The skeletal response to matt and polished cemented femoral stems

Barker, D.S.; Wang, A. W.; Yeo, M.F.; Nawana, Namal S.; Brumby, Scott; Pearcy, Mark J.; Howie, Donald W.

doi:10.1302/0301-620x.82b8.9864

Cited by 7 publications

(4 citation statements)

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“…The implant stem and bone/cement meshes were congruent at their interface, which was modeled with a contact pair containing 1512 quadratic contact and target elements. This interface was bonded in the intact case and modeled with Coulomb friction in the implanted case, using a static coefficient of friction of 0.2 [28].…”

Section: Finite Elementmentioning

confidence: 99%

Activity and Loading Influence the Predicted Bone Remodeling Around Cemented Hip Replacements

Dickinson

2014

Journal of Biomechanical Engineering

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Periprosthetic bone remodeling is frequently observed after total hip replacement. Reduced bone density increases the implant and bone fracture risk, and a gross loss of bone density challenges fixation in subsequent revision surgery. Computational approaches allow bone remodeling to be predicted in agreement with the general clinical observations of proximal resorption and distal hypertrophy. However, these models do not reproduce other clinically observed bone density trends, including faster stabilizing mid-stem density losses, and loss-recovery trends around the distal stem. These may resemble trends in postoperative joint loading and activity, during recovery and rehabilitation, but the established remodeling prediction approach is often used with identical pre- and postoperative load and activity assumptions. Therefore, this study aimed to evaluate the influence of pre- to postoperative changes in activity and loading upon the predicted progression of remodeling. A strain-adaptive finite element model of a femur implanted with a cemented Charnley stem was generated, to predict 60 months of periprosthetic remodeling. A control set of model input data assumed identical pre- and postoperative loading and activity, and was compared to the results obtained from another set of inputs with three varying activity and load profiles. These represented activity changes during rehabilitation for weak, intermediate and strong recoveries, and pre- to postoperative joint force changes due to hip center translation and the use of walking aids. Predicted temporal bone density change trends were analyzed, and absolute bone density changes and the time to homeostasis were inspected, alongside virtual X-rays. The predicted periprosthetic bone density changes obtained using modified loading inputs demonstrated closer agreement with clinical measurements than the control. The modified inputs also predicted the clinically observed temporal density change trends, but still under-estimated density loss during the first three postoperative months. This suggests that other mechanobiological factors have an influence, including the repair of surgical micro-fractures, thermal damage and vascular interruption. This study demonstrates the importance of accounting for pre- to postoperative changes in joint loading and patient activity when predicting periprosthetic bone remodeling. The study's main weakness is the use of an individual patient model; computational expense is a limitation of all previously reported iterative remodeling analysis studies. However, this model showed sufficient computational efficiency for application in probabilistic analysis, and is an easily implemented modification of a well-established technique.

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Section: Finite Elementmentioning

confidence: 99%

Activity and Loading Influence the Predicted Bone Remodeling Around Cemented Hip Replacements

Dickinson

2014

Journal of Biomechanical Engineering

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“…Both models are considered to be suitable for studies of this type. Other authors have confirmed sheep to be an appropriate model for hip arthroplasty (Phillips et al 1987, Brumby et al 1998, Barker et al 2000). The bony acetabulum of the sheep is made up of the 3 bones of the pelvis, as it is in man.…”

Section: Introductionmentioning

confidence: 86%

A modified cementing technique using BoneSource to augment fixation of the acetabulum in a sheep model

Timperley

Nusem

Wilson³

et al. 2010

Acta Orthopaedica

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Background and purposeOur aim was to assess in an animal model whether the use of HA paste at the cement-bone interface in the acetabulum improves fixation. We examined, in sheep, the effect of interposing a layer of hydroxyapatite cement around the periphery of a polyethylene socket prior to fixing it using polymethylmethacrylate (PMMA).MethodsWe performed a randomized study involving 22 sheep that had BoneSource hydroxyapatite material applied to the surface of the acetabulum before cementing a polyethylene cup at arthroplasty. We studied the gross radiographic appearance of the implant-bone interface and the histological appearance at the interface.ResultsThere were more radiolucencies evident in the control group. Histologically, only sheep randomized into the BoneSource group exhibited a fully osseointegrated interface. Use of the hydroxyapatite material did not give any detrimental effects. In some cases, the material appeared to have been fully resorbed. When the material was evident in histological sections, it was incorporated into an osseointegrated interface. There was no giant cell reaction present. There was no evidence of migration of BoneSource to the articulation.InterpretationThe application of HA material prior to cementation of a socket produced an improved interface. The technique may be useful in humans, to extend the longevity of the cemented implant by protecting the socket interface from the effect of hydrodynamic fluid flow and particulate debris.

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“…Clinical studies have shown that creep deformation is essential for the optimum performance of cemented hip prostheses that achieve stable fixation through taper-locking of the femoral stem within the cement mantle [10][11][12][13][14][15][16]. A number of studies have used finite element analysis (FEA) to investigate the effects of cement creep on the distribution of stresses within the cement, as well as on the magnitude of the micromotion of the stem in the cement mantle [17][18][19][20][21][22][23].…”

Section: Introductionmentioning

confidence: 99%

“…These difficulties might be one of the reasons that none of the published FEA models of cemented hip prostheses have attempted to calculate the creep component of the deformation of the cement mantle using step-wise integration over a typical hip loading profile. Rather, previous investigators have used simplified load profiles [17][18][19][20][21][22][23].…”

Section: Introductionmentioning

confidence: 99%

The use of a constant load to generate equivalent viscoelastic strain in finite element analysis of cemented prosthetic joints subjected to cyclic loading

McKellop

2011

Proc Inst Mech Eng H

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Polymers such as polymethyl-methacrylate (PMMA) surgical cement undergo elastic and viscoelastic deformation (creep) in response to physiological cyclic loading. Theoretically, the effect of gradual creep deformation on the stresses, strains, and displacements of a prosthetic joint can be evaluated by running a finite element analysis (FEA) model through a large number of loading cycles. However, with complex (i.e. realistic) models, this approach may require extensive computational time, and may accumulate unacceptably large numerical errors over the many iterations of the model. The present study utilized a Fourier series to represent a periodic stress and incorporated it in the linear viscoelastic constitutive equation. It was demonstrated that, for a linear viscoelastic material, the time average (i.e. the constant in the Fourier series) of the cyclic stress determined the accumulated creep strain and the sinusoidal components of the stress produced the periodic creep strain with a zero average and negligible amplitude. For a geometrically linear FEA model, the solution based on a cyclic stress can be readily applied to an external cyclic load, that is, the creep strain is determined by the time average of the cyclic load. While femoral component models were considered as geometrically non-linear, an FEA model of a femur implanted with an Exeter hip prosthesis showed that there was only a minor difference between the profile of the applied sinusoidal load and that of the resulting displacement. In such cases, applying the time average of a cyclic load to calculate the resulting creep strain with a given duration of loading should expect to provide acceptable accuracy, with a marked reduction in the computational time.

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The skeletal response to matt and polished cemented femoral stems

Cited by 7 publications

References 0 publications

Activity and Loading Influence the Predicted Bone Remodeling Around Cemented Hip Replacements

Activity and Loading Influence the Predicted Bone Remodeling Around Cemented Hip Replacements

A modified cementing technique using BoneSource to augment fixation of the acetabulum in a sheep model

The use of a constant load to generate equivalent viscoelastic strain in finite element analysis of cemented prosthetic joints subjected to cyclic loading

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