[Relationship between avascular necrosis and lipid and purine metabolisms].

The serum levels of uric acid, triglycerides, cholesterol, and lipoproteins were determined in 35 patients suffering from primary avascular necrosis. The results were compared with those of a control group and with those of patients suffering from gout. The frequency distribution of the results in the three groups was of the log-normal type and statistical calculations were made on logarithmic transformations of the serum values. In comparison with the control group, significant increases in the levels of triglycerides, cholesterol, pre-beta-lipoproteins, and uric acid were observed in patients presenting an avascular necrosis. No significant differences were observed between these patients and patients with gout in the levels of lipids and lipoproteins. Uricaemia was higher in the gout patients. Contrary to observations made on the gout patients, there was no correlation in the avascular necrosis patients between the uric acid level and the serum levels of lipids or lipoproteins. In an earlier study the authors put forward an hypothesis according to which the close relationship between the lipid and purine metabolisms in gout patients was due to a genetic linkage based on a common enzyme defect, which directly affected the two metabolisms. In avascular necrosis there is no common enzyme defect; the initial event is a disturbance in the lipid metabolism. The authors conclude with data which tend to show that the bone necrosis observed in patients using steroids or alcohol is not directly induced by these substances, but that once again the initial event is a disturbance in the lipid metabolism.