Trabecular metal-backed glenoid component - does this innovation add value for the patient with shoulder arthritis?

Two-year results of a multi-centre, randomized controlled trial comparing a second-generation uncemented trabecular metal-backed versus cemented polyethylene glenoid component in total shoulder arthroplasty 

These authors report two-year postoperative findings from a randomized controlled trial (RCT) comparing  disease-specific quality of life (QOL), clinical, patient-reported, and radiological outcomes in patients undergoing a total shoulder arthroplasty (TSA) with a Zimmer/Biomet cemented polyethylene glenoid (POLY) component to those receiving a second-generation Zimmer/Biomet uncemented trabecular metal (TM) glenoid shown below

A total of 93 patients were randomized (46 TM; 47 POLY). 

No significant or clinically important differences were found with patient-reported outcomes at 24-month follow-up.  Grade 1 metal debris was observed in three (6.5%) patients with TM glenoids.

There was no radiological evidence of glenoid component migration in either group.  Radiolucent lines around the glenoid implant were observed in eight patients (17%) in the POLY group but the severity was minor in most patients (6 = 1 mm; 1 = 2 mm; 1 = 6 mm). In the TM group, ‘possible’ lucency around the glenoid was reported in one patient.

With respect to the humeral stem, subsidence was observed in four (8.5%) patients in the POLY group and seven (15.2%) in the TM group.  Radiolucent lines  were observed in three (6.4%) and five (10.9%) patients in the POLY and TM groups, respectively.

Comment: This is a well-done randomized controlled trial. The two year data do not demonstrate an advantage of the metal-backed component over an all polyethylene component. The authors noted metal debris in three patients, but this did not appear to be associated with inferior outcomes. 

In their discussion they pointed out that an issue with this metal backed component is that should revision, for example to a reverse total shoulder because of cuff failure, is difficult because of the large glenoid bone defect left after removal of the metal-backed ingrowth glenoid component.

While metal backed glenoid components tend to have low rates of radiolucent lines and loosening, they have been found to have higher revision rates in large population studies such as that of the Australian Registry

Metal back glenoid components have also been found to have failure modes that differ from those of all-polyethylene components, see: Metal-Backed Glenoid Components Have a Higher Rate of Failure and Fail by Different Modes in Comparison with All-Polyethylene Components: A Systematic Review

By contrast, long-term revision rates for all-polyethylene glenoid components using modern materials and techniques appear to be low, as shown by these data from the Australian Registry

At present, evidence is lacking to support the view that metal-backed glenoids offer increased value to the patient with glenohumeral arthritis in comparison to an all-polyethylene component. 

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Here are some videos that are of shoulder interest

Shoulder arthritis - what you need to know (see this link)

The smooth and move for irreparable cuff tears (see this link)

The total shoulder arthroplasty (see this link).

The ream and run technique is shown in this link.

The cuff tear arthropathy arthroplasty (see this link).

The reverse total shoulder arthroplasty (see this link).

Shoulder rehabilitation exercises (see this link).

Metal back, uncemented glenoid components in total shoulder arthroplasty?

 Cemented vs. uncemented glenoid fixation in total shoulder arthroplasty for osteoarthritis: a New Zealand Joint Registry study

These authors used the New Zealand Joint Registry (NZJR) data from from January 2000 to December 2017 to compare all-cause revision rates and functional scores for total shoulder arthroplasty (TSA) and investigated the trends of glenoid fixation used in New Zealand.

A total of 2613 TSAs were performed for OA during the study period, representing 85.0% of all TSAs in New Zealand. 69.6% of glenoids were cemented and 30.4% uncemented. The most common uncemented MB glenoids were the SMR 86.6% (LimaCorporate) and the Bigliani-Flatow.

 The most common cemented glenoid components were Global (DePuy) 49.8% and Aequalis.

 

The revision rate for TSA with uncemented glenoids was significantly higher at 2.03 compared with cemented at 0.41 per 100 component-years. 

