Haughom Bryan, Schairer William, Souza Richard B, Carpenter Dana, Ma C Benjamin, Li Xiaojuan
University of California San Francisco, School of Medicine, USA.
Knee. 2012 Aug;19(4):482-7. doi: 10.1016/j.knee.2011.06.015. Epub 2011 Jul 31.
Altered kinematics following ACL-reconstruction may be a cause of post-traumatic osteoarthritis. T(1ρ) MRI is a technique that detects early cartilage matrix degeneration. Our study aimed to evaluate kinematics following ACL-reconstruction, cartilage health (using T(1ρ) MRI), and assess whether altered kinematics following ACL-reconstruction are associated with early cartilage degeneration.
Eleven patients (average age: 33 ± 9 years) underwent 3T MRI 18 ± 5 months following ACL-reconstruction. Images were obtained at extension and 30° flexion under simulated loading (125 N). Tibial rotation (TR) and anterior tibial translation (ATT) between flexion and extension, and T(1ρ) relaxation times of the knee cartilage were analyzed. Cartilage was divided into five compartments: medial and lateral femoral condyles (MFC/LFC), medial and lateral tibias (MT/LT), and patella. A sub-analysis of the femoral weight-bearing (wb) regions was also performed. Patients were categorized as having "abnormal" or "restored" ATT and TR, and T(1ρ) percentage increase was compared between these two groups of patients.
As a group, there were no significant differences between ACL-reconstructed and contralateral knee kinematics, however, there were individual variations. T(1ρ) relaxation times of the MFC and MFC-wb region were elevated (p ≤ 0.05) in the ACL-reconstructed knees compared to the uninjured contralateral knees. There were increases (p ≤ 0.05) in the MFC-wb, MT, patella and overall average cartilage T(1ρ) values of the "abnormal" ATT group compared to "restored" ATT group. The percentage increase in the T(1ρ) relaxation time in the MFC-wb cartilage approached significance (p=0.08) in the "abnormal" versus "restored" TR patients.
Abnormal kinematics following ACL-reconstruction appear to lead to cartilage degeneration, particularly in the medial compartment.
前交叉韧带重建术后运动学改变可能是创伤后骨关节炎的一个原因。T(1ρ)磁共振成像（MRI）是一种检测早期软骨基质退变的技术。我们的研究旨在评估前交叉韧带重建术后的运动学、软骨健康状况（使用T(1ρ) MRI），并评估前交叉韧带重建术后运动学改变是否与早期软骨退变相关。
11例患者（平均年龄：33±9岁）在接受前交叉韧带重建术后18±5个月接受了3T MRI检查。在模拟负荷（125 N）下，于伸直位和30°屈曲位获取图像。分析了屈伸之间的胫骨旋转（TR）和胫骨前移（ATT），以及膝关节软骨的T(1ρ)弛豫时间。软骨被分为五个区域：内侧和外侧股骨髁（MFC/LFC）、内侧和外侧胫骨（MT/LT）以及髌骨。还对股骨负重（wb）区域进行了亚分析。患者被分为ATT和TR“异常”或“恢复正常”两组，并比较这两组患者之间T(1ρ)百分比增加情况。
总体而言，前交叉韧带重建侧与对侧膝关节运动学之间无显著差异，但存在个体差异。与未受伤的对侧膝关节相比，前交叉韧带重建侧膝关节的MFC和MFC-wb区域的T(1ρ)弛豫时间升高（p≤0.05）。与“恢复正常”的ATT组相比，“异常”的ATT组的MFC-wb、MT、髌骨以及整体平均软骨T(1ρ)值均升高（p≤0.05）。在“异常”与“恢复正常”的TR患者中，MFC-wb软骨的T(1ρ)弛豫时间百分比增加接近显著水平（p = 0.08）。
前交叉韧带重建术后的异常运动学似乎会导致软骨退变，尤其是在内侧区域。
