Motor imagery in high-functioning individuals with chronic anterior cruciate ligament deficiency: A cross-sectional study

Background: There is increasing evidence that motor imagery performance (MIP) is impaired in conditions that have a component of movement dysfunction. However, MIP has not been investigated in people with chronic anterior cruciate ligament (ACL) deficiency who experience limited disability and function at high levels. Hypothesis: This study had three objectives: (1) to assess implicit MIP in individuals with a chronic ACL deficient (ACLD) knee compared with healthy controls (i.e., intact anterior cruciate ligament); (2) to determine if the location of ACL deficiency affects MIP (dominant versus non-dominant leg); and (3) to determine if impairment in MIP is specific to the side (injured versus non-injured) of ACL deficiency. Methods: Forty-five participants with chronic ACLD knee and 44 healthy controls completed a left/right judgement task of pictured knees using the “Recognise” app to evaluate implicit MIP. Accuracy and reaction time of judgements were compared between groups. Additionally, within the chronic ACLD knee group, we made comparisons between the dominant ACLD knee and non-dominant ACLD knee subgroups and between the injured knee and the non-injured knee of the ACLD group. Results: There were no differences in implicit MIP between the ACLD knee and the control group, the non-injured knee versus injured knee of the ACLD knee group, or the dominant ACLD knee versus non-dominant ACLD knee subgroups. Conclusion: Implicit MIP is not disrupted in high functioning individuals with chronic ACLD knee.