Washington University School of Medicine, Mallinckrodt Institute of Radiology, 510 S Kingshighway Blvd, St. Louis, MO 63110.
AJR Am J Roentgenol. 2020 Nov;215(5):1163-1170. doi: 10.2214/AJR.19.22556. Epub 2020 Sep 9.
The purpose of this study was to investigate the reproducibility of three quantitative MRI parameters associated with patellar instability and to determine whether they measure anatomic predisposition to patellar instability individually or in combination with the other parameters. In this retrospective study, 100 patients diagnosed with a patellar dislocation injury and 100 age- and sex-matched control patients were examined using MRI. The distance between the tibial tubercle and posterior cruciate ligament (TT-PCL), distance between the tibial tubercle and trochlear groove (TT-TG), and TG depth (trochlear dysplasia) were measured independently by three fellowship-trained musculoskeletal radiologists. Intraclass correlation coefficient (ICC) was used to assess intraobserver and interobserver reliability. The parameters in both groups were tested for interdependence on each other and were compared for prevalence and association with patellar instability. All three parameters showed almost perfect intraobserver (TT-PCL ICC, ≥ 0.88; TT-TG ICC, 0.96; trochlear dysplasia ICC, ≥ 0.92) and interobserver (TT-PCL ICC, 0.82; TT-TG ICC, 0.94; trochlear dysplasia ICC, 0.91) reliability and were significantly more common in the patellar instability group. Trochlear dysplasia had the highest association with patellar instability, both as a unique parameter and in pairwise combination with an abnormal TT-TG. Optimal cutoff thresholds for normal TT-TG and TT-PCL were 15.00 mm or less and 21.30 mm or less, respectively. The optimal normal cutoff threshold for evaluating trochlear dysplasia via trochlear depth was 4.95 mm or more. Patellar instability is multifactorial. Highly reproducible parameters derived from MRI reveal both unique and overlapping anatomic predispositions, and considering all parameters together may help individualize patient management when selecting orthopedic procedures.
本研究旨在探讨与髌股关节不稳定相关的三种定量 MRI 参数的可重复性，并确定它们是否单独或与其他参数联合测量髌股关节不稳定的解剖学倾向。在这项回顾性研究中，对 100 例被诊断为髌脱位损伤的患者和 100 例年龄和性别匹配的对照组患者进行了 MRI 检查。由 3 位 fellowship培训的肌肉骨骼放射科医生分别测量胫骨结节与后交叉韧带（TT-PCL）之间的距离、胫骨结节与滑车沟（TT-TG）之间的距离和滑车深度（滑车发育不良）。采用组内相关系数（ICC）评估观察者内和观察者间的可靠性。比较两组之间参数的相互依赖性，并比较其患病率和与髌股关节不稳定的相关性。所有三个参数的观察者内（TT-PCL ICC，≥0.88；TT-TG ICC，0.96；滑车发育不良 ICC，≥0.92）和观察者间（TT-PCL ICC，0.82；TT-TG ICC，0.94；滑车发育不良 ICC，0.91）可靠性均几乎达到完美，并且在髌股关节不稳定组中更为常见。滑车发育不良与髌股关节不稳定的相关性最高，无论是作为单一参数还是与异常 TT-TG 配对组合。正常 TT-TG 和 TT-PCL 的最佳截断阈值分别为 15.00mm 或更小和 21.30mm 或更小。通过滑车深度评估滑车发育不良的最佳正常截断阈值为 4.95mm 或更大。髌股关节不稳定是多因素的。从 MRI 得出的高度可重复的参数既揭示了独特的解剖学倾向，也揭示了重叠的解剖学倾向，并且在选择骨科手术时综合考虑所有参数可能有助于个体化患者管理。