The hazard ratio was 5.0 for revision of uncemented glenoids. 

The most common mode of failure was glenoid loosening in cemented glenoids (44.4%), and component failure in uncemented (34.8%). 

Revision for rotator cuff, deep infection, and instability were comparable between

groups. 

When excluding SMR L2, uncemented MB glenoid all-cause revision rates remained significantly higher than cemented (1.42 vs. 0.41 per 100 component-years, P < .001). SMR L1 uncemented MB glenoids had a higher revision rate than the non-SMR uncemented glenoids (1.61 vs. 0.18 per 100 component-years. 

Uncemented glenoid use peaked in New Zealand in 2011 at 46.7% of TSAs but declined to 20.1% in 2017.

Comment: These data reinforce prior studies showing the superior survivorship for cemented cross linked all-polyethylene glenoids (see data below from the Australian Orthopaedic Association). 

Our approach to total shoulder arthroplasty is shown in this link.

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Use the "Search" box to the right to find other topics of interest to you.

You may be interested in some of our most visited web pages  arthritis, total shoulder, ream and run, reverse total shoulder, CTA arthroplasty, and rotator cuff surgery as well as the 'ream and run essentials'

Metal backed glenoids: the problem of poly failure

Medium-term rates of radiolucency after primary total shoulder arthroplasty using a cementless metal-backed pegged polyethylene glenoid

Shoulder & Elbow  2020 DOI: 10.1177/1758573219901122

These authors investigated periprosthetic radiolucency rates associated with an uncemented,metal-backed polyethylene glenoid component with medium-term results.

Methods: A single centre retrospective study examining radiological outcomes of the Epoca metal-backed glenoid component

Forty-one patients were followed up with a mean follow-up time of 5.5 years (3–8 years). At follow-up six patients had undergone revision (14.6%). Three patients required revision for cuff failure and were revised to reverse total shoulders. Three patients required revision for failure secondary to polyethylene wear and lysis
Six patients had  radiolucency on follow-up radiographs. 

Comment: The high failure rate of metal backed glenoids from polyethylene failure has been previously described. See the additional references below:

Metal-Backed Glenoid Components Have a Higher Rate of Failure and Fail by Different Modes in Comparison with All-Polyethylene Components: A Systematic Review.

To review, the abstract is reproduced here

BACKGROUND: Glenoid component failure is a common and serious complication of total shoulder arthroplasty. The purpose of this study was to evaluate published evidence on whether metal backing lessens the rate of glenoid component failure.

METHODS: A comprehensive systematic review yielded twenty-one studies on radiolucency, radiographic failure, and revision after arthroplasty with metal-backed glenoid components and twenty-three studies with all-polyethylene components. Our analysis included data on 1571 metal-backed and 3035 all-polyethylene components. The mean duration of follow-up was 5.8 years in the studies with metal-backed components and 7.3 years with all-polyethylene components.

RESULTS: All-polyethylene components had a 42.5% rate of radiolucency compared with 34.9% for metal-backed components (p = 0.0026) and a 21.1% rate of radiographic loosening or failure compared with 16.8% for metal-backed components (p = 0.0005). However, the rate of revision was more than three times higher with metal-backed components (14.0%) than with all-polyethylene components (3.8%, p < 0.0001). Although 77% of the revisions of all-polyethylene components were for loosening, 62% of the revisions of metal-backed components were for other reasons, such as component fracture, screw breakage, component dissociation, polyethylene wear, metal wear, and rotator cuff tear (p < 0.0001).

CONCLUSIONS: The published evidence indicates that metal-backed glenoid components require revision at a significantly higher rate and for different reasons in comparison with all-polyethylene components.

Metal-backed glenoid implant with polyethylene insert is not a viable long-term therapeutic option

These authors reviewed 165 cases of primary osteoarthritis treated with an anatomic total shoulder arthroplasty using an uncemented metal-backed (MB) glenoid components with a polyethylene (PE) insert; the mean patient age was 68 years.

