vogel D, Sander M, Bader R. Calibration of crushable foam plasticity models for synthetic bone material for use in finite element analysis of acetabular cup deformation and primary stability. Comput Methods Biomech Biomed Engin 2018; 22:25-37. [PMID: 30449160 DOI: 10.1080/10255842.2018.1524884] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Polyurethane (PU) foam is a material often used in biomechanical experiments and demands for the definition of crushable foam plasticity (CFP) in numerical simulations of the primary stability and deformation of implants, to describe the crushing behaviour appropriately. Material data of PU foams with five different densities (10-40 pounds per cubic foot were ascertained experimentally in uniaxial compression test and used to calibrate CFP models for finite element modelling. Additionally, experimental and numerical deformation, push-out and lever-out tests of press-fit acetabular cups were carried out to assess the influence of the chosen material definition (linear elastic and CFP) on the numerical results. Comparison of the experimentally and numerically determined force-displacement curves of the uniaxial compression test showed a mean deviation of less than 3%. In primary stability testing, the deviation between the experimental and numerical results was in a range of 0%-27% for CFP modelling and 64%-341% for the linear elastic model. The material definition selected, highly influenced the numerical results in the current study. The use of a CFP model is recommended for further numerical simulations, when a deformation of the foam beyond the yield strength is likely to occur.
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Affiliation(s)
- Christian Schulze
- a Biomechanics and Implant Technology Research Laboratory, Department of Orthopaedics , University Medicine Rostock , Rostock , Germany
| | - Danny Vogel
- a Biomechanics and Implant Technology Research Laboratory, Department of Orthopaedics , University Medicine Rostock , Rostock , Germany
| | - Manuela Sander
- b Department of Structural Mechanics , University of Rostock , Rostock , Germany
| | - Rainer Bader
- a Biomechanics and Implant Technology Research Laboratory, Department of Orthopaedics , University Medicine Rostock , Rostock , Germany
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Jahnke A, Schroeder S, Fonseca Ulloa CA, Ahmed GA, Ishaque BA, Rickert M. Effect of bearing friction torques on the primary stability of press-fit acetabular cups: A novel in vitro method. J Orthop Res 2018; 36:2745-2753. [PMID: 29744927 DOI: 10.1002/jor.24041] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 04/27/2018] [Indexed: 02/04/2023]
Abstract
Aseptic loosening is the main reason for revision of total hip arthroplasty, and relative micromotions between cementless acetabular cups and bone play an important role regarding their comparatively high loosening rate. Therefore, the aim of the present study was to analyze the influence of resulting frictional torques on the primary stability of press-fit acetabular cups subjected to two different bearing partners. A cementless press-fit cup was implanted in bone-like foam. Primary stability of the cup was analyzed by determining spatial total, translational, and rotational interface micromotions by means of an eddy current sensor measuring system. Torque transmission into the cup was realized by three synchronous servomotors considering resultant friction torques based on constant friction for ceramic-on-ceramic (CoC: μ = 0.044; max. resultant torque: 1.5 Nm) and for ceramic-on-polyethylene (CoP: μ = 0.063; max. resultant torque: 1.9 Nm) bearing partners. Rotational micromotion of CoC was 8.99 ± 0.85 µm and of CoP 13.39 ± 1.43 µm. Translational micromotion of CoC was 29.93 ± 1.44 μm and of CoP 39.91 ± 2.25 μm. Maximum total relative micromotions were 37.10 ± 1.07 μm for CoC and 51.64 ± 2.18 μm for CoP. Micromotions resulting from CoC were statistically lower than those resulting from CoP (p < 0.05). The described 3D-measuring set-up offers a novel in vitro method of measuring primary stability of acetabular cups. We can therefore conclude, that primary stability of acetabular cup systems can be observed using either the lower friction curve (CoC) or the higher friction curve (CoP). In future studies different cup designs or cup fixation mechanisms may be tested and compared in vitro and assessed prior to implantation. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2745-2753, 2018.
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Affiliation(s)
- Alexander Jahnke
- Laboratory of Biomechanics, Justus-Liebig-University Giessen, Klinikstrasse 29, 35392, Giessen, Germany
| | - Stefan Schroeder
- Laboratory of Biomechanics, Justus-Liebig-University Giessen, Klinikstrasse 29, 35392, Giessen, Germany
| | - Carlos A Fonseca Ulloa
- Laboratory of Biomechanics, Justus-Liebig-University Giessen, Klinikstrasse 29, 35392, Giessen, Germany
| | - Gafar A Ahmed
- Laboratory of Biomechanics, Justus-Liebig-University Giessen, Klinikstrasse 29, 35392, Giessen, Germany.,Department of Orthopaedics and Orthopaedic Surgery, University Hospital Giessen and Marburg (UKGM), Klinikstrasse 33, 35392, Giessen, Germany
| | - Bernd A Ishaque
- Laboratory of Biomechanics, Justus-Liebig-University Giessen, Klinikstrasse 29, 35392, Giessen, Germany.,Department of Orthopaedics and Orthopaedic Surgery, University Hospital Giessen and Marburg (UKGM), Klinikstrasse 33, 35392, Giessen, Germany
| | - Markus Rickert
- Laboratory of Biomechanics, Justus-Liebig-University Giessen, Klinikstrasse 29, 35392, Giessen, Germany.,Department of Orthopaedics and Orthopaedic Surgery, University Hospital Giessen and Marburg (UKGM), Klinikstrasse 33, 35392, Giessen, Germany
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Vogel D, Schulze C, Dempwolf H, Kluess D, Bader R. Biomechanical behavior of modular acetabular cups made of poly-ether-ether-ketone: A finite element study. Proc Inst Mech Eng H 2018; 232:1030-1038. [DOI: 10.1177/0954411918797600] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
After total hip arthroplasty, stress-shielding is a potential risk factor for aseptic loosening of acetabular cups made of metals. This might be avoided by the use of acetabular cups made of implant materials with lower stiffness. The purpose of this numerical study was to determine whether a modular acetabular cup with a shell made of poly-ether-ether-ketone or poly-ether-ether-ketone reinforced with carbon fibers might be an alternative to conventional metallic shells. Therefore, the press-fit implantation of modular cups with shells made of different materials (Ti6Al4V, poly-ether-ether-ketone, and poly-ether-ether-ketone reinforced with carbon fibers) and varying liner materials (ceramics and ultra-high-molecular-weight polyethylene) into an artificial bone cavity was simulated using finite element analysis. The shell material had a major impact on the radial shell deformation determined at the rim of the shell, ranging from 17.9 µm for titanium over 92.2 µm for poly-ether-ether-ketone reinforced with carbon fibers up to 475.9 µm for poly-ether-ether-ketone. Larger radial liner deformations (up to 618.4 µm) occurred in combination with the shells made of poly-ether-ether-ketone compared to titanium and poly-ether-ether-ketone reinforced with carbon fibers. Hence, it can be stated that conventional poly-ether-ether-ketone is not a suitable shell material for modular acetabular cups. However, the radial shell deformation can be reduced if the poly-ether-ether-ketone reinforced with carbon fiber material is used, while deformation of ceramic liners is similar to the deformation in combination with titanium shells.
