CUTTING-OUT OF THE LAG SCREW AFTER INTERNAL-FIXATION WITH THE ASIATICGAMMA-NAIL

Sixty consecutive intertrochanteric femoral fractures were treated wit h the Asiatic gamma nail followed by early postoperative weight bearin g Cutting-out of the lag screw from the femoral head occurred in six f ractures and were analysed radiographically with regard to fracture ty pe (Evans' classification), osteoporosis (Singh grade), accuracy of po st-operative reduction (neck-shaft angle and diastasis of the fracture ), and location of the lag screw ill the femoral head (depth, height, and antero-posterior deviation). Shallow insertion of the lag screw on the antero-posterior radiograph and large antero-posterior deviation of the lag screw were significantly related to the increased incidence of the screw cutting-out. This suggests that deep insertion of the la g screw on the antero-posterior view with central placement on the lat eral view is all optimal location in the femoral head. The 'cut-out in dex' (the multiplication value of the depth and the antero-posterior d eviation of the lag screw ill the femoral head) is an excellent measur e of the risk of the lag screw cutting-out. (C) 1998 Published by Else vier Science Ltd. All rights reserved.