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Effect of local TGF-beta1 and IGF-1 release on implant fixation: comparison with hydroxyapatite coating: a paired study in dogs.

Lamberg A, Bechtold JE, Baas J, Søballe K, Elmengaard B - Acta Orthop (2009)

Bottom Line: Here, we have compared the effect of local release of TGF-beta1 and IGF-1 with that of hydroxyapatite coating on implant fixation.There was no difference in any of the mechanical parameters.While HA mainly stimulated bone ongrowth, local release of TGF-beta1 and IGF-1 stimulated gap healing.

View Article: PubMed Central - PubMed

Affiliation: Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, Aarhus University Hospital, Denmark. anders@lamberg.dk

ABSTRACT

Background and purpose: Hydroxyapatite (HA) coating stimulates the osseointegration of cementless orthopedic implants. Recently, locally released osteogenic growth factors have also been shown experimentally to stimulate osseointegration so that bone fills gaps around orthopedic implants. Here, we have compared the effect of local release of TGF-beta1 and IGF-1 with that of hydroxyapatite coating on implant fixation.

Method: Weight-bearing implants with a 0.75-mm surrounding gap were inserted bilaterally in the knees of 10 dogs. Growth factors were incorporated in a biodegradable poly(D,L-lactide) coating on porous coated titanium implants. Plasma-sprayed HA implants served as controls. The dogs were killed at 4 weeks and the implants were evaluated by mechanical push-out test and by histomorphometry.

Results: There was no difference in any of the mechanical parameters. Bone ongrowth was 3-fold higher for HA-coated implants (p < 0.001). For growth factor-coated implants, bone volume was 26% higher in the inner half of the gap and 28% higher in the outer half compared to HA (p < 0.03).

Interpretation: The mechanical fixation of porous-coated titanium implants with local growth factor release is comparable to that of HA coating. While HA mainly stimulated bone ongrowth, local release of TGF-beta1 and IGF-1 stimulated gap healing.

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Graph showing percentage of fibrous tissue on the implant surface (ongrowth), and in the inner gap (p = 0.05). Paired data are shown interconnected. HA: Hydroxyapatite, GF: growth factor.
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Figure 0004: Graph showing percentage of fibrous tissue on the implant surface (ongrowth), and in the inner gap (p = 0.05). Paired data are shown interconnected. HA: Hydroxyapatite, GF: growth factor.

Mentions: In contrast to the push-out test, the histomorphometric analysis showed differences in tissue distribution around the implants. Bone ongrowth to the implants was 3-fold higher for HA-coated implants (p < 0.001) (Table 2). There was ongrowth of fibrous tissue in 4 of the 10 HA-coated implants (up to 8%), and no fibrous tissue on the growth factor-coated implants (p = 0.05) (Figure 4). In the inner half of the gap, the bone volume fraction was 26% higher in the growth factor-coated implant group (p = 0.01) (Table 2). In the outer half of the gap, the bone volume fraction was 28% higher in the growth factor-coated implant group (p = 0.03) (Figure 5). There were no signs of residual polymer on the implant surfaces.


Effect of local TGF-beta1 and IGF-1 release on implant fixation: comparison with hydroxyapatite coating: a paired study in dogs.

Lamberg A, Bechtold JE, Baas J, Søballe K, Elmengaard B - Acta Orthop (2009)

Graph showing percentage of fibrous tissue on the implant surface (ongrowth), and in the inner gap (p = 0.05). Paired data are shown interconnected. HA: Hydroxyapatite, GF: growth factor.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2823183&req=5

Figure 0004: Graph showing percentage of fibrous tissue on the implant surface (ongrowth), and in the inner gap (p = 0.05). Paired data are shown interconnected. HA: Hydroxyapatite, GF: growth factor.
Mentions: In contrast to the push-out test, the histomorphometric analysis showed differences in tissue distribution around the implants. Bone ongrowth to the implants was 3-fold higher for HA-coated implants (p < 0.001) (Table 2). There was ongrowth of fibrous tissue in 4 of the 10 HA-coated implants (up to 8%), and no fibrous tissue on the growth factor-coated implants (p = 0.05) (Figure 4). In the inner half of the gap, the bone volume fraction was 26% higher in the growth factor-coated implant group (p = 0.01) (Table 2). In the outer half of the gap, the bone volume fraction was 28% higher in the growth factor-coated implant group (p = 0.03) (Figure 5). There were no signs of residual polymer on the implant surfaces.

Bottom Line: Here, we have compared the effect of local release of TGF-beta1 and IGF-1 with that of hydroxyapatite coating on implant fixation.There was no difference in any of the mechanical parameters.While HA mainly stimulated bone ongrowth, local release of TGF-beta1 and IGF-1 stimulated gap healing.

View Article: PubMed Central - PubMed

Affiliation: Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, Aarhus University Hospital, Denmark. anders@lamberg.dk

ABSTRACT

Background and purpose: Hydroxyapatite (HA) coating stimulates the osseointegration of cementless orthopedic implants. Recently, locally released osteogenic growth factors have also been shown experimentally to stimulate osseointegration so that bone fills gaps around orthopedic implants. Here, we have compared the effect of local release of TGF-beta1 and IGF-1 with that of hydroxyapatite coating on implant fixation.

Method: Weight-bearing implants with a 0.75-mm surrounding gap were inserted bilaterally in the knees of 10 dogs. Growth factors were incorporated in a biodegradable poly(D,L-lactide) coating on porous coated titanium implants. Plasma-sprayed HA implants served as controls. The dogs were killed at 4 weeks and the implants were evaluated by mechanical push-out test and by histomorphometry.

Results: There was no difference in any of the mechanical parameters. Bone ongrowth was 3-fold higher for HA-coated implants (p < 0.001). For growth factor-coated implants, bone volume was 26% higher in the inner half of the gap and 28% higher in the outer half compared to HA (p < 0.03).

Interpretation: The mechanical fixation of porous-coated titanium implants with local growth factor release is comparable to that of HA coating. While HA mainly stimulated bone ongrowth, local release of TGF-beta1 and IGF-1 stimulated gap healing.

Show MeSH
Related in: MedlinePlus