Structural-Geometric Functionalization of the Additively Manufactured Prototype of Biomimetic Multispiked Connecting Ti-Alloy Scaffold for Entirely Noncemented Resurfacing Arthroplasty Endoprostheses.

Ryszard Uklejewski,Adam Patalas,Mariusz Winiecki,Piotr Rogala

doi:10.1155/2017/5638680

Abstract

The multispiked connecting scaffold (MSC-Scaffold) prototype, inspired by the biological system of anchorage of the articular cartilage in the periarticular trabecular bone by means of subchondral bone interdigitations, is the essential innovation in fixation of the bone in resurfacing arthroplasty (RA) endoprostheses. The biomimetic MSC‐Scaffold, due to its complex geometric structure, can be manufactured only using additive technology, for example, selective laser melting (SLM). The major purpose of this work is determination of constructional possibilities for the structural-geometric functionalization of SLM‐manufactured MSC‐Scaffold prototype, compensating the reduced ability—due to the SLM technological limitations—to accommodate the ingrowing bone filling the interspike space of the prototype, which is important for the prototype bioengineering design. Confocal microscopy scanning of components of the SLM‐manufactured prototype of total hip resurfacing arthroplasty (THRA) endoprosthesis with the MSC‐Scaffold was performed. It was followed by the geometric measurements of a variety of specimens designed as the fragments of the MSC-Scaffold of both THRA endoprosthesis components. The reduced ability to accommodate the ingrowing bone tissue in the SLM‐manufactured prototypes versus that in the corresponding CAD models has been quantitatively determined. Obtained results enabled to establish a way of compensatory structural‐geometric functionalization, allowing the MSC‐Scaffold adequate redesigning and manufacturing in additive SLM technology.

Highlights

The extensive development of additive technologies made it possible to design and to build the complex freeform structural constructs of metal or alloy powders
In case of bone ingrowth into the porous coatings and the porous scaffolds, it has to be underlined that the morphological or the topological factors are the most important factors influencing bone ingrowth [15], and this structural-geometric proosteoconductive potential can be controlled by additive manufacturing [16, 17]. 3D pores as the microenvironment of bone ingrowth play an important role in osteoconductivity and bone formation
The CAD models of femoral and acetabular components of our total hip resurfacing arthroplasty (THRA) endoprosthesis prototype [14] were designed as solids of revolution generated by revolving the specific contour in the three-dimensional space about the axis coplanar with contour

Summary

Introduction

The extensive development of additive technologies made it possible to design and to build the complex freeform structural constructs of metal or alloy powders. A very good example of such promising perspective for artificial joint development is the biomimetic Ti-alloy prototype of the multispiked connecting scaffold (MSC-Scaffold) for entirely noncemented and bone tissuepreserving fixation on the periarticular trabecular bone of both components of hip resurfacing arthroplasty (RA) endoprostheses This biomimetic fixation technique was invented by Rogala [8,9,10], designed and manufactured using Selective Laser Melting (SLM) technology, and developed by our research team [11,12,13,14]. The structural-geometric pro-osteoconduction potential of the MSC-Scaffold is the most important factor influencing the bone ingrowth and affecting the periimplant bone tissue regeneration to provide the successive bone-implant fixation

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