Brain Activation for Knee Movement Measured Days Before Second Anterior Cruciate Ligament Injury: Neuroimaging in Musculoskeletal Medicine.

BACKGROUND:   Anterior cruciate ligament (ACL) injury has multifactorial causes encompassing mechanical, hormonal, exposure, and anatomical factors. Alterations in the central nervous system also play a role, but their influence after injury, recovery, and recurrent injury remain unknown. Modern neuroimaging techniques can be used to elucidate the underlying functional and structural alterations of the brain that predicate the neuromuscular control adaptations associated with ACL injury. This knowledge will further our understanding of the neural adaptations after ACL injury and rehabilitation and in relation to future injury risk. In this paper, we describe the measurement of brain activation during knee extension-flexion after ACL injury and reconstruction and 26 days before a contralateral ACL injury.

METHODS:   Brain functional magnetic resonance imaging data for an ACL-injured participant and a matched control participant were collected and contrasted.

RESULTS:   Relative to the matched control participant, the ACL-injured participant exhibited increased activation of motor planning, sensory processing, and visual-motor control areas. A similar activation pattern was present for the contralateral knee that sustained a subsequent injury.

CONCLUSIONS:   Bilateral neuroplasticity after ACL injury may contribute to risk of second injury, or aspects of neurophysiology may be predisposing factors to primary injury.

CLINICAL IMPLICATIONS:   Sensory-visual-motor function and motor-learning adaptations may provide targets for rehabilitation.