Article

Characteristics of bone ingrowth and interface mechanics of a new porous tantalum biomaterial. J Bone Joint Surg 81-B:907-914

Montreal General Hospital and McGill University, Québec, Canada.
The Bone & Joint Journal (Impact Factor: 3.31). 10/1999; 81(5):907-14. DOI: 10.1302/0301-620X.81B5.9283
Source: PubMed

ABSTRACT

We have studied the characteristics of bone ingrowth of a new porous tantalum biomaterial in a simple transcortical canine model using cylindrical implants 5 x 10 mm in size. The material was 75% to 80% porous by volume and had a repeating arrangement of slender interconnecting struts which formed a regular array of dodecahedron-shaped pores. We performed histological studies on two types of material, one with a smaller pore size averaging 430 microm at 4, 16 and 52 weeks and the other with a larger pore size averaging 650 microm at 2, 3, 4, 16 and 52 weeks. Mechanical push-out tests at 4 and 16 weeks were used to assess the shear strength of the bone-implant interface on implants of the smaller pore size. The extent of filling of the pores of the tantalum material with new bone increased from 13% at two weeks to between 42% and 53% at four weeks. By 16 and 52 weeks the average extent of bone ingrowth ranged from 63% to 80%. The tissue response to the small and large pore sizes was similar, with regions of contact between bone and implant increasing with time and with evidence of Haversian remodelling within the pores at later periods. Mechanical tests at four weeks indicated a minimum shear fixation strength of 18.5 MPa, substantially higher than has been obtained with other porous materials with less volumetric porosity. This porous tantalum biomaterial has desirable characteristics for bone ingrowth; further studies are warranted to ascertain its potential for clinical reconstructive orthopaedics.

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    • "Porous surfaces have been shown to have a superior bony response than surfaces treated by grit-blasting alone, highlighting that surface texture is important in achieving good biological fixation (Dávid et al. 1995). Potential problems with the use of coatings to create surface roughness and porosity include coating delamination and cracking under fatigue (Murr et al. 2012), as well as a limit to the volume of porosity achieved by these methods (Bobyn et al. 1999). To overcome such issues, additive manufacture (AM) has become an area of growing interest for manufacturing parts with complex surface geometries. "
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