Load-shift—numerical evaluation of a new design philosophy for uncemented hip prostheses

Goetzen, Nils; Lampe, Frank; Nassut, R; Morlock, Michael M.

doi:10.1016/j.jbiomech.2004.01.023

Cited by 23 publications

(21 citation statements)

References 25 publications

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“…For uncoated surfaces the friction is much lower. In this work, to accentuate the difference between the interface conditions for both regions, frictionless contact is considered for uncoated regions (Keaveny and Bartel, 1994;Fernandes et al, 2002;Goetzen et al, 2005;Folgado et al, 2009).…”

Section: Multi-criteria Optimization For Stem Designmentioning

confidence: 99%

On the optimal shape of hip implants

Ruben¹,

Fernandes²,

Folgado³

2012

Journal of Biomechanics

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Section: Multi-criteria Optimization For Stem Designmentioning

confidence: 99%

On the optimal shape of hip implants

Ruben¹,

Fernandes²,

Folgado³

2012

Journal of Biomechanics

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“…However, Tai et al [13], and other researchers as well [18][19][20][21], examined only half the femur in their numerical investigations. According to Duda et al [16,22], this does not correspond to Stress shielding in total hip prosthesesthe physiological facts.…”

Section: Fig 1 Loading Of the Femur (Data Obtained From Reference [17])mentioning

confidence: 99%

“…However, only a reduced muscle system was used, obtained from Heller et al [17], to save time in the modelling process. The same reduced system was also used by Goetzen et al [21], while Taylor et al [24] took all muscle forces into account.…”

Section: Fig 1 Loading Of the Femur (Data Obtained From Reference [17])mentioning

confidence: 99%

“…Many researches [13,16,[18][19][20][21] have not considered the anisotropy of the femoral bone, although numerous experiments have proven that the femur has no isotropic elasticity properties [14,25,26]. In order to have a realistic simulation of the load distribution in the femur, a description of the bone elasticity properties as exact as possible is crucial.…”

Section: Fig 1 Loading Of the Femur (Data Obtained From Reference [17])mentioning

confidence: 99%

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Numerical investigations of stress shielding in total hip prostheses

Behrens

Wirth

Nolte

et al. 2008

Proc Inst Mech Eng H

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Aseptic loosening of the prosthesis is still a problem in artificial joint implants. The loosening can be caused by, among other factors, resorption of the bone surrounding the prosthesis owing to stress shielding. In order to find out the influence of the prosthesis type on post-operative stress shielding, a static finite element analysis of a femur provided with the conventional uncemented stem BICONTACT and of one with the femoral neck prosthesis SPIRON was carried out. Strain energy densities and maximal principal strain distributions were calculated and compared with the physiological situation. Here, stress shielding was demonstrated in both periprosthetic femora. To determine the areas of the stress shielding, the bone in each FE model was subdivided into three regions of interest (ROI): proximal, diaphyseal, and distal. The numerical computations show stress shielding in the proximal ROI of both periprosthetic femora. Diaphyseally, the femoral neck prosthesis SPIRON, in contrast to the conventional uncemented long-stem prosthesis BICONTACT, causes no decrease in the strain distribution and thus no stress shielding. Distally, no change in the load distribution of either periprosthetic femur could be found, compared with the physiological situation.

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“…In Sakai et al [25] a new type of fixation was compared with the traditional ones. Goetzen et al [26] presented computational results for a new distal design. The stem has a biodegradable pin to increase the distal diameter and thus to improve distal fixation.…”

Section: Uncemented Stemsmentioning

confidence: 99%

Bone Implant Design Using Optimization Methods

Fernandes

Ruben

Folgado

2010

Biomechanics of Hard Tissues

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Total hip arthroplasty (THA) is a successful treatment for joint and bone diseases as well as in fracture repair [1]. It involves the replacement of the natural joint by an artificial one, composed of a femoral stem and an acetabular component as shown in Figure 10.1. The femoral component can be classified as cemented or uncemented depending on the mode of fixation. Cemented stems are fixed using a bone cement layer between the femur and the implant, while cementless stems are placed directly in contact with the bone. In this case, the biological fixation is promoted by the stem coating such as hydroxyapatite or in general a porous surface.In the first 10 years after surgery, the THA success is greater than 80%; nevertheless, it is possible to indentify some causes of failure. Aseptic loosening is the main cause for failure, being responsible for approximately 60% of revisions [1,4]. This failure can be due to mechanical problems such as excessive bone loss [5], inefficient initial stability [6], or cement mantle fatigue [7]. Thigh pain is another important mechanical cause for implant failure, with more than 6% of incidence [4]. On the other hand, deep infection is the major biological problem with more than 5% of prevalence [1,4]. Actually, the majority of failures of the THA are related to mechanical factors.Regarding the mode of fixation, cemented stems are globally more durable than cementless ones, with a 90% survival rate after 12 years. For uncemented implants this rate is less than 80% [1]. However, some cementless stems achieve more than 95% survival rate after 12 years. In fact, cementless stems with good initial stability and osseointegration exhibit a superior performance [8]. Cemented stems are preferred for elderly people, but, for patients less than 60 years old, the number of uncemented stems has increased, particularly, in the past few decades. In the early 1990s cementless stems represented only 20% of THA and in 2005 this value increased to approximately 45% [1].As stated above, the long-term implant success is strongly related to mechanical factors. For cementless stems the initial mechanical conditions on bone-implant interface (primary stability) are very important for success of the prosthesis. In

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Load-shift—numerical evaluation of a new design philosophy for uncemented hip prostheses

Cited by 23 publications

References 25 publications

On the optimal shape of hip implants

On the optimal shape of hip implants

Numerical investigations of stress shielding in total hip prostheses

Bone Implant Design Using Optimization Methods

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