Cutting-out of the lag screw after internal fixation with the Asiatic gamma nail

Sixty consecutive intertrochanteric femoral fractures were treated with the Asiatic gamma nail followed by early postoperative weight bearing Cutting-out of the lag screw from the femoral head occurred in six fractures and were analysed radiographically with regard to fracture type (Evans' classification), osteoporosis (Singh grade), accuracy of post-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 lag screw on the antero-posterior view with central placement on the lateral view is all optimal location in the femoral head. The 'cut-out index' (the multiplication value of the depth and the antero-posterior deviation of the lag screw ill the femoral head) is an excellent measure of the risk of the lag screw cutting-out. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.