Der posteriore tibiale Slope als intrinsischer Risikofaktor
摘要
The posterior tibial slope (PTS) is the inclination of the tibial plateau in the sagittal plane and is an important factor for knee joint biomechanics. A normal PTS lies between 6 and 12°. Deviations, such as a steeper slope (> 12°) or a flatter slope (< 5°), are associated with characteristic biomechanical changes.
ObjectiveThis paper addresses the clinical significance of sagittal alignment and its effects on the risk of injury to cruciate ligaments, menisci, and cartilage. Furthermore, common radiological measurement methods and surgical corrections for pathological PTS values are investigated.
Material and methodsThe work summarizes findings from numerous biomechanical and clinical studies. The radiological determination of the PTS, as well as the surgical correction options, are presented in detail.
ResultsAn increased PTS is a significant risk factor for ACL (anterior cruciate ligament) ruptures and graft failure after reconstruction. A value of > 12° has emerged as a statistical threshold in many studies, above which the risk increases significantly. Increased slope values are also associated with an elevated risk of meniscal root and ramp lesions. The evidence for an association with cartilage damage is still low. Conversely, a flatter slope (< 5°) increases the risk for PCL (posterior cruciate ligament) ruptures and re-ruptures. The correction of the PTS through a closed-wedge osteotomy is frequently discussed in the literature for values > 12° and appears to reduce the risk of a renewed ACL rupture.
DiscussionThe strong correlation between sagittal alignment and ligament instability underscores the central importance of the PTS in knee joint biomechanics. Consequently, PTS must be systematically included in the diagnostic workup as a primary risk factor. In cases of ACL or PCL graft failure combined with a pathological slope, operative correction should be discussed as a causal therapeutic option to minimize graft strain. However, high-quality prospective studies are necessary to conclusively prove the long-term superiority of this combined approach.