Selective laser melted prototype of original minimally invasive resurfacing hip endoprosthesis

Abstract

PurposeThe aim of this paper is to present the main results of a research project finished in 2008 which concerned the selective laser melted (SLM) prototype of a new kind of minimally invasive resurfacing hip arthroplasty (RHA) endoprosthesis with the original multi‐spiked connecting scaffold (MSC‐Scaffold). Previous attempts performed in pre‐Direct Metal Manufacturing (DMM) era demonstrated that it was impossible to manufacture suitable prototypes of this RHA endoprosthesis (especially of the MSC‐Scaffold) using traditional machining technologies. Owing to an extensive development of DMM technologies observed in recent years the manufacturing of such prototypes has become possible.Design/methodology/approachComputer aided design models of pre‐prototypes and the prototype of the RHA endoprosthesis with MSC‐Scaffold were designed and initially optimized within the claims and the general assumptions of international patents by Rogala. Prototyping in SLM technology was subcontracted to SLM Tech Center (Paderborn, Germany). Macroscopic and SEM microscopic evaluation of the MSC‐Scaffold was performed using SLM manufactured prototypes and paying special attention to the quality and precision of manufacturing.FindingsIt was found that SLM can be successfully applied to manufacturing of prototypes of the original minimally invasive RHA endoprosthesis. The manufacturing quality of the 3D spikes system of the MSC‐Scaffold, which mimics the interdigitations of articular subchondral bone, has been proved to be geometrically corresponding to the biological original. Nevertheless, some pores and non‐melted zones were found in SLM prototyped RHA endoprosthesis cross‐sections which need to be eliminated to minimize the potential risk of clinical failure.Research limitations/implicationsThe presented case study was performed with a limited number of samples. More research needs to be performed on the rapid prototyped samples including microstructural and mechanical tests. The results may enable the optimization of the SLM manufacturing process of the prototypes of the minimally invasive RHA endoprosthesis with MSC‐Scaffold.Practical implicationsThe SLM can be considered as potentially suitable for the fabrication of patient‐fitted minimally invasive RHA endoprostheses with MSC‐Scaffold.Originality/valueFor the first time, largely owing to SLM technology, it was possible to manufacture the prototype of the original minimally invasive RHA endoprosthesis with MSC‐Scaffold suitable for further research.