Correlation of estradiol in pregnancy and anterior cruciate ligament laxity

The purpose of this study was to determine whether a correlation existed between estradiol in pregnancy and laxity of the anterior cruciate ligament by measuring anterior tibial translation. All patients underwent measurement of anterior tibial translation using KT-1000 knee arthrometer testing and serum estradiol determination during the third trimester of pregnancy and postpartum. Forty knees were studied. The average serum estradiol levels decreased from 10,755.0 ng/L to 50.3 ng/L. There was an average decrease anterior tibial translation with a manual maximum displacement of 3.0 mm (range, 1 mm-5 mm) from the first to second examinations. Average measurement of anterior tibial translation in pregnant women showed a statistically significant increase in laxity in the third trimester of pregnancy compared with the postpartum laxity. The results of this study show that high serum estradiol levels during the third trimester of pregnancy correlate with increased anterior tibial translation and that this anterior tibial translation decreases with the return of serum estradiol to nonpregnant levels.