Skip to main content

Table 1 Changes in pullout strength by inserting a conventional- or helical blade-type hip screw into a polyurethane bone model of different bone densities, with the types of the leading and following screws kept the same or alternated

From: Conventional versus helical blade screw insertion following the removal of the femoral head screw: a biomechanical evaluation using trochanteric gamma 3 locking nail versus PFN antirotation

BMD 1 2 Pullout p value
Average (min–max) (N)
5 C1 C2 174.55 (138–207)a  
5 C1 ROH2 107.03 (96–120)b < 0.001
5 C1 RXH2 111.56 (90–135)b  
5 H1 H2 128.85 (106–148)b  
5 H1 ROC2 158.97 (135–194)a < 0.001
5 H1 RXC2 160.36 (101–222)a  
10 C1 C2 445.64 (348–552)a  
10 C1 ROH2 285.17 (256–314)b < 0.001
10 C1 RXH2 272.63 (253–290)c  
10 H1 H2 318.17 (279–382)b  
10 H1 ROC2 338.81 (284–382)a < 0.001
10 H1 RXC2 351.22 (299–395)a  
15 C1 C2 914.53 (665–1106)a  
15 C1 ROH2 636.36 (507–726)b < 0.001
15 C1 RXH2 626.09 (536–733)b  
15 H1 H2 833.24 (777–892)b  
15 H1 ROC2 868.54 (727–966)a < 0.001
15 H1 RXC2 879.78 (744–1004)a  
  1. 1, leading screw; 2, following screw; C, conventional-type screw; H, helical blade-type screw RO, following screw insertion after reaming; RX, following screw insertion without reaming; BMD bone model density