Shekhbihi Abdelkader, Itoi Eiji, Dag Dilek, Blakeney William G, Walch Arnaud, Bauer Stefan
Department of Trauma Surgery, Lörrach District Hospital, Lörrach, Baden-Württemberg, Germany.
Department of Orthopaedic Surgery, Tohoku Rosai Hospital, Sendai, Japan.
Eur J Orthop Surg Traumatol. 2025 Mar 3;35(1):88. doi: 10.1007/s00590-025-04210-x.
Radiographic measurements have gained wide acceptance in anticipating the risk of inappropriate glenoid component positioning in reverse shoulder arthroplasty (RSA). This study aims to investigate whether the RSA angle overcorrects the base plate inclination, tilting it inferiorly, compared to the base plate correction angle (BCA), which provides neutral inclination and lateralization.
One hundred normal anteroposterior shoulder radiographs were evaluated to determine the average values of the RSA angle, BCA, base plate orientation angle (BOA), and the base plate shoulder angle (BSA), which represents the amount of overcorrection accomplished via the RSA angle beyond the BCA's scope. The interobserver reliability among two independent testers was assessed by the intraclass correlation coefficient. A t-test was applied to compare the mean values of the BCA and RSA angle.
The mean BOA and BCA values were 118° ± 5.7° and 17° ± 4.6°, respectively. The RSA angle value was 23° ± 6°. Compared to the BCA, the RSA angle overcorrected the base plate inclination by 15° ± 5° (BSA). The Student's t-test showed a statistically significant difference between the values of the BCA and RSA angle (p-value = 0.000). The interobserver reliability was excellent for all angle measurements among two independent testers.
The RSA angle and the BOA/BCA are reliable radiographic measurements to determine the inclination of the inferior glenoid segment prior to RSA. However, surgeons need to consider the inherent inferior inclination associated with positioning the base plate according to the RSA angle (15° ± 5°).
在预测反式肩关节置换术（RSA）中盂肱关节组件放置不当的风险方面，影像学测量已得到广泛认可。本研究旨在调查与提供中立倾斜和侧方移位的基板矫正角度（BCA）相比，RSA角度是否会过度矫正基板倾斜度，使其向下倾斜。
评估100张正常的肩关节前后位X线片，以确定RSA角度、BCA、基板方向角度（BOA）以及基板肩角（BSA）的平均值，其中BSA代表通过RSA角度在BCA范围之外实现的过度矫正量。通过组内相关系数评估两名独立测试者之间的观察者间可靠性。应用t检验比较BCA和RSA角度的平均值。
平均BOA和BCA值分别为118°±5.7°和17°±4.6°。RSA角度值为23°±6°。与BCA相比，RSA角度使基板倾斜度过度矫正了15°±5°（BSA）。学生t检验显示BCA和RSA角度值之间存在统计学显著差异（p值 = 0.000）。两名独立测试者之间所有角度测量的观察者间可靠性都非常好。
RSA角度和BOA/BCA是用于确定RSA术前肩胛盂下段倾斜度的可靠影像学测量方法。然而，外科医生需要考虑根据RSA角度放置基板时固有的向下倾斜度（15°±5°）。
