2 Clinical Trials for Various Conditions
The purpose of this study is to expand on previous knowledge of the hormonal effects, specifically estrogen, on ligament laxity, motor control and timing of muscle activation in females. A significant amount of research has previously been done on the effects of estrogen throughout the menstrual cycle on ligament laxity with some showing a correlation of increased estrogen levels with increased ligament laxity. There have also been several studies that investigated muscle activation and ground reaction forces as related to hormone levels and stages of the menstrual cycle. A recent systematic review found a lack of research investigating muscle activation timing as related to hormonal changes despite theories suggesting muscle function including timing could be an explanation as to the potential causes for increased ACL injury correlated with the luteal phase of the menstrual cycle. The aim of this study is therefore to investigate whether hormonal changes throughout the menstrual cycle correlate with changes in ligament laxity, motor control, muscle activation and timing. This study will be a longitudinal controlled study with two groups both containing females ages 18-35 years of age. The subjects will be placed into either the Experimental Group (no birth control) or the Control Group (on birth control) depending on the status of their contraceptive use.
The proposed research will focus on determining the effect of methylsulfonylmethane (MSM) on knee laxity changes through the menstrual cycle in young active females. As an extension to recent discovery, that MSM reverses the negative effect of estrogen on engineered ligament function, the proposed work is designed to determine whether MSM can decrease the negative effect of estrogen on knee laxity in females. Ligament function is determined by the content and cross-linking of collagen, which is influenced by a milieu of biochemical and mechanical parameters. The greater the amount and cross-linking the greater the stiffness and strength of these connective tissues. In engineered ligaments it has been previously shown that the high levels of estrogen, normally present in the days before and after ovulation, can inhibit the cross-linking enzyme lysyl oxidase. This decrease in collagen cross-linking likely increases connective tissue laxity and contributes to observed 4-fold greater occurrence of anterior cruciate ligament (ACL) rupture in females. Conversely, MSM increases collagen cross-linking and recent work conducted by the Baar lab in engineered human ligaments treated with high estrogen demonstrated that MSM could completely reverse the effects of estrogen on ligament mechanics. The proposed research aims to advance this promising pre-clinical data and apply in a clinical trial. This research also proposes to quantify that knee laxity increases up to 5mm between the first day of menstruation and the day after ovulation and also that the magnitude of the increase in laxity is directly related to the magnitude of the change in estrogen. Importantly, a direct relationship between knee laxity and ACL rupture exists. For every 1.3mm increase in anterior-posterior knee displacement, the odds of ACL rupture increase 4-fold. Therefore, any treatment that decreases knee laxity could be expected to reduce ACL ruptures and have widespread application across the general active population and high-level athletics.