Self-reported oral contraceptive use and peripheral joint laxity

Study Design: A masked, single-factor, posttest-only control group design. Objective: To explore the relationship between reported oral contraceptive use and peripheral joint laxity. Background: Studies have found an association between increased ligamentous laxity and changes in serum levels of hormones such as estrogen, progesterone, and relaxin. Two of these hormones, estrogen and progesterone, are present in most oral contraceptives. Oral contraceptive users, therefore, provide a population for studying the effects of these hormones on the degree of ligamentous laxity. Methods and Measures: Fifty-five women between the ages of 20 and 25 years participated in this study. Thirty users of oral contraceptives were a test group and 25 nonusers of oral contraceptives were controls. The KT-1000 Arthrometer was used to measure passive anterior translation of the tibia in relation to the femur in both knees. Passive abduction and adduction of the proximal interphalangeal (PIP) joint of the second digit of the nondominant hand and distal interphalangeal (DIP) joint hyperextension of the fifth digit of the nondominant. hand were measured using a goniometer. A subjective measurement of passive second PIP joint motion was also assessed and a value of minimum, moderate, or maximum laxity was assigned. Independent sample t tests were performed to compare the measurements of the oral contraceptive user and nonuser groups for each joint. A chi-square test compared the subjective PIP joint data between the 2 groups. Results: No significant differences in laxity measurements at the knee or hand were found between the 2 groups. Average knee laxity varied between 5.7-7.9 mm of anterior displacement for both groups. Average PIP abduction and adduction varied between 6.5-6.7 degrees for both groups and DIP hyperextension was 28.6-29.9 degrees. Conclusions: Results of this study indicate that self-reported oral contraceptive use was not associated with peripheral joint laxity.