Structure, metallurgy, and mechanical properties of a porous tantalum foam

Coatings such as diamond-like carbon (DLC) and titanium nitride (TiN) are employed in joint implants due to their excellent tribological properties. Recently, graphite-like carbon (GLC) and tantalum (Ta) have been proven to have good potential as coating as they possess mechanical properties similar to bones—high hardness and high flexibility. The purpose of this systematic literature review is to summarize the coating techniques of these four materials in order to compare their mechanical properties and tribological outcomes. Eighteen studies published between January 2000 and February 2013 have met the inclusion criteria for this review. Details of their fabrication parameters, material and mechanical properties along with the tribological outcomes, such as friction and wear rate, were identified and are presented in a systematic way. Although experiment conditions varied, we conclude that Ta has the lowest wear rate compared to DLC, GLC and TiN because it has a lower wear rate with high contact pressure as well as higher hardness to elasticity ratio. However, a further tribology test is needed in an environment which replicates artificial joints to confirm the acceptability of these findings.

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“…GLC possess both hardness and flexibility [19]. Porous Ta is found to have a similar material structure to bone [20, 21]. …”

Section: Resultsmentioning

confidence: 99%

Effects of surface coating on reducing friction and wear of orthopaedic implants

Ching

Choudhury

Nine

et al. 2014

Science and Technology of Advanced Materials

215

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“…PMMA, a polymer used as bone cement, did not trend towards an endurance limit and possessed much lower fatigue strength than PEEK-SP in the high cycle regime. Similarly, porous tantalum, a bulk porous metallic implant material used clinically to facilitate osseointegration, has fatigue performance almost 43% lower than surface porous PEEK at similar cycle number [39]. …”

Section: Discussionmentioning

confidence: 99%

“…S-N curve comparing the fatigue behavior of PEEK-SP using the load-bearing, A LB , and the total area, A T , to solid PEEK, PMMA, and bulk porous tantalum tested by another group [39]. Arrows denote tests that were halted after reaching 10 6 cycles (solid PEEK, PEEK-SP), which is defined as the runout stress.…”

Section: Figmentioning

confidence: 99%

High-strength, surface-porous polyether-ether-ketone for load-bearing orthopedic implants

Evans

Torstrick

Lee³

et al. 2015

Acta Biomaterialia

163

138

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Despite its widespread clinical use in load-bearing orthopaedic implants, polyether-ether-ketone (PEEK) is often associated with poor osseointegration. In this study, a surface porous PEEK material (PEEK-SP) was created using a melt extrusion technique. The porous layer thickness was 399.6±63.3 µm and possessed a mean pore size of 279.9±31.6 µm, strut spacing of 186.8±55.5 µm, porosity of 67.3±3.1%, and interconnectivity of 99.9±0.1%. Monotonic tensile tests showed that PEEK-SP preserved 73.9% of the strength (71.06±2.17 MPa) and 73.4% of the elastic modulus (2.45±0.31 GPa) of as-received, injection molded PEEK. PEEK-SP further demonstrated a fatigue strength of 60.0 MPa at one million cycles, preserving 73.4% of the fatigue resistance of injection molded PEEK. Interfacial shear testing showed the pore layer shear strength to be 23.96±2.26 MPa. An osseointegration model in the rat revealed substantial bone formation within the pore layer at 6 and 12 weeks via µCT and histological evaluation. Ingrown bone was more closely apposed to the pore wall and fibrous tissue growth was reduced in PEEK-SP when compared to non-porous PEEK controls. These results indicate that PEEK-SP could provide improved osseointegration while maintaining the structural integrity necessary for load-bearing orthopaedic applications.

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“…Trabecular metal (Zimmer, Warsaw, IN) is a new material available for use in uncemented total knee arthroplasty. It is a porous biomaterial with morphology and mechanical properties resembling those of trabecular bone (Bobyn et al 1999a,b, Zardiackas et al 2001, Levine et al 2006, Balla et al 2010). In a previous paper, we presented the 2-year implant migration results of the trabecular metal tibial monoblock component using radiostereometric analysis (RSA) (Dunbar et al 2009).…”

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confidence: 99%

Continued stabilization of trabecular metal tibial monoblock total knee arthroplasty components at 5 years—measured with radiostereometric analysis

Wilson¹,

Richardson

Hennigar

et al. 2011

Acta Orthopaedica

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Background and purpose The trabecular metal tibial monoblock component (TM) is a relatively new option available for total knee arthroplasty. We have previously reported a large degree of early migration of the trabecular metal component in a subset of patients. These implants all appeared to stabilize at 2 years. We now present 5-year RSA results of the TM and compare them with those of the NexGen Option Stemmed cemented tibial component (Zimmer, Warsaw IN).Patients and methods 70 patients with osteoarthritis were randomized to receive either the TM implant or the cemented component. RSA examination was done postoperatively and at 6 months, 1 year, 2 years, and 5 years. RSA outcomes were translations, rotations, and maximum total point motion (MTPM) of the components. MTPM values were used to classify implants as “at risk” or “stable”.Results At the 5-year follow-up, 45 patients were available for analysis. There were 27 in the TM group and 18 in the cemented group. MTPM values were similar in the 2 groups (p = 0.9). The TM components had significantly greater subsidence than the cemented components (p = 0.001). The proportion of “at risk” components at 5 years was 2 of 18 in the cemented group and 0 of 27 in the TM group (p = 0.2).Interpretation In the previous 2-year report, we expressed our uncertainty concerning the long-term stability of the TM implant due to the high initial migration seen in some cases. Here, we report stability of this implant up to 5 years in all cases. The implant appears to achieve solid fixation despite high levels of migration initially.

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Structure, metallurgy, and mechanical properties of a porous tantalum foam

Cited by 321 publications

References 5 publications

Effects of surface coating on reducing friction and wear of orthopaedic implants

Effects of surface coating on reducing friction and wear of orthopaedic implants

High-strength, surface-porous polyether-ether-ketone for load-bearing orthopedic implants

Continued stabilization of trabecular metal tibial monoblock total knee arthroplasty components at 5 years—measured with radiostereometric analysis

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