Interface Mechanics and Bone Growth into Porous Co???Cr???Mo Alloy Implants

Cook, Stephen D.; Walsh, Kimberly A.; Haddad, Ray J.

doi:10.1097/00003086-198503000-00037

Cited by 79 publications

(41 citation statements)

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“…Porous coatings provide a structural basis for bone ongrowth and thereby mechanical anchorage mediated by bone tissue (Cook, Walsh and Haddad 1985;Engh et al 1994). RhTGF-β1 will also stimu- Photomicrographs showing ongrowth to an implant without rhTGF-β1 stimulation (a) and to an implant with 0.3 µg rhTGF-β1 stimulation (b).…”

Section: Discussionmentioning

confidence: 99%

TRANSFORMING GROWTH FACTOR-β1 STIMULATES BONE ONGROWTH TO WEIGHT-LOADED TRICALCIUM PHOSPHATE COATED IMPLANTS

Lind¹,

Overgaard²,

Ongpipattanakul³

et al. 1996

The Journal of Bone and Joint Surgery. British volume

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Bone growth into cementless prosthetic components is compromised by osteoporosis, by any gap between the implant and the bone, by micromotion, and after the revision of failed prostheses. Recombinant human transforming growth factor-β β β β1 (rhTGF-β1) has recently been shown to be a potent stimulator of bone healing and bone formation in various models in vivo.We have investigated the potential of rhTGF-β1, adsorbed on to weight-loaded tricalcium phosphate (TCP) coated implants, to enhance bone ongrowth and mechanical fixation. We inserted cylindrical grit-blasted titanium alloy implants bilaterally into the weightbearing part of the medial femoral condyles of ten skeletally mature dogs. The implants were mounted on special devices which ensured stable weight-loading during each gait cycle. All implants were initially surrounded by a 0.75 mm gap and were coated with TCP ceramic.Each animal received two implants, one with 0.3 µg rhTGF-β β β β1 adsorbed on the ceramic surface and the other without growth factor. Histological analysis showed that bone ongrowth was significantly increased from 22 ± 5.6% bone-implant contact in the control group to 36 ± 2.9% in the rhTGF-β β β β stimulated group, an increase of 59%. The volume of bone in the gap was increased by 16% in rhTGF-β β β β1-stimulated TCP-coated implants, but this difference was not significant.Mechanical push-out tests showed no difference in fixation of the implant between the two groups. Our study suggests that rhTGF-β β β β1 adsorbed on TCPceramic-coated implants can enhance bone ongrowth.

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Section: Discussionmentioning

confidence: 99%

TRANSFORMING GROWTH FACTOR-β1 STIMULATES BONE ONGROWTH TO WEIGHT-LOADED TRICALCIUM PHOSPHATE COATED IMPLANTS

Lind¹,

Overgaard²,

Ongpipattanakul³

et al. 1996

The Journal of Bone and Joint Surgery. British volume

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“…Porous coatings can also be manufactured with other technologies e.g. : sintering powders, fibres or beads on implant surface [5], wire mesh diffusion bonding [6], powder metallurgy [7,8], etc. The variety of types of porous coatings available for biologic ingrowth is presented in Figure 1.…”

Section: Introductionmentioning

confidence: 99%

Computer Aided Stereometric Evaluation of Porostructuralosteoconductive Properties of Intra-Osseous Implant Porous Coatings

Uklejewski¹,

Winiecki²,

Rogala³

2013

Metrology and Measurement Systems

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The proper interaction of bone tissue -the natural porous biomaterial -with a porous coated intra-osseous implant is conditioned, among others, by the implant porous coating poroaccessibility for bone tissue adaptive ingrowth. The poroaccessibility is the ability of implant porous coating outer layer to accommodate the ingrowing bone tissue filling in its pore space and effective new formed bone mineralizing in the pores to form a biomechanically functional bone-implant fixation. The functional features of the microtopography of intra-osseous implant porous surfaces together with the porosity of pore space of the outer layer of the porous coating are called by bioengineers the porostructural-osteoconductive properties of the porous coated implant. The properties are crucial for successful adaptive bone tissue ingrowth and further long-term (secondary) biomechanical stability of the boneimplant interface. The poroaccessibility of intra-osseous implants porous coating outer layers is characterized bythe introduced in our previous papers -set of stereometric parameters of poroaccessibility: the effective volumetric porosity I Vef , the index of the porous coating space capacity V PM , the representative surface porosity I Srep , the representative pore size p Srep , the representative angle of the poroaccessibility :rep and the bone-implant interface adhesive surface enlargement index \. Presented in this paper, an original method of evaluation of the porostructural-osteoconductive properties of intra-osseous implant porous coatings outer layer by means of the parameters of poroaccessibility was preliminary verified during experimental tests performed on the representative examples of porous coated femoral stems and acetabular cups of various hip endoprostheses. The computer-aided stereometric evaluation of the microstructure of implant porous coatings outer layer can be now realized by the authoring application software PoroAccess_1.0 elaborated in our research team in Java programming language.

