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Table 3 Pullout and rotational strengths by inserting a conventional- or helical blade-type hip screw into a polyurethane bone model, with the leading (original) screw

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 Original C Original H p value
  Pullout  
  Average (min–max) (N) Average (min–max) (N)  
5 253.36 (225.9–280.1) 146.15 (114.9–162.7) < 0.001
10 575.76 (504.7–669.1) 322.81 (257.0–374.2) < 0.001
15 1261.33 (1078.0–1497.5) 870.87 (784.1–957.7) 0.031
  CW rotation  
  Average (min–max) (N) Average (min–max) (N)  
5 41.39 (35.5–46.1) 99.73 (91.9–110.0) < 0.001
10 98.47 (82.8–116.6) 154.02 (132.2–174.3) < 0.001
15 167.93 (143.4–188.8) 244.74 (197.7–300.4) < 0.001
  CCW rotation  
  Average (min–max) (N) Average (min–max) (N)  
5 17.68 (16.2–19.3) 85.42 (75.1–95.4) < 0.001
10 57.68 (38.9–72.1) 147.6 (123.0–163.2) < 0.001
15 111.27 (82.1–157.5) 211.49 (118.2–272.7) < 0.001
  1. BMD bone model density; CCW counterclockwise strength; CW clockwise strength; C conventional-type screw; H helical blade-type screw