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

Abstract

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 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 the 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.

Keywords: functional magnetic resonance imaging; motor control; neuroplasticity.

Figures

Figure 1.

A–E, Experimental setup. The stimulus was cued with an auditory metronome and a 2-second visual prompt.

Figure 2.

Regions with greater activation in movement of the anterior cruciate ligament-reconstructed knee. A, Right premotor and motor cortex. B, Right lingual gyrus. C, Right crus II cerebellum. D, Left secondary somatosensory. E, Region with lower activation in movement for the anterior cruciate ligament-reconstructed knee: Left crus I cerebellum. All values reported are cluster corrected for multiple comparisons at P < .01. Abbreviation: MNI, Montreal Neurological Institute and Hospital. Color image available in online version.