Outcomes were assessed both clinically and radiologically with a minimum of 2 years of follow-up. The survival endpoint was either partial or complete revision.

Survival rate free of revision was 46% at 12 years. At a mean follow-up of 8.5 years (range, 2-16 years), revision was required in 61 patients (37%); 80% of shoulders undergoing revision (49 of 61) had evidence of PE wear. Glenoid loosening (because of osteolysis secondary to wear debris), soft tissue deficiency, and prosthetic instability were the most common modes of failure. Younger patients and biconcave glenoids (with posterior humeral subluxation) had a negative effect on implant survival. Proximal humerus osteolysis was significantly more frequent in shoulders with PE wear as shown in their figure below.

Exchange of the PE insert (with conservation of the MB tray) was possible in only 3% of the revised shoulders.

This study indicates that polyethylene wear with secondary osteolysis from polyethylene and metal debris are the primary failure mechanisms for metal backed glenoids in anatomic total shoulders. 

One of the most important figures in this paper is shown below. It indicates that the often applied standard of a minimum two year followup for arthroplasties does not come close to indicating the failure rate that occurs later on.

The high rate of failure of metal-backed glenoid components - especially with eccentric loading - is explained in large part by examining the Young's modulus of the materials involved. This quantity, also known as the tensile modulus or elastic is a measure of the stiffness of a material.

Here are some representative values of the materials of interest in total shoulder arthroplasty. Young's modulus is expressed in Giga Pascals (GPa).

Cancellous Bone 0.4

Ultra high molecular weight polyethylene 0.5

PMMA bone cement 2

Cortical Bone 8

Titanium 112

Cobalt chrome 200

Thus with a metal backed glenoid there are two critical mismatches of Young's modulus: (1) that of metal (100-200) to bone (0.4-8) and (2) that of metal (100-200) to polyethylene (0.5). The first may account for stress shielding of the glenoid bone and the second may account for the increased rate of polyethylene wear and polyethylene-metal dissociation seen with metal backed components. By contrast, all polyethylene components have better modulus matches with bone. PMMA bone cement also has a similar modulus to that of bone and polyethylene.

What this means is that when the component is loaded, the materials of similar Young's modulus deform similarly, whereas those with mismatched Young's modulus do not, resulting in relative displacement at the interface.

See also the post "The challenges of metal backed glenoids - why do they fail more often?" as well as the information posted here and here and here.

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To see a YouTube of our technique for total shoulder arthroplasty, click on this link.

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To see our new series of youtube videos on important shoulder surgeries and how they are done, click here.

Use the "Search" box to the right to find other topics of interest to you.

How you can support progress in shoulder surgery

You may be interested in some of our most visited web pages  arthritis, total shoulder, ream and run, reverse total shoulder, CTA arthroplasty, and rotator cuff surgery as well as the 'ream and run essentials'

Metal backed glenoids for anatomic total shoulders

Loosening and revision rates after total shoulder arthroplasty: a systematic review of cemented all-polyethylene glenoid and three modern designs of metal-backed glenoid

These authors suggest that metal-backed glenoids (MBG) have been devised to problems of glenoid component loosening and failure.

They compared articles comparing rates of complications and revision surgeries between cemented polyethylene glenoid (PEG articles=35) and three examples of modern MBG (articles=10).

 The mean duration of follow-up was greater for the PEG group (73.1 (12–211) months and 56.1 (24–100) months for the MBG. 

Overall, the rate of the radiolucent lines was 354/1302 (27%) for the PEG group and 47/282 (17%) for the MBG group.

The loosening rates were 465/3185 (15%) and 22/449 (5%), and the failure rate was 189/3316 (6%) and 11/457 (2%), for PEG and MBG, respectively. 

The results of < 36-month and 36–72-month subgroups showed lower rates of radiolucency and loosening in the cemented PEG group.

