Traumatic uraemia is of particular significance to orthopaedic surgeons in so far as this complication is responsible for high mortality in cases of severe injury, crushing injury, traumatic shock, gun-shot wounds, incompatible blood transfusions, and the misuse of tourniquets. In this contribution the association between muscle injury and renal failure is reviewed.

The syndrome of the "crush kidney," which at first was thought to be the result of deposition of myohaemoglobin in the renal tubules, is almost certainly due to the association of many factors, all of which lead to alteration of the renal circulation and renal ischaemia.

Certainly the combination of ischaemia of the kidney with deposition of pigment and haemolysis of blood causes a high mortality in animals, and it is believed that this may account for the serious prognosis in human cases where there is both shock and haemolysis.

Disturbance of water balance, allergic phenomena, and chemical nephrotoxic action are also discussed. The pathology is considered together with significant changes in the blood chemistry.

A plea is made for early recognition of this clinical syndrome with its characteristic features. Important aspects of treatment are discussed. The dangers of excessive intravenous infusion are emphasised.

Closer investigation and further research promise to throw light on the more accurate localisation of function in the nephron, to add to our knowledge of traumatic arterial spasm, and to explain many orthopaedic problems which hitherto appeared insoluble.