Abstract
Testing of internal fixation hardness of proximal ulnar fractures (simulated) with different internal extramedullar fixators was performed (hardness for break, hardness for tension, hardness for torsion). Hardness for break and tension appeared sufficient for all internal extramedullar fixators. On the other hand, hardness for torsion was different. It increased for fracture fixed with additional screw through three fragments for all fixators and for fracture fixed with long compressive screw and plate (patent).