Effect of tourniquet ischaemia on muscle energy metabolism in meniscectomy patients.

The enzyme levels of muscle energy metabolism were studied in eight male meniscectomy patients before and 10 minutes after release of the tourniquet and on the third post-operative day. The average tourniquet time was 65.1 min. The muscle samples were taken from the vastus lateralis muscles; the healthy side served as the control. The greatest enzyme changes 10 min after release of the tourniquet were the falls in succinate dehydrogenase (SDH) and creatine phosphokinase (CPK) activities, (p less than 0.01 and p less than 0.025 respectively). On the 3rd day phosphofructokinase (FFK) and malate dehydrokinase (MDH) activities were also lowered in the tourniquet limb, but the lactate dehydrogenase (LDH) was not changed significantly. In the control extremity only SDH showed a lowered value on the 3rd post-operative day (p less than 0.05), perhaps due to hypokinesia in hospital. The results indicate that even one-hour tourniquet ischaemia causes an enzyme release from muscle and for at least three days after the tourniquet enzyme activities in muscle are lowered, perhaps because of the combined effect of the tourniquet ischaemia and hypokinesia after the operation.