Uses of the Less Invasive Stabilization System in the Treatment of Peri-articular Knee Fractures

The development of the less invasive stabilization system (LISS) for the management of distal femoral fractures and proximal lateral tibial fractures was the technical answer to the clinical need of a less invasive plate osteosynthesis.The LISS is an anatomically pre-shaped internal fixator which can be inserted percutaneously by means of an adaptable insertion guide. In combination with a trocar assembly, the handle also serves as an aiming instrument for an exact percutaneous placement of screws.Based on extensive anatomical studies, the orientation of the individual screws is predetermined. As the LISS plate is anatomically pre-shaped, small variations between the plate shape and the anatomical topography can be encountered.To compensate for these variations, special locking head screws have been developed. A conical outer thread of the screw head and an inner thread of the plate hole, locks the screw into the plate, as soon as the threaded screw head engages the threaded plate hole and the screw are tightened together. The locking head screw locks the distance between the bone and the plate as well as the screw axis relative to the plate-hole axis (angular stability).To facilitate the placement of screws trough small skin incisions, the LISS locking head screws are self tapping and self drilling. The self drilling feature can only be implemented, while the screws are place unicortically.In contrast to any previous osteosynthesis plate, the LISS plate is forged out of a titanium alloy and stainless steel, to improve cyclic load to failure. Again this production process can only be used, when the plates are not shaped by the surgeon in situ..