[Rotational instability of trochanteric femoral fractures secured with the dynamic hip screw. A radiologic analysis].

In this study, a retrospective analysis of patients with trochanteric fractures fixed with a dynamic hip screw was performed (n = 238). Analysis of the complete X-rays (n = 115) revealed rotation of the head-neck fragment in 12% of the cases (n = 14). Patients with complex fracture types were more often affected by this complication (p < 0.05). The distance of lateral impaction was significantly higher in the group with rotation of the proximal fragment compared to patients without rotation (p < 0.001). The rate of cutting-out (p < 0.01), the rate of delayed union (p < 0.01) and the rate of varus angulation (p < 0.01) was significantly higher. Reoperation was necessary in 14% of the patients compared to 2% in the group without rotation. We conclude that rotational instability of a gliding implant system is a severe complication in the treatment of trochanteric fractures.