Examining Neuromuscular and Cortical Activity Over 1 Year Following Anterior Cruciate Ligament Reconstruction

Cross-sectional studies have indicated impaired neuromuscular and cortical activities following anterior cruciate ligament (ACL) reconstruction. However, adaptations throughout the recovery process remain unclear. Therefore, this study aimed to examine neuromuscular and cortical activity over the first year following ACL reconstruction. A prospective observational study was conducted, including 31 participants following ACL reconstruction (12 females, age: 25 ± 6 years, height: 173 ± 9 cm, mass: 72 ± 11 kg) and 31 healthy controls (12 females, age: 26 ± 6 years, height: 175 ± 9 cm, mass: 70 ± 10 kg). Electroencephalography and electromyography were used to assess cortical and neuromuscular activity during joint position sense (JPS) test, while only neuromuscular activity was recorded during stair descent and single-leg hop tasks. The ACL group underwent evaluation at five postsurgical intervals (1.5, 3-4, 6, 9, and 12 months), while the control group was assessed on a single occasion. Linear mixed models were used to compute differences in neuromuscular and cortical activity across the various time points and groups in JPS testing and stair descent, while independent and dependent t-tests were employed for analysis of the neuromuscular activity during single-leg hop. ACL-reconstructed participants demonstrated sustained altered neuromuscular activity in both involved and noninvolved limbs during JPS and stair descent tasks compared to controls (p < 0.05) with differences present across all measured time points. No significant differences in cortical EEG activity during JPS test were detected. Neuromuscular alterations were observed consistently throughout the initial year of recovery. The absence of cortical activity changes suggests a reassessment of more challenging tasks. Further investigation is required into neuromuscular and motor relearning protocols to ascertain their impact on rehabilitation and return to sport.