NEW YORK (Reuters Health) - Cerebral fat microembolism during joint replacement is not clearly associated with the cognitive decline that may follow, according to a report in the March issue of Stroke.

"Given the fact that cognitive decline is well described after orthopedic procedures, we were quite surprised to not find any correlation between microemboli and cognitive outcome," Dr. Sebastian Koch from University of Miami, Miller School of Medicine, Florida told Reuters Health.

Dr. Koch and associates examined 24 patients age 65 years and older following hip or knee replacement. All 24 patients had intraoperative microemboli, the authors report, and there were no differences in the sizes of emboli in patients with and without a venous-arterial shunt.

Three-quarters of the patients had cognitive decline at discharge, the results indicate, and 10 of 22 patients continued to have cognitive decline at 3 months.

There were no significant differences in microemboli between patients with and without cognitive deficits at any time studied, the researchers note.

"A question remaining is if we captured all the emboli possible," Dr. Koch said. "I suspect that some patients may embolize once surgery is completed. We only monitored patients intraoperatively. This is something that may be worth looking into further."

"At this point, I believe that the subject deserves further study, and it may be too premature to discard microemboli as the etiology of cognitive dysfunction seen after orthopedic surgery," Dr. Koch concluded.