In the > 72-month subgroup, MBG was better in terms of loosening and failure rates

Comment: This article attempts to compare studies reporting all-poly glenoids with those studies reporting metal backed glenoids. Such an analysis of studies is complicated in contrast to the study of individual patients performed by the Australian Orthopedic Association (see this link), which demonstrates higher rates of revision for metal backed glenoid components.


The 10 year revision rate for all-poly glenoids with cross linked polyethylene was less than 5% across the population of individual patients.

However, it is interesting to compare the causes of revision: a common cause of revision for the all-poly glenoids was loosening while fracture of the glenoid component was a common cause of revision for the metal-backed components.

To see a YouTube of our technique for total shoulder arthroplasty, click on this link.

=====

To see our new series of youtube videos on important shoulder surgeries and how they are done, click here.

Use the "Search" box to the right to find other topics of interest to you.

How you can support progress in shoulder surgery

You may be interested in some of our most visited web pages  arthritis, total shoulder, ream and run, reverse total shoulder, CTA arthroplasty, and rotator cuff surgery as well as the 'ream and run essentials'

Metal backed glenoid components - high failure rate

Outcomes of Trabecular Metal–backed glenoid components in anatomic total shoulder arthroplasty

These authors state that "the current design of the Trabecular Metal–backed glenoid component (Zimmer) was released in 2009. Although over 10,000 of these glenoid components have been implanted worldwide, evidence on either the intermediate- or long-term survival of Trabecular Metal–backed glenoid components in anatomic TSA is very limited."

After a Class 2 recall in 2005 because of concern for fracture at the junction of the base and the trabecular metal keel (see this link), this component was cleared by the FDA (see this link) based on its being substantially equivalent to the predicate recalled devices.

The authors investigated implant survival and two year (average 41 month) clinical outcomes for 36 of 47 patients who received a Trabecular Metal–backed glenoid component (see this link) during primary anatomic total shoulder arthroplasty performed by an individual surgeon.

Three patients showed signs of osteolysis, 4 had radiographic evidence of metal debris, and 1 patient had a catastrophic failure after a fall. Of the 47 TSAs, 5 (11%) were revised to a reverse TSA for subscapularis failure and pain. The authors concluded that Trabecular Metal–backed glenoids had a 25% rate of radiographic metal debris and osteolysis at a minimum 2-year follow-up in this series with one catastrophic failure.

This publication on failures of metal backed glenoids is consistent with a prior post, reproduced below

Early Debris Formation with a Porous Tantalum Glenoid Component: Radiographic Analysis with 2-Year Minimum Follow-up.

These authors point out that a first-generation porous tantalum glenoid component previously demonstrated failure, usually preceded by the appearance of intra-articular metallic debris. An example of component dissociation with this first-generation component is shown here.

After redesign, the component was reintroduced in 2009.

The authors reviewed 68 patients receiving a Trabecular Metal porous tantalum glenoid component (73 components; 5 patients underwent staged bilateral procedures) inserted without polymethylmethacrylate cement (representing off-label usage in the U.S.).

Sixty-six (90%) of the 73 components were evaluated at a minimum of 2 years of follow-up (mean radiographic follow-up of 50.8 months; range, 24 to 68 months). Of these, 92.4% demonstrated minimal or no glenoid radiolucency. Overall, the prevalence of metallic tantalum debris formation was 44% (29 of 66). Sequential radiograph review demonstrated that the incidence of metallic debris formation increased for each year of follow-up, with radiographs from 2, 3, 4, and ≥5 years of follow-up demonstrating a metallic debris incidence of 23%, 36%, 49%, and 52%, respectively.

The severity of metallic debris formation also increased with follow-up duration.

Here's an example of Grade 1, debris noted at the bone-metal interface;

of Grade 2, debris visible in soft tissues intra-articularly;

of Grade 3, visible but incomplete cracking or fracturing of the metal component;

                                      

They concluded that the development of metallic debris, increasing in both overall incidence and degree of severity over time, raises concern for potential failure of this glenoid component.

