Abstract: Self-tapping screw for small-bone surgery, includes a threaded proximal head (2), a threaded distal shank with greater pitch and an internal cannula (4), characterized in that the distal shank (3) is threaded over its entire length in that the end of the shank has, apart from milled portions forming self-tapping faces on the first distal threads, at least two milled faces and which with the cannula, determine at least two notches (11), and at least two self-boring edges at the distal end of the screw, and in that the thread of the head has, aside from milled portions forming self-tapping faces on the first threads of the proximal screw thread, chamfered faces (16–19), determining boring edges (12b–15b) preceded by a short groove.

Abstract: A self-compressive and atraumatic osteosynthesis screw, includes a threaded proximal head, a body forming a threaded distal portion and, between the head and the distal part, a smooth section of short length relatively to the distal portion length, the threading thereof having a greater pitch than that of the proximal head threading, and a longitudinal channel provided from one end to the other of the screw to receive a guide pin. The screw includes a mechanism enabling it to fix small bones or small bone fragments of the skeleton after an osteotomy or a fracture, and in particular one of the five metatarsals of a human foot, including a threading diameter of the distal portion slightly greater than the diameter of the thread root of the proximal head and the diameter of the channel ranges between about 0.8 and 1.0 mm.

Abstract: Self-tapping screw for small-bone surgery, comprising a threaded proximal head (2), a threaded distal shank with greater pitch and an internal cannula (4), characterized in that the distal shank (3) is threaded over its entire length in that the end of the shank has, apart from milled portions forming self-tapping faces on the first distal threads, at least two milled faces and which with the cannula, determine at least two notches (11) and at least two self-boring edges at the distal end of the screw, and in that the thread of the head has, aside from milled portions forming self-tapping faces on the first threads of the proximal screw thread, chamfered faces (16-19), determining boring edges (12b-15b) preceded by a short groove.

Abstract: A screw device for the coaptation of two small bone fragments includes a threaded proximal head part and a threaded distal part, the proximal part having a diameter greater than the distal part and having a thread pitch smaller than that of the distal part. The distal part is threaded over substantially its entire length and a short length smooth portion is provided between the proximal and distal parts. The upper edges of the threads of the two threaded parts are perpendicular to the axis of the thread, while their lower edges are oblique, and each threaded part has at its base at least one tapping notch. An axial channel is provided in the screw for permitting the use of a guide pin.