Comparison of demineralized allogeneic bone matrix grafting (the Urist procedure) and the Ilizarov procedure in large diaphyseal defects in sheep

Abstract

The bone inductive capability of the Urist and Ilizarov procedures was compared in the repair of large diaphyseal defects in sheep. In 30 animals, a 4 cm segmental defect was created in the middle portion of the right femur and was stabilized with an external fixator. The sheep were divided into four groups according to the type of reconstruction of the defect. In group 1, a demineralized allogeneic bone matrix (DABM) cylinder was used; in group 2, DABM chips; and in group 3, gradual transport of a piece of bone detached from the proximal femoral fragment was used to fill the defect. Group 4 served as a control (the defect was left empty). New bone formation was assessed by serial radiographs until the time of death at 2 or 4 months. Postmortem specimens were analyzed with respect to bone mineral content, uptake of isotopes (45Ca and 3H-proline), and histology. The first signs of new bone formation were radiographically evident at 4 weeks. In the two groups in which reconstruction involved DABM (Urist procedures), new bone failed to form in eight of the 13 animals. Full bridging of the defect was observed at 8 weeks in one animal with a DABM cylinder and two with DABM chips. No decisive difference in bone yield could be demonstrated between the two Urist procedures. In the group treated with the Ilizarov procedure, new bone formation consistently occurred at a high rate; full bridging of the defect was observed in seven of the eight animals. Bone mineral scanning and histologic analysis essentially confirmed the radiographic results. Uptake of isotopes was selectively analyzed in two sheep from each experimental group in which new bone formation was exhibited in the defect; new bone formation was increased compared with that in the contralateral femur but was equal among the three experimental groups. Our study shows that gradual transport of a detached piece of autogeneic bone (Ilizarov procedure) is more effective than implantation of DABM (Urist procedure) in eliciting new bone formation in large diaphyseal defects in sheep. The variable bone induction by DABM may be explained by differences in host immune responses to the implants.

Tibial segmental bone defect treated with bone plate and cage filled with either xenogeneic composite or autologous cortical bone graft

“…The processing of bovine bone mayr esult in different biomaterials with specific properties. Demineralized bone presentsosteoinductivea nd osteoconductive properties (9,10,25,26,27), while sinteredinorganic bone matrixare osteoconductive (28).…”

“…However, due to its high collagen content, demineralizedb one matrix is readilya bsorbed and its effect wasrelated to the BMP content (25,27). In this study, thecomposite testedalso contained ap ool of bBMPs that wouldb ee xpected to enhancet he osteoinductiveeffect (25).…”

“…However, due to its high collagen content, demineralizedb one matrix is readilya bsorbed and its effect wasrelated to the BMP content (25,27). In this study, thecomposite testedalso contained ap ool of bBMPs that wouldb ee xpected to enhancet he osteoinductiveeffect (25). The inorganicbone matrix present in thec omposite wasn ot absorbed until 90 days after surgery, it didnot produce aforeign body reactionand someof thep articles were wrapped by newf ormed bone.…”

Goniometria dos membros torácicos e pélvicos de ovinos em duas faixas etárias

“…Em virtude das restrições do uso de animais de estimação em experimentação, especialmente cães e gatos, os ovinos tem se tornado uma opção importante na área de ortopedia e traumatologia (Ehrnberg et al 1993, Teixeira et al 2007, Hette et al 2009, Meller et al 2009), requerendo assim estudos com relação à função articular. Dentre os métodos objetivos de avaliação das articulações podem ser citados a cinemática, que requer equipamentos mais complexos e analisa a geometria do movimento quanto ao deslocamento, à velocidade e à aceleração (Gillete & Angle 2008), e a goniometria, que apesar de ser uma análise estática, tem por vantagens a simplicidade e o baixo custo (Norkin e White 1997, Jaegger et al 2002, Hesbach et al 2007.…”