Mayer Philipp, Hielscher Lotta, Schuster Philipp, Schlumberger Michael, Rolvien Tim, Geßlein Markus, Beel Wouter, Richter Jörg
Orthopedic Hospital Markgroeningen, Centre for Sports Orthopaedics and Special Joint Surgery, Markgroeningen, Germany.
Department of Orthopaedics and Traumatology, Paracelsus Medical University, Clinic Nuremberg, Nuremberg, Germany.
Orthop J Sports Med. 2025 Jan 27;13(1):23259671241296858. doi: 10.1177/23259671241296858. eCollection 2025 Jan.
Distal tibial deformities are not assessed using the proximal anatomical axis (PAA) to determine the posterior tibial slope (PTS). Therefore, it seems advantageous to measure PTS on full-length lateral tibial radiographs using the mechanical axis (MA).
To (1) compare the PTS measurements using the MA and the PAA and (2) determine whether using the PAA fails to detect a certain number of significantly elevated PTS values compared with using the MA.
Cohort study (Diagnosis); Level of evidence, 3.
Full-length lateral tibial radiographs of 218 consecutive cases were reviewed. Radiographs were checked for malrotation. Therefore, the distance between the posterior tibial condyles was measured in millimeters. Patients with a difference of ≥7 mm between the posterior tibial condyles were excluded, leaving 196 cases for the final statistical analysis. The PTS was measured using the MA and the PAA. Differences between these 2 techniques were analyzed. The sensitivity and specificity of the PAA as a screening method for pathological PTS were calculated, with the MA as the standard for comparison. Four subgroups were formed, all with PAA <12° and different lower limits for the MA: group 1, MA ≥10°; group 2, MA ≥10.5°; group 3, MA ≥11°; and group 4, MA ≥11.5°.
Radiographs with ≥7 mm between the posterior tibial condyles showed an increased inconsistency between the PTS measurement with the MA and the PAA. In the group with a distance of <7 mm between the posterior tibial condyles (n = 196), the mean PTS measured with the MA was 9.4°± 3.8° (range, 0.4° to 21.9°), and the mean PTS was 10.5°± 3.5° (range, 1.7° to 20.9°) according to the PAA. The mean difference in PTS between the PAA and the MA was 1.1°± 1.2° (range, -2.4° to 4.1°; < .001). Group 1 had a sensitivity of 73% and specificity of 98%; group 2, sensitivity of 84% and specificity of 97%; group 3, sensitivity of 87% and specificity of 93%; and group 4, sensitivity of 95% and specificity of 89%.
Measuring the PTS using the MA was advantageous, as the measurement with the PAA did not correctly identify all cases with sagittal alignment changes. The proportion of patients with pathologically increased PTS not identified with the proximal anatomical measurement, reflected by the sensitivity, depended on the threshold value defined for the MA. Lateral radiographs, showing an increased distance between the posterior tibial condyles, indicated malrotation of the tibia leading to measurement inaccuracy.
在评估胫骨远端畸形时，并不使用近端解剖轴（PAA）来确定胫骨后倾角度（PTS）。因此，在全长胫骨侧位X线片上使用机械轴（MA）测量PTS似乎更具优势。
（1）比较使用MA和PAA测量PTS的结果；（2）确定与使用MA相比，使用PAA是否无法检测到一定数量的明显升高的PTS值。
队列研究（诊断）；证据等级，3级。
回顾了218例连续病例的全长胫骨侧位X线片。检查X线片是否存在旋转不良。因此，以毫米为单位测量胫骨后髁之间的距离。胫骨后髁之间差异≥7mm的患者被排除，最终纳入196例进行统计分析。使用MA和PAA测量PTS。分析这两种技术之间的差异。以MA作为比较标准，计算PAA作为病理性PTS筛查方法的敏感性和特异性。形成四个亚组，所有亚组的PAA均<12°，MA的下限不同：第1组，MA≥10°；第2组，MA≥10.5°；第3组，MA≥11°；第4组，MA≥11.5°。
胫骨后髁之间距离≥7mm的X线片显示，使用MA和PAA测量PTS时的不一致性增加。在胫骨后髁之间距离<7mm的组（n = 196）中，使用MA测量的平均PTS为9.4°±3.8°（范围，0.4°至21.9°），根据PAA测量的平均PTS为10.5°±3.5°（范围，1.7°至20.9°）。PAA和MA之间PTS的平均差异为1.1°±1.2°（范围，-2.4°至4.1°；P <.001）。第1组的敏感性为73%，特异性为98%；第2组，敏感性为84%，特异性为97%；第3组，敏感性为87%，特异性为93%；第4组，敏感性为95%，特异性为89%。
使用MA测量PTS具有优势，因为使用PAA不能正确识别所有矢状位对线改变的病例。未通过近端解剖测量识别出的病理性PTS增加患者的比例，以敏感性反映，取决于为MA定义的阈值。显示胫骨后髁之间距离增加的侧位X线片表明胫骨旋转不良导致测量不准确。
