The authors compared the informative value of the intraoperative criteria for assessing viability of muscles in high amputations of limbs for chronic critical ischaemia. It was revealed that such signs as subjectively evaluated bleeding, contractility and oedema of muscles possess low specificity in relation to the development of early postoperative complications. Intraoperative macroscopic histochemical study (IHCS) of the activity of muscular tissue lactate dehydrogenase at the level of amputation showed sensitivity of 96,3% and specificity of 92,9 %. Taking into consideration the results of IHCS for objectivization of the choice of the level of amputation made it possible to save the knee joint in 8,9 % of patients with gangrene on the background of high occlusion of lower limb arteries and to decrease the frequency of postoperative necrosis of muscle of the stump from 15,0% to 3,5%.