Shimizu Tomohiro, Markes Alexander R, Samaan Michael A, Tanaka Matthew S, Souza Richard B, Li Xiaojuan, Ma C Benjamin
Department of Orthopaedic Surgery, University of California, San Francisco, California, USA.
Musculoskeletal Quantitative Imaging Research Group, Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA.
Orthop J Sports Med. 2020 Jan 23;8(1):2325967119895248. doi: 10.1177/2325967119895248. eCollection 2020 Jan.
Several reports have shown that altered biomechanics after anterior cruciate ligament reconstruction (ACLR) are associated with the development of posttraumatic osteoarthritis. However, it is not fully understood whether altered biomechanics are associated with meniscal changes after ACLR.
To investigate changes in gait and landing biomechanics over a 3-year period and their correlation with meniscal matrix alterations present before and after ACLR through use of magnetic resonance T1ρ/T2 mapping, which can allow detection of early meniscal degeneration.
Cohort study; Level of evidence, 2.
A total of 36 patients with ACLR and 14 healthy controls were included in this study. All patients underwent magnetic resonance imaging and biomechanical analysis during gait of the injured knee and contralateral knee preoperatively and at 6 months, 1 year, 2 years, and 3 years after ACLR, as well as biomechanical analysis during drop-landing from 6 months to 3 years postoperatively. To evaluate biochemical changes of the mensical matrix, T1ρ/T2 relaxation times of the meniscus were calculated.
Mean T1ρ/T2 values of ACLR knees were significantly higher than values in the contralateral and control knees in the posterior lateral and medial horns up to 1 year after surgery; however, the differences were not seen at 3 years after surgery. The ACLR knee exhibited significantly lower peak knee flexion moment and angle during gait at 6 months compared with baseline and continued to decrease until 3 years. The ACLR knee exhibited significantly lower peak vertical ground-reaction force and peak knee flexion moment and angle during landing at 6 months. However, the differences were no longer present at 3 years. Biomechanics at 6 months had significant correlations with changes of mean T1ρ/T2 values in the medial posterior horn from 6 months to 3 years after ACLR.
Although mean T1ρ/T2 values of meniscus seen before ACLR improved after 3 years, approximately 30% of patients with ACLR did not show decreases from 6 months to 3 years. Patients with abnormal lower limb kinetics of the ACLR knee at 6 months showed less recovery in the medial posterior horn from 6 months to 3 years, suggesting that biomechanical parameters during the early stage of recovery might be potential biomarkers for predicting persistent medial meniscal abnormality after ACLR.
多项报告显示，前交叉韧带重建术（ACLR）后生物力学改变与创伤后骨关节炎的发生有关。然而，生物力学改变是否与ACLR后的半月板变化相关尚不完全清楚。
通过使用磁共振T1ρ/T2成像技术来研究3年期间的步态和落地生物力学变化，以及它们与ACLR前后半月板基质改变的相关性，该技术可检测早期半月板退变。
队列研究；证据等级，2级。
本研究共纳入36例ACLR患者和14名健康对照者。所有患者在术前以及ACLR后6个月、1年、2年和3年时，对患侧膝关节和对侧膝关节进行步态期间的磁共振成像和生物力学分析，以及术后6个月至3年期间下落着地时的生物力学分析。为评估半月板基质的生化变化，计算半月板的T1ρ/T2弛豫时间。
术后1年内，ACLR膝关节后外侧和内侧半月板角的平均T1ρ/T2值显著高于对侧和对照膝关节；然而，术后3年未见差异。与基线相比，ACLR膝关节在术后6个月时步态期间的膝关节屈曲峰值力矩和角度显著降低，并持续下降至3年。ACLR膝关节在术后6个月着地时的垂直地面反作用力峰值、膝关节屈曲峰值力矩和角度显著降低。然而，3年时差异不再存在。术后6个月的生物力学与ACLR后6个月至3年内侧后角平均T1ρ/T2值的变化显著相关。
尽管ACLR前观察到的半月板平均T1ρ/T2值在3年后有所改善，但约30%的ACLR患者在6个月至3年期间并未出现下降。术后6个月ACLR膝关节下肢动力学异常的患者在6个月至3年期间内侧后角恢复较差，这表明恢复早期的生物力学参数可能是预测ACLR后内侧半月板持续异常的潜在生物标志物。