Comment: Metal backed glenoid components continue to manifest problems not present with all-polyethylene components. They demonstrate an increased rate of revision because of loosening, front side and back side polyethylene wear, component dissociation, fracture, instability, and cuff failure (possibility related to the increased thickness of the components) - see this link and the figure below.

 If an arthroplasty with bone ingrowth components requires revision because of infection, cuff failure or instability, removal of the components can result in substantial problems with bone integrity. Such bone damage may compromise secure fixation of a reverse total shoulder glenoid component.

This article presents another issue with metal-backed glenoid components, that of metallic debris, that appears to increase in rate and severity with time after implantation. The mechanism for this debris formation is unclear, but it could be that micromotion of the component pulls the porous trabeculated metal apart.

It can be seen from the list of Young's moduli below (in GPa), that the elastic modulus of polyethylene is closest to that of cortical and cancellous bone:
Cancellous Bone 0.4
Ultra high molecular weight polyethylene 0.5
PMMA bone cement 2
Cortical Bone 8
Titanium 112

Tantalum 186
Cobalt chrome 200.

The Young's modulus of a porous material can be modified by changing the degree of porosity. This is demonstrated in a recent article regarding porous tanalum (see this link). Here is the abstract:

"Relatively high cost of manufacturing and inability to produce modular all tantalum implants has limited its widespread acceptance, in spite of its excellent in vitro and in vivo biocompatibility. In this article, we report how to process Ta to create net shape porous structures with varying porosity using Laser Engineered Net Shaping (LENS™) for the first time. Porous Ta samples with relative densities between 45 to 73% have been successfully fabricated and characterized for their mechanical properties. In vitro cell materials interactions, using human osteoblast cell line hFOB, have been accessed on these porous Ta structures and compared with porous Ti control samples. The results show that the Young’s modulus of porous Ta can be tailored between 1.5 to 20 GPa by changing the pore volume fraction between 27 and 55%. In vitro biocompatibility in terms of MTT assay and immunochemistry study showed excellent cellular adherence, growth and differentitation with abundant extracellular matrix formation on porous Ta structures compared to porous Ti control. These results indicate that porous Ta structures can promote enhanced/early biological fixation. The enhanced in vitro cell-materials interactions on porous Ta surface are attributed to chemistry and its high wettability and surface energy relative to porous Ti. Our results show that these laser processed porous Ta structures can find numerous applications, particularly among older patients, for metallic implants because of their excellent bioactivity."

Nevertheless, based on the evidence available, metal backed glenoids may not offer to the patient advantages over an all polyethylene component as discussed below.

Radiographic and clinical outcomes of total shoulder arthroplasty with an all-polyethylene pegged bone ingrowth glenoid component: prospective short- to medium-term follow-up.

These authors reviewed 80 total shoulders using an all polyethylene glenoid component.  The glenoid was reamed minimally to preserve subchondral bone, which was given priority above correcting retroversion.

1 of 80 shoulders was revised for aseptic glenoid loosening.  81.6% had a radiolucency grade of 0 or 1. Nearly 90% had a glenoid seating grade of A or B. Grade 2 or 3 bone around the central peg was seen in 88.2%. 

No statistical association existed between Walch glenoid types and radiolucency grades, bone grades around the central peg, perfect radiolucency grade, seating grade, and grade 3 bone around the central peg. 

Comment: We previously posted on this article here, emphasizing the importance of register (see link).

We'd like to add a few additional thoughts. These authors use a technique similar to the one used in our practice (see link).  No patient-specific instrumentation or complex 3D reconstructions were used. The glenoid was reamed conservatively to a single concavity without emphasizing a change in version. 

