Anterior cruciate ligament laxity related to the menstrual cycle: an updated systematic review of the literature

The purpose of this study was to conduct a systematic review regarding the purported differences in anterior cruciate ligament (ACL) laxity throughout the course of the menstrual cycle. A systematic review was performed by searching electronic databases, along with hand-searching of journals and reference tracking for any study that assessed ACL integrity throughout the menstrual cycle from 1998 until 2011. Studies that met the pre-defined inclusion criteria were evaluated using the Modified Sackett Score (MSS) instrument that assessed their methodological quality. Thirteen articles out of a possible 28 met the inclusion criteria. This systematic review found 13 clinical trials investigating the effect of the menstrual cycle on ACL laxity. There is evidence to support the hypothesis that the ACL changes throughout the menstrual cycle, with it becoming more lax during the pre-ovulatory (luteal) phase. Overall, these reviews found statistically significant differences for variation in ACL laxity and injury throughout the menstrual cycle, especially during the pre-ovulatory phase. Female athletes may need to take precautions in order to reduce the likelihood of ACL injury. However, the quality of the assessments was low and the evidence is still very limited. More and better quality research is needed in this area.