[Biomechanical study of new type two-head automatic pressure external fixator (TAPEF) for the treatment of intertrochanteric fracture].

Objective: To investigate the mechanical characteristics of new type two-head automatic pressure external fixator in the view of biomechanics.

Methods: Fifteen fresh and humid specimens were selected and divided into experimental group (5 cases) and control group (10 cases). The control group were respectively applied with DHS (5 cases) and traditional external fixator (5 cases). In order to compare the different apparatus, the strength, stiffness and twist mechanical function of femoral intertrochanteric fracture with different device were measured respectively when the specimens were under the pressure of 0-1800 N and loading speed 1.4 mn/min.

Results: The strength, stiffness, twist mechanical function and maximum endurance of femora in the experimental group were obviously superior than that of DHS and traditional external fixator (P < 0.05).

Conclusion: Two head automatic new type pressure external fixator can embed more tightly without sliding, also can prevent the occurrence of coxa vara effectively.