The healing of grafts combining freeze-dried and demineralized allogeneic bone in rabbits.
The adjunctive role of demineralized bone matrix (DBM) in enhancing the incorporation of segmental freeze dried (FD)-allogeneic bone grafts has been studied in the rabbit ulna and fibula. The studies compared the healing patterns of fresh segmental autografts, FD-allografts, DBM-allografts, and FD-allografts supplemented at the graft-host junctions with FD- or DBM-allografts as particulates (ulna) or as segmental struts (fibula). The outcome was evaluated at five and ten weeks by a radiologic score, by biomechanical properties (breaking strength, energy to failure, stiffness), and histology. The ulnar autografts healed most rapidly (ten weeks = 100%), followed by DBM allografts (60%). By all criteria, FD-allografts were poorly incorporated (20-40%), and the process was not improved by supplements of FD- or DBM-particulate/strut bone. Histologically, the DBM component of composite fibular strut grafts was osteoinductive and united with host tissues within 35 days. The contiguous FD-allograft struts were not incorporated, showing fibrocartilaginous nonunions and resorptive foci. While the addition of DBM does not protect FD-allograft integrity in the rabbit, segmental mineralized FD-allografts could provide mechanical support for some intervals until, in such composite grafts, osteoinductive processes produced biomechanically competent new bone.
Yang
C Y
CY
Department of Surgery, University of Texas Medical Branch, Galveston 77555.
Simmons
D J
DJ
Lozano
R
R
D000818:Animals; D001696:Biomechanical Phenomena; D001857:Bone Matrix; D016025:Bone Transplantation / Q000379:methods*; D005360:Fibula / Q000033:anatomy & histology / Q000502:physiology; D005612:Freeze Drying; D008297:Male; D008903:Minerals; D016348:Osseointegration; D011817:Rabbits; D014021:Tissue Preservation / Q000379:methods*; D014184:Transplantation, Homologous; D014457:Ulna / Q000033:anatomy & histology / Q000502:physiology; D014945:Wound Healing
D008903:Minerals