Lepley Adam S, Grooms Dustin R, Burland Julie P, Davi Steven M, Kinsella-Shaw Jeffrey M, Lepley Lindsey K
Department of Kinesiology, University of Connecticut, Biology Building 4, Room 015, 3107 Horsebarn Hill Rd, 4137 Unit, Storrs, CT, 06269-4137, USA.
Department of Orthopaedic Surgery, University of Connecticut Health Center, Farmington, CT, USA.
Exp Brain Res. 2019 May;237(5):1267-1278. doi: 10.1007/s00221-019-05499-x. Epub 2019 Mar 9.
Quadriceps muscle dysfunction is common following anterior cruciate ligament reconstruction (ACLR). Data considering the diversity of neural changes, in-concert with morphological adaptations of the quadriceps muscle, are lacking. We investigated bilateral differences in neural and morphological characteristics of the quadriceps muscle in ACLR participants (n = 11, month post-surgery: 69.4 ± 22.4) compared to controls matched by sex, age, height, weight, limb dominance, and activity level. Spinal reflex excitability was assessed using Hoffmann reflexes (H:M); corticospinal excitability was quantified via active motor thresholds (AMT) and motor-evoked potentials (MEP) using transcranial magnetic stimulation. Cortical activation was assessed using a knee flexion/extension task with functional magnetic resonance imaging (fMRI). Muscle volume was quantified using structural MRI. Muscle strength and patient-reported outcomes were also collected. 2 × 2 RM ANOVAs were used to evaluate group differences. Smaller quadriceps muscle volume (total volume, rectus femoris, vastus medialis, and intermedius) and lower strength were detected compared to contralateral and control limbs. Individuals with ACLR reported higher levels of pain and fear and lower levels of knee function compared to controls. No differences were observed for H:M. ACLR individuals demonstrated higher AMT bilaterally and smaller MEPs in the injured limb, compared to the controls. ACLR participants demonstrated greater activation in frontal lobe areas responsible for motor and pain processing compared to controls, which were associated with self-reported pain. Our results suggest that individuals with ACLR demonstrate systemic neural differences compared to controls, which are observed concurrently with smaller quadriceps muscle volume, quadriceps muscle weakness, and self-reported dysfunction.
前交叉韧带重建（ACLR）术后股四头肌功能障碍很常见。目前缺乏考虑神经变化多样性以及与股四头肌形态学适应协同作用的数据。我们调查了ACLR参与者（n = 11，术后月数：69.4±22.4）与在性别、年龄、身高、体重、肢体优势和活动水平相匹配的对照组相比，股四头肌神经和形态学特征的双侧差异。使用霍夫曼反射（H:M）评估脊髓反射兴奋性；通过经颅磁刺激使用主动运动阈值（AMT）和运动诱发电位（MEP）量化皮质脊髓兴奋性。使用功能磁共振成像（fMRI）的膝关节屈伸任务评估皮质激活。使用结构MRI量化肌肉体积。还收集了肌肉力量和患者报告的结果。使用2×2重复测量方差分析评估组间差异。与对侧和对照肢体相比，检测到股四头肌体积较小（总体积、股直肌、股内侧肌和股中间肌）和力量较低。与对照组相比，ACLR个体报告的疼痛和恐惧水平较高，膝关节功能水平较低。未观察到H:M的差异。与对照组相比，ACLR个体双侧AMT较高，受伤肢体的MEP较小。与对照组相比，ACLR参与者在负责运动和疼痛处理的额叶区域表现出更大的激活，这与自我报告的疼痛相关。我们的结果表明，与对照组相比，ACLR个体表现出系统性神经差异，同时伴有股四头肌体积较小、股四头肌无力和自我报告的功能障碍。
