Die Dynamisierung der winkelstabilen Plattenosteosynthese mit Hilfe der "Dynamic Locking Screw" (DLS) - Eine experimentelle Studie an Schafen

Abstract

In this in vivo study a new generation of locking screws was tested. A unilateral 45°osteotomy was performed on the tibia of 37 sheep. The created fracture gap of 0, 1 and 3 mm was fixed using a locking compression plate in combination with the dynamic locking screws (DLS). The healing process was monitored radiographicaly every 3 weeks for 6, respectively 12 weeks. After this time the isolated bones were tested biomechanically, measured in the micro-CT and evaluated histologically. The design of the DLS enables the dynamisation of the cortex under the plate (cis-cortex) and therefore allowing almost parallel interfragmentary closure of the fracture gap. This animal study could show that this interfragmentary movement (IFM) stimulates the synthesis of new bone matrix, especially under the plate, thus could solve a current limitation in normal human bone healing. The best results of this IFM were shown in the 0 mm configuration. The bones of this group have shown histomorphometricaly the most distinct callus formation on the cis-cortex and the highest torsional stiffness relative to the untreated limb, 12 weeks after surgery.