Surface Texture Evaluation of Additively Manufactured Metallic Cellular Scaffolds for Acetabular Implants Using X-ray Computed Tomography

The surface topography of acetabular implants plays a key role in providing cell attachment and proliferation. The measurement and characterisation of the surface texture of the cellular scaffold layer on the acetabular cup are very difficult due to the 3D nature of scaffold geometry. It is proposed to use X-ray computed tomography (XCT) to measure the surface texture of an electron beam melting-produced titanium acetabular cup. The surface texture of its cellular scaffold is evaluated using the newly developed 3D surface texture parameters, which allows surface characterisation on 3D triangular mesh surfaces. Four commonly used height parameters, i.e. the arithmetical mean height Sa, the root mean square height Sq, the skewness Ssk and the kurtosis Sku, are calculated from surface patches extracted from the XCT scanned triangular mesh surface. In addition, the surface peak density and pit density, which are more related to cell communication and proliferation, are estimated based on the 3D watershed segmentation. The Wolf pruning with an empirical threshold 12 µm is used to control the over-segmentation.