DOS 2017

176

· DOS Abstracts

Composite Biomaterial as a Carrier for Bone Active

Substances for Metaphyseal Tibial Bone Defect Re-

construction in Rats

Peter Frederik Horstmann, Bushan Raina Raina, Hanna Isaksson, Werner Hettwer,

Lars Lidgren, Michael Mørk Petersen, Magnus Tägil

Department of Orthopedics, University of Copenhagen, Rigshospitalet; Depart-

ment of Orthopedics, Clinical Sciences, Lund University; Department of Bio-

medical Engineering, Lund University; Department of Orthopedics, University

of Copenhagen, Rigshospitalet; Department of Orthopedics, Clinical Sciences,

Lund University; Department of Orthopedics, University of Copenhagen, Rig-

shospitalet; Department of Orthopedics, Clinical Sciences, Lund University

Background:

Method of choice for reconstruction of cavitary bone defects

after curettage of bone lesions, such as giant cell tumors of bone (GCT), remain

controversial. Local zoledronic acid (ZA) has shown promising results as a local

adjuvant in the treatment of GCT.

Purpose / Aim of Study:

To investigate if a composite biomaterial (CBM) can

be used for delivery of ZA, and bone morphogenic protein 2 (BMP-2).

Materials and Methods:

50 Sprague-Dawley rats were allocated to one of

five groups (n=10/group) according to treatment of a 3- mm unicortical me-

taphyseal defect in the proximal tibia: 1) Empty defect; 2) Bone allograft; 3)

CBM (CERAMENT™|G, BONESUPPORT AB); 4) CBM and ZA; 5) CBM, ZA and

BMP-2. At 4-weeks, in-vivo micro-CT imaging was performed. At 8-weeks, all

animals were examined with ex-vivo micro-CT, DXA, and histology.

Findings / Results:

In-vivo micro-CT images at 4-weeks showed significantly

higher mineralized volume (MV) in the defect in all CBM-treated groups. Ex-

vivo micro-CT and DXA at 8-weeks showed that addition of ZA, even without

BMP-2, increased MV, although the highest MV was seen in the BMP-2-treated

group. Qualitative histological analysis found normal cortical bone architecture

in the empty and the allograft groups, without convincing signs of trabecular

bone formation inside the defect area. Trabecular bone and remnants of CBM

were seen inside the original defect in all CBM-treated groups. The addition of

ZA increased cortical thickness, and addition of BMP-2 further increased callus

size with a visible callus extending beyond the margins of the old cortex.

Conclusions:

The biomaterial used in our study can carry anabolic (BMP-2)

and anti-catabolic (ZA) agents, which appears to significantly enhance bone

mineralization beyond mere physical defect filling.

Conflict of interest:

Peter Frederik Horstmann: BONESUPPORT AB, Sweden

Lars Lidgren:Board member, BONESUPPORT AB, Sweden

128.