Over a physiologically reasonable range of stress-intensity factor, fatigue crack propagation rates for Sub- cement were higher by a factor of 25+/-19. Static mechanical properties were approximately equivalent to normal cement. This reduced the molecular weight of the inter-bead matrix without changing reaction-rate or handling characteristics. Sub- cement was made by adding a chain-transfer agent to standard polymethylmethacrylate (PMMA) cement. We formulated bone cement with degraded fatigue fracture properties (Sub- cement) such that long-term fatigue could be simulated in short-term cadaver tests.

Pre-clinical screening of cemented implant systems could be improved by modeling the longer-term response of the implant/cement/bone construct to cyclic loading. Race, Amos Miller, Mark A Mann, Kenneth A Published by Wiley Periodicals, Inc.Ī modified PMMA cement (Sub- cement) for accelerated fatigue testing of cemented implant constructs using cadaveric bone. Contact between the cement and underlying cortex may dramatically reduce trabecular bone stresses surrounding the cement, and this contact depends on bone shape, cement amount, and implant positioning. The amount of trabecular bone with high stress was strongly negatively correlated with both cement volume and contact between the cement and cortex (r =â€‰-0.85 and -0.84, p implant-cortex distance.

Correlation analysis was completed across all specimens for pairs of morphological and mechanical variables. Axial loading was applied to the implant of each model and stress distributions were characterized. Bone volume fraction, glenoid width, implant-cortex distance, cement volume, cement-cortex contact, and cement-bone interface area were measured. Specimens were imaged by micro-CT, and subject-specific finite element models were developed. Eight glenoid cadavers were implanted with a cemented central peg implant. Utilizing high resolution finite element analysis of a series of implanted cadaver glenoids, the objective of this study was to quantify relationships between construct morphology and resulting mechanical stresses in cement and trabeculae. Wee, Hwabok Armstrong, April D Flint, Wesley W Kunselman, Allen R Lewis, Gregory SĪseptic loosening of cemented joint replacements is a complex biological and mechanical process, and remains a clinical concern especially in patients with poor bone quality.

Peri- implant stress correlates with bone and cement morphology: Micro-FE modeling of implanted cadaveric glenoids.

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