Primary stability of uncemented femoral resurfacing implants for varying interface parameters and material formulations during walking and stair climbing

Rothstock, Stephan; Uhlenbrock, Anne Gebert de; Bishop, Nick; Morlock, Michael M.

doi:10.1016/j.jbiomech.2009.09.052

Cited by 14 publications

(10 citation statements)

References 30 publications

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“…Modelling press-fit interfaces is often achieved by pre-positioning an oversized implant in a cavity and then virtually eliminating or adjusting the radial interference prior to analysis (Gebert et al, 2009;Goetzen et al, 2005;Kluess et al, 2009;Ramamurti et al, 1997;Rothstock et al, 2010). Interferences implemented in models are often much smaller than nominal interferences designed by manufacturers, since stresses would otherwise exceed the strength of the cortical bone shell.…”

Section: Discussionmentioning

confidence: 99%

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Friction coefficient and effective interference at the implant-bone interface

Damm

Morlock

Bishop

2015

Journal of Biomechanics

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Section: Discussionmentioning

confidence: 99%

“…This might explain the use of small interferences in modelling press-fit implantation to prevent unreasonably high stresses in the bone (Abdul-Kadir et al, 2008;Gebert et al, 2009;Rothstock et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Friction coefficient and effective interference at the implant-bone interface

Damm

Morlock

Bishop

2015

Journal of Biomechanics

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“…Most studies assume that the supporting bone is linear elastic (Chong et al, 2010;Reggiani et al, 2008;Abdul-Kadir et al, 2008;Bah et al, 2011), despite some studies reporting stresses that approach or exceed the yield stress (Taylor et al, 1995;Kelly et al, 2013;Rohlmann et al, 1988;Ong et al, 2006;Hothi et al, 2011;Rothstock et al, 2010). In addition, the viscoelastic properties will lead to stress relaxation, particularly if an interference fit is simulated.…”

Section: Simulation Of the Initial Mechanical Environment Of The Bonementioning

confidence: 99%

Four decades of finite element analysis of orthopaedic devices: Where are we now and what are the opportunities?

Taylor

Prendergast

2015

Journal of Biomechanics

140

106

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a b s t r a c tFinite element has been used for more than four decades to study and evaluate the mechanical behaviour total joint replacements. In Huiskes seminal paper "Failed innovation in total hip replacement: diagnosis and proposals for a cure", finite element modelling was one of the potential cures to avoid poorly performing designs reaching the market place. The size and sophistication of models has increased significantly since that paper and a range of techniques are available from predicting the initial mechanical environment through to advanced adaptive simulations including bone adaptation, tissue differentiation, damage accumulation and wear. However, are we any closer to FE becoming an effective screening tool for new devices? This review contains a critical analysis of currently available finite element modelling techniques including (i) development of the basic model, the application of appropriate material properties, loading and boundary conditions, (ii) describing the initial mechanical environment of the bone-implant system, (iii) capturing the time dependent behaviour in adaptive simulations, (iv) the design and implementation of computer based experiments and (v) determining suitable performance metrics.The development of the underlying tools and techniques appears to have plateaued and further advances appear to be limited either by a lack of data to populate the models or the need to better understand the fundamentals of the mechanical and biological processes. There has been progress in the design of computer based experiments. Historically, FE has been used in a similar way to in vitro tests, by running only a limited set of analyses, typically of a single bone segment or joint under idealised conditions. The power of finite element is the ability to run multiple simulations and explore the performance of a device under a variety of conditions. There has been increasing usage of design of experiments, probabilistic techniques and more recently population based modelling to account for patient and surgical variability. In order to have effective screening methods, we need to continue to develop these approaches to examine the behaviour and performance of total joint replacements and benchmark them for devices with known clinical performance.Finite element will increasingly be used in the design, development and pre-clinical testing of total joint replacements. However, simulations must include holistic, closely corroborated, multi-domain analyses which account for real world variability.

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“…Despite the recent clinical interest in cementless fixation, there is a lack of reported biomechanical studies on uncemented femoral resurfacing that could be used as a basis to understand the load transfer and its relationship with probable failure mechanisms [19][20][21][22]. The study by Ong et al [19] is the only investigation on the effects of different methods of fixation (cemented versus uncemented) and different interface conditions (bonded versus debonded) on the load transfer within a resurfaced femur implanted with a BHR, using threedimensional (3D) finite element (FE) models.…”

Section: Introductionmentioning

confidence: 99%

“…Instead the implant-bone interfacial conditions were assumed arbitrarily and kept uniform post-operative throughout the iterative simulation of the bone remodelling [20]. Whilst the effect of press-fit parameters on the primary stability of uncemented femoral implants has been studied by Gebert et al [21] and Rothstock et al [22], little is known about the effect of micromotions on the implant stability and the load transfer within an uncemented resurfaced femur. It is hypothesized that the amount of micromotion and osseointegration between the resurfacing implant and the bone affect short-term peak stresses and strain and peri-prosthetic bone adaptation, subsequent to primary and secondary stability.…”

Section: Introductionmentioning

confidence: 99%

The effect of primary stability on load transfer and bone remodelling within the uncemented resurfaced femur

Pal

Gupta

2011

Proc Inst Mech Eng H

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One of the major causes of aseptic loosening in an uncemented implant is the lack of any attachment between the implant and the bone. The implant's stability depends on a combination of primary stability (mechanical stability) and secondary stability (biological stability). The primary stability may affect the implant-bone interface condition and thus influence the load transfer and mechanical stimuli for bone remodelling in the resurfaced femur. This paper reports the results of a study into the affect of primary stability on load transfer and bone adaptation for an uncemented resurfaced femur. Three-dimensional finite element models were used to simulate the intact and resurfaced femurs and the bone remodelling. As a first step towards assessing the immediate post-operative condition, a debonded interfacial contact condition with varying levels of the friction coefficient (0.4, 0.5, and 0.6) was simulated at the implant-bone interface. Then, using a threshold value of micromotion of 50 microm, the implant-bone interfacial condition was varied along the implant-bone boundary to mechanically represent non-osseointegrated or osseointegrated regions of the interface. The considered applied loading conditions included normal walking and stair climbing. Resurfacing leads to strain shielding in the femoral head (20-75 per cent strain reductions). In immediate post-operative conditions, there was no occurrence of elevated strains in the cancellous bone around the proximal femoral neck-component junction resulting in a lower risk of neck fracture. Predominantly, the micromotions were observed to remain below 50 microm at the implant-bone interface, which represents 97-99 per cent of the interfacial surface area. The predicted micromotions at the implant-bone interface strongly suggest the likelihood of bone ingrowth onto the coated surface of the implant, thereby enhancing implant fixation. For the osseointegrated implant-bone interface, the effect of strain shielding was observed in a considerably greater bone volume in the femoral head as compared to the initial debonded interfacial condition. A 50-80 per cent peri-prosthetic bone density reduction was predicted as compared to the value of the intact femur, indicating bone resorption within the superior resurfaced head. Although primary fixation of the resurfacing component may be achieved, the presence of high strain shielding and peri-prosthetic bone resorption are a major concern.

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Primary stability of uncemented femoral resurfacing implants for varying interface parameters and material formulations during walking and stair climbing

Cited by 14 publications

References 30 publications

Friction coefficient and effective interference at the implant-bone interface

Friction coefficient and effective interference at the implant-bone interface

Four decades of finite element analysis of orthopaedic devices: Where are we now and what are the opportunities?

The effect of primary stability on load transfer and bone remodelling within the uncemented resurfaced femur

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