Measurement of Posterior Tibial Slope Using Magnetic Resonance Imaging

Background: Posterior tibial slope (PTS) is an important factor in the knee joint biomechanics and one of the bone features, which leads to knee joint stability. Posterior tibial slope affects flexion gap, knee joint stability and posterior femoral rollback that are related to wide range of knee motion. During high tibial osteotomy and total knee arthroplasty (TKA) surgery, proper retaining the mechanical and anatomical axis is important. The aim of this study was to evaluate the value of posterior tibial slope in medial and lateral compartments of tibial plateau and to assess the relationship among the slope with age, gender and other variables of tibial plateau surface. Materials and methods: This descriptive study was conducted on 132 healthy knees (80 males and 52 females) with a mean age of 38.26±11.45 (20-60 years) at a medical center in Mashhad, Iran. All patients required to MRI admitted for knee pain with uncertain clinical history and physical examination that were reported healthy at knee examination were enrolled in the study. Results: The mean posterior tibial slope was 7.78±2.48 degrees in the medial compartment and 6.85±2.24 degrees in lateral compartment. No significant correlation was found between age and gender with posterior tibial slope (P≥0.05), but there was significant relationship among PTS with mediolateral width, plateau area and medial plateau. Conclusions: Comparison of different studies revealed that the PTS value in our study is different from other communities, which genetic and racial factors can be involved in these differences. The results of our study are useful to PTS reconstruction in surgeries.