Rotational stability of diaphyseal fractures of the radius and ulna fixed with Rush pins and/or fracture bracing

The rotational stability of fractures of the radius and ulna treated with Rush pins and/or fracture bracing was studied in six fresh cadaver forearms. Forearm rotation and fracture site motion (rotation) were measured as functions of applied forearm torque and rotation (pronation-supination). Values were obtained from the forearm: (1) intact and with both bones fractured; (2) without fixation; (3) with a fracture brace; (4) with Rush pins; and (5) with a combination of Rush pins and a fracture brace. A brace was ineffectual in reducing fracture site motion when the wrist was rotated to specified angles compared to fracture site motion for the forearm with no fixation treatment rotated to the same angles. When loading to specific torque levels, however, the brace reduced fracture site motion to one-half the motion with no fixation treatment. Under both loading conditions, Rush pin fixation significantly and markedly reduced the fracture site motion (to approximately one eighth of the motion with no fixation treatment), whereas a brace in conjunction with Rush pins did not significantly further reduce the fracture site motion. The radius showed more motion at fracture site than the ulna.