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Affiliation(s)
- Danny Vogel
- Department of Orthopaedics, Biomechanics and Implant Technology Research Laboratory, University of Rostock, Rostock, Germany
| | - Christian Schulze
- Department of Orthopaedics, Biomechanics and Implant Technology Research Laboratory, University of Rostock, Rostock, Germany
| | - Henry Dempwolf
- Department of Orthopaedics, Biomechanics and Implant Technology Research Laboratory, University of Rostock, Rostock, Germany
| | - Daniel Kluess
- Department of Orthopaedics, Biomechanics and Implant Technology Research Laboratory, University of Rostock, Rostock, Germany
| | - Rainer Bader
- Department of Orthopaedics, Biomechanics and Implant Technology Research Laboratory, University of Rostock, Rostock, Germany
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Manning WA, Pandorf T, Deehan DJ, Holland J. Early shape change behaviour of an uncemented contemporary hip cup: A cadaveric experiment replicating host bone behaviour through temperature control. Proc Inst Mech Eng H 2018; 232:843-849. [DOI: 10.1177/0954411918790776] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Modular uncemented acetabular components are in common use. Fixation is dependent upon press-fit but the forces necessary to achieve initial stability of the construct at implantation may deform the shell and prevent optimal seating of the polyethylene liner insert. Previous work using single-time point measurements in uncontrolled ambient temperature poorly replicates the native state. A controlled study was performed to observe the time-dependent behaviour of an uncemented acetabular shell in the early phase after implantation into the human acetabulum at near physiological temperature. Using a previously validated cadaveric hip model at controlled near physiological temperature with standardised surgical technique, immediate and delayed shell geometry was determined. Eight custom made 3-mm-thick titanium alloy (TiAl6V4) shells were implanted into four cadavers (eight hips). Time-dependent shell deformation was determined using the previously validated ATOS Triple Scan III (ATOS) optical measurement system. The pattern of change in the shape of the surgically implanted shell was measured at three time points after insertion. We found a consistent pattern for quantitative and directional deformation of the shells. In addition, there was consistency for relaxation of the deformation with time. Immediate mean change in shell radius was 104 µm (standard deviation 32, range 67–153) relaxing to mean 96 µm (standard deviation 32, range 63–150) after 10 min and mean 92 µm (standard deviation 28, range 66–138) after 20 min. The clinical significance of this work is the finding of a time-dependent early deformation of acetabular titanium shells on insertion adjusted for near physiological temperature-controlled host bone.
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Affiliation(s)
- William A Manning
- Newcastle Surgical Training Centre, Freeman Hospital, Newcastle upon Tyne, UK
| | - Thomas Pandorf
- Medical Products Division, CeramTec GmbH, Plochingen, Germany
| | - David J Deehan
- Newcastle Surgical Training Centre, Freeman Hospital, Newcastle upon Tyne, UK
| | - James Holland
- Newcastle Surgical Training Centre, Freeman Hospital, Newcastle upon Tyne, UK
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14
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Nguyen VH, Rosi G, Naili S, Michel A, Raffa ML, Bosc R, Meningaud JP, Chappard C, Takano N, Haiat G. Influence of anisotropic bone properties on the biomechanical behavior of the acetabular cup implant: a multiscale finite element study. Comput Methods Biomech Biomed Engin 2017; 20:1312-1325. [PMID: 28768422 DOI: 10.1080/10255842.2017.1357703] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Although the biomechanical behavior of the acetabular cup (AC) implant is determinant for the surgical success, it remains difficult to be assessed due to the multiscale and anisotropic nature of bone tissue. The aim of the present study was to investigate the influence of the anisotropic properties of peri-implant trabecular bone tissue on the biomechanical behavior of the AC implant at the macroscopic scale. Thirteen bovine trabecular bone samples were imaged using micro-computed tomography (μCT) with a resolution of 18 μm. The anisotropic biomechanical properties of each sample were determined at the scale of the centimeter based on a dedicated method using asymptotic homogenization. The material properties obtained with this multiscale approach were used as input data in a 3D finite element model to simulate the macroscopic mechanical behavior of the AC implant under different loading conditions. The largest stress and strain magnitudes were found around the equatorial rim and in the polar area of the AC implant. All macroscopic stiffness quantities were significantly correlated (R2 > 0.85, p < 6.5 e-6) with BV/TV (bone volume/total volume). Moreover, the maximum value of the von Mises stress field was significantly correlated with BV/TV (R2 > 0.61, p < 1.6 e-3) and was always found at the bone-implant interface. However, the mean value of the microscopic stress (at the scale of the trabeculae) decrease as a function of BV/TV for vertical and torsional loading and do not depend on BV/TV for horizontal loading. These results highlight the importance of the anisotropic properties of bone tissue.
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Affiliation(s)
- Vu-Hieu Nguyen
- a Laboratoire de Modélisation et de Simulation MultiEchelle, UMR CNRS 8208 , Université Paris-Est , Créteil , France
| | - Giuseppe Rosi
- a Laboratoire de Modélisation et de Simulation MultiEchelle, UMR CNRS 8208 , Université Paris-Est , Créteil , France
| | - Salah Naili
- a Laboratoire de Modélisation et de Simulation MultiEchelle, UMR CNRS 8208 , Université Paris-Est , Créteil , France
| | - Adrien Michel
- a Laboratoire de Modélisation et de Simulation MultiEchelle, UMR CNRS 8208 , Université Paris-Est , Créteil , France
| | - Maria-Letizia Raffa
- a Laboratoire de Modélisation et de Simulation MultiEchelle, UMR CNRS 8208 , Université Paris-Est , Créteil , France
| | - Romain Bosc
- b INSERM U955 , Université Paris-Est , Créteil , France
| | | | - Christine Chappard
- c Laboratoire Bioingénierie Biomécanique Ostéo-Articulaires, UMR CNRS 7052 , Université Paris Diderot , Paris , France
| | - Naoki Takano
- d Faculty of Science and Engineering, Department of Mechanical Engineering , Keio University , Yokohama , Japan
| | - Guillaume Haiat
- e Laboratoire de Modélisation et de Simulation Multi-Echelle, UMR CNRS 8208 , Créteil , France.,f École de technologie supérieure , Montreal , Canada.,g Research Center, Hôpital du Sacré-Cœur de Montréal , Montreal , Canada
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15
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Mukherjee K, Gupta S. Combined Bone Ingrowth and Remodeling Around Uncemented Acetabular Component: A Multiscale Mechanobiology-Based Finite Element Analysis. J Biomech Eng 2017; 139:2644120. [PMID: 28696483 DOI: 10.1115/1.4037223] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Indexed: 11/08/2022]
Abstract
Bone ingrowth and remodeling are two different evolutionary processes which might occur simultaneously. Both these processes are influenced by local mechanical stimulus. However, a combined study on bone ingrowth and remodeling has rarely been performed. This study is aimed at understanding the relationship between bone ingrowth and adaptation and their combined influence on fixation of the acetabular component. Based on three-dimensional (3D) macroscale finite element (FE) model of implanted pelvis and microscale FE model of implant–bone interface, a multiscale framework has been developed. The numerical prediction of peri-acetabular bone adaptation was based on a strain-energy density-based formulation. Bone ingrowth in the microscale models was simulated using the mechanoregulatory algorithm. An increase in bone strains near the acetabular rim was observed in the implanted pelvis model, whereas the central part of the acetabulum was observed to be stress shielded. Consequently, progressive bone apposition near the acetabular rim and resorption near the central region were observed. Bone remodeling caused a gradual increase in the implant–bone relative displacements. Evolutionary bone ingrowth was observed around the entire acetabular component. Poor bone ingrowth of 3–5% was predicted around the centro-inferio and inferio-posterio-superio-peripheral regions owing to higher implant–bone relative displacements, whereas the anterio-inferior and centro-superior regions exhibited improved bone ingrowth of 35–55% due to moderate implant–bone relative displacement. For an uncemented acetabular CoCrMo component, bone ingrowth had hardly any effect on bone remodeling; however, bone remodeling had considerable influence on bone ingrowth.
