FRACTURE FIXATION APPARATUS

摘要

An apparatus for treating a bone fracture comprises an intramedullary rod (12) extending through a first bone segment of a fractured bone. A lag screw assembly (14) extends through a first transverse aperture in the rod, while a control member (16) extends through a second transverse aperture longitudinally offset from the first aperture. The lag screw assembly includes a lag screw engaged to the second bone segment and a locking sleeve (40) mounted over a proximal portion of the lag screw. The locking sleeve defines a groove (44) aligned with the second aperture. The control member includes a distal portion penetrating the bone segments, an intermediate portion configured to engage the second aperture, and an enlarged head (65) configured to slidably engage the groove. The groove includes a terminus that contacts the head of the control member after a predetermined amount of lateral migration of the lag screw as the fracture collapses.