Hopf JC, Mehler D, Nowak TE, et al. - A newly designed ulna nail was compared with angular stable plating in a biomechanical testing setup of an ulna shaft fracture with a diaphyseal defect. With an interlocked nail or locked plate osteosynthesis, ten pairs of sawbones with a defect osteotomy of the ulna shaft were fixed. The constructs were investigated under four-point bending, torsional loading and axial loading in a servo-pneumatic testing machine to correlate the stiffness of both stabilization methods. The data reveal that when compared with rigid angular stable plating, intramedullary nailing of ulna shaft fractures obtains sufficient but lower stability in bending and torsional loading and could be an alternative technique to plate fixation. The results exhibit that the lower stability and the closed stabilization procedure permit for a rapid periosteal healing, which is not present in stiffer constructs.