DOS 2016

DOS Kongressen 2016 ·

Implant fixation with BMP-2 and Zolendronate in a peri-

implant gap - with and without allograft

Rasmus Cleemann, Mette Sørensen, Jørgen Baas, Joanie Bechtold, Kjeld Søballe

Orthopedic, Orthopedic Research Laboratory & Elective Surgery Centre, Aarhus

University Hospital & Silkeborg Regional Hospital - DK; Orthopedic Research

Laboratory, Aarhus University Hospital - DK; Orthopedic, Aarhus University

Hospital - DK; , University of Minnesota, Minneapolis, MN - USA; Orthopedic,

Aarhus University Hospital - DK

Background:

BMP-2 stimulates formation of new bone; if Zolendronate can

prevent BMP-2 associated bone resorption, this may improve implant fixation.

Purpose / Aim of Study:

To quantify effects in a peri-implant gap with or

without allograft, with 3 BMP-2 doses locally and with systemic Zolendronate.

Materials and Methods:

In 12 male canines, 4 implants were inserted in 2.5

mm allografted gaps in bilateral proximal humerei, and 4 implants were inserted

in 0.75 mm non-grafted gaps in bilateral femoral condyles. The implant surface

was coated with 240 μg, 60 μg, 15 μg of BMP-2 or control. Zolendronate (0.1

mg/kg) was administered once IV, 10 days post surgery. After 28 days, speci-

mens were evaluated by histomorphometry and mechanical push- out.

Findings / Results:

Grafted gap: Compared to any BMP-2 dose, control had

the best mechanical fixation, the most bone at implant surface, the most volume

of new bone near the implant (from 0-1 mm but not 1-2 mm), and the most

retained allograft. With any BMP-2 dose, volume of allograft decreased near

the surface (0-1 mm) and dose dependently further away (1-2 mm). Non-

grafted gap: 15 μg BMP-2 had the best mechanical fixation, the most bone at

implant surface and in the gap compared to control, 60 μg and 240 μg BMP-

2.15 μg and control did not differ in volume of new bone in the gap. Outside the

original implant gap, volume of new bone correlated to increasing BMP-2 dose.

Conclusions:

The different surface fraction and volume of new bone in the

grafted and non-grafted gap settings suggest a variable response to the com-

bined anabolic and catabolic stimuli when graft is present. BMP-2 can augument

implant fixation, but the therapeutic window seems narrow and addition and

timing of Zolendronate administration is essential to harvest a positive effect

on initial implant fixationt. Both areas need further experimental investigation.

No conflicts of interest reported