Department of Orthopaedic Surgery, University of California, San Francisco, San Francisco, California, USA.
University of California, Berkeley, Berkeley, California, USA.
Am J Sports Med. 2017 Apr;45(5):1075-1084. doi: 10.1177/0363546516677794. Epub 2017 Jan 27.
Quantitative magnetic resonance (qMR) can be used to measure macromolecules in tissues and is a potential method of observing early cartilage changes in the development of posttraumatic osteoarthritis. Hypothesis/Purpose: We hypothesized that specific patient and surgical factors affecting cartilage matrix composition after anterior cruciate ligament (ACL) reconstruction (ACLR) can be detected using T1ρ and T2 relaxation times. Our purpose was to demonstrate this ability in a multicenter feasibility study.
Case series; Level of evidence, 4.
A total of 54 patients who underwent ACLR underwent bilateral MRI at baseline before surgery and 6 months postoperatively. Operative findings were recorded. T1ρ and T2 relaxation times were calculated for 6 cartilage regions: the medial femur, lateral femur, medial tibia, lateral tibia, patella, and trochlea. A paired t test compared relaxation times at baseline and 6 months, univariate regression identified regions that influenced patient-reported outcome measures, and analysis of covariance was used to determine the surgical factors that resulted in elevated relaxation times at 6 months.
The injured knee had significantly prolonged T1ρ and T2 relaxation times in the tibiofemoral compartment at baseline and 6 months but had shorter values in the patellofemoral compartment compared with the uninjured knee. Prolonged T1ρ and T2 times at 6 months were noted for both the injured and uninjured knees. At 6 months, prolongation of T1ρ and T2 times in the tibial region was associated with lower patient-reported outcome measures. ACLR performed within 30 days of injury had significantly shorter T1ρ times in the tibial regions, and lateral meniscal tears treated with repair had significantly shorter T1ρ times than those treated with excision.
Prolonged relaxation times in multiple regions demonstrate how the injury affects the entire joint after an ACL tear. Changes observed in the uninjured knee may be caused by increased loading during rehabilitation, especially in the patellofemoral articular cartilage and distal femur. Relaxation times in the tibial regions may be predictive of patient symptoms at 6 months. These same regions are affected by surgical timing as early as 30 days after injury, but this may partially be reflective of the severity of the preoperative injury and the choice of treatment of meniscal tears.
定量磁共振（qMR）可用于测量组织中的大分子，是观察创伤后骨关节炎早期软骨变化的潜在方法。假设/目的：我们假设，在前交叉韧带（ACL）重建（ACLR）后，影响软骨基质组成的特定患者和手术因素可以通过 T1ρ 和 T2 弛豫时间来检测。我们的目的是在一项多中心可行性研究中证明这一能力。
病例系列；证据水平，4 级。
共 54 例 ACLR 患者在术前和术后 6 个月行双侧 MRI。记录手术结果。计算 6 个软骨区域的 T1ρ 和 T2 弛豫时间：股骨内侧、股骨外侧、胫骨内侧、胫骨外侧、髌骨和滑车。配对 t 检验比较基线和 6 个月时的弛豫时间，单变量回归确定影响患者报告结局测量的区域，协方差分析确定导致 6 个月时弛豫时间升高的手术因素。
受伤膝关节在基线和 6 个月时的胫股关节区 T1ρ 和 T2 弛豫时间明显延长，但髌股关节区的弛豫时间较未受伤膝关节短。受伤和未受伤膝关节在 6 个月时均出现 T1ρ 和 T2 弛豫时间延长。6 个月时，胫骨区域 T1ρ 和 T2 弛豫时间延长与患者报告结局测量值较低相关。ACL 重建在受伤后 30 天内进行，胫骨区域 T1ρ 时间明显缩短，外侧半月板撕裂采用修复治疗的 T1ρ 时间明显短于采用切除治疗的 T1ρ 时间。
多个区域延长的弛豫时间表明 ACL 撕裂后受伤如何影响整个关节。未受伤膝关节的变化可能是由于康复期间负荷增加引起的，尤其是髌股关节软骨和股骨远端。胫骨区域的弛豫时间可能可以预测 6 个月时患者的症状。这些相同的区域早在受伤后 30 天就受到手术时机的影响，但这可能部分反映了术前损伤的严重程度和半月板撕裂的治疗选择。
