Do ethnicity and gender influence posterior tibial slope?

Abstract

Background Ethnicity and gender can affect posterior tibial slope; however, studies on this topic have limitations and are in disagreement. The aim of the present study was to evaluate posterior tibial slope in a large group of consecutive patients, determining whether ethnicity and gender can influence its value. Secondly, to determine intra-and inter-rater reliability of the two radiographic methods adopted. Materials and methods Posterior tibial slope was calculated (rater 1) in lateral view X-rays of the knee according to the posterior tibial cortex (PTC) and tibial proximal anatomical axis (TPAA) methods. Data were matched with ethnicity and gender. For determination of intra-and interrater reliability, 50 random X-rays were selected, and blindly measured by two other raters (2 and 3). Results A total of 581 radiographs were included (413 white and 168 black knees). Comparing white and black subjects, a statistically significant difference was found for both PTC (4.9 ± 1.2 vs 7.1 ± 2.9, p \ 0.0001), and for TPAA (7.7 ± 1.1 vs 10.2 ± 3.0, p \ 0.0001). In white subjects, an influence of gender was found only for TPAA (6.4 ± 1.1 in males vs 7.6 ± 1.1 in females, p \ 0.0001). In black subjects, an influence of gender was found only for PTC (7.4 ± 3.0 in males vs 6.2 ± 2.9 in females, p = 0.01). Intra-rater reliability was good for both methods for rater 1, and very good for rater 2. Inter-rater reliability among the 3 raters was very good for both methods. Conclusions Differences in posterior tibial slope between different ethnic groups exist. Differences observed between genders are conflicting and might be too small to have implications in clinical practice. The TPAA method is recommended for the evaluation of posterior tibial slope because of higher intra-and inter-rater reliability. Level of evidence 3 Case-control study.

Posterior Tibial Slope and Risk of Posterior Cruciate Ligament Injury

“…28 Another limitation of the study was that matching patients by ethnicity was not possible, owing to the retrospective nature of the study design, although previous studies reported race-based differences in native tibial slope. 3,29…”

Measurement of proximal tibial morphology in northeast Chinese population based on three-dimensional reconstruction computer tomography

“…[1] Bisicchia et al measured PTS using lateral X-Ray and deemed that Asian population had PTS of 7.7°, which was larger than 6.4° of Caucasian population. [10] In our study, mean PTS of Northeast Chinese male was 8.64 ± 2.72° (Range: 4.41∼14.15°) and 9.36 ± 2.75° (Range: 4.07∼13.83°) of Northeast Chinese female. Given the different methods between above studies and our study, there was reference meaning of these studies.…”

“…First, rotation of tibia could damage the measurement accuracy and lead to overestimation. [10,15,17,23] Second, owing to overlap of medial and lateral tibia plateau, merely the PTS of proximal side could be assessed. In contrast, MPTS and LPTS could be measured respectively in 3D-level.…”

“…Coronal tibial slope was defined as intersection angle between tML line of tibia plateau and tibial mechanical shaft which might interfere measurement result of PTS. [10,17] Measurement of coronal tibial slope should be carried out to explain its correlation with sagittal PTS. The third limitation was lack of multi-ethnic CT data.…”

“…[8,9] Posterior tibial slope (PTS) also has great influence on postoperative stability and range of motion (ROM) of knee joint. [10–19] It was generally reported that Asia population has higher PTS than that of Caucasian. [1,3] Mean PTS of Asian people was 11° in Ho et al's study, which was far from that of 2.8° to 7.0° in Caucasian population.…”