Clinical Features Post Anterior Cruciate Ligament Reconstruction Associated with Structural Alterations in Corticospinal Tract.

Context: Structural evidence for corticospinal tract (CST) abnormality between patients with ACLR and healthy controls, and the relationships between CST structure and clinical features of the patients (e.g., objective sensorimotor outcomes, postoperative duration) are lacking.

Objectives: To investigate whether the structural features of CST 1) differ between patients with ACLR and healthy controls, and 2) were associated with clinical features in patients following ACLR.

Design: Cross-sectional study.

Setting: Sports medicine laboratory.

Patients or other participants: Twenty-six patients who had undergone ACLR and twenty-six healthy controls were enrolled in this cross-sectional investigation.

Main outcome measure(s): Using the CST as the region of interest, we performed diffusion tensor imaging to measure the microstructure of white matter tracts. Between-group comparisons and correlation analyses with clinical features in patients with ACLR were performed.

Results: The patients with ACLR showed significant, moderate lower fractional anisotropy (FA, Cohen's d = -0.666, 95% CIs -1.221 to -0.104), lower axial diffusivity (AD, Cohen's d = -0.526, 95% CIs -1.077 to 0.030), and higher radial diffusivity (RD, Cohen's d = 0.514, 95% CIs -0.042 to 1.064) when compared to that of healthy controls, with the RD values being significantly correlated with the postoperative duration (r = 0.623, p < 0.001) after controlling the age, sex, and BMI in patients with ACLR.

Conclusions: This study revealed that patients with ACLR have impaired integrity (lower FA values and higher RD values) in the CST contralateral to the ACLR injured limb in comparison with healthy controls. Decreased integrity (higher RD) of the CST in patients was significantly associated with longer postoperative duration, which hinted that impaired structural integrity of the CST may be a maladaptive process of neuroplasticity in ACLR.