Part 1: Neural Correlates of Motor Imagery in ACLR Patients This cross-sectional study aims to systematically compare differences in electroencephalographic (EEG) activity between patients who have returned to sport one year after anterior cruciate ligament reconstruction (ACLR) and healthy controls during functional tasks and associated motor imagery. We will collect EEG activity and behavioral performance data from both groups during task execution and imagination. The primary objective is to verify whether ACLR patients exhibit a specific deficit in motor imagery capability and to characterize the abnormal functional patterns within their central sensorimotor networks. By providing an objective, neurophysiological explanation for why patients struggle to return to sport, this study seeks to establish quantifiable baseline metrics for subsequent interventional research. Part 2: Effects and Cortical Plasticity Changes Following Motor Imagery-Enhanced Rehabilitation This randomized controlled trial (RCT) combines short-term intervention with long-term follow-up to systematically evaluate the efficacy and mechanisms of motor imagery therapy in ACLR patients. The specific objectives are threefold: First, to verify the immediate effects of the intervention on enhancing neuroplasticity and restoring motor function. Second, to assess the long-term impact on definitive clinical outcomes-specifically return-to-sport rates and time to return-through a 12-month follow-up. Third, to perform a longitudinal analysis determining whether early improvements in neurophysiological indicators can predict subsequent gains in motor performance and successful return-to-sport outcomes.
Part 1 employs a cross-sectional design, comparing patients one year after anterior cruciate ligament reconstruction (ACLR) (experimental group) with healthy adults (control group). This phase aims to acquire electroencephalography (EEG) and lower limb functional data across different states to elucidate the correlation between cortical function and motor behavior. Part 2 will conduct a 12-week randomized controlled trial (RCT). ACL rupture patients will be allocated to either a motor imagery intervention group or a conventional rehabilitation control group. We will integrate EEG and kinematic analysis to systematically evaluate the therapy's effects on knee function, neuromuscular control, and brain network connectivity. Furthermore, by combining longitudinal EEG and resting-state functional magnetic resonance imaging (rs-fMRI), we will investigate the underlying neuroplastic mechanisms driving functional remodeling within the sensorimotor networks. This research is expected to establish a novel, active intervention strategy based on the "central-driven peripheral" paradigm for ACL postoperative rehabilitation.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
80
Part 2 will conduct a 12-week RCT. The experimental group will receive conventional rehabilitation augmented with motor imagery training. This training will be delivered via a hybrid model (in-person and online) and consist primarily of video-guided imagery sessions.
The control group received conventional rehabilitation only. During in-person sessions, they engaged in passive observation of static photographs, without any form of active mental simulation or motor rehearsal. During remote sessions, they watched the same videos as the experimental group but proceeded directly to physical practice without prior motor imagery.
Peking University Third Hospital
Beijing, Beijing Municipality, China
RECRUITINGEEG delta band (0.5-4 Hz) absolute power
Raw EEG data were collected via Smarting Pro during functional assessments.
Time frame: Part 1 involves a cross-sectional assessment at 12 months after ACL reconstruction. Part 2 is a longitudinal study evaluating patients at four time points: preoperative baseline, 12 weeks, 6 months, and 12 months postoperatively.
EEG theta band (4-8 Hz) absolute power
Raw EEG data were collected via Smarting Pro during functional assessments.
Time frame: Part 1 involves a cross-sectional assessment at 12 months after ACL reconstruction. Part 2 is a longitudinal study evaluating patients at four time points: preoperative baseline, 12 weeks, 6 months, and 12 months postoperatively.
EEG alpha band (8-13 Hz) absolute power
Raw EEG data were collected via Smarting Pro during functional assessments.
Time frame: Part 1 involves a cross-sectional assessment at 12 months after ACL reconstruction. Part 2 is a longitudinal study evaluating patients at four time points: preoperative baseline, 12 weeks, 6 months, and 12 months postoperatively.
EEG beta band (13-30 Hz) absolute power
Raw EEG data were collected via Smarting Pro during functional assessments.
Time frame: Part 1 involves a cross-sectional assessment at 12 months after ACL reconstruction. Part 2 is a longitudinal study evaluating patients at four time points: preoperative baseline, 12 weeks, 6 months, and 12 months postoperatively.
EEG gamma band (30-50 Hz) absolute power
Raw EEG data were collected via Smarting Pro during functional assessments.
Time frame: Part 1 involves a cross-sectional assessment at 12 months after ACL reconstruction. Part 2 is a longitudinal study evaluating patients at four time points: preoperative baseline, 12 weeks, 6 months, and 12 months postoperatively.
Vicon 3D Gait Analysis-Spatiotemporal parameters-Gait Speed
Gait speed recorded during walking using Vicon 3D gait analysis.Unit of Measure: m/s
Time frame: Part 1: cross-sectional assessment at 12 months after ACL reconstruction. Part 2: longitudinal study evaluating patients at preoperative baseline, 12 weeks, 6 months, and 12 months postoperatively.
Vicon 3D Gait Analysis-Spatiotemporal parameters-Step Length
Step length recorded during walking using Vicon 3D gait analysis.Unit of Measure: m
Time frame: Part 1: cross-sectional assessment at 12 months after ACL reconstruction. Part 2: longitudinal study evaluating patients at preoperative baseline, 12 weeks, 6 months, and 12 months postoperatively.
Vicon 3D Gait Analysis-Spatiotemporal parameters-Cadence
Cadence recorded during walking using Vicon 3D gait analysis.Unit of Measure: steps/min
Time frame: Part 1: cross-sectional assessment at 12 months after ACL reconstruction. Part 2: longitudinal study evaluating patients at preoperative baseline, 12 weeks, 6 months, and 12 months postoperatively.
Vicon 3D Gait Analysis-Peak Knee Flexion Angle
Peak knee flexion angle during walking measured using Vicon 3D gait analysis. Unit of Measure: degrees
Time frame: Part 1 involves a cross-sectional assessment at 12 months after ACL reconstruction. Part 2 is a longitudinal study evaluating patients at four time points: preoperative baseline, 12 weeks, 6 months, and 12 months postoperatively.
Vicon 3D Gait Analysis-Peak Knee Extension Angle
Peak knee extension angle during walking measured using Vicon 3D gait analysis.Unit of Measure: degrees
Time frame: Part 1 involves a cross-sectional assessment at 12 months after ACL reconstruction. Part 2 is a longitudinal study evaluating patients at four time points: preoperative baseline, 12 weeks, 6 months, and 12 months postoperatively.
Vicon 3D Gait Analysis-Peak Knee Abduction Angle
Peak knee abduction angle during walking measured using Vicon 3D gait analysis.Unit of Measure: degrees
Time frame: Part 1 involves a cross-sectional assessment at 12 months after ACL reconstruction. Part 2 is a longitudinal study evaluating patients at four time points: preoperative baseline, 12 weeks, 6 months, and 12 months postoperatively.
Vicon 3D Gait Analysis-Peak Knee Adduction Angle
Peak knee adduction angle during walking measured using Vicon 3D gait analysis.Unit of Measure: degrees
Time frame: Part 1 involves a cross-sectional assessment at 12 months after ACL reconstruction. Part 2 is a longitudinal study evaluating patients at four time points: preoperative baseline, 12 weeks, 6 months, and 12 months postoperatively.
Vicon 3D Gait Analysis-Ground Reaction Force - Peak at Initial Contact
Peak vertical ground reaction force at initial contact during walking measured using Vicon 3D gait analysis.Unit of Measure: N/kg
Time frame: Part 1 involves a cross-sectional assessment at 12 months after ACL reconstruction. Part 2 is a longitudinal study evaluating patients at four time points: preoperative baseline, 12 weeks, 6 months, and 12 months postoperatively.
Vicon 3D Gait Analysis-Peak Knee Flexion Moment
Peak external knee flexion moment during walking measured using Vicon 3D gait analysis.Unit of Measure: Nm/kg
Time frame: Part 1 involves a cross-sectional assessment at 12 months after ACL reconstruction. Part 2 is a longitudinal study evaluating patients at four time points: preoperative baseline, 12 weeks, 6 months, and 12 months postoperatively.
Electromyography (EMG) testing -Frequency-Domain
Surface electromyography (sEMG) signals were collected from the lower extremity muscles during the Vicon 3D gait analysis to extract frequency-domain features for muscle fatigue assessment.
Time frame: Part 1 involves a cross-sectional assessment at 12 months after ACL reconstruction. Part 2 is a longitudinal study evaluating patients at four time points: preoperative baseline, 12 weeks, 6 months, and 12 months postoperatively
Electromyography (EMG) testing -Time-Domain
Surface electromyography (sEMG) signals were collected from the lower extremity muscles during the Vicon 3D gait analysis to extract time-domain features quantifying muscle activation levels.
Time frame: Part 1 involves a cross-sectional assessment at 12 months after ACL reconstruction. Part 2 is a longitudinal study evaluating patients at four time points: preoperative baseline, 12 weeks, 6 months, and 12 months postoperatively
Functional Magnetic Resonance Imaging (fMRI) testing
A subset of participants underwent task-based fMRI to identify cortical activation patterns during motor imagery.
Time frame: Part 2 includes longitudinal neuroimaging assessments. Resting-state functional magnetic resonance imaging (rs-fMRI) will be performed at preoperative baseline,6 month , and 12 months postoperatively to investigate changes in sensorimotor network conne
Isokinetic muscle strength testing
Isokinetic peak torque of the quadriceps and hamstrings was measured to evaluate muscle strength symmetry between the injured and uninjured limbs.
Time frame: For Part 2, assessments will be conducted at 6 and 12 months postoperatively.
Mental chronometry
Mental chronometry was assessed to compare the imagined duration of movement with the actual execution time.
Time frame: Part 1 involves a cross-sectional assessment at 12 months after ACL reconstruction. Part 2 is a longitudinal study evaluating patients at four time points: preoperative baseline, 12 weeks, 6 months, and 12 months postoperatively.
Kinesthetic and Visual Imagery Questionnaire-20
The KVIQ-20 assesses subjective kinesthetic (body sensations) and visual (mental pictures) imagery abilities related to leg movements. The questionnaire consists of 20 items divided into two dimensions: Kinesthetic and Visual. Each item is rated on a 6-point Likert scale from 0 to 5 based on the clarity and richness of the imagery experienced. The total score ranges from 0 to 100. A higher score indicates greater imagery ability, meaning the patient can more vividly see the movement and feel the muscle/joint activity in their mind.
Time frame: Part 1 involves a cross-sectional assessment at 12 months after ACL reconstruction. Part 2 is a longitudinal study evaluating patients at four time points: preoperative baseline, 12 weeks, 6 months, and 12 months postoperatively.
Tegner Activity Scale
used to assess patients' level of physical activity and participation in sports. This scale ranges from 0 to 10, with higher scores indicating higher activity levels. A score of 0 represents disability due to knee problems (sick leave), while a score of 10 represents participation in competitive sports such as soccer or rugby at a national elite level. The scale captures both work and recreational activities, providing a comprehensive measure of functional activity beyond simple symptom relief.
Time frame: Part 1 involves a cross-sectional assessment at 12 months after ACL reconstruction. Part 2 is a longitudinal study evaluating patients at four time points: preoperative baseline, 12 weeks, 6 months, and 12 months postoperatively.
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Visual Analogue Score, VAS
The Visual Analogue Scale (VAS) was used to assess patients' pain intensity at rest or during activity. The scale is typically represented as a 10 cm horizontal line, with "No pain" at one end and "Worst imaginable pain" at the other. Patients mark a point on the line corresponding to their perceived pain level, and the distance from the start is measured as the score.
Time frame: Part 1 involves a cross-sectional assessment at 12 months after ACL reconstruction. Part 2 is a longitudinal study evaluating patients at four time points: preoperative baseline, 12 weeks, 6 months, and 12 months postoperatively.
International Knee Documentation Committee, IKDC
The IKDC Subjective Knee Form was used to evaluate symptoms (pain, stiffness, swelling, locking/giving way) and functional limitations related to sports and daily activities following ACL reconstruction, as well as current knee function relative to pre-injury status. A normalized total score is calculated from these domains. Scoring Interpretation Minimum Value: Approximately 0 points (representing severe symptoms or complete loss of function) Maximum Value: 100 points (representing no symptoms and fully normal function) Does a higher score mean a better outcome?: Yes. A higher score indicates fewer knee symptoms and better motor function and daily activity performance.
Time frame: Part 1 involves a cross-sectional assessment at 12 months after ACL reconstruction. Part 2 is a longitudinal study evaluating patients at four time points: preoperative baseline, 12 weeks, 6 months, and 12 months postoperatively.
Tampa Scale for Kinesiophobia-11 (TSK-11)
Kinesiophobia was assessed using the Tampa Scale for Kinesiophobia-11 (TSK-11). The TSK-11 is an 11-item self-report questionnaire measuring fear of movement and re-injury, rated on a 4-point Likert scale (1 = strongly disagree to 4 = strongly agree). Total scores range from 11 to 44, with higher scores indicating greater kinesiophobia. Scores reflect the severity of fear; therefore, a higher score represents a worse outcome (indicating greater fear).
Time frame: Part 1 involves a cross-sectional assessment at 12 months after ACL reconstruction. Part 2 is a longitudinal study evaluating patients at four time points: preoperative baseline, 12 weeks, 6 months, and 12 months postoperatively.