Evaluating knee ligament laxity in healthy women during their menstrual cycle

Evaluation of Anterior Tibial Translation of the Knee in Healthy Women, at Two Times of the Menstrual Cycle, on Hormonal Contraceptives or Not (FLEX)

Not applicable Interventional Centre Hospitalier Universitaire de Nice · NCT05177549

This study is testing how different phases of the menstrual cycle affect knee ligament looseness in healthy women to see if hormonal changes influence the risk of knee injuries.

Quick facts

PhaseNot applicable
Study typeInterventional
Enrollment90 (estimated)
Ages18 Years to 40 Years
SexFemale
SponsorCentre Hospitalier Universitaire de Nice Academic / other
Locations1 site (Nice)
Trial IDNCT05177549 on ClinicalTrials.gov

What this trial studies

This study investigates the impact of hormonal factors and menstrual cycle phases on anterior tibial translation in healthy women, focusing on those who are either using hormonal contraceptives or not. By examining the knee's ligament laxity at a specific point in the menstrual cycle, the research aims to understand the relationship between hormonal changes and the risk of anterior cruciate ligament injuries. The study involves bilateral knee examinations using a Lachmeter® to measure laxity. This research is particularly relevant given the increased risk of ACL injuries in women compared to men.

Who should consider this trial

Good fit: Ideal candidates are healthy women aged 18 to 40 with regular menstrual cycles and no history of lower limb surgery.

Not a fit: Patients who have undergone lower limb surgery or have irregular menstrual cycles may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could lead to improved understanding and prevention strategies for ACL injuries in women.

How similar studies have performed: This approach is novel, as no previous studies have specifically investigated the relationship between hormonal factors and ligament laxity in this context.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Woman between 18 and 40 years old
* No history of surgery of the 2 lower limbs
* No change in contraceptive method in the last 6 months
* Signature of the informed consent
* Affiliation to the social security system
* To be at Day 14 of her menstrual cycle (+/-1 day) (the first day of the cycle (Day1) being considered as the first day of the menstrual period), except for those on micro-progestative contraception not regulated

By inclusion group:

- For women without hormonal contraception: No method of contraception Or a copper intrauterine device Regular cycles of 26 to 33 days

- For women on estrogen-progestin contraception: Correct use of the estrogen-progestin pill according to the MA Or wearing a vaginal ring according to the MA protocol Or wearing a contraceptive skin patch according to the MA protocol Regular cycles of 26 to 33 days

- For women on micro-progestin contraception : Continuous use of the micro-progestogen pill Or wearing a subcutaneous hormonal implant,

Exception: women on micro-progestin contraception who are not regulated:

* They may have an irregular cycle or no cycle to be included
* They can be included on any day if they have no cycle

Exclusion Criteria:

* Pregnancy or breastfeeding in progress
* Hormonal intrauterine device or injectable contraception
* Menopause (defined as no menstruation for one year)
* Surgery: tubal ligation, oophorectomy, adnexectomy, hysterectomy
* History of microcrystalline or infectious pathology localized to the knee
* History of systemic or localized inflammatory joint disease of the knee
* History of fracture, severe sprain or dislocation of the knee joint
* History of osteoarticular or congenital diseases that may lead to laxity (Marfan syndrome, trisomy 21, Ehlers-Danlos syndrome...)
* Sign of hyperlaxity evaluated by a Beighton score higher than 4 (see appendix)
* BMI \> 25
* Daily alcohol consumption above the thresholds recommended by Public Health in France (more than 2 glasses per day)
* Woman unable to understand the protocol
* Intense or unusual physical exercise during the last 72 hours (e.g.: marathon, triathlon, competitive cycling race...)
* Woman under guardianship, curatorship or deprived of liberty

Where this trial is running

Nice

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions LigamentLaxityhormonal impregnation
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.