Characteristics of corticospinal excitability following anterior cruciate ligament reconstruction and immediate effects of transcutaneous spinal direct current stimulation: A preliminary study.

Abstract

After patients underwent standard postoperative rehabilitation following anterior cruciate ligament reconstruction (ACLR), some still exhibited persistent functional deficits postoperatively, which might be associated with adaptive changes in the excitability of neural pathways. This study investigated corticospinal excitability in patients following ACLR and examined the immediate neuromodulatory effects of transcutaneous spinal direct current stimulation (tsDCS). Twenty ACLR patients and 20 age- and sex-matched healthy controls underwent monopulse transcranial magnetic stimulation of the quadriceps motor cortex to determine motor threshold (MT) and motor evoked potential (MEP) amplitude. ACLR participants subsequently received a single session of tsDCS (2.0 mA, 20 min), with the cathode placed over the T10 spinous process and the anode on the contralateral deltoid muscle. MT and MEP were re-assessed immediately after intervention to evaluate acute neuromodulatory effects. All participants were right-leg dominant. Compared with controls, ACLR patients exhibited significantly higher MT values in both the reconstructed and non-reconstructed legs (P < 0.05), indicating bilateral reductions in corticospinal excitability, with more pronounced impairment in the reconstructed leg. Although MEP amplitudes were lower in the reconstructed leg, the differences did not reach statistical significance. Following stimulation, MT significantly decreased in the reconstructed leg (P < 0.05), while MEP amplitudes remained unchanged. No effects were observed in the non-reconstructed leg. These findings suggest that ACLR is associated with bilateral corticospinal hypoexcitability and that tsDCS can acutely enhance excitability in the reconstructed leg. The tsDCS may represent a promising adjuvant neuromodulatory strategy to complement conventional rehabilitation in ACLR patients.