Department of Joint Surgery, The Third Hospital of Hebei Medical University, Shijiazhuang, China.
Orthop Surg. 2021 Jun;13(4):1196-1204. doi: 10.1111/os.12971. Epub 2021 May 4.
To explore morphological characteristics of patellofemoral joint surface of patients with patellar instability by adopting the MRI-based method.
A retrospective analysis was performed from March 2016 to January 2020 to assess morphological characteristics of the patellofemoral joint surface by Magnetic Resonance Imaging (MRI) scanning knees of 30 patients (24 females, six males) with patellar instability and trochlear dysplasia and knees of 30 subjects from a randomly selected control group (25 females, five males). The control group was matched as per age and sex. All participants had undergone MRI scans in the supine position and keep knees in or near full extension. Six parts were measured in total, including thickness of trochlear cartilage, thickness of patella cartilage, cartilaginous sulcus angle, cartilaginous Wiberg angle, contact range and frequency and distributions of the mean difference measurement of the femoral trochlea, to evaluate the difference of trochlear and patellar morphology between the patient group and the control group. The threshold for statistical significance was set at P < 0.05.
There were significant differences in four values between the two groups (P < 0.05). The cartilage thickness two-third along the lateral condyle in the patient group was significantly lower than that in the control group (LCT2,1.80 ± 0.37 vs 2.06 ± 0.52, 1.92 ± 0.36 vs 2.17 ± 0.50), but there was no significant difference in other sites. There was no significant difference in patella thickness between the patient group and the control group. The cartilaginous sulcus angle in the patient group was larger than that in the control group (157.90 ± 6.64 vs 142.23 ± 3.95, P < 0.001), but there was no significant difference in cartilaginous Wiberg angle. The patient group had a larger initial contact ratio (59.47 ± 6.13 vs 46.50 ± 3.67, P < 0.001), and a smaller contact range (16.55 ± 4.14 vs 27.55 ± 4.09, P < 0.001). The deepest part of the intercondylar suclus appears more often in the lateral of the deepest part of the osseous concavity of the femoral trochlea. Among the patient group, 18 cases (60%) were found with the deepest part of the intercondylar suclus lateral to the deepest point of the osseous concavity of the femoral trochlea while among the control group only 4 cases (13.33%) were found. The distribution of trochlear dysplasia of Dejour grades was type B (n = 22), type C (n = 5), and type D (n = 3).
Thickness of partial lateral trochlear cartilage decreases in patients with patellar instability and the trochlear cartilage develops abnormal morphological characteristics. Moreover, it also suggests that MRI can be used to further present the morphology of cartilage for the convenience of surgical planning.
通过基于 MRI 的方法探讨髌股关节面形态特征不稳定的髌股关节。
回顾性分析 2016 年 3 月至 2020 年 1 月的 30 例（24 例女性，6 例男性）髌股关节面形态特征的 MRI 扫描膝关节不稳伴滑车发育不良的患者和 30 例随机选择的对照组（25 例女性，5 例男性）的膝关节。对照组根据年龄和性别进行匹配。所有参与者均仰卧位进行 MRI 扫描，保持膝关节伸直或接近伸直。共测量了 6 个部位，包括滑车软骨厚度、髌骨软骨厚度、软骨沟角、软骨 Wiberg 角、接触范围和频率以及股骨滑车平均差值测量的分布，以评估患者组和对照组之间滑车和髌骨形态的差异。统计学意义的阈值设为 P<0.05。
两组有四个值存在显著差异（P<0.05）。患者组外侧髁软骨厚度的三分之二明显低于对照组（LCT2，1.80±0.37 对 2.06±0.52，1.92±0.36 对 2.17±0.50），但其他部位无明显差异。患者组与对照组髌骨厚度无差异。患者组软骨沟角大于对照组（157.90±6.64 对 142.23±3.95，P<0.001），但软骨 Wiberg 角无差异。患者组初始接触比（59.47±6.13 对 46.50±3.67，P<0.001）更大，接触范围（16.55±4.14 对 27.55±4.09，P<0.001）更小。髁间窝的最深部分更常出现在股骨滑车骨凹陷的最深部分的外侧。在患者组中，18 例（60%）患者的髁间窝最深部分位于股骨滑车骨凹陷的最深点外侧，而在对照组中仅 4 例（13.33%）患者的髁间窝最深部分位于股骨滑车骨凹陷的最深点外侧。Dejour 分级的滑车发育不良分布为 B 型（n=22）、C 型（n=5）和 D 型（n=3）。
髌股关节不稳定患者部分外侧滑车软骨厚度变薄，滑车软骨出现异常形态特征。此外，这也表明 MRI 可用于进一步显示软骨形态，方便手术规划。
