Engineering news
Surgeons have successfully used 3D printing to make “significant advances” in the design of hip replacements, but they have struggled to devise easy ways of checking the designs without destroying the parts in the process.
Doctors use bone-mimetic biomaterials, as their mechanical properties and porous structure allows bone ‘ingrowth’ and helps fix implants in place. For parts to be used, however, surgeons need a very high degree of quality assurance.
To tackle the issue, researchers from the Warwick Manufacturing Group at the University of Warwick used their X-Ray Computed Topography equipment – normally used to research and test automotive components – to help test parts from orthopaedic specialist Corin Ltd without destroying them.
“We were delighted to be able to test this method on an innovative hip prosthesis cup prototype,” said professor Mark Williams from the WMG’s Centre for Imaging, Metrology and Additive Manufacturing.
The researchers examined a prototype artificial acetabular cup, the cup-shaped socket of the hip joint. The technology produced a scan of fine 2D slices made up of 3D pixels, called voxels, at a resolution of 43 microns, or millionths of a metre.
Grey scale tones revealed the atomic density of the material at precise points, with air showing black and higher density material showing as light grey. Operators can analyse the 3D data further to provide dimensional information, volumetric analysis and other measures.
The scanning technology gave a precise validation that pores and struts within the material were optimised for integration into a patient’s body.
“We have shown that this non-destructive, non-contact examination method can provide very detailed information on the interconnectivity of the porous structure,” said professor Williams. “In particular, this leads to much easier identification of weak regions that could inhibit a successful bond with the bone.”
The research was published in Additive Manufacturing.
Content published by Professional Engineering does not necessarily represent the views of the Institution of Mechanical Engineers.