Past fixation projects

Characterising a novel carbon nano-tube reinforced bone cement

Since the discovery of multi-walled carbon nanotubes (MWCNTs) in 1991, followed by the synthesis of single-walled carbon nanotubes (SWCNTs) in 1994, a number of experimental and theoretical studies documenting their remarkable chemical, electronic and mechanical properties have appeared in the literature. It has further been shown that CNTs may offer valuable bio-functionality, with potential applications in neurological probes, biosensors, drug delivery and structural bone cements. This project aims to compare the mechanical properties of CNT containing bone cement with standard medical grade cement, assess bio-compatibility of CNT cement and model the material on a multi scale basis.

novel carbon nano-tube reinforced bone cement

Staff:
Polly Sinnett-Jones
Ian Sinclair
Martin Browne

Computational simulation of shrinkage stresses in bone cement

Residual stress is generated within the cement mantle surrounding all cemented joint replacement components as a result of mechanical property changes, chemical shrinkage and thermal expansion and subsequent contraction during cure. This initial stress distribution has been associated with pre-load cracking and may be detrimental to the longevity of the reconstruction. The current work aims to develop a method of residual stress measurement that can yield results for volume change and mechanical property evolution simultaneously by measuring all mechanical properties including real and complex modulus using ultrasound techniques.

Computational simulation of shrinkage stresses

Staff:
Adam Briscoe
Andrew New

Modelling cement mantle fatigue cracking using continuum damage mechanics

Formerly in the group, an algorithm was developed that could simulate fatigue cracking in bone cement that was capable of replicating experimental results quite well. Cement mantle fatigue cracking has been identified as a possible loosening mechanism for cemented hip replacements. The aim of this project is to utilise the cement fatigue algorithm to compare the long term cement mantle failure of two commercially available hip prosthesis designs - the Exeter (Stryker) and the C-Stem (DePuy). These stems both have a highly polished surface finish and achieve stability by wedging tighter in the cement under load. The Exeter is known as a double taper design, whereas the C-Stem has a third taper towards the medial side of the cross section and is therefore unimaginatively called a triple taper design.

Modelling cement mantle fatigue cracking

Staff:
Jonathan Jeffers
Mike Wroblewski
Mark Taylor