Alterations in Knee Kinematics and Dynamic Stability Associated with Chronic Ankle Instability (Original Research) (Report‪)‬

Lateral ankle sprain is one of the most common injuries among athletes and in the general population, (1) with an estimated daily injury rate of 1 in 10 000 people. (2) Yearly costs for the management and treatment of ankle injuries have been estimated to be greater than $2 billion. (3) Among those sustaining a first-time injury, the recurrence rate of ankle injury among active individuals is reported to be as high as 80%. (4) Altered ankle function due to repeated disruptions in the structural integrity of the ankle, with resultant perceived and observed deficits in neuromuscular control and mechanical stability, has been described as chronic ankle instability (CAI). (5) It has been reported that CAI is associated with deficits in dynamic postural control as quantified through measures of lower extremity reaching distance using the Star Excursion Balance Test, (6-8) kinematic and kinetic assessments of jump landing, (9,10) and the ability to create stability after landing from a jump. (11-15) Although these measures have consistently exposed deficits in measures of dynamic postural control related to CAI, most investigators have not quantified the contributions of the ankle, knee, and hip in completing the dynamic postural control task. Yet the few groups (7-10) that have examined these relationships showed a consistent alteration in proximal joint kinematics in the limbs of those with CAI.