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Affiliation(s)
- Kaushik Mukherjee
- Department of Mechanical Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721 302, West Bengal, India
| | - Sanjay Gupta
- Professor Department of Mechanical Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721 302, West Bengal, India e-mail:
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16
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Panjeton GD, Kim SE, Chang K, Palm LS, Ifju PG. Deformation of the Zurich cementless acetabular cup caused by implantation in a canine cadaver model. Vet Surg 2017; 46:441-447. [PMID: 28198543 DOI: 10.1111/vsu.12629] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 11/16/2016] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To evaluate the change in geometry of the Zurich total hip arthroplasty (THA) acetabular component after implantation. ANIMALS Hemipelves from adult mix-breed dogs weighing between 20 and 25 kg. METHODS Digital image correlation imaging was performed prior to, immediately after, and 24 hours after impaction of Zurich THA acetabular component, and after removal of the cup from the specimen. Patterns of deformation were qualitatively described, and maximal deformations were compared between time points. RESULTS All cups deformed after implantation into the hemipelves by "pinching" in a cranial-caudal direction and dorsoventral expansion, resulting in an ellipsoid configuration to the peripheral rim. The mean ± SD maximum deformation at the rim immediately post-impaction was 0.202 ± 0.052 mm, or approximately 0.4 mm of diametrical deformation. Deformation did not change after the 24-hour saline bath. Impaction and subsequent extraction had a marginal effect on the original cup geometry, as maximum deformation at the rim after cup extraction was 0.074 ± 0.032 mm, relative to prior to impaction. CONCLUSIONS The original Zurich cup geometry is distorted as a consequence of the press-fit mechanism. Further studies are required to determine whether deformation induced by impaction has any association with polyethylene wear rates or other prosthesis-related complications.
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Affiliation(s)
- Geoffrey D Panjeton
- Comparative Orthopedics Biomechanics Laboratory, University of Florida, Gainesville, Florida
| | - Stanley E Kim
- Comparative Orthopedics Biomechanics Laboratory, University of Florida, Gainesville, Florida
| | - Kelvin Chang
- Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, Florida
| | - Lindsey S Palm
- Comparative Orthopedics Biomechanics Laboratory, University of Florida, Gainesville, Florida
| | - Peter G Ifju
- Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, Florida
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17
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Mukherjee K, Gupta S. Influence of Implant Surface Texture Design on Peri-Acetabular Bone Ingrowth: A Mechanobiology Based Finite Element Analysis. J Biomech Eng 2017; 139:2592752. [PMID: 27925634 DOI: 10.1115/1.4035369] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Indexed: 11/08/2022]
Abstract
The fixation of uncemented acetabular components largely depends on the amount of bone ingrowth, which is influenced by the design of the implant surface texture. The objective of this numerical study is to evaluate the effect of these implant texture design factors on bone ingrowth around an acetabular component. The novelty of this study lies in comparative finite element (FE) analysis of 3D microscale models of the implant-bone interface, considering patient-specific mechanical environment, host bone material property and implant-bone relative displacement, in combination with sequential mechanoregulatory algorithm and design of experiment (DOE) based statistical framework. Results indicated that the bone ingrowth process was inhibited due to an increase in interbead spacing from 200 μm to 600 μm and bead diameter from 1000 μm to 1500 μm and a reduction in bead height from 900 μm to 600 μm. Bead height, a main effect, was found to have a predominant influence on bone ingrowth. Among the interaction effects, the combination of bead height and bead diameter was found to have a pronounced influence on bone ingrowth process. A combination of low interbead spacing (P = 200 μm), low bead diameter (D = 1000 μm), and high bead height (H = 900 μm) facilitated peri-acetabular bone ingrowth and an increase in average Young's modulus of newly formed tissue layer. Hence, such a surface texture design seemed to provide improved fixation of the acetabular component.
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Affiliation(s)
- Kaushik Mukherjee
- Department of Mechanical Engineering, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal 721 302, India
| | - Sanjay Gupta
- Professor Department of Mechanical Engineering, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal 721 302, India e-mail:
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18
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Michel A, Nguyen VH, Bosc R, Vayron R, Hernigou P, Naili S, Haiat G. Finite element model of the impaction of a press-fitted acetabular cup. Med Biol Eng Comput 2016; 55:781-791. [PMID: 27491803 DOI: 10.1007/s11517-016-1545-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Accepted: 07/03/2016] [Indexed: 01/07/2023]
Abstract
Press-fit surgical procedures aim at providing primary stability to acetabular cup (AC) implants. Impact analysis constitutes a powerful approach to retrieve the AC implant insertion properties. The aim of this numerical study was to investigate the dynamic interaction occurring between the hammer, the ancillary and bone tissue during the impact and to assess the potential of impact analysis to retrieve AC implant insertion conditions. A dynamic two-dimensional axisymmetric model was developed to simulate the impaction of the AC implant into bone tissue assuming friction at the bone-implant interface and large deformations. Different values of interference fit (from 0.5 to 2 mm) and impact velocities (from 1 to 2 m.s-1) were considered. For each configuration, the variation of the force applied between the hammer and the ancillary was analyzed and an indicator I was determined based on the impact momentum of the signal. The simulated results are compared to the experiments. The value of the polar gap decreases with the impact velocity and increases with the interference fit. The bone-implant contact area was significantly correlated with the resonance frequency (R 2 = 0.94) and the indicator (R 2 = 0.95). The results show the potential of impact analyses to retrieve the bone-implant contact properties.
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Affiliation(s)
- Adrien Michel
- Université Paris Est, Laboratoire de Modélisation et de Simulation Multi-Echelle, UMR CNRS 8208, 61 avenue du Général de Gaulle, 94010, Créteil, France
| | - Vu-Hieu Nguyen
- Université Paris Est, Laboratoire de Modélisation et de Simulation Multi-Echelle, UMR CNRS 8208, 61 avenue du Général de Gaulle, 94010, Créteil, France
| | - Romain Bosc
- Service de Chirurgie Plastique et Reconstructive, Hôpital Henri Mondor AP-HP, CHU Paris 12, Université Paris-Est, 51 avenue du Maréchal de Lattre de Tassigny, 94000, Créteil, France
| | - Romain Vayron
- Université Paris Est, Laboratoire de Modélisation et de Simulation Multi-Echelle, UMR CNRS 8208, 61 avenue du Général de Gaulle, 94010, Créteil, France
| | - Philippe Hernigou
- Service de Chirurgie Orthopédique, Hôpital Henri Mondor AP-HP, CHU Paris 12, Université Paris-Est, 51 avenue du Maréchal de Lattre de Tassigny, 94000, Créteil, France
| | - Salah Naili
- Université Paris Est, Laboratoire de Modélisation et de Simulation Multi-Echelle, UMR CNRS 8208, 61 avenue du Général de Gaulle, 94010, Créteil, France
| | - Guillaume Haiat
- CNRS, Laboratoire de Modélisation et de Simulation Multi‑Echelle, UMR CNRS 8208, 61 avenue du Général de Gaulle, 94010, Créteil, France.
- École de technologie supérieure, 1100 Notre-Dame Street West, Montreal, QC, H3C 1K3, Canada.
- Research Center, Hôpital du Sacré-Cœur de Montréal, 5400, Gouin Boul. West, Montreal, QC, H4J 1C5, Canada.
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19
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Mukherjee K, Gupta S. The effects of musculoskeletal loading regimes on numerical evaluations of acetabular component. Proc Inst Mech Eng H 2016; 230:918-29. [DOI: 10.1177/0954411916661368] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 07/05/2016] [Indexed: 11/17/2022]
Abstract
The importance of clinical studies notwithstanding, the failure assessment of implant–bone structure has alternatively been carried out using finite element analysis. However, the accuracy of the finite element predicted results is dependent on the applied loading and boundary conditions. Nevertheless, most finite element–based evaluations on acetabular component used a few selective load cases instead of the eight load cases representing the entire gait cycle. These in silico evaluations often suffer from limitations regarding the use of simplified musculoskeletal loading regimes. This study attempts to analyse the influence of three different loading regimes representing a gait cycle, on numerical evaluations of acetabular component. Patient-specific computer tomography scan-based models of intact and resurfaced pelvises were used. One such loading regime consisted of the second load case that corresponded to peak hip joint reaction force. Whereas the other loading regime consisted of the second and fifth load cases, which corresponded to peak hip joint reaction force and peak muscle forces, respectively. The third loading regime included all the eight load cases. Considerable deviations in peri-acetabular strains, standard error ranging between 115 and 400 µε, were observed for different loading regimes. The predicted bone strains were lower when selective loading regimes were used. Despite minor quantitative variations in bone density changes (less than 0.15 g cm−3), the final bone density pattern after bone remodelling was found to be similar for all the loading regimes. Underestimations in implant–bone micromotions (40–50 µm) were observed for selective loading regimes after bone remodelling. However, at immediate post-operative condition, such underestimations were found to be less (less than 5 µm). The predicted results highlight the importance of inclusion of eight load cases representing the gait cycle for in silico evaluations of resurfaced pelvis.
