[Surface characterisation of shot peened implants with glas beads in total hip arthroplasty]

Alumina-blasting is used to create a rougher surface of Titanium implants in cementless total hip arthroplasty to achieve a better bony ingrowth. An increasing number of publications in maxillofacial surgery and orthopaedic surgery show that there is a significant contamination in Alumina blasted surfaces. Latest research published an effect of contaminant particles on early loosening of endoprostheses associated with third body wear. Due to our knowledge no previous study analysed surface contamination of hip endoprostheses with glass beads. Aim of our work was to evaluate the percentage of contaminated surface of hip endoprostheses with glass beads.

The surface of 5 Ti-VPS sprayed Phoenix cups and 5 morse-taper-junctions of the MRP-Titan revision stem (Peter Brehm, Chirurgie Mechanik, Weisendorf) were analysed with respect to glass particles. Shot peening was performed with glass beads "BALLOTINI" MGL, Fa. Würth Strahlmittel. A field emission scanning electron microscopy (LEO 1525) was used for the detection of the glass-particles on the implant surface with a backscattered electron detector. The particle covering position was calculated by means of an imaging analyze software (analySIS, Soft Imaging System GmbH).

The surface of the Ti-VPS sprayed Phoenix cups showed a contaminated area at a mean of 9.2 +/- 1.3 %, morse-taper-junctions of the MRP-Titan stem at a mean of 9.6 +/- 2.1 % with glass particle contact.

The results of this study clearly show that there is a contamination of shot pinned Titanium surfaces with glass particles in a significant percentage. With respect to third body wear in total hip arthroplasty further studies are necessary to minimize contamination.