Sacha Stevenson

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This laboratory has developed a semiquantitative scale for grading the natural healing process of defects drilled into articular cartilage. The scale is composed of four parameters: percent filling of the defect, reconstitution of the osteochondral junction, matrix staining and cell morphology; it has a score range from 0 (best) to 14 (worst). The scale was(More)
This study describes the biologic integration of grit-blasted titanium alloy (Ti-6A1-4V) implants that were press fit into the distal femoral canal of young adult rabbits and evaluated by histologic, histomorphometric, and biomechanical methods. Polished and aluminum oxide grit-blasted (4.2 +/- 0.7 microns surface roughness) solid implants were compared(More)
Successful graft incorporation requires that an appropriate match be made among the biologic activity of a bone graft, the condition of the perigraft environment, and the mechanical environment. The authors have studied, in a wide variety of animal models, the factors that affect the main components of bone graft incorporation: revascularization, new bone(More)
The clinical outcome of bone grafting procedures depends on many factors, including type and fixation of the bone graft as well as the site and status of the host bed. Bone grafts serve one or both of two main functions, as a source of osteogenetic cells and as a mechanical support. Autografts, both cancellous and cortical, are usually implanted fresh and(More)
Our goal in this study was to evaluate the effects of and the interaction between the hypothesized principal determinants of the incorporation of grafts: antigenicity and treatment of the graft. We implanted fresh and frozen cortical bone grafts that were matched for both major and non-major histocompatibility complex antigens (syngeneic grafts), matched(More)
The early (3 months) and later (6 months) patterns of incorporation and bone formation have been evaluated histomorphometrically for different types of bone grafts; that is, vascularized and nonvascularized autografts with and without ciclosporin, and vascularized and nonvascularized dog leukocyte antigen (DLA)-mismatched allografts with and without(More)
The apposition of new bone to polished solid implants and to implants with surfaces that had been blasted with one of three methods of grit-blasting was studied in a rabbit intramedullary model to test the hypothesis that blasted implant surfaces support osseous integration. Intramedullary titanium-alloy (Ti-6Al-4V) plugs, press-fit into the distal aspect(More)
Dog leukocyte antigen (DLA)-matched and mismatched, fresh and frozen (cryopreserved) osteochondral allografts of the proximal part of the radius were implanted orthotopically in beagles. The systemic and local (intra-articular) immune responses were monitored for eleven months using a 51chromium release assay with donor peripheral-blood lymphocytes as(More)
The factors contributing to a delayed union or nonunion are many. In general they may be divided into three major categories: deficiencies in vascularity and angiogenesis, deficiencies in the robustness of the chondroosseous response, and deficiencies in stability, strain, or physical continuity. Frequently, deficiencies in more than one category are(More)