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Affiliation(s)
- Kaushik Mukherjee
- Department of Mechanical Engineering, Indian Institute of Technology Kharagpur, Kharagpur, India
| | - Sanjay Gupta
- Department of Mechanical Engineering, Indian Institute of Technology Kharagpur, Kharagpur, India
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20
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Mechanobiological simulations of peri-acetabular bone ingrowth: a comparative analysis of cell-phenotype specific and phenomenological algorithms. Med Biol Eng Comput 2016; 55:449-465. [DOI: 10.1007/s11517-016-1528-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 05/13/2016] [Indexed: 10/21/2022]
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21
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Medley JB. Can physical joint simulators be used to anticipate clinical wear problems of new joint replacement implants prior to market release? Proc Inst Mech Eng H 2016; 230:347-58. [PMID: 27160555 DOI: 10.1177/0954411916643902] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2016] [Accepted: 03/18/2016] [Indexed: 11/16/2022]
Abstract
One of the most important mandates of physical joint simulators is to provide test results that allow the implant manufacturer to anticipate and perhaps avoid clinical wear problems with their new products. This is best done before market release. This study gives four steps to follow in conducting such wear simulator testing. Two major examples involving hip wear simulators are discussed in which attempts had been made to predict clinical wear performance prior to market release. The second one, involving the DePuy ASR implant systems, is chosen for more extensive treatment by making it an illustrative example to explore whether wear simulator testing can anticipate clinical wear problems. It is concluded that hip wear simulator testing did provide data in the academic literature that indicated some risk of clinical wear problems prior to market release of the ASR implant systems. This supports the idea that physical joint simulators have an important role in the pre-market testing of new joint replacement implants.
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Affiliation(s)
- John B Medley
- Department of Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo, ON, Canada
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22
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Qiu C, Wang L, Li D, Jin Z. The influence of metallic shell deformation on the contact mechanics of a ceramic-on-ceramic total hip arthroplasty. Proc Inst Mech Eng H 2015; 230:4-12. [PMID: 26511269 DOI: 10.1177/0954411915614514] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2015] [Accepted: 09/14/2015] [Indexed: 11/17/2022]
Abstract
Total hip arthroplasty of ceramic-on-ceramic bearing combinations is increasingly used clinically. The majority of these implants are used with cementless fixation that a metal-backing shell is press-fitted into the pelvic bone. This usually results in the deformation of the metallic shell, which may also influence the ceramic liner deformation and consequently the contact mechanics between the liner and the femoral head under loading. The explicit dynamic finite element method was applied to model the implantation of a cementless ceramic-on-ceramic with a titanium shell and subsequently to investigate the effect of the metallic shell deformation on the contact mechanics. A total of three impacts were found to be necessary to seat the titanium alloy shell into the pelvic bone cavity with a 1 mm diameter interference and a 1.3 kg impactor at 4500 mm s(-1) velocity. The maximum deformation of the metallic shell was found to be 160 µm in the antero-superior and postero-inferior direction and 97 µm in the antero-inferior and postero-superior direction after the press-fit. The corresponding values were slightly reduced to 67 and 45 µm after the ceramic liner was inserted and then modified to 74 and 43 µm under loading, respectively. The maximum deformation and the maximum principal stress of the ceramic liner were 31 µm and 144 MPa (tensile stress), respectively, after it was inserted into the shell and further increased to 52 µm and 245 MPa under loading. This research highlights the importance of the press-fit of the metallic shell on the contact mechanics of the ceramic liner for ceramic-on-ceramic total hip arthroplasties and potential clinical performances.
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Affiliation(s)
- Changdong Qiu
- State Key Laboratory for Manufacturing Systems Engineering, School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an, China
| | - Ling Wang
- State Key Laboratory for Manufacturing Systems Engineering, School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an, China
| | - Dichen Li
- State Key Laboratory for Manufacturing Systems Engineering, School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an, China
| | - Zhongmin Jin
- State Key Laboratory for Manufacturing Systems Engineering, School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an, China Institute of Medical and Biological Engineering, School of Mechanical Engineering, University of Leeds, Leeds, UK
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23
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Bone ingrowth around porous-coated acetabular implant: a three-dimensional finite element study using mechanoregulatory algorithm. Biomech Model Mechanobiol 2015; 15:389-403. [PMID: 26130375 DOI: 10.1007/s10237-015-0696-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Accepted: 06/15/2015] [Indexed: 10/23/2022]
Abstract
Fixation of uncemented implant is influenced by peri-prosthetic bone ingrowth, which is dependent on the mechanical environment of the implant-bone structure. The objective of the study is to gain an insight into the tissue differentiation around an acetabular component. A mapping framework has been developed to simulate appropriate mechanical environment in the three-dimensional microscale model, implement the mechanoregulatory tissue differentiation algorithm and subsequently assess spatial distribution of bone ingrowth around an acetabular component, quantitatively. The FE model of implanted pelvis subjected to eight static load cases during a normal walking cycle was first solved. Thereafter, a mapping algorithm has been employed to include the variations in implant-bone relative displacement and host bone material properties from the macroscale FE model of implanted pelvis to the microscale FE model of the beaded implant-bone interface. The evolutionary tissue differentiation was observed in each of the 13 microscale models corresponding to 13 acetabular regions. The total implant-bone relative displacements, averaged over each region of the acetabulum, were found to vary between 10 and 60 μm. Both the linear elastic and biphasic poroelastic models predicted similar mechanoregulatory peri-prosthetic tissue differentiation. Considerable variations in bone ingrowth (13-88%), interdigitation depth (0.2-0.82 mm) and average tissue Young's modulus (970-3430 MPa) were predicted around the acetabular cup. A progressive increase in the average Young's modulus, interdigitation depth and decrease in average radial strains of newly formed tissue layer were also observed. This scheme can be extended to investigate tissue differentiation for different surface texture designs on the implants.
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24
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Bone MC, Dold P, Flohr M, Preuss R, Joyce TJ, Aspden RM, Holland J, Deehan D. The influence of the strength of bone on the deformation of acetabular shells: a laboratory experiment in cadavers. Bone Joint J 2015; 97-B:473-7. [PMID: 25820884 DOI: 10.1302/0301-620x.97b4.35017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Concerns have been raised that deformation of acetabular shells may disrupt the assembly process of modular prostheses. In this study we aimed to examine the effect that the strength of bone has on the amount of deformation of the acetabular shell. The hypothesis was that stronger bone would result in greater deformation. A total of 17 acetabular shells were inserted into the acetabula of eight cadavers, and deformation was measured using an optical measuring system. Cores of bone from the femoral head were taken from each cadaver and compressed using a materials testing machine. The highest peak modulus and yield stress for each cadaver were used to represent the strength of the bone and compared with the values for the deformation and the surgeon's subjective assessment of the hardness of the bone. The mean deformation of the shell was 129 µm (3 to 340). No correlation was found between deformation and either the maximum peak modulus (r² = 0.011, t = 0.426, p = 0.676) or the yield stress (r² = 0.024, t = 0.614, p = 0.549) of the bone. Although no correlation was found between the strength of the bone and deformation, the values for the deformation observed could be sufficient to disrupt the assembly process of modular acetabular components.
