Low stiffness porous Ti structures for load-bearing implants.

The need for unique mechanical and functional properties coupled with manufacturing flexibility for a wide range of metallic implant materials necessitates the use of novel design and fabrication approaches. In this work, we have demonstrated that application of proposed design concepts in combination with laser-engineered net shaping (LENStrade mark) can significantly increase the processing flexibility of complex-shaped metallic implants with three-dimensionally interconnected, designed and functionally graded porosities down to 70vol.%, to reduce effective stiffness for load-bearing implants. Young's modulus and 0.2% proof strength of these porous Ti samples having 35-42vol.% porosity are found to be similar to those of human cortical bone.

[1]  G. K. Lewis,et al.  Practical considerations and capabilities for laser assisted direct metal deposition , 2000 .

[2]  N Kuwayama,et al.  Mechanical properties and biomechanical compatibility of porous titanium for dental implants. , 1985, Journal of biomedical materials research.

[3]  Jing Liang,et al.  Microstructures of laser-deposited Ti–6Al–4V , 2004 .

[4]  Abhay Pandit,et al.  Fabrication methods of porous metals for use in orthopaedic applications. , 2006, Biomaterials.

[5]  K. Seah,et al.  The influence of pore morphology on corrosion , 1998 .

[6]  Xin Lin,et al.  Laser rapid forming of SS316L/Rene88DT graded material , 2005 .

[7]  W. Harris,et al.  Effects on intact femora of dogs of the application and removal of metal plates. A metabolic and structural study comparing stiffer and more flexible plates. , 1978, The Journal of bone and joint surgery. American volume.

[8]  W. Head,et al.  Titanium as the material of choice for cementless femoral components in total hip arthroplasty. , 1995, Clinical orthopaedics and related research.

[9]  Peter C. Collins,et al.  Direct laser deposition of in situ Ti–6Al–4V–TiB composites , 2003 .

[10]  A. Boccaccini,et al.  Determination of stress concentration factors in porous materials , 1996 .

[11]  M. Spector,et al.  Porous titanium endosseous dental implants in Rhesus monkeys: microradiography and histological evaluation. , 1979, Journal of biomedical materials research.

[12]  H. Hahn,et al.  Preliminary evaluation of porous metal surfaced titanium for orthopedic implants. , 1970, Journal of biomedical materials research.

[13]  R. Pilliar,et al.  The fatigue strength of porous-coated Ti-6%Al-4%V implant alloy. , 1984, Journal of biomedical materials research.

[14]  H. Skinner,et al.  Fatigue properties of carbon- and porous-coated Ti-6Al-4V alloy. , 1984, Journal of biomedical materials research.

[15]  R. Chahal,et al.  Preliminary observations of bone ingrowth into porous materials. , 1976, Journal of biomedical materials research.

[16]  G. Parr,et al.  Titanium: the mystery metal of implant dentistry. Dental materials aspects. , 1985, The Journal of prosthetic dentistry.

[17]  Peter C. Collins,et al.  Direct laser deposition of alloys from elemental powder blends , 2001 .

[18]  Mitsuo Niinomi,et al.  Recent metallic materials for biomedical applications , 2002 .

[19]  R. Pilliar,et al.  A porous metal system for joint replacement surgery. , 1978, The International journal of artificial organs.

[20]  H. Fraser,et al.  Laser deposition of compositionally graded titanium–vanadium and titanium–molybdenum alloys , 2003 .

[21]  Mamoru Mabuchi,et al.  Processing of biocompatible porous Ti and Mg , 2001 .

[22]  A M Weinstein,et al.  Interface mechanics of porous titanium implants. , 1981, Journal of biomedical materials research.

[23]  Y Okazak,et al.  Surface analysis of Ti-15Zr-4Nb-4Ta alloy after implantation in rat tibia. , 2001, Biomaterials.

[24]  J. Mei,et al.  Near net shape manufacturing of components using direct laser fabrication technology , 2003 .

[25]  Andrew J. Pinkerton,et al.  Microstructure characterisation and process optimization of laser assisted rapid fabrication of 316L stainless steel , 2005 .

[26]  D. Kaplan,et al.  Porosity of 3D biomaterial scaffolds and osteogenesis. , 2005, Biomaterials.

[27]  I. Noda,et al.  The development of new titanium arc-sprayed artificial joints , 1995 .

[28]  Alexis M Pietak,et al.  Magnesium and its alloys as orthopedic biomaterials: a review. , 2006, Biomaterials.

[29]  M. Eudier.  THE MECHANICAL PROPERTIES OF SINTERED LOW-ALLOY STEELS , 1962 .

[30]  W. Harris,et al.  Comparison of bone ingrowth into cobalt chrome sphere and titanium fiber mesh porous coated cementless canine acetabular components. , 1993, Journal of biomedical materials research.

[31]  L. Dorr,et al.  Postmortem Analysis of Bone Growth into Porous-Coated Acetabular Components* , 1997, The Journal of bone and joint surgery. American volume.

[32]  H. Uhthoff,et al.  The effects of metal plates on post-traumatic remodelling and bone mass. , 1983, The Journal of bone and joint surgery. British volume.

[33]  Peter C. Collins,et al.  Microstructural evolution in laser deposited compositionally graded α/β titanium-vanadium alloys , 2003 .

[34]  Soumya Nag,et al.  A novel combinatorial approach to the development of beta titanium alloys for orthopaedic implants , 2005 .

[35]  E Schneider,et al.  A comparative study of the initial stability of cementless hip prostheses. , 1989, Clinical orthopaedics and related research.

[36]  F. Bergner,et al.  Titanium Powder Sintering for Preparation of a Porous FGM Destined as a Skeletal Replacement Implant , 1999 .

[37]  Naoyuki Nomura,et al.  Mechanical properties of porous titanium compacts prepared by powder sintering , 2003 .

[38]  L. F. Nielsen.  Elasticity and Damping of Porous Materials and Impregnated Materials , 1984 .

[39]  Joon B. Park.  Biomaterials:An Introduction , 1992 .

[40]  K. Katti,et al.  Biomaterials in total joint replacement. , 2004, Colloids and surfaces. B, Biointerfaces.

[41]  M. Niinomi,et al.  Design and mechanical properties of new β type titanium alloys for implant materials , 1998 .

[42]  John N. DuPont,et al.  Fabrication of functionally graded TiC/Ti composites by Laser Engineered Net Shaping , 2003 .