Summary
Increased anterior knee joint laxity during ovulation, measured by an arthrometer, may elevate ACL injury risk in women.
Abstract
Objective
Anterior knee joint laxity is closely linked to injuries of the anterior cruciate ligament (ACL). Women are about three times more likely to tear their ACL than men [1, 2]. The ovulation phase appears to be a risk factor for ACL ruptures [1, 4]. The aim of this study is to determine the influence of the menstrual cycle on anterior knee joint laxity, measured using an arthrometer.
Methods
In a prospective clinical setting, anterior knee joint laxity was measured in six healthy female participants using the Lachman test with an arthrometer (Rolimeter ®CE) on the right knee. Measurements were taken across three menstrual cycles during the menstruation, follicular, ovulation, and luteal phases. The current cycle phase was determined using a commercially available ovulation test (urine sample) and a menstrual cycle questionnaire. Additionally, a pregnancy test was performed at the final testing session using a ß-hCG urine measurement. Data analysis was conducted using SPSS. If a normal distribution was confirmed via the Shapiro-Wilk test, repeated measures ANOVA was performed. Significance was set at p<0.05.
Results
Repeated measures ANOVA revealed a significant difference in anterior knee joint laxity across the menstrual cycle phases (p<0.001). Post-hoc Bonferroni analyses indicated a significantly increased anterior knee laxity during the ovulation phase compared to all other phases. Anterior knee laxity measured 8.1 mm (+/- 0.3 mm) in the ovulation phase, 7.1 mm (+/- 0.4 mm) in the follicular phase, 6.7 mm (+/- 0.4 mm) in the luteal phase, and 7.0 mm (+/- 0.4 mm) in the menstruation phase.
Conclusion
These findings contribute to reducing the "gender data gap." The increased anterior knee joint laxity observed during the ovulation phase may lead to a higher incidence of ACL injuries. Follow-up studies will further explore how these insights can help optimize surgical timing, physiotherapy rehabilitation, and return-to-sport testing in relation to the menstrual cycle.
References:
1. Somerson, J.S., et al., The Menstrual Cycle May Affect Anterior Knee Laxity
and the Rate of Anterior Cruciate Ligament Rupture: A Systematic Review and
Meta-Analysis. JBJS Rev, 2019. 7(9): p. e2.
2. Montalvo, A.M., et al., Anterior Cruciate Ligament Injury Risk in Sport: A
Systematic Review and Meta-Analysis of Injury Incidence by Sex and Sport
Classification. J Athl Train, 2019. 54(5): p. 472-482.
3. Wojtys, E.M., et al., The effect of the menstrual cycle on anterior cruciate ligament
injuries in women as determined by hormone levels. Am J Sports Med, 2002. 30(2):
p. 182-8.