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Affiliation(s)
- M C Bone
- Newcastle University, Stephenson Building, Claremont Road, Tyne and Wear NE1 7RU, UK
| | - P Dold
- CeramTec GmbH, 73207 Plochingen, Germany
| | - M Flohr
- CeramTec GmbH, 73207 Plochingen, Germany
| | - R Preuss
- CeramTec GmbH, 73207 Plochingen, Germany
| | - T J Joyce
- Newcastle University, Stephenson Building, Claremont Road, Tyne and Wear NE1 7RU, UK
| | - R M Aspden
- University of Aberdeen, IMS Building, Foresterhill, Aberdeen AB25 2ZD, UK
| | - J Holland
- Freeman Hospital, Newcastle Upon Tyne NE7 7AH, UK
| | - D Deehan
- Freeman Hospital, Newcastle Upon Tyne NE7 7AH, UK
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25
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Dold P, Bone MC, Flohr M, Preuss R, Joyce TJ, Deehan D, Holland J. Validation of an optical system to measure acetabular shell deformation in cadavers. Proc Inst Mech Eng H 2014; 228:781-6. [DOI: 10.1177/0954411914546562] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Deformation of the acetabular shell at the time of surgery can result in poor performance and early failure of the hip replacement. The study aim was to validate an ATOS III Triple Scan optical measurement system against a co-ordinate measuring machine using in vitro testing and to check repeatability under cadaver laboratory conditions. Two sizes of custom-made acetabular shells were deformed using a uniaxial/two-point loading frame and measured at different loads. Roundness measurements were performed using both the ATOS III Triple Scan optical system and a co-ordinate measuring machine and then compared. The repeatability was also tested by measuring shells pre- and post-insertion in a cadaver laboratory multiple times. The in vitro comparison with the co-ordinate measuring machine demonstrated a maximum difference of 5 µm at the rim and 9 µm at the measurement closest to the pole of the shell. Maximum repeatability was below 1 µm for the co-ordinate measuring machine and 3 µm for the ATOS III Triple Scan optical system. Repeatability was comparable between the pre-insertion (below 2 µm) and post-insertion (below 3 µm) measurements in the cadaver laboratory. This study supports the view that the ATOS III Triple Scan optical system fulfils the necessary requirements to accurately measure shell deformation in cadavers.
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Affiliation(s)
- Philipp Dold
- Medical Products Division, CeramTec GmbH, Plochingen, Germany
| | - Martin C Bone
- School of Mechanical Engineering, Newcastle University, Newcastle upon Tyne, UK
| | - Markus Flohr
- Medical Products Division, CeramTec GmbH, Plochingen, Germany
| | - Roman Preuss
- Medical Products Division, CeramTec GmbH, Plochingen, Germany
| | - Tom J Joyce
- School of Mechanical Engineering, Newcastle University, Newcastle upon Tyne, UK
| | - David Deehan
- Newcastle Surgical Training Centre, Freeman Hospital, Newcastle upon Tyne, UK
| | - James Holland
- Newcastle Surgical Training Centre, Freeman Hospital, Newcastle upon Tyne, UK
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26
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Dickinson AS, Browne M, Roques AC, Taylor AC. A fatigue assessment technique for modular and pre-stressed orthopaedic implants. Med Eng Phys 2013; 36:72-80. [PMID: 24148237 DOI: 10.1016/j.medengphy.2013.09.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Revised: 08/09/2013] [Accepted: 09/18/2013] [Indexed: 11/27/2022]
Abstract
Orthopaedic implants experience large cyclic loads, and pre-clinical analysis is conducted to ensure they can withstand millions of loading cycles. Acetabular cup developments aim to reduce wall thickness to conserve bone, and this produces high pre-stress in modular implants. As part of an implant development process, we propose a technique for preclinical fatigue strength assessment of modular implants which accounts for this mean stress, stress concentrating features and material processing. A modular cup's stress distributions were predicted computationally, under assembly and in vivo loads, and its cyclic residual stress and stress amplitude were calculated. For verification against damage initiation in low-cycle-fatigue (LCF), the peak stress was compared to the material's yield strength. For verification against failure in high-cycle-fatigue (HCF) each element's reserve factor was calculated using the conservative Soderberg infinite life criterion. Results demonstrated the importance of accounting for mean stress. The cup was predicted to experience high cyclic mean stress with low magnitude stress amplitude: a low cyclic load ratio (Rl=0.1) produced a high cyclic stress ratio (Rs=0.80). Furthermore the locations of highest cyclic mean stress and stress amplitude did not coincide. The minimum predicted reserve factor Nf was 1.96 (HCF) and 2.08 (LCF). If mean stress were neglected or if the stress ratio were assumed to equal the load ratio, the reserve factor would be considerably lower, potentially leading to over-engineering, reducing bone conservation. Fatigue strength evaluation is only one step in a broader development process, which should involve a series of verifications with the full range of normal and traumatic physiological loading scenarios, with representative boundary conditions and a representative environment. This study presents and justifies a fatigue analysis methodology which could be applied in early stage development to a variety of modular and pre-stressed prosthesis concepts, and is particularly relevant as implant development aims to maximise modularity and bone conservation.
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Affiliation(s)
- A S Dickinson
- Bioengineering Science Research Group, University of Southampton, Southampton, UK; Aurora Medical Ltd., Southampton Science Park, Chilworth, Southampton, UK.
| | - M Browne
- Bioengineering Science Research Group, University of Southampton, Southampton, UK
| | - A C Roques
- Aurora Medical Ltd., Southampton Science Park, Chilworth, Southampton, UK
| | - A C Taylor
- Aurora Medical Ltd., Southampton Science Park, Chilworth, Southampton, UK
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Meding JB, Small SR, Jones ME, Berend ME, Ritter MA. Acetabular cup design influences deformational response in total hip arthroplasty. Clin Orthop Relat Res 2013; 471:403-9. [PMID: 22948528 PMCID: PMC3549190 DOI: 10.1007/s11999-012-2553-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Press-fit acetabular components are susceptible to deformation in an underreamed socket, with excessive deformation of metal-on-metal (MOM) components potentially leading to increased torsional friction and micromotion. Specifically, however, it remains unclear how cup diameter, design, and time from implantation affect shell deformation. QUESTIONS/PURPOSES We asked whether (1) changes in component geometry and material altered maximum shell deformation and (2) time-dependent deformational relaxation processes occurred. METHODS Diametral deformation was quantified after press-fit implantation of metal shells into a previously validated polyurethane model. Experimental groups (n = 6-8) consisted of 48-, 54-, 60-, and 66-mm MOM cups of 6-mm wall thickness, 58-mm cups of 10-mm wall thickness, and CoCrMo and Ti6Al4V 58-mm modular cups. RESULTS Greater cup diameter, thinner wall construction, and Ti6Al4V modular designs generated conditions for maximum shell deformation ranging from 0.047 to 0.267 mm. Relaxation (18%-32%) was observed 120 hours postimplantation in thin-walled and modular designs. CONCLUSIONS Our findings demonstrate a reduction of shell deformation over time and suggest, under physiologic loading, early component deformation varies with design. CLINICAL RELEVANCE Component deformation should be a design consideration regardless of bearing surface. Designs neglecting to adequately address deformational changes in vivo could be susceptible to diminished cup survival, increased wear, and premature revision.
