Nuffield Orthopaedic Centre

About: Nuffield Orthopaedic Centre is a healthcare organization based out in Oxford, United Kingdom. It is known for research contribution in the topics: Population & Arthroplasty. The organization has 2082 authors who have published 2920 publications receiving 145718 citations.

Outcome Instruments: Rationale for Their Use

Abstract: The number of outcome instruments available for use in orthopaedic observational studies has increased dramatically in recent years. Properly developed and tested outcome instruments provide a very useful tool for orthopaedic research. Criteria have been proposed to assess the measurement properties and quality of health-status instruments. Unfortunately, not all instruments are developed with use of strict quality criteria. In this article, we discuss these quality criteria and provide the reader with a tool to help select the most appropriate instrument for use in an observational study. We also review the steps for future use of outcome instruments, including the standardization of their use in orthopaedic research.

Mechanical influences on tibial fracture healing.

Abstract: Selected studies are summarized that measure interfragmentary fracture displacements in 6 degrees of freedom at intervals throughout healing in groups of patients with tibial diaphyseal fractures treated by external skeletal fixation. The results are compared with those obtained from experimental studies in which the ideal mechanical conditions for fracture healing were predicted. A finite element analysis model of the healing tibial fracture also was developed. Measured data were used for the analysis, and stress and strain patterns were defined for different stages of healing. Interfragmentary movement measured in the first 6 weeks after injury usually is a magnitude smaller in patients treated by external fixation than in patients treated with cast immobilization. This movement can be much smaller than that predicted to be optimal by experimental studies. A greater amplitude can be achieved, even in stable fractures, by ensuring patient activity. The interfragmentary movement is elastic during loading activity and is generally sinusoidal during steady walking. At the time of dynamization (the unlocking of the frame), a permanent set occurs at the fracture site in all planes. The cyclical movement range in each plane often decreases immediately after unlocking. The model analysis study of fracture healing predicts that tissue damage may occur in the later (hard callus) phase of healing, even while the fixation device is in place, because of abnormally high stresses and strains. This study indicates that fracture mechanics should be controlled more rigorously to provide amplitudes of movement in the first 4 to 6 weeks after fracture. The rigidity of fixation should be increased in the subsequent weeks until the fracture has healed and the frame is removed.

Histogenesis of bone cells

Abstract: Interesting information on the origin of osteogenic cells is currently being obtained from studies of marrow tissue. Experimental evidence shows that marrow contains two main cellular systems, the stroma and the hemopoietic system, and that these are derived from histogenetically distinct cell lines in the postnatal organism. Stromal cells of marrow have potential for bone formation whereas the cells responsible for bone resorption, the osteoclasts, are derived from monocytic cells, components of the hemopoietic system. The possibility that, in the postnatal organism, there is interchange between osteoblasts, osteoclasts and their precursors or that they are derived f rom a common ancestral cell, has been a controversial subject for many years. Whether there is t ransformation between stromal and hemopoietic cells, or a pluripotent stem cell capable of giving rise to both, is very relevant to the subject under consideration. Recent observations using transmission and scanning electron microscopy have demonstrated that the stroma of marrow consists mainly of a network of reticular cells and fibers together with the endothelial cells lining the walls of the sinusoidal vessels. The cytoplasm of reticular and endothelial cells are rich in filaments and rough endoplasmic reticulum and there are fine fibrous elements associated with the cell surfaces. As judged by their morphological appearance these cells are members of the ' f ibroblas t ' family, i.e. capable of producing extracellular connective tissue fibers. The hemopoietic cells are supported by the stromal network, most of them being loosely held in it. An exception are the macrophages whose long processes appear to intertwine with and enwrap the stromal cells and consequently are difficult to dislodge from the stromal network, although they are in fact physically separate f rom it and a different cell type. Because of this close association, macrophages together with reticular and endothelial cells have been included under the term reticuloendothelial system and due to the presence of the macrophages