A New Testing Method for Ceramic Hip Joint Heads According Conditions In Vivo

Oberbach, Thomas; Salomon, Dirk; Glien, Wilfried

doi:10.4028/0-87849-992-x.1195

Cited by 2 publications

(2 citation statements)

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“…The FE method is considered to be an effective method for calculating stress distributions in a mechanical system consisting of different deformable components in contact with each other. In the past, many FE analyses of hip joint implants have been performed in order to determine stress distributions in ball heads under different conditions [17][18][19]. In ball heads, the stress distribution can be considered as a superimposition of the stresses caused by clamping the head on the conical end of the taper and by external forces occurring during movements.…”

Section: Methodsmentioning

confidence: 99%

Proof testing of ceramic femoral heads for hip joint implants

Weisse

Affolter

Koller

et al. 2010

Proc Inst Mech Eng H

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A proof test procedure for the rejection of defective ceramic hip ball heads in the production line is presented. The procedure consists of applying a load to each ceramic ball head. This load, being somewhat higher than the maximum physiological load, should not cause any damage in cases where the highly stressed areas are free of flaws. In this procedure, a polymer ring is positioned inside the ball head bore between a socket and the head of a tie bolt. Once the tie bolt is pulled downwards, the ring creates a radial pressure on the inner bore surface of the ball head. With an iterative approach based on finite element analysis, the proof test design was optimized in order to obtain a stress distribution in the ball head similar to that resulting in in vivo conditions. The calculated results were validated by strain gauge measurements performed on an assembled proof test apparatus. Several polymers were considered for the ring. Ultrahigh-molecular-weight polyethylene (UHMWPE grade RCH 1000) showed the best durability properties and lowest wear rates. The requirement to perform 1000 reruns without significant reduction of stress in the ball head was fulfilled. Although other proof test procedures for ceramic femoral heads already exist, the procedure presented in this article shows advantages concerning maintenance and operating costs.

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Section: Methodsmentioning

confidence: 99%

Proof testing of ceramic femoral heads for hip joint implants

Weisse

Affolter

Koller

et al. 2010

Proc Inst Mech Eng H

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show abstract

“…These studies showed that the stress distribution in the taper region was axisymmetric. However, the stress distribution in the taper region would be more likely to be non-axisymmetric under in vivo physiological circumstances (3,10) .…”

Section: Introductionmentioning

confidence: 99%

Alternative Mechanical Evaluation Method for Ceramic Hip Joint Implants Utilizing Finite Element Analysis under <I>in vivo</I>-like Conditions

Han

Chu

Song

et al. 2012

JBSE

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This study proposes an alternative mechanical simulation protocol for ceramic femoral heads under in vivo-like conditions. A 3D pelvis model is obtained from CT images and the finite elements of the implanted models are validated based on Kwong's experimental results. The stress distribution of nine different femoral head models is then compared when using the conventional proof test (standard ISO 7206-10) and proposed test protocol (postoperative models). Both test methods show a decrease in the maximum stress when increasing the size of the femoral head and bore depth. However, for the stress distribution, the postoperative models reveal a concentration on the superior inner region of femoral head cranial, while the proof test shows an axisymmetric shape in the tangential direction. As a non-uniformed stress distribution increases the probability of fracture, the mechanical testing of ceramic femoral heads should be considered under in vivo-like conditions in order to improve the mechanical reliability of the joint. Thus, the current results show the necessity and viability of an alternative mechanical evaluation method for ceramic hip implants.

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A New Testing Method for Ceramic Hip Joint Heads According Conditions In Vivo

Cited by 2 publications

References 0 publications

Proof testing of ceramic femoral heads for hip joint implants

Proof testing of ceramic femoral heads for hip joint implants

Alternative Mechanical Evaluation Method for Ceramic Hip Joint Implants Utilizing Finite Element Analysis under <I>in vivo</I>-like Conditions

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