An episode ofhypotension is common during cemented joint replacement, and has been associated with circulatory collapse and sudden death. We studied the mechanism of hypotension in two groups of six dogs after simulated bilateral cemented arthroplasty. In one group, with no lavage, the insertion of cement and prosthesis was followed by severe hypotension, elevated pulmonary artery pressure, decreased systemic vascular resistance and a 21% reduction in cardiac output. In the other group, pulsatile intramedullary lavage was performed before the simulated arthroplasties. Hypotension was less, and although systemic vascular resistance decreased, the cardiac output did not change. The severity ofthe hypotension, the decrease in cardiac output and an increase in prostaglandin metabolites were related to the magnitude of pulmonary fat embolism. Pulsatile lavage prevents much of this fat embolism, and hence the decrease in cardiac output. The relatively mild hypotension after lavage was secondary to transient vasodilatation, which may accentuate the hypotension caused by the decreased cardiac output due to a large embolic fat load. We make recommendations for the prevention and management of hypotension during cemented arthroplasty.

An analysis of 51 type III open tibial fractures treated by external skeletal fixation is presented. The fractures are subdivided according to the classification of Gustilo, Mendoza and Williams (1984) into types IIIa, IIIb and IIIc. The different prognoses of these fracture subtypes is examined. The use of the Hoffmann and Hughes external fixators in the management of type III open tibial fractures is presented and it is suggested that the prognosis is independent of the type of fixator used.

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