Using the all poly glenoid after careful glenoid preparation with minimal reaming yields consistently better results than those achieved with metal backed components (see link). The DePuy and the Tornier versions of the modern all-poly glenoids are shown below. Other relevant links are here and here. 

The quality of fixation and the bone ingrowth into the pegs is substantial as shown in some of our cases below.

Against this background, we wonder whether more complex components, such as the one shown below and discussed here, provide additional value.

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The reader may also be interested in these posts:

Healing through joint replacement

Supporting progress in shoulder surgery

Consultation for those who live a distance away from Seattle.

Click here to see the new Shoulder Arthritis Book.

Click here to see the new Rotator Cuff Book

Information about shoulder exercises can be found at this link.

Use the "Search" box to the right to find other topics of interest to you.

You may be interested in some of our most visited web pages including:shoulder arthritis, total shoulder, ream and run, reverse total shoulder, CTA arthroplasty, and rotator cuff surgery as well as the 'ream and run essentials'

See from which cities our patients come.

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Metal backed glenoid components and failure rate.

The weak link in metal-backed glenoid implants is the polyethylene

These surgeons have authored a most thoughtful letter regarding the metal backed glenoid. We encourage reading of the complete letter (see this link) and their original article (see this link).

Here we paraphrase their letter. "the results this clinical study, showing poor results with metal backed (MB) glenoid implants at medium- to long-term follow-up, are in accordance with other long-term clinical studies reporting on a high number of patients and with a recent systematic review showing that the revision rate with MB glenoid components is 3 times higher than with all-PE components (see this link). Finally, biomechanics studies have demonstrated the problems created by the metallic interface in anatomic TSA on both the plastic side and the bone side. All these are good reasons, published in the literature, that do not encourage the use of MB glenoid components for anatomic TSA. Careful consideration of the inherent risks is warranted if future exploration of MB anatomic glenoid components is undertaken. The success of MB glenoid components for reverse TSA should not lead to confusion of surgeons: the biomechanical environment is very different in reverse TSA, in which a metallic sphere is associated to a metallic baseplate."

Comment: We have posted some informative links on this topic (see here, and here). In a recent post (see here) we point out that in addition to problems of thickness and back side wear, the issue is in large part the mismatch in the material properties of polyethylene and the metal backing.

Additional data on the difficulties associated with metal backed implants can be found from the robust database of the Australian Orthopaedic Association (see here), showing 'higher than anticipated rates of revision' for metal backed glenoid components.

Examples of these components are shown below:

While no prosthetic glenoid component is perfect, the current evidence is that the safest and most durable implants are the pegged all-polyethylene component

 inserted with careful and conservative glenoid bone preparation.

===

Consultation for those who live a distance away from Seattle.

Click here to see the new Shoulder Arthritis Book.

Click here to see the new Rotator Cuff Book

Information about shoulder exercises can be found at this link.

Use the "Search" box to the right to find other topics of interest to you.

You may be interested in some of our most visited web pages including:shoulder arthritis, total shoulder, ream and run, reverse total shoulder, CTA arthroplasty, and rotator cuff surgery as well as the 'ream and run essentials'

See from which cities our patients come.

See the countries from which our readers come on this post.

Metal backed porous tantalum glenoid components - debris formation, more on trabeculated metal

Early Debris Formation with a Porous Tantalum Glenoid Component: Radiographic Analysis with 2-Year Minimum Follow-up.

These authors point out that a first-generation porous tantalum glenoid component previously demonstrated failure, usually preceded by the appearance of intra-articular metallic debris. An example of component dissociation with this first-generation component is shown here.

After redesign, the component was reintroduced in 2009.

The authors reviewed 68 patients receiving a Trabecular Metal porous tantalum glenoid component (73 components; 5 patients underwent staged bilateral procedures) inserted without polymethylmethacrylate cement (representing off-label usage in the U.S.).

