Premium
Corticospinal and intracortical excitability differ between athletes early after ACLR and matched controls
Author(s) -
Zarzycki Ryan,
Morton Susanne M.,
Charalambous Charalambos C.,
Marmon Adam,
SnyderMackler Lynn
Publication year - 2018
Publication title -
journal of orthopaedic research®
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.041
H-Index - 155
eISSN - 1554-527X
pISSN - 0736-0266
DOI - 10.1002/jor.24062
Subject(s) - neuroscience , athletes , medicine , physical medicine and rehabilitation , psychology , physical therapy
Neuromuscular impairments, such as quadriceps weakness and activation deficits, persist after anterior cruciate ligament reconstruction (ACLR). Recent research demonstrating changes in the function of the primary motor cortex after ACLR posits that quadriceps impairments may be influenced by reduced corticospinal excitability. The purpose of this study was to investigate whether the integrity of the neuromotor axis of the vastus medialis is altered in subjects 2 weeks post‐ACLR compared to uninjured control subjects. Eighteen athletes 2 weeks post‐ACLR and 18 age and sex matched uninjured control subjects participated in this cross‐sectional study. We quantified corticospinal (resting motor threshold, RMT; motor evoked potential amplitudes at 120% RMT, MEP 120 ) and intracortical (inhibition and facilitation) excitability using single and paired pulse transcranial magnetic stimulation (TMS), respectively. We assessed spinal‐reflex excitability (H‐reflex amplitude normalized to maximal M‐wave, H/M ratio) using peripheral stimulation. Subjects post‐ACLR had higher RMTs ( p = 0.001), greater MEP 120 amplitudes ( p = 0.001), and more asymmetric facilitation ( p = 0.041) than the uninjured control subjects. No significant group differences were found for intracortical inhibition ( p = 0.289) and H/M ratio ( p = 0.332). Our findings indicate that both intracortical and corticospinal excitability of vastus medialis are bilaterally altered in subjects 2 weeks after ACLR. Given persistent neuromuscular deficits seen after ACLR, rehabilitation strategies targeting intracortical and corticospinal deficits may potentially improve clinical outcomes. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2941–2948, 2018.