Estrogen effects on ACL laxity and neurocognitive function in young women

Abstract

Objective: To examine the effect of 17β estradiol (E2) on anterior cruciate ligament (ACL) laxity and neurocognitive function in healthy, young women. ☐ Subjects: Six healthy, young women between ages 18-35 years old were recruited for this pilot study. ☐ Design and Setting: Women underwent a controlled hormone intervention to prevent endogenous production of estrogens and progesterone using a gonadotropin releasing hormone antagonist (GnRHant, Ganirelix) for 10 days; E2 was selectively added back (0.1mg/day patch, Vivelle Dot) over the last 7 days. ☐ Measurements: ACL laxity was measured in millimeters during hormone suppression (day 3 of GnRHant) and again after 7 days of E2 administration using the KT 2000 knee arthrometer with customized computer software. Neurocognitive function was assessed via computerized test (Immediate Post- Concussion Assessment and Cognitive Test, ImPACT) on the same days. Composite scores from the ImPACT test were used to evaluate neurocognitive function. A two-tailed, paired samples t-test was used to compare differences between GnRHant and E2 conditions. ☐ Results: Six women enrolled in the study, and 2 dropped out; pilot data presented is on four women (25±6 yrs, 169.2±6.7cm, 69.6±10.4 kg). ACL laxity during GnRHant (4.43 ± 2.15 mm) and E2 conditions (5.44 ± 1.08 mm) were not different (p = 0.437). Verbal memory (91.87 ± 2.29, 98.00 ± 2.65, p=0.424), visual memory (85.00 ± 11.27, 74.67 ± 21.73, p=0.247), motor speed (34.90 ± 8.15, 38.52 ± 5.74, p=0.135) and reaction time (0.703 ± 0.10 s, 0.610 ± .061 s, p=0.327) were also not different between GnRHant and E2 conditions. ☐ Conclusion: These preliminary results suggest minimal changes in ACL laxity or neurocognitive function during short duration E2 administration. Additional research is needed to fully characterize the interactions among ACL laxity, estrogen, and neurocognitive function in women. ☐ Key Words: estrogen, hormones, anterior cruciate ligament, neurocognitive function, KT-2000, knee laxity, female