Department of Orthopaedics and Traumatology, Institute of Orthopaedics and Traumatology, University of São Paulo, Ovídio Pires de Campos St, 333, 2nd Floor, Cerqueira César, São Paulo, SP, 5403-010, Brazil.
Department of Musculoskeletal Radiology, University of São Paulo, São Paulo, SP, 55403-010, Brazil.
Knee Surg Sports Traumatol Arthrosc. 2017 Oct;25(10):3053-3060. doi: 10.1007/s00167-016-4095-0. Epub 2016 Mar 31.
To determine whether the tibial tuberosity-to-trochlear groove distance (TT-TG) and patellar tendon-to-trochlear groove distance (PT-TG) are equal, whether the bony and cartilaginous points coincide in the trochlea, and whether the insertion of the PT coincides with the most anterior point of the TT in patients with patellar instability.
Fifty-three MRI scans of patients with patellar instability were examined. TT-TG and PT-TG were measured by three examiners in 31 knees. Additionally, the bone-cartilage distance in the trochlea [trochlear cartilage to trochlear bone (TC-TB)] and the distance between the mid-point of the PT insertion and the most anterior point of the TT (PT-TT) were measured by one examiner. The intraclass correlation coefficient was used to evaluate the reliability of the measurements between the three examiners. The relationships between the measurements were determined, the means of the measurements were calculated, and the correlations between PT-TG and TT-TG, PT-TT, and TC-TB were assessed.
The ICC was above 0.8. PT-TG was 3.7 mm greater than TT-TG. The TC and TB coincided in 73 % of cases, and the mean TC-TB was 0.3 mm. The PT was lateral to the TT in 94 % of the cases, and the mean PT-TT was 3.4 mm. The Pearson's correlation coefficients between PT-TG and TT-TG, PT-TT, and TC-TB were 0.946, 0.679, and 0.199, respectively.
TT-TG underestimated PT-TG, primarily due to the lateralization of the PT insertion relative to the most anterior point of the TT.
our study shows that in patients with patellar instability, there are differences in the absolute values of TT-TG and PT-TG, as previously reported for patients without patellar instability. Hence, normal cut-off values based on case-control studies of TT-TG cannot be equivalently used when measuring PT-TG to indicate TT medialization in patients with patellar instability. It is also important to note that the clinical outcomes cannot be directly compared between patients evaluated using TT-TG versus PT-TG measurements.
III.
确定髌股关节不稳患者的胫骨结节-滑车沟距离（TT-TG）与髌腱-滑车沟距离（PT-TG）是否相等，滑车的骨性和软骨点是否重合，以及髌腱的止点是否与 TT 的最前点重合。
检查了 53 例髌股关节不稳患者的 MRI 扫描图像。由 3 位检查者在 31 个膝关节中测量 TT-TG 和 PT-TG。另外，由 1 位检查者测量滑车的骨软骨距离[滑车软骨到滑车骨（TC-TB）]以及髌腱止点中点与 TT 最前点之间的距离（PT-TT）。采用组内相关系数评估 3 位检查者之间测量值的可靠性。确定测量值之间的关系，计算测量值的平均值，并评估 PT-TG 与 TT-TG、PT-TT 和 TC-TB 的相关性。
ICC 均大于 0.8。PT-TG 比 TT-TG 大 3.7mm。73%的病例 TC 和 TB 重合，平均 TC-TB 为 0.3mm。94%的病例 PT 位于 TT 的外侧，平均 PT-TT 为 3.4mm。PT-TG 与 TT-TG、PT-TT 和 TC-TB 的 Pearson 相关系数分别为 0.946、0.679 和 0.199。
TT-TG 低估了 PT-TG，主要是由于 PT 止点相对于 TT 的最前点发生了外侧移位。
本研究表明，在髌股关节不稳患者中，TT-TG 和 PT-TG 的绝对值存在差异，这与先前报道的髌股关节不稳患者一致。因此，在髌股关节不稳患者中，不能使用基于 TT-TG 的病例对照研究得出的正常截断值来测量 PT-TG 以指示 TT 内侧化。还需要注意的是，不能直接比较使用 TT-TG 与 PT-TG 测量值评估的患者的临床结果。
III 级。
