Knöcherne Deformitätenkorrektur bei vorderer Instabilität?: „Slope“ und „varus thrust“

The inclination of the tibial plateau in the sagittal plane (“slope”) influences the stability of the knee joint. As a result of the posteriorly inclined articulating surface, the tibia slides anteriorly under load. An increased ”slope“ can therefore contribute to anterior instabilities. In addition, deformities in the frontal plane can have an effect on the stability of the knee joint. Anterolateral accompanying instabilities can induce an additional ligamentous varus moment in the case of a pre-existing osseous varus deformity (double varus situation). The radiological gap of the lateral joint space is called the “varus thrust” phenomenon. For these reasons, deformities in the sagittal and frontal plane should be considered in the treatment of ligament instabilities. This applies particularly to cases in which an ACL plasty has already failed (revisions). Tibial osteotomies (extending and valgus) are suitable for the correction of these deformities. The use of angular-stable implants for the stabilization of the osteotomy allows an early rehabilitationunder partial weight bearing. These procedures can be combined with one or two stage ACL reconstruction. To date, the clinical experience with these interventions is limited but promising.