Abstract: A bone fixation device (1) comprises an elongated member (2) and a washer (3) assembled in a manner to prevent relative longitudinal displacement at the same time allowing axial rotation of the washer (3) with respect of the elongated member (2). The elongated member (2) comprises a proximal head (4) and an elongated shaft (5). The proximal head (4) comprises at least a distal spherical portion (8) having a diameter (D) and defining a maximum transversal dimension (Dh) of the proximal head (4). The washer (3) has a central cavity (14) configured to seat the proximal head (4) and comprising a central spherical portion (15) having the same diameter (D) of the distal spherical portion (8) of the proximal head (4). The central spherical portion (15) extends between a distal rim (16) and a proximal rim (17).

Abstract: A bone fastening system may include a cannulated screw component, a seating component, and a holding component. The screw component may include a screw head arranged in the region of a proximal end of the screw component, and an elongate screw shaft extending from the screw head along a longitudinal axis towards a distal end of the screw component. The screw head may include a proximal surface on a front side facing the proximal end and a distal surface on a back side facing the distal end. A portion of the distal surface may form a contact surface. The seating component may include a central opening having an opening diameter larger than the maximum diameter of the screw shaft and smaller than the maximum diameter of the screw head.

Abstract: A bone fixation device (1) comprises an elongated member (2) and a washer (3) assembled in a manner to prevent relative longitudinal displacement at the same time allowing axial rotation of the washer (3) with respect of the elongated member (2). The elongated member (2) comprises a proximal head (4) and an elongated shaft (5). The proximal head (4) comprises at least a distal spherical portion (8) having a diameter (D) and defining a maximum transversal dimension (Dh) of the proximal head (4). The washer (3) has a central cavity (14) configured to seat the proximal head (4) and comprising a central spherical portion (15) having the same diameter (D) of the distal spherical portion (8) of the proximal head (4). The central spherical portion (15) extends between a distal rim (16) and a proximal rim (17).

Abstract: A bone fastening system may include a cannulated screw component, a seating component, and a holding component. The screw component may include a screw head arranged in the region of a proximal end of the screw component, and an elongate screw shaft extending from the screw head along a longitudinal axis towards a distal end of the screw component. The screw head may include a proximal surface on a front side facing the proximal end and a distal surface on a back side facing the distal end. A portion of the distal surface may form a contact surface. The seating component may include a central opening having an opening diameter larger than the maximum diameter of the screw shaft and smaller than the maximum diameter of the screw head.