In vivo decellularized massive bone allograft: Preliminary results on a large preclinical animal model

Abstract text (incl. references and figure legends)

Introduction

Massive bone allografts may be used to reconstruct large bone defects. They do however show high complication rates¹. We hypothesize that the residual donor cellular tissue causes immunogenicity, which may be the cause of this high complication rate². A decellularization by perfusion protocol was set up to overcome this and the allografts were tested and compared in a large animal model.

Material & Methods

Four 60kg adults minipigs underwent the same orthopaedic procedure that consists of a bilateral 2,5 cm femoral diaphyseal resection followed by a reconstruction with a massive bone allograft. One femur received a "fresh frozen" massive bone allograft while the other side was implanted with a decellularized by perfusion massive bone allograft. Osteosynthesis was performed with two orthogonal LCP plates. Both grafts came from the same donor. Grafts were explanted at 3 months postoperatively. Clinical follow-up, imaging (X-ray and CT-scan) and histology were performed to assess the osteointegration.

Results

Imaging did not show any difference between the time to fusion of both grafts but decellularized grafts achieved a better mineral consolidation process. Furthermore, decellularized grafts showed larger amount of newly formed bone.

Histology showed a qualitatively higher bone remodelling around and inside the decellularized grafts. We also observed larger osteoclast populations followed by a very active bone remodelling and a neovascularization inside the decellularized graft. Fresh frozen graft showed also good consolidation with thick bone callus on the periphery with less remodelling.

Conclusions

Our preliminary results show that, based on imaging and histological findings, perfusion-decellularized massive bone allografts demonstrate a better capacity for osseointegration and bone remodelling compared to "fresh frozen" massive bone allografts.

Reference

Delloye, C. et al. 2014 Sanders, P. T. J. et al. 2020

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