Mechanical performance of hybrid Ilizarov frames containing full-threaded Schanz screws.

Modification of circular Ilizarov frames is necessary to overcome the difficulties in pin positioning due to unfavorable anatomic site or local soft-tissue conditions. Hybrid frame configurations consisting of half pins or full-threaded schanz screws are widely used in clinical practice. This study compared the mechanical performance of hybrid frames and a standard system. One standard and five modified hybrid systems were tested under axial compression, four-point bending, and torsional forces. Systems modified with full-threaded schanz screws showed a higher stiffness than half pin modifications and exhibited a similar mechanical performance of a standard system.