Fatigue properties of acrylic bone cement:S-N,P-N, andP-S-N data

Abstract

The determination of the fatigue properties of a material is a fundamental criteria in the engineering design process. The fatigue properties are governed by a number of factors, one of which is the inherent scatter in the data. In order to take into account this scatter in the results, the concept of the probability of failure (P) is introduced and interconnected with the well known stress (S) versus number of cycles to failure (N) data. This report determines the S-N curve, P-N curve, and P-S-N contour for the three leading acrylic bone cements: Surgical Simplex P, Zimmer LVC, and Zimmer Regular. Tensile specimens were fabricated according to ASTM D638 specifications and tested in uniaxial, zero-tension fatigue. The resulting stress versus number of cycles to failure data was subjected to a nonlinear least-squares analysis to determine the mathematical expression of the fatigue curve. Statistical analysis showed excellent fit of the data to the predicted curve for estimation of the endurance limit of each cement. The results indicated that Zimmer LVC had the highest endurance limit while the limit of Simplex-P and Zimmer Regular were significantly lower. No significant difference was noted in the endurance limit between Simplex-P and Zimmer Regular. The probability of failure at each stress level was determined with respect to fatigue distribution functions. Using the normal distribution function and previous S-N data, the P-S-N contour was generated for each cement. The P-S-N contour fully describes the fatigue characteristics of the material.

Nanoparticulate fillers improve the mechanical strength of bone cement

“…Commercial acrylic or polymethylmethacrylate (PMMA) bone cements have been used successfully in total joint replacement surgery for over four decades, and have been thoroughly characterized (Saha and Pal 1984, Krause and Mathis 1988, Demian and McDermott 1998, Lewis 2003. Fatigue and fracture properties of cement continue to be investigated since cement failure can lead to undesirable particle shedding or fracture.…”

Influence of test specimen fabrication method and cross-section configuration on tension–tension fatigue life of PMMA bone cement

“…Depending on the patient's age and activity, their hips and knees typically encounter between 0.5 to 2 million load cycles per year (Wallbridge and Dowson, 1982) and in cemented joint replacements these are transmitted by the cement mantle. Despite theories stating bone cement surrounding an arthroplasty is subjected to a combination of fatigue loading modes (Krause and Mathis, 1988;Lewis and Nyman, 2000;Lewis et al, 2003;Miller et al, 2011;Dunne et al, 2014), the material is thought to fracture primarily due to the tensile phases of the applied stresses (Gates et al, 1983, Harper andBonfield, 2000). Dunne et al (2014) point out that while in vitro tension can be a more important factor inducing cement failure than compression, both loading modes occur.…”

Dynamic creep behavior of acrylic bone cement

“…One should realize that both the creep and the elastic strains depend on stress level. The latter has a linear relationship, while the relationship of the creep strain on stress level can be described using Equation (4). At a stress level of 15 MPa it takes about 4000 h before the creep strain exceeds the elastic strain.…”