How do knee joint and its alignment contribute to the postural control of quiet stance?

Abstract

The control of human quiet stance has long been the subject of interest for decades. Biomechanical and neurological studies have been extensively evaluated to create the
understanding of how human control their stance stability. Even though many studies have committed that human stance is much similar to the single inverted pendulum (SIP), recent studies revealed the multi-joint coordination to be more efficiently control strategy. The studies of multijoint coordination are growing in number these
days, and this may indicate the importance to study the role of other joints, i.e., the knee joint, in contributing to balance control during quiet standing. Despite aiding in control balance, the exact role of the knee joint has never been reported, further investigations are needed. Since the ankle and hip joints are linked at the knee joint,
thus the alignment of the knee joint may affect the postural strategies elicited during balance correction. Researchers found that individuals with knee hyperextension, mal-alignment between femur and tibia, demonstrated poorer stance stability, but they were still be able to respond to external perturbations resemble to normal knee
alignment individuals. Some researchers speculated that individuals with hyper-mobility of the knee joint may have impaired proprioception of the knee near end range from flexion to extension. When the proprioception is altered, the postural control system might also be altered since the proprioception is important for planning
and adjusting body position and movement. In spite of the same postural responses, the question of how the central nervous system (CNS) controls those movements remains.