Quantitation of Bone Ingrowth into Porous Implants Submitted to Pulsed Electromagnetic Fields

Abstract

This study has been conducted to evaluate the effect of electromagnetic fields of low frequency and low amplitude on bone growth into porous implants in order to consider a potential clinical application—that is, improvement of the anchorage in articular prostheses intended to be implanted without cement. The experiment has been conducted in vivo on sheep, using porous implants made of Ti-6Al-4V alloy implanted in the cortical bone. The electromagnetic stimulation was provided by external generators connected to Helmholtz coils placed on each side of the stimulated limb. The results of this stimulation have been quantified by measuring the shear properties of the bone/implant interface and the bone regrowth around and into the porous implants in control and stimulated animals. These results were measured in a total of 16 animals sacrificed at three and five weeks after implantation. No improvement was shown in the mechanical properties of the bone/implant interface. On the other hand, the depth of bone tissue ingrowth and the ratio of bony ingrowth within the implant to the total new bone formation increased at five weeks (13 and 20%, respectively) when electromagnetic fields were used. However, this increase is not statistically significant.

Porous titanium scaffolds produced by powder metallurgy for biomedical applications

“…This powder metallurgy technique can be used to produce dense titanium samples without additional materials, or scaffolds of porous titanium with controlled porosity, pore size and morphology, which is ensured through the selection of appropriate spacers 1,14,18,27 . Furthermore, the main advantage of this technique it allows for the preparation of implants with interconnected pores resembling a three-dimensional network 17,18,24 , a feature that was observed in this study. Another important aspect to control during the preparation of a Ti powder metallurgy product is its oxygen content 35 ; hence, all the titanium samples were manufactured under vacuum (10 -7 torr).…”

“…The majority of earlier studies reported porous structures with pore diameters of 100 to 500 µm 10,11,[24][25][26][27][28] , and a total porosity of approximately 40% 10,11,18,[24][25][26][27] . A suitable porous network is required to promote extensive vascularization for bone ingrowth, rapid bone regeneration and good implant integration.…”