Sixty-six (90%) of the 73 components were evaluated at a minimum of 2 years of follow-up (mean radiographic follow-up of 50.8 months; range, 24 to 68 months). Of these, 92.4% demonstrated minimal or no glenoid radiolucency. Overall, the prevalence of metallic tantalum debris formation was 44% (29 of 66). Sequential radiograph review demonstrated that the incidence of metallic debris formation increased for each year of follow-up, with radiographs from 2, 3, 4, and ≥5 years of follow-up demonstrating a metallic debris incidence of 23%, 36%, 49%, and 52%, respectively.

The severity of metallic debris formation also increased with follow-up duration.

Here's an example of Grade 1, debris noted at the bone-metal interface;

of Grade 2, debris visible in soft tissues intra-articularly;

of Grade 3, visible but incomplete cracking or fracturing of the metal component;

                                      

They concluded that the development of metallic debris, increasing in both overall incidence and degree of severity over time, raises concern for potential failure of this glenoid component.

Comment: Metal backed glenoid components continue to manifest problems not present with all-polyethylene components. They demonstrate an increased rate of revision because of loosening, front side and back side polyethylene wear, component dissociation, fracture, instability, and cuff failure (possibility related to the increased thickness of the components) - see this link and the figure below.

 If an arthroplasty with bone ingrowth components requires revision because of infection, cuff failure or instability, removal of the components can result in substantial problems with bone integrity. Such bone damage may compromise secure fixation of a reverse total shoulder glenoid component.

This article presents another issue with metal-backed glenoid components, that of metallic debris, that appears to increase in rate and severity with time after implantation. The mechanism for this debris formation is unclear, but it could be that micromotion of the component pulls the porous trabeculated metal apart.

It can be seen from the list of Young's moduli below (in GPa), that the elastic modulus of polyethylene is closest to that of cortical and cancellous bone:
Cancellous Bone 0.4
Ultra high molecular weight polyethylene 0.5
PMMA bone cement 2
Cortical Bone 8
Titanium 112

Tantalum 186
Cobalt chrome 200.

The Young's modulus of a porous material can be modified by changing the degree of porosity. This is demonstrated in a recent article regarding porous tanalum (see this link). Here is the abstract:

"Relatively high cost of manufacturing and inability to produce modular all tantalum implants has limited its widespread acceptance, in spite of its excellent in vitro and in vivo biocompatibility. In this article, we report how to process Ta to create net shape porous structures with varying porosity using Laser Engineered Net Shaping (LENS™) for the first time. Porous Ta samples with relative densities between 45 to 73% have been successfully fabricated and characterized for their mechanical properties. In vitro cell materials interactions, using human osteoblast cell line hFOB, have been accessed on these porous Ta structures and compared with porous Ti control samples. The results show that the Young’s modulus of porous Ta can be tailored between 1.5 to 20 GPa by changing the pore volume fraction between 27 and 55%. In vitro biocompatibility in terms of MTT assay and immunochemistry study showed excellent cellular adherence, growth and differentitation with abundant extracellular matrix formation on porous Ta structures compared to porous Ti control. These results indicate that porous Ta structures can promote enhanced/early biological fixation. The enhanced in vitro cell-materials interactions on porous Ta surface are attributed to chemistry and its high wettability and surface energy relative to porous Ti. Our results show that these laser processed porous Ta structures can find numerous applications, particularly among older patients, for metallic implants because of their excellent bioactivity."

Nevertheless, based on the evidence available, metal backed glenoids may not offer to the patient advantages over an all polyethylene component.

===

Consultation for those who live a distance away from Seattle.

Click here to see the new Shoulder Arthritis Book

Click here to see the new Rotator Cuff Book

Use the "Search" box to the right to find other topics of interest to you.

You may be interested in some of our most visited web pages including:shoulder arthritis, total shoulder, ream and run, reverse total shoulder, CTA arthroplasty, and rotator cuff surgery as well as the 'ream and run essentials'

See from which cities our patients come.

See the countries from which our readers come on this post.