Context: Analyzing ligament stiffness between males and females at 3 maturational stages across the lifespan may provide insight into whether changes in ligament behavior with aging may contribute to joint laxity.Objective: To compare the stiffness of the medial structures of the tibiofemoral joint and the medial collateral ligament to determine if there are differences at 3 distinct ages and between the sexes.Design: Cross-sectional study. Setting: Laboratory. Patients or Other Participants: A total of 108 healthy and physically active volunteers with no previous knee surgery, no acute knee injury, and no use of exogenous hormones in the past 6 months participated. They were divided into 6 groups based on sex and age (8-10, 18-40, 50-75 years).Main Outcome Measure(s): Ligament stiffness of the tibiofemoral joint was measured with an arthrometer in 08 and 208 of tibiofemoral-joint flexion. The slope values of the forcestrain line that represents stiffness of the medial tibiofemoral joint at 08 and the medial collateral ligament at 208 of flexion were obtained.Results: When height and mass were controlled, we found a main effect (P , .001) for age group: the 8-to 10-year olds were less stiff than both the 18-to 40-and the 50-to 75-year-old groups. No effects of sex or tibiofemoral-joint position on stiffness measures were noted when height and mass were included as covariates.Conclusions: Prepubescent medial tibiofemoral-joint stiffness was less than postpubescent knee stiffness. Medial tibiofemoral-joint stiffness was related to height and mass after puberty in men and women.Key Words: medial collateral ligament, arthrometry, hormones, sex differences
Key PointsMedial tibiofemoral-joint stiffness was less in prepubescents than in postpubescents. After puberty, medial tibiofemoral-joint stiffness was influenced by height and mass in both men and women.