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DOS Kongressen 2017 ·
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Radiographic biodegradation patterns of a hy-
droxyapatite / calcium sulfate biocomposite. Re-
sults from a large animal bone defect model.
Werner Hettwer
Orthopaedic Surgery, Rigshospitalet
Background:
Ceramic biomaterials can be used as bone graft substitutes for
reconstruction of bone defects. However, post-operative imaging features are
often unique and difficult to interpret, particularly without histological correla-
tion.
Purpose / Aim of Study:
The aim of this study was to establish a clinically
relevant large animal bone defect model that allows further characterisation,
analysis and correlation of imaging and histology findings.
Materials and Methods:
Standardised bone defects (diameter 2.5cm, depth
2cm, volume approx. 10ml) were created in the medial femoral condyles of ten
merino-wool sheep (age 2 -4 years). The defects were filled with a ceramic bio-
material (Cerament BVF or G), allograft or left empty for comparison. After the
initial procedure on the right hind leg, an identical intervention was performed
on the contralateral side 3 months later, so that a spectrum of differentially
treated bone voids could be obtained by sacrifice at various time points post-
implantation.
Findings / Results:
We present our radiographic results after a follow-up of 12
months and describe a consistent pattern of radiographic signs of biodegrada-
tion of the implanted biomaterial which overlaps the simultaneously ongoing
process of bone formation. We consistently observed a radio-dense area in the
periphery of the lesion (“halo sign”) progressively migrating towards the spheri-
cal biocomposite remnant, located at centre of the treated defects (“marble
sign”). Both signs became more and more indistinct from surrounding cancellous
bone and progressively disappeared with time.
Conclusions:
We have established a large animal model, which appears to
reproduce comparable radiographic post- implantation features regularly ob-
served in clinical cases. This model provides valuable information regarding con-
clusive interpretation of basic & advanced imaging features.
No conflicts of interest reported
131.