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Affiliation(s)
- John B. Meding
- Joint Replacement Surgeons of Indiana Foundation, Inc, 1199 Hadley Road, Mooresville, IN 46158 USA
| | - Scott R. Small
- Joint Replacement Surgeons of Indiana Foundation, Inc, 1199 Hadley Road, Mooresville, IN 46158 USA
| | - Mary E. Jones
- Department of Applied Biology and Biomedical Engineering, Rose-Hulman Institute of Technology, Terre Haute, IN USA
| | - Michael E. Berend
- Joint Replacement Surgeons of Indiana Foundation, Inc, 1199 Hadley Road, Mooresville, IN 46158 USA
| | - Merrill A. Ritter
- Joint Replacement Surgeons of Indiana Foundation, Inc, 1199 Hadley Road, Mooresville, IN 46158 USA
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Hothi HS, Busfield JJ, Shelton JC. Deformation of uncemented metal acetabular cups following impaction: experimental and finite element study. Comput Methods Biomech Biomed Engin 2012; 17:1261-74. [DOI: 10.1080/10255842.2012.744397] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Liu F, Chen Z, Gu Y, Wang Q, Cui W, Fan W. Deformation of the Durom acetabular component and its impact on tribology in a cadaveric model--a simulator study. PLoS One 2012; 7:e45786. [PMID: 23144694 PMCID: PMC3483233 DOI: 10.1371/journal.pone.0045786] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Accepted: 08/22/2012] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Recent studies have shown that the acetabular component frequently becomes deformed during press-fit insertion. The aim of this study was to explore the deformation of the Durom cup after implantation and to clarify the impact of deformation on wear and ion release of the Durom large head metal-on-metal (MOM) total hips in simulators. METHODS Six Durom cups impacted into reamed acetabula of fresh cadavers were used as the experimental group and another 6 size-paired intact Durom cups constituted the control group. All 12 Durom MOM total hips were put through a 3 million cycle (MC) wear test in simulators. RESULTS The 6 cups in the experimental group were all deformed, with a mean deformation of 41.78 ± 8.86 µm. The average volumetric wear rate in the experimental group and in the control group in the first million cycle was 6.65 ± 0.29 mm(3)/MC and 0.89 ± 0.04 mm(3)/MC (t = 48.43, p = 0.000). The ion levels of Cr and Co in the experimental group were also higher than those in the control group before 2.0 MC. However there was no difference in the ion levels between 2.0 and 3.0 MC. CONCLUSIONS This finding implies that the non-modular acetabular component of Durom total hip prosthesis is likely to become deformed during press-fit insertion, and that the deformation will result in increased volumetric wear and increased ion release. CLINICAL RELEVANCE This study was determined to explore the deformation of the Durom cup after implantation and to clarify the impact of deformation on wear and ion release of the prosthesis. Deformation of the cup after implantation increases the wear of MOM bearings and the resulting ion levels. The clinical use of the Durom large head prosthesis should be with great care.
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Affiliation(s)
- Feng Liu
- Department of Orthopedics, the First Affiliated Hospital with Nanjing Medical University, Nanjing, China
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Souffrant R, Zietz C, Fritsche A, Kluess D, Mittelmeier W, Bader R. Advanced material modelling in numerical simulation of primary acetabular press-fit cup stability. Comput Methods Biomech Biomed Engin 2012; 15:787-93. [DOI: 10.1080/10255842.2011.561012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Underwood RJ, Zografos A, Sayles RS, Hart A, Cann P. Edge loading in metal-on-metal hips: low clearance is a new risk factor. Proc Inst Mech Eng H 2012; 226:217-26. [PMID: 22558836 PMCID: PMC4107799 DOI: 10.1177/0954411911431397] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The revision rate of large head metal-on-metal and resurfacing hips are significantly
higher than conventional total hip replacements. The revision of these components has been
linked to high wear caused by edge loading; which occurs when the head–cup contact patch
extends over the cup rim. There are two current explanations for this; first, there is
loss of entrainment of synovial fluid resulting in breakdown of the lubricating film and
second, edge loading results in a large local increase in contact pressure and consequent
film thickness reduction at the cup rim, which causes an increase in wear. This paper develops a method to calculate the distance between the joint reaction force
vector and the cup rim – the contact patch centre to rim (CPCR) distance. However, the
critical distance for the risk of edge loading is the distance from the contact patch edge
to rim (CPER) distance. An analysis of explanted hip components, divided into edge worn
and non-edge-worn components showed that there was no statistical difference in CPCR
values, but the CPER value was significantly lower for edge worn hips. Low clearance hips, which have a more conformal contact, have a larger diameter contact
patch and thus are more at risk of edge loading for similarly positioned hips.
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Clarke SG, Phillips ATM, Bull AMJ. Validation of FE micromotions and strains around a press-fit cup: introducing a new micromotion measuring technique. Ann Biomed Eng 2012; 40:1586-96. [PMID: 22350664 DOI: 10.1007/s10439-012-0523-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2011] [Accepted: 01/21/2012] [Indexed: 11/29/2022]
Abstract
Finite element (FE) analysis provides an useful tool with which to analyze the potential performance of implantations in a variety of surgical, patient and design scenarios. To enable the use of FE analysis in the investigation of such implants, models must be experimentally validated. Validation of a pelvic model with an implanted press-fit cup in terms of micromotion and strain is presented here. A new method of micromotion has been introduced to better describe the overall movement of the cup within the pelvis. The method uses a digitizing arm to monitor the relative movement between markers on the cup and the surrounding acetabulum. FE analysis was used to replicate an experimental set up using a synthetic hemi-pelvis with a press-fitted all-metal cup, subject to the maximum loading observed during normal walking. The work presented here has confirmed the ability of FE models to accurately describe the mechanical performance of the press-fitted acetabulum and surrounding bone under typical loading conditions in terms of micromotion and strain distribution, but has demonstrated limitations in its ability to predict numerical micromotion values. A promising digitizing technique for measuring acetabular micromotions has also been introduced.
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Affiliation(s)
- S G Clarke
- Department of Civil and Environmental Engineering, Imperial College London, Skempton Building, South Kensington Campus, London, SW7 2AZ, UK.
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Daniel J, Holland J, Quigley L, Sprague S, Bhandari M. Pseudotumors associated with total hip arthroplasty. J Bone Joint Surg Am 2012; 94:86-93. [PMID: 22218386 DOI: 10.2106/jbjs.j.01612] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Pseudotumors are a rare but important complication occurring with all types of hip replacements.The true prevalence of pseudotumors is debated.Potential causes of pseudotumors may include foreign-body reaction, hypersensitivity, and wear debris.The conduct of clinical trials on the incidence, causes, and treatments of pseudotumors has been inadequate as few investigators have used a randomized controlled design to compare various implant types.
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Affiliation(s)
- Joseph Daniel
- Hip and Knee Reconstruction, The McMinn Centre, 25 Highfield Road, Edgbaston, Birmingham, B15 3DP, UK
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Abstract
The success of metal bearings is dependent on several parameters. The effects of in vivo forces on the deformation of monoblock acetabular components have yet to be determined. The purpose of our study was to assess the amount of deformation with press-fit fixation of 1-piece metal acetabular components. Four manufacturers provided 1-piece metal acetabular components in each size (30 cups). Testing was conducted using a custom vise to simulate press-fit fixation, and measurements were performed with a Mitutoyo Test device (Aurora, Ill). Previously determined in vivo forces were used in the press-fit simulation. All components deformed under simulated in vivo applied loads. Component deformation ranged from 15 to 300 µm. Larger cups with thinner walls to accommodate larger heads had the greatest deformation and often exceeded the range of reported clearances from the manufacturers (76-227 µm).
