The impact of differential knee laxity on brain activation during passive knee joint loading

Although higher anterior knee laxity (AKL) is an established risk factor of anterior cruciate ligament injury, underlying mechanisms are uncertain. While decreased proprioception and altered movement patterns in individuals with AKL have been identified, the potential impact of higher laxity on brain activity is not well understood. Thus, the purpose of this study is to identify the impact of different magnitudes of knee laxity on brain function during anterior knee joint loading. Twenty-seven healthy and active female college students without any previous severe lower leg injuries volunteered for this study. AKL was measured using a knee arthrometer KT-2000 to assign participants to a higher laxity (N = 15) or relatively lower laxity group (N = 12). Functional magnetic resonance images were obtained during passive anterior knee joint loading in a task-based design using a 3 T MRI scanner. Higher knee laxity individuals demonstrated diminished cortical activation in the left superior parietal lobe during passive anterior knee joint loading. Less brain activation in the regions associated with awareness of bodily movements in females with higher knee laxity may indicate a possible connection between brain activity and knee laxity. The results of this study may help researchers and clinicians develop effective rehabilitation programs for individuals with increased knee laxity.