The biomechanical comparison of screw fixation and cross pinning methods in salter harris type 2 distal femoral fractures using the finite element method

Öner K., Özer A., Paksoy A. E.

Annals of Clinical and Analytical Medicine, vol.12, no.2, pp.205-209, 2021 (ESCI)


Aim: The most common type of distal femur physis fractures is Salter-Harris type 2 (SH type 2). These fractures have high complication rates and can cause
a significant loss of function. Anatomical reduction is important in treatment. In this study, we aimed to compare two methods commonly used in SH type 2
fractures, cross pinning, and two parallel screw fixation methods using the finite element method.
Material and Methods: The SH type 2 fracture model was created in the femur model obtained from the 3-dimension (3D) computed tomography (CT) scans.
The fracture in the first model was fixed with crossed Kirschner (K) wires. The fracture in the second model was fixed with two parallel screws placed from
the metaphyseal part. The two models created were moved to the Ansys Workbench program. Axial overload, varus, valgus, anterior, posterior bending, and
torsional forces were applied and analyzed with the 3D finite element method.
Results: In axial overload, the max stress in growth cartilage K wire was 0.40 MPa, while in the screw- 1.24 MPa. The varus bending was 0.32 MPa and 1.71
MPa, respectively. Also, the valgus bending was 0.15 MPa and 0.56 MPa, respectively. The anterior bending was 0.85 MPa and 1.30 MPa, respectively. Also,
the posterior bending was 0.56