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“…The pore size for the controls in the present study was 229-344 um. Cook et al, 3 using very similar mechanical testing conditions, measured a stress of 21.2 ± 9.2 MPa (12 weeks) for porous CoCrMo alloy implants with bead diameter ranging from 355-500 um. In a later study, they observed a stress of 18.8 ± 3.7 MPa (12 weeks, n = 12) for a bilayered titanium porous beaded coating with a pore size of 275 um.…”

Section: Discussionmentioning

confidence: 99%

“…This sectioning yielded two specimens (medial and lateral) for mechanical testing. This method, devised by Cook et al, 3 provides the mechanical test specimens with uniform measurable cortical thickness for calculation of shear stress, and a flat surface for the pushout test.…”

Section: Mechanical Evaluationmentioning

confidence: 99%

“…Various surface treatments have been investigated in efforts to optimize ingrowth, and thereby effectively stabilize the implant. Such methods include texturing of the metal surface by grit blasting, 1 as well as the addition of layers of sintered beads of different sizes, 2,3 or sintered wire mesh. 4 Pore size in porous coated implants has been investigated and optimized for bone ingrowth.…”

Section: Introductionmentioning

confidence: 99%

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Three-dimensional printing and porous metallic surfaces: A new orthopedic application

Melican

Zimmerman

Dhillon³

et al. 2001

J. Biomed. Mater. Res.

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As-cast, porous surfaced CoCr implants were tested for bone interfacial shear strength in a canine transcortical model. Three-dimensional printing (3DP) was used to create complex molds with a dimensional resolution of 175 microm. 3DP is a solid freeform fabrication technique that can generate ceramic pieces by printing binder onto a bed of ceramic powder. A printhead is rastered across the powder, building a monolithic mold, layer by layer. Using these 3DP molds, surfaces can be textured "as-cast," eliminating the need for additional processing as with commercially available sintered beads or wire mesh surfaces. Three experimental textures were fabricated, each consisting of a surface layer and deep layer with distinct individual porosities. The surface layer ranged from a porosity of 38% (Surface Y) to 67% (Surface Z), whereas the deep layer ranged from 39% (Surface Z) to 63% (Surface Y). An intermediate texture was fabricated that consisted of 43% porosity in both surface and deep layers (Surface X). Control surfaces were commercial sintered beaded coatings with a nominal porosity of 37%. A well-documented canine transcortical implant model was utilized to evaluate these experimental surfaces. In this model, five cylindrical implants were placed in transverse bicortical defects in each femur of purpose bred coonhounds. A Latin Square technique was used to randomize the experimental implants left to right and proximal to distal within a given animal and among animals. Each experimental site was paired with a porous coated control site located at the same level in the contralateral limb. Thus, for each of the three time periods (6, 12, and 26 weeks) five dogs were utilized, yielding a total of 24 experimental sites and 24 matched pair control sites. At each time period, mechanical push-out tests were used to evaluate interfacial shear strength. Other specimens were subjected to histomorphometric analysis. Macrotexture Z, with the highest surface porosity, failed at a significantly higher shear stress (p = 0.05) than the porous coated controls at 26 weeks. It is postulated that an increased volume of ingrown bone, resulting from a combination of high surface porosity and a high percentage of ingrowth, was responsible for the observed improvement in strength. Macrotextures X and Y also had significantly greater bone ingrowth than the controls (p = 0.05 at 26 weeks), and displayed, on average, greater interfacial shear strengths than controls, although they were not statistically significant.

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Interface Mechanics and Bone Growth into Porous Co???Cr???Mo Alloy Implants

Cited by 79 publications

References 0 publications

TRANSFORMING GROWTH FACTOR-β1 STIMULATES BONE ONGROWTH TO WEIGHT-LOADED TRICALCIUM PHOSPHATE COATED IMPLANTS

TRANSFORMING GROWTH FACTOR-β1 STIMULATES BONE ONGROWTH TO WEIGHT-LOADED TRICALCIUM PHOSPHATE COATED IMPLANTS

Computer Aided Stereometric Evaluation of Porostructuralosteoconductive Properties of Intra-Osseous Implant Porous Coatings

Three-dimensional printing and porous metallic surfaces: A new orthopedic application

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