The Effects of Interfacial Conditions and Stem Length on Potential Failure Mechanisms in the Uncemented Resurfaced Femur

Gupta, Sanjay; Pal, Bidyut; New, A.M.R.

doi:10.1007/s10439-010-0007-5

Cited by 13 publications

(7 citation statements)

References 28 publications

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“…5(b)). The changes in bone density distribution are considerably different for the bonded implant-bone interface in comparison with the debonded interface condition [20]. The effect of bone resorption occurs in greater volume Fig.…”

Section: Discussionmentioning

confidence: 90%

“…The effect of bone resorption occurs in greater volume Fig. 5 Bone density distributions in the resurfaced femoral head, mid-frontal view: (a) immediate post-operative; and (b) osseointegrated, after equilibrium in bone remodelling of bone (in ROIs 1 and 2) for a fully bonded interface as compared with those for the debonded condition [20]. However, bone apposition corresponding to a 50-80 per cent increase in bone density, is observed for both models around the distal tip of the stem.…”

Section: Discussionmentioning

confidence: 99%

“…Their study concluded that the comparison of cemented and uncemented fixation showed no advantage for either with regard to bone loading. In contrast, a recent investigation into the effects of changes in stem length in combination with implant-bone interfacial conditions on the failure mechanisms of uncemented resurfaced femurs reported that cementless fixation might be a viable alternative to cemented fixation, provided that sufficient initial fixation and secondary stability through bone ingrowth is achieved [20]. That study investigated load transfer and adaptive bone remodelling within cementless resurfaced femoral heads assuming either debonded (with friction level m 5 0.4) or bonded implant-bone interface conditions.…”

Section: Introductionmentioning

confidence: 97%

“…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%

“…The effect of primary stability and the evolution of the living implant-bone interface were not considered. 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.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Discussionmentioning

confidence: 90%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

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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Modeling the debonding process of osseointegrated implants due to coupled adhesion and friction

Immel

Nguyen

Haïat

et al. 2022

Biomech Model Mechanobiol

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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 $$\mu _\text {b}$$ μ b , the trabecular Young’s modulus $$E_\text {b}$$ E b , and the interference fit $$I\!F$$ I F 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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The Relevance of Biomechanical Analysis in Joint Replacements: A Review

Pal

Gupta

2020

J. Inst. Eng. India Ser. C

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The Effects of Interfacial Conditions and Stem Length on Potential Failure Mechanisms in the Uncemented Resurfaced Femur

Cited by 13 publications

References 28 publications

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

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

Modeling the debonding process of osseointegrated implants due to coupled adhesion and friction

The Relevance of Biomechanical Analysis in Joint Replacements: A Review

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