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Deformation characteristics and eigenfrequencies of press-fit acetabular cups. Clin Biomech (Bristol, Avon) 2011; 26:46-51. [PMID: 20888676 DOI: 10.1016/j.clinbiomech.2010.08.015] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2010] [Revised: 08/30/2010] [Accepted: 08/31/2010] [Indexed: 02/07/2023]
Abstract
BACKGROUND elastic deformation of press-fitted acetabular cups during implantation provides primary stability. Excessive deformation can lead to chipping or improper seating of ceramic inlays and is dictated by cup stiffness, which also affects its vibrational characteristics. Purpose was to investigate the influence of cup design on deformation during press-fitting and on vibration properties. METHODS deformation of ten acetabular cups (with and without ceramic inlay) was tested for radial loads clinically occurring during press-fitting (0-2000N). Eigenfrequencies were measured using experimental modal analysis and related to mass and stiffness. FINDINGS the first eigenfrequency of the shells varied greatly (4-9kHz); insertion of inlays caused an increase (16-33 kHz). The range of shell stiffness was high (2.7-48.4kN/mm), increasing due to inlay insertion (124.7-376.2kN/mm). Stiffness and mass were sufficient predictors for eigenfrequencies (p<0.001,R²=0.94). INTERPRETATION the cups investigated represent a large stiffness range. Lower cup stiffness can increase primary stability but jeopardize inlay seating, and a suitable balance must be achieved by the designer. Eigenfrequencies also decrease with decreasing stiffness but were all found to lie considerably above clinically observed squeaking frequencies, indicating that these cup designs play no predominant role in the squeaking phenomenon. The observed relation between eigenfrequencies and the quotient of stiffness and mass might be used in the development of new thin walled cup designs so that their contribution to system vibrations is prevented. Presently, surgeons should be aware of the deformation characteristics of cups in order to select a suitable press-fit magnitude.
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Shimmin AJ, Walter WL, Esposito C. The influence of the size of the component on the outcome of resurfacing arthroplasty of the hip. ACTA ACUST UNITED AC 2010; 92:469-76. [DOI: 10.1302/0301-620x.92b4.22967] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The survivorship of contemporary resurfacing arthroplasty of the hip using metal-on-metal bearings is better than that of first generation designs, but short-term failures still occur. The most common reasons for failure are fracture of the femoral neck, loosening of the component, osteonecrosis of the femoral head, reaction to metal debris and malpositioning of the component. In 2008 the Australian National Joint Registry reported an inverse relationship between the size of the head component and the risk of revision in resurfacing hip arthroplasty. Hips with a femoral component size of ≤ 44 mm have a fivefold increased risk of revision than those with femoral components of ≥ 55 mm irrespective of gender. We have reviewed the literature to explore this observation and to identify possible reasons including the design of the implant, loading of the femoral neck, the orientation of the component, the production of wear debris and the effects of metal ions, penetration of cement and vascularity of the femoral head. Our conclusion is that although multifactorial, the most important contributors to failure in resurfacing arthroplasty of the hip are likely to be the design and geometry of the component and the orientation of the acetabular component.
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Affiliation(s)
- A. J. Shimmin
- Melbourne Orthopaedic Group Research Foundation, 33 The Avenue, Windsor, 3181 Victoria, Australia
| | - W. L. Walter
- Specialist Orthopaedic Group Mater Clinic, Suite 1.08, 3-9 Gillies Street, North Sydney, New South Wales 2060, Australia
| | - C. Esposito
- Specialist Orthopaedic Group Mater Clinic, Suite 1.08, 3-9 Gillies Street, North Sydney, New South Wales 2060, Australia
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37
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Amanatullah DF, Cheung Y, Di Cesare PE. Hip resurfacing arthroplasty: a review of the evidence for surgical technique, outcome, and complications. Orthop Clin North Am 2010; 41:263-72. [PMID: 20399365 DOI: 10.1016/j.ocl.2010.01.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Hip resurfacing arthroplasty has reemerged as a valid reconstruction option for the osteoarthritic hip. Patient selection is critical for excellent surgical outcomes, especially when compared with total hip arthroplasty. However, concerns regarding surgical technique and postsurgical complications persist. The authors review the evidence for surgical technique, outcomes, and complications related to modern metal-on-metal hip resurfacing arthroplasty.
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Affiliation(s)
- Derek F Amanatullah
- Department of Orthopaedic Surgery, University of California Davis Medical Center, 4860 Y Street, Suite 3800, Sacramento, CA 95817, USA
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38
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Meng Q, Gao L, Liu F, Yang P, Fisher J, Jin Z. Contact mechanics and elastohydrodynamic lubrication in a novel metal-on-metal hip implant with an aspherical bearing surface. J Biomech 2009; 43:849-57. [PMID: 20003978 DOI: 10.1016/j.jbiomech.2009.11.018] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2009] [Revised: 11/15/2009] [Accepted: 11/16/2009] [Indexed: 12/16/2022]
Abstract
Diameter and diametral clearance of the bearing surfaces of metal-on-metal hip implants and structural supports have been recognised as key factors to reduce the dry contact and hydrodynamic pressures and improve lubrication performance. On the other hand, application of aspherical bearing surfaces can also significantly affect the contact mechanics and lubrication performance by changing the radius of the curvature of a bearing surface and consequently improving the conformity between the head and the cup. In this study, a novel metal-on-metal hip implant employing a specific aspherical bearing surface, Alpharabola, as the acetabular surface was investigated for both contact mechanics and elastohydrodynamic lubrication under steady-state conditions. When compared with conventional spherical bearing surfaces, a more uniform pressure distribution and a thicker lubricant film thickness within the loaded conjunction were predicted for this novel Alpharabola hip implant. The effects of the geometric parameters of this novel acetabular surface on the pressure distribution and lubricant thickness were investigated. A significant increase in the predicted lubricant film thickness and a significant decrease in the dry contact and hydrodynamic pressures were found with appropriate combinations of these geometric parameters, compared with the spherical bearing surface.
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Affiliation(s)
- Qingen Meng
- Institute of Medical and Biological Engineering, School of Mechanical Engineering, University of Leeds, UK.
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Naal FD, Kain MSH, Hersche O, Munzinger U, Leunig M. Does hip resurfacing require larger acetabular cups than conventional THA? Clin Orthop Relat Res 2009; 467:923-8. [PMID: 19142691 PMCID: PMC2650072 DOI: 10.1007/s11999-008-0689-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2008] [Accepted: 12/15/2008] [Indexed: 01/31/2023]
Abstract
UNLABELLED Hip resurfacing is femoral bone preserving, but there is controversy regarding the amount of bone removed at the acetabular side. We therefore compared the implanted acetabular cup sizes in primary THAs between two resurfacing devices and a conventional press-fit cup using a series of 2134 THAs (Allofit cup 1643 hips, Durom Hip Resurfacing 249 hips, and Birmingham Hip Resurfacing 242 hips). The effects of patient demographics and cup position in the horizontal plane also were assessed. After controlling for gender, patients were matched for height, weight, body mass index, and age. The mean size for Allofit cups was smaller than the sizes for Durom and Birmingham Hip Resurfacing cups in women (49.9 mm, 51.6 mm, 52.3 mm, respectively) and men (55.1 mm, 56.7 mm, 57.8 mm; respectively). Although patient height was associated with the implanted cup size, the cup position in the horizontal plane had no effect on the size used. Larger cups were used with hip resurfacing than for THA with a conventional press-fit cup. However, additional studies are needed to determine whether these small differences have any clinical implications in the long term. The association of cup size and patient height should be considered in future studies comparing component sizes among different implants. LEVEL OF EVIDENCE Level III, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.
