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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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Illustrations of the model. The polyethylene plug transferring load from the tibial cartilage to the implant is not shown. The implant is surrounded by a 0.75-mm gap, and it is loaded during each gait cycle. In addition, there is a constant flow of joint fluid passing the surface. The HA-coated implants were inserted in the left femur and the growth factor-coated implants in the right femur.
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Figure 0001: Illustrations of the model. The polyethylene plug transferring load from the tibial cartilage to the implant is not shown. The implant is surrounded by a 0.75-mm gap, and it is loaded during each gait cycle. In addition, there is a constant flow of joint fluid passing the surface. The HA-coated implants were inserted in the left femur and the growth factor-coated implants in the right femur.

Mentions: Following approval of the institutional Animal Care and Use committee, we performed a paired study in 10 skeletally mature purpose-bred hound dogs with a mean weight of 22 (SD 1.2) kg. We used an established model (Soballe et al. 1992) in which the implants are weight bearing and surrounded by a circumferential gap of 0.75 mm (Figure 1). Implants were inserted in the distal femur, in a cancellous bone site oriented along the medial condyles' major weight-bearing axis. The growth factor-coated implants were inserted in the right femoral condyle, and the HA-coated control implants were inserted in the left femoral condyle. The observation period was 4 weeks.


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)

Illustrations of the model. The polyethylene plug transferring load from the tibial cartilage to the implant is not shown. The implant is surrounded by a 0.75-mm gap, and it is loaded during each gait cycle. In addition, there is a constant flow of joint fluid passing the surface. The HA-coated implants were inserted in the left femur and the growth factor-coated implants in the right femur.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 0001: Illustrations of the model. The polyethylene plug transferring load from the tibial cartilage to the implant is not shown. The implant is surrounded by a 0.75-mm gap, and it is loaded during each gait cycle. In addition, there is a constant flow of joint fluid passing the surface. The HA-coated implants were inserted in the left femur and the growth factor-coated implants in the right femur.
Mentions: Following approval of the institutional Animal Care and Use committee, we performed a paired study in 10 skeletally mature purpose-bred hound dogs with a mean weight of 22 (SD 1.2) kg. We used an established model (Soballe et al. 1992) in which the implants are weight bearing and surrounded by a circumferential gap of 0.75 mm (Figure 1). Implants were inserted in the distal femur, in a cancellous bone site oriented along the medial condyles' major weight-bearing axis. The growth factor-coated implants were inserted in the right femoral condyle, and the HA-coated control implants were inserted in the left femoral condyle. The observation period was 4 weeks.

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