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PROGETTO ARCHITETTONICO - Reti esibite
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Dynamic axial fixation. A rational alternative for the external fixation of fractures
Conventional external fixation systems neither inhibit motion at the fracture site sufficiently to permit primary bone healing, nor do they allow sufficient motion to encourage adequate external callus formation. Healing with such systems is therefore prolonged. These methods are usually reserved for the most severe fractures when internal fixation may be contraindicated. A unilateral, dynamic axial fixation system (Orthofix - registered trademark) is described which allows for simple conversion from a rigid to a dynamic mode, and so can be readily adapted to the changing physiological patterns of fracture repair. In 288 fresh fractures a success rate of 94% was achieved, with an average time to healing of 4.4 months. The incidence of pin-track infection was only 0.6%. The contribution which the mechanical and design features of the apparatus make to the results obtained is discussed. It is suggested that the system is capable of extending the range of indications for an externally mounted system to include many cases which would formerly have been treated by internal fixation, plaster cast or traction
Limb lengthening by distraction of the epiphyseal plate. A comparison of two techniques in the rabbit
We have compared, in rabbits, two techniques of limb lengthening by distraction of the epiphyseal plate using a unilateral external fixation frame. In all cases, 14 mm of symmetrical lengthening without deviation was achieved. With rapid distraction at rates of 1 mm per day (distractional epiphyseolysis) separation of the epiphysis from the metaphysis occurred by day 7, and by day 70 almost complete ossification of the cartilage and the elongated segment was evident. In contrast, slow distraction at 0.25 mm every 12 hours (chondrodiatasis) produced hyperplasia of growth cartilage without any evidence of detachment at 28 days, the end of the distraction period. By day 70 the epiphyseal plate had returned to normal thickness with normal cellular morphology, while the lengthened segment was occupied by ossified tissue. The significance of these findings is discussed
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