Fatigue Strength of Cobalt-Base Alloys with High Corrosion Resistance for Artificial Hip Joints

Lorenz, Mylena; Semlitsch, M.; Panic, B.; Weber, H. P.; Willert, H.‐G.

doi:10.1243/emed_jour_1978_007_061_02

Cited by 34 publications

(6 citation statements)

References 13 publications

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“…Surprisingly, it has also been reported that strength was not markedly enhanced by unidirectional solidification. 2 The results contradict not only the reported improvement of fatigue life using unidirectional solidification but also, for example, the investigation of VerSnyder,3 who observed the improvement of high-temperature fatigue life of turbine blades using unidirectional solidification.…”

Section: Fatigue Testmentioning

confidence: 69%

Optimizing the corrosion fatigue properties of Co-Cr-Mo Hip joints

Tensi¹,

Hooputra²,

Weinfurtner³

et al. 1995

JOM

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Section: Fatigue Testmentioning

confidence: 69%

Optimizing the corrosion fatigue properties of Co-Cr-Mo Hip joints

Tensi¹,

Hooputra²,

Weinfurtner³

et al. 1995

JOM

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“…The cast CoCr alloy used in the 1950s for the Austin Moore prosthesis had an endurance limit in the range of 175-280 MPa for zero-tension loading (16,19,24). Defects in the cast metal could further decrease fatigue strength (24,27).…”

Section: Discussionmentioning

confidence: 99%

Load transfer with the austin moore cementless hip prosthesis

Keaveny

Bartel

1993

Journal Orthopaedic Research

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More than 1,300 Austin Moore hemiarthroplasties have been reviewed in the literature, with no reports of fracture of the stem. Many patients with these hip implants had good function. The lack of stem fractures in patients with good functions has not been explained and contrasts with stem fractures that have occurred in patients with cemented prostheses of other designs during the same time. We used three-dimensional finite-element analysis and free-body diagrams to explain the lack of fractures for this device by a description of the probable load-transfer mechanisms between the prosthesis and the bone. Results from our finite-element analysis indicate that, with good calcar-collar support, the stresses in the stem are small because the stem portion of the prosthesis and the bone are uncoupled and, consequently, do not share the resultant bending moment of the head and abductor forces. If the stem is coupled to the bone so that the resultant bending moment is shared, high stresses in the stem are predicted; such stresses are inconsistent with the complete absence of fractures of these prostheses. The results of the finite-element analysis further showed that loss of calcar-collar support with proximal fixation through the fenestrations resulted in high stresses in the stem and stress shielding of the proximal medial cortex. The uncoupled prosthesis also may be modeled with a free-body diagram as a three-force member loaded at the head, stem tip, and in the proximal region. With this model, it can be shown that the reaction force of the stem tip, and thus the peak bending stress in the stem, increases as calcar-collar support is decreased. If there is no calcar-collar support, proximal support must be provided by some combination of integration of bone in the fenestrations and wedging due to the lateral-medial taper of the device. Stresses in the stem are largest when there is no wedging, but high stresses develop in the cancellous bone in the fenestrations. When there is wedging, stresses in the stem can be low, but stresses in the supporting cancellous bone can be high; additional proximal support through the fenestrations substantially reduces these bone stresses. If reduced stresses in the cancellous bone are indicative of a stable device, these mechanisms indicate that fractures of the Austin Moore prosthesis have not occurred in normally loaded hips because load was transferred primarily either through the collar or by wedging, with additional support at the fenestrations.

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“…The risk of cement fracture was assessed against fatigue. Cement cracks where found to propagate in mode I (opening mode) in stable implants with no evidence of ongoing adverse biological processes; this mode is typically related to tensile stresses [42]. The highest tensile strains induced in the cement by common activities of daily living were compared with the endurance limit for acrylic bone cement to verify that non-relevant damage accumulation was possible.…”

Section: Aseptic Looseningmentioning

confidence: 99%

Extensive Risk Analysis of Mechanical Failure for an Epiphyseal Hip Prothesis: A Combined Numerical—Experimental Approach

Martelli

Taddei

Cristofolini

et al. 2010

Proc Inst Mech Eng H

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There has been recent renewed interest in proximal femur epiphyseal replacement as an alternative to conventional total hip replacement. In many branches of engineering, risk analysis has proved to be an efficient tool for avoiding premature failures of innovative devices. An extensive risk analysis procedure has been developed for epiphyseal hip prostheses and the predictions of this method have been compared to the known clinical outcomes of a well-established contemporary design, namely hip resurfacing devices. Clinical scenarios leading to revision (i.e. loosening, neck fracture and failure of the prosthetic component) were associated with potential failure modes (i.e. overload, fatigue, wear, fibrotic tissue differentiation and bone remodelling). Driving parameters of the corresponding failure mode were identified together with their safe thresholds. For each failure mode, a failure criterion was identified and studied under the most relevant physiological loading conditions. All failure modes were investigated with the most suitable investigation tool, either numerical or experimental. Results showed a low risk for each failure scenario either in the immediate postoperative period or in the long term. These findings are in agreement with those reported by the majority of clinical studies for correctly implanted devices. Although further work is needed to confirm the predictions of this method, it was concluded that the proposed risk analysis procedure has the potential to increase the efficacy of preclinical validation protocols for new epiphyseal replacement devices.

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Fatigue Strength of Cobalt-Base Alloys with High Corrosion Resistance for Artificial Hip Joints

Cited by 34 publications

References 13 publications

Optimizing the corrosion fatigue properties of Co-Cr-Mo Hip joints

Optimizing the corrosion fatigue properties of Co-Cr-Mo Hip joints

Load transfer with the austin moore cementless hip prosthesis

Extensive Risk Analysis of Mechanical Failure for an Epiphyseal Hip Prothesis: A Combined Numerical—Experimental Approach

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