Fig. 2

The three groups of fixation models studied in the clinical and biomechanical investigations included the Alpha (G-ALP), Inverted Triangle (G-ITR), and Triangle (G-TRI) groups. Three parallel screws were all positioned dispersedly, at 2.5 mm to the cortex and 5 mm distal to the subchondral bone in the femoral head. The off-axis screw in G-ALP was implanted 5 mm proximal to the most prominent part of the great trochanter and targeted at the inferior femoral head-neck junction. DHS was implanted inferiorly. The anti-rotational screw was 1.5 cm parallel and superior to the nail