1,721,103 research outputs found
Fragmentation of methylmethacrylate: a cause of late failure of total hip replacement. A case report.
No full textExtensive localized bone lysis in the femur following implantation of a metal-on-metal total hip prosthesis was observed. Fragmentation of the cement occurred 10 years after implantation. Histologic and ultrastructural features of macrophages are consistent with the hypothesis that particles from the acrylic resin were the factors stimulating the macrophagic reaction. Both mechanical factors and changes of the physico-chemical properties of the cement may have an etiologic role
Periosteal and endosteal reaction to reaming and nailing: the possible role of revascolarization on the endosteal anchorage of cementless stems.
No full textThe reaction of bone to titanium implants of different shapes inserted in the rabbit tibia was investigated with histological and perfusion techniques to determine the pattern of vessel distribution. The experimental implants included full cylindrical rods, hollow rods with holes on the surface and wire mesh rods. In the implanted bones the rods were found to fill a large area of the medullary canal; however, owing to the discrepancy between the shape of the diaphysis and the implant, the endosteal contact was never complete. In an early phase, reactive bone filled the gap between the endosteal and the implant surface; in hollow and wire mesh rods bone had grown inside through the lateral holes or loops of the mesh. Revascularization took place together with remodelling of the endosteal, primary bone to mature lamellar. In full implants a reticle of newly formed vessels developed around the rods; in hollow and wire mesh implants vessels had grown inside the implant itself and the endosteal surface had a more regular profile than in full rods. Wire mesh plugs prevented formation of a peripheral medullary space and showed no encapsulation; wires in contact with or in proximity to the endosteal surface were incorporated by lamellar systems with strong connections with the original cortical bone
Periosteal chondroma of the humerus leading to shortening. A case report.
No full textWe report a case of periosteal chondroma of the proximal humerus with multiple cartilaginous masses extending around two-thirds of the metaphysial circumference. The humerus was short, presumably because the tumour interfered with growth at the epiphysial plate
Oto-Palato-Digital syndrome in four generations of a large family.
No full textA new large family, affected by O-P-D syndrome is reported. Nine members in four consecutive generations have been studied. Computerized tomography study of spine and skull showed abnormalities to be confined to mesodermal derivates, while nervous structures were normal. Transmission pattern may be X-linked with intermediate expression in the female or autosomal dominant with sex limitation of expression
Pathology of the bone-cement interface in loosening of total hip replacement.
No full textThe histopathology of the bone-cement interface in nine retrieved hip prostheses is reported. Three cases presented features similar to those observed by Charnley in highly successful implants, and they were classified as stable prostheses, although signs of periprosthetic bone resorption were already present. In this group a macrophagic reaction was evident even in the presence of a stable bone-cement interface, supporting the view that the release of particles by the cement or by the prosthetic components can precede the mechanical instability and be the primary cause of loosening. In six prostheses the connective tissue layer between the cement and the bone was thick and no bone trabecula reached the cement surface. The polymorphous features of this connective membrane probably resulted from instability and movement at the bone-cement and stem-cement interfaces. On the basis of the pathological changes observed in the study, the process of loosening must be far advanced before it is detected on radiographs; it is suggested that scintigraphy is the best noninvasive technique to demonstrate macrophage activation and increased bone remodeling around the cement in the early phases of loosening
Bone resorption in vitro: macrophages and giant cells from failed total hip replacement versus osteoclasts.
No full textMacrophages and giant cells which ingested material particles in loosening of total hip prostheses were tested for their ability to resorb bone in vitro, using osteoclasts as the control. Macrophages and giant cells did not form pits or resorption lacunae on the bone substrates as osteoclasts did. The results support the view that around implants also bone resorption is mediated by osteoclasts. A role of macrophages in the attachment phase of bone resorption is suggested
The role of macrophages and giant cells in loosening of joint replacement.
No full textMacrophages and foreign-body giant cells from the bone-cement interface of loosened joint replacement were assayed for direct bone resorption in an in vitro experimental model. Human osteoclasts from giant cell tumors and experimental animal osteoclasts were not capable of resorbing the bone under experimental conditions, but osteoclasts are. It is suggested that macrophages and giant cells in loosened implants may initiate bone resorption, removing the extra-cellular barrier that normally protects mineral crystals from osteoclastic recognition
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