Platelet activity (malondialdehyde production) after orthopaedic surgery: the effect of aspirin.

Using a biochemical assay of the prostaglandin endoperoxide metabolite malondialdehyde, platelet activity was evaluated in 147 patients who were undergoing orthopaedic surgical procedures. Assays were performed before and after operation and the results were correlated with the type of operation, the sex of the patient, and the use of aspirin as an antiplatelet-aggregation agent. Postoperatively, statistically significant elevations of platelet activity were found in patients who were not taking aspirin, while highly statistically significant suppressions of this activity were found after total hip arthroplasties and other surgical procedures in patients who had received aspirin. Men and women had similar levels of suppression of platelet aggregability with aspirin.