Corticomuscular Coherences 1.5 And 6 Months After ACL Reconstruction Compared To A Healthy Control Group - An Exploratory Study

PURPOSE: To evaluate quadriceps corticomuscular coherence (CMC) 1.5 and 6 months after anterior cruciate ligament reconstruction (ACLR) in comparison to a healthy control group during a joint position sense (JPS) test. METHODS: ACLR (n=14) and healthy matched controls (n=14) performed a seated JPS test with both knees, with a starting angle of 90° flexion and a target angle of 50° (0° = full extension). Measurements consisted of two blocks of continuous angle reproduction with 3 minutes per block. Electromyographic activity of the quadriceps (vastus medialis and lateralis and rectus femoris) and cortical activity via electroencephalography were recorded simultaneously. CMC in beta (13-30 Hz) and gamma (31-80 Hz) frequency bands for the frontal (F3, F4, Fz), central (C3, C4 Cz) and parietal (P3, P4, Pz) regions of interest (ROI) during epochs of the extension to the target angle were processed for further analysis. Linear mixed models were used to compare the CMC of ACLR cross-sectionally with the control group at the first measurement as well as between time points within the ACLR group. RESULTS: Data from the ACLR group is available 1.5 ± 0.2 and 6.1 ± 0.3 months after surgery while the control group was only measured once. Cross-sectional analysis revealed no significant difference between the ACLR and healthy control group over both frequency bands and all regions of interest. Significant interaction effects were found between time points and legs in the ACLR group. Gamma CMC was reduced in the parietal ROI in the reconstructed compared to the contralateral leg at the first time point (β = -0.002; p = 0.01) as well as compared to the reconstructed leg at the second time point (β = -0.004; p = 0.03). The contralateral leg demonstrated elevated beta and gamma band CMC in the frontal and parietal ROI at first compared to the second time point (0.003 < β < 0.007; 0.007 < p < 0.03). CONCLUSIONS: The functional connection between the cortex and muscles seems to differ in the first 6 months after ACL reconstruction. Reduced neuronal connectivity was observed in the contralateral leg at the later time point. Rehabilitation programs should possibly also focus on the contralateral side to prevent secondary injuries. This study was funded by the Campus SLB Sonnenhof AG–Stiftung Lindenhof