Evaluation of the posterior tibial slope on MR images in different population groups using the tibial proximal anatomical axis.

We measured the posterior tibial slope for the medial and lateral tibial plateau separately in MR images of 143 knees (71 women, 72 men) and compared the measurements between genders and different ethnic groups. For the whole population the mean medial slope was 5.7 degrees and the mean lateral slope 5.6 degrees. There was a significant difference between the medial and lateral posterior tibial slope in the Asian patients compared with other ethnic groups (p < 0.001). We have shown that measurement of the posterior tibial slope (PTS) could be reliably performed on MR images, revealing a gender difference. These findings might have clinical relevance when performing reconstructive surgery at the knee in determining ideal placement of the tibial component.