Medial Tibiofemoral-Joint Stiffness in Males and Females Across the Lifespan

Abstract

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 0° and 20° of tibiofemoral-joint flexion. The slope values of the force-strain line that represents stiffness of the medial tibiofemoral joint at 0° and the medial collateral ligament at 20° 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.