Cyclic variations in multiplanar knee laxity influence landing biomechanics

Area of Science:

• Biomechanics
• Kinesiology
• Orthopedics

Background:

• Female knee laxity exhibits significant cyclic fluctuations throughout the menstrual cycle.
• The biomechanical consequences of these menstrual cycle-related laxity changes remain largely unexplored.

Purpose of the Study:

• To categorize females based on distinct patterns of multiplanar knee laxity changes across the menstrual cycle.
• To compare landing biomechanics between identified female clusters and a male group, focusing on shifts from minimum to maximum laxity.

Main Methods:

• Collected data on anterior knee laxity (AKL), genu recurvatum (GR), varus-valgus (VV), and internal-external rotation (IER) laxity in 71 females and 49 males.
• Performed biomechanical analysis of a drop jump at minimum (T₁) and maximum (T₂) laxity points for females.
• Utilized cluster analysis to identify four distinct female laxity patterns (C₁-C₄); males served as a control group.

Main Results:

• Female clusters (C₃, C₄) with increased sagittal and frontal plane laxity exhibited significantly greater knee valgus during landing compared to C₁.
• Females with increased internal-external rotation (IER) but not AKL (C₂) showed greater internal rotation than those with increased AKL and IER (C₃, C₄) or males.

Conclusions:

• Menstrual cycle-induced knee kinematic alterations depend on the magnitude and interplay of multiplanar laxity changes.
• Specific patterns of increased multiplanar laxity (e.g., C₄) correlate with higher-risk knee joint positions during landing, suggesting potential injury susceptibility.