Kim Ji Su, Yun Seong Jong, Jin Wook, Kim Gou Young, Park So Young, Park Ji Seon, Ryu Kyung Nam
1 Department of Radiology, Kyung Hee University Hospital at Gangdong, Kyung Hee University School of Medicine, 149 Sangil-dong, Gangdong-gu, Seoul 134-727, Korea.
2 Department of Medicine, Graduate School, Kyung Hee University, Dongdaemun-gu, Seoul, Korea.
AJR Am J Roentgenol. 2017 May;208(5):1103-1109. doi: 10.2214/AJR.16.17034. Epub 2017 Feb 15.
The purpose of this study is to retrospectively investigate the frequency of a focal defect at the lateral patellar retinaculum on knee MRI and to determine the variables that are significantly associated with the defect.
Two radiologists independently reviewed 99 knee MR images for the presence of a focal defect at the lateral patellar retinaculum and categorized patients with concordant results into two groups: a group with the defect (≥ 3 mm; group 1) and a group without the defect (< 3 mm; group 2). Clinical and radiologic variables, including the Kellgren-Lawrence radiographic grade, subcutaneous fat thickness, infrapatellar fat pad area, and the amount of joint effusion, were evaluated. The size and location of the defect were measured in group 1. To correlate MRI and histologic findings, MRI was performed for 11 cadavers, and three histologic specimens were obtained.
Of the 99 knee MR images, concordant results between two reviewers were obtained for a total of 96 knees (97%): 25 knees (26%) in group 1 and 71 knees (74%) in group 2. A statistically significant difference between groups (p = 0.033) was noted for the infrapatellar fat pad area only. In all three cadaveric specimens, the lateral patellar retinaculum was more loose and sparse than the medial patellar retinaculum, and this site corresponded to the location of the defect on MRI.
A focal defect of the lateral patellar retinaculum was not found to be a rare finding on knee MRI (frequency, 26%), and it may be a normal variant rather than a pathologic change. In addition, we suspect that a focal defect can be a route of infrapatellar fat herniation and a route of superficial extension of the infrapatellar fat pad lesion without a lateral patellar retinaculum tear or invasion.
本研究旨在回顾性调查膝关节MRI上髌骨外侧支持带局灶性缺损的发生率，并确定与该缺损显著相关的变量。
两名放射科医生独立检查99例膝关节MR图像，以确定髌骨外侧支持带是否存在局灶性缺损，并将结果一致的患者分为两组：有缺损组（≥3 mm；第1组）和无缺损组（<3 mm；第2组）。评估临床和影像学变量，包括Kellgren-Lawrence放射学分级、皮下脂肪厚度、髌下脂肪垫面积和关节积液量。在第1组中测量缺损的大小和位置。为了关联MRI和组织学结果，对11具尸体进行了MRI检查，并获取了三个组织学标本。
在99例膝关节MR图像中，两名观察者对96例膝关节（97%）的结果一致：第1组25例（26%），第2组71例（74%）。仅髌下脂肪垫面积在两组之间存在统计学显著差异（p = 0.033）。在所有三个尸体标本中，髌骨外侧支持带比内侧支持带更松弛、更稀疏，该部位与MRI上缺损的位置相对应。
髌骨外侧支持带局灶性缺损在膝关节MRI上并非罕见发现（发生率为26%），它可能是一种正常变异而非病理改变。此外，我们怀疑局灶性缺损可能是髌下脂肪疝出的途径，也是髌下脂肪垫病变在无髌骨外侧支持带撕裂或侵犯情况下向浅层延伸的途径。