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Affiliation(s)
- Florian D. Naal
- Department of Orthopaedic Surgery, Schulthess Clinic, Lengghalde 2, 8008 Zurich, Switzerland
| | - Michael S. H. Kain
- M.E. Müller Foundation of North America Hip Fellow at Schulthess Clinic, Zurich, Switzerland
| | - Otmar Hersche
- Department of Orthopaedic Surgery, Schulthess Clinic, Lengghalde 2, 8008 Zurich, Switzerland
| | - Urs Munzinger
- Department of Orthopaedic Surgery, Schulthess Clinic, Lengghalde 2, 8008 Zurich, Switzerland
| | - Michael Leunig
- Department of Orthopaedic Surgery, Schulthess Clinic, Lengghalde 2, 8008 Zurich, Switzerland ,University of Berne, Berne, Switzerland
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Langton DJ, Jameson SS, Joyce TJ, Webb J, Nargol AVF. The effect of component size and orientation on the concentrations of metal ions after resurfacing arthroplasty of the hip. ACTA ACUST UNITED AC 2008; 90:1143-51. [PMID: 18757952 DOI: 10.1302/0301-620x.90b9.20785] [Citation(s) in RCA: 270] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Increased concentrations of metal ions after metal-on-metal resurfacing arthroplasty of the hip remain a concern. Although there has been no proven link to long-term health problems or early prosthetic failure, variables associated with high metal ion concentrations should be identified and, if possible, corrected. Our study provides data on metal ion levels from a series of 76 consecutive patients (76 hips) after resurfacing arthroplasty with the Articular Surface Replacement. Chromium and cobalt ion concentrations in the whole blood of patients with smaller (<or= 51 mm) femoral components were significantly higher than in those with the larger (>or= 53 mm) components (p < 0.01). Ion concentrations in the former group were significantly related to the inclination (p = 0.01) and anteversion (p = 0.01) of the acetabular component. The same relationships were not significant in the patients with larger femoral components (p = 0.61 and p = 0.49, respectively). Accurate positioning of the acetabular component intra-operatively is essential in order to reduce the concentration of metal ions in the blood after hip resurfacing arthroplasty with the Articular Surface Replacement implant.
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Affiliation(s)
- D J Langton
- Joint Replacement Unit, University Hospital of North Tees, Hardwick, Stockton-on-Tees TS19 8PE, UK.
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41
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Ong KL, Manley MT, Kurtz SM. Have contemporary hip resurfacing designs reached maturity? A review. J Bone Joint Surg Am 2008; 90 Suppl 3:81-8. [PMID: 18676941 DOI: 10.2106/jbjs.h.00574] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The increasing prevalence of hip replacements in young patients is expected to fuel the demand for hip resurfacing arthroplasty. Patient selection, surgical technique, and implant design can influence the clinical outcomes for these patients. In this review, we discuss whether contemporary hip resurfacing designs have reached maturity and suggest design considerations for future-generation implants. These design-related factors include the amount and extent of cement fixation, adoption of cementless femoral fixation, optimization of implant position, minimization of stress-shielding, improvement in modularity or sizing and geometry options, metallurgy, development of alternative bearing options, and examination of in vivo cup deformation. In addition, this review is based on an understanding of the causes of failure of revision hip resurfacing arthroplasty, which is essential to help guide research, implant design, and clinical decision-making.
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Affiliation(s)
- Kevin L Ong
- Exponent Incorporated, 3401 Market Street, Suite 300, Philadelphia, PA 19104, USA.
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Abstract
The main advantage of hip resurfacing is bone conservation for patients likely to outlive a primary conventional hip replacement. Previous attempts at hip resurfacing failed predominantly because of the consequences of a high amount of wear of thin polyethylene acetabular components and poor femoral component fixation. With correct patient selection, surgeon education, and operative technique, survivorship at five years is comparable with that of traditional hip replacements. Hip resurfacing has its own unique set of complications, including a fractured neck of the femur. It is necessary to understand the risk factors prior to performing the procedure.
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Affiliation(s)
- Andrew Shimmin
- Melbourne Orthopaedic Group, 33 The Avenue, Windsor, Victoria 3181, Australia.
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Udofia I, Liu F, Jin Z, Roberts P, Grigoris P. The initial stability and contact mechanics of a press-fit resurfacing arthroplasty of the hip. ACTA ACUST UNITED AC 2007; 89:549-56. [PMID: 17463130 DOI: 10.1302/0301-620x.89b4.18055] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Finite element analysis was used to examine the initial stability after hip resurfacing and the effect of the procedure on the contact mechanics at the articulating surfaces. Models were created with the components positioned anatomically and loaded physiologically through major muscle forces. Total micromovement of less than 10 μm was predicted for the press-fit acetabular components models, much below the 50 μm limit required to encourage osseointegration. Relatively high compressive acetabular and contact stresses were observed in these models. The press-fit procedure showed a moderate influence on the contact mechanics at the bearing surfaces, but produced marked deformation of the acetabular components. No edge contact was predicted for the acetabular components studied. It is concluded that the frictional compressive stresses generated by the 1 mm to 2 mm interference-fit acetabular components, together with the minimal micromovement, would provide adequate stability for the implant, at least in the immediate post-operative situation.
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Affiliation(s)
- I Udofia
- Computational Bioengineering Institute of Medical and Biological Engineering, School of Mechanical Engineering, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, UK.
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Squire M, Griffin WL, Mason JB, Peindl RD, Odum S. Acetabular component deformation with press-fit fixation. J Arthroplasty 2006; 21:72-7. [PMID: 16950065 DOI: 10.1016/j.arth.2006.04.016] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2006] [Accepted: 04/13/2006] [Indexed: 02/01/2023] Open
Abstract
Acetabular component deformation secondary to forces encountered during insertion is a potential consequence of the press-fit technique. This study characterized the stiffness of Pinnacle 100 cups (DePuy, Warsaw, Ind) via mechanical testing and used this information with intraoperative measurements of cup deformation to calculate the in vivo forces acting on cups inserted during hip arthroplasty in 21 patients. We found that 90.5% of cups had measurable compression deformity, averaging 0.16 +/- 0.16 mm. The corresponding forces acting on these cups averaged 414 +/- 421 N. For hard-on-hard bearing surfaces, such in vivo deformation of acetabular shells may result in negative clinical consequences such as equatorial loading with increased wear and potential seizing of components, chipping of ceramic inserts, or locking mechanism damage.
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Affiliation(s)
- Matthew Squire
- Department of Orthopedics and Rehabilitation, University of Wisconsin Hospitals and Clinics, Madison, Wisconsin, USA
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Lin ZM, Meakins S, Morlock MM, Parsons P, Hardaker C, Flett M, Isaac G. Deformation of press-fitted metallic resurfacing cups. Part 1: Experimental simulation. Proc Inst Mech Eng H 2006; 220:299-309. [PMID: 16669396 DOI: 10.1243/095441105x69150] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The interference press fit of a metallic one-piece acetabular cup employed for metal-on-metal hip resurfacing procedures was investigated experimentally under laboratory conditions in the present study, in particular regarding the cup deformation. Tests were carried out in cadavers as well as polyurethane foams of various grades with different elastic moduli to represent different cancellous bone qualities. The cadaver test was used to establish the most suitable configuration of the foam model representing realistic support and geometrical conditions at the pelvis. It was found that a spherical cavity, with two identical areas relieved on opposite sides, was capable of creating a two-point pinching action of the ischeal and ilial columns on the cup as the worst-case scenario. Furthermore, the cup deformation produced from such a two-point loading model with a grade 30 foam was similar to that measured from the cadaver test. Therefore, such a protocol was employed in subsequent experimental tests. For a given size of the outside diameter of the cup of 60 mm, the cup deflection was shown to be dependent largely on the cup wall thickness and the diametral interference between cup and prepared cavity at implantation. For a relatively thin cup with a wall thickness between 2.3 mm (equator) and 4 mm (pole) and with a modest nominal diametral interference of 1 mm, which corresponds to an actual interference of approximately 0.5 mm, the maximum diametral cup deflection (at the rim) was around 60 μm, compared with a diametral clearance of 80-120 μm between the femoral head and the acetabular cup, generally required for fluid-film lubrication and tribological performances. Stiffening of the cup, by both thickening and lateralizing by 1 mm, reduced the cup deformation to between 30 and 50 μm with actual diametral interferences between 0.5 and 1 mm.
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Affiliation(s)
- Z M Lin
- School of Mechanical Engineering, University of Leeds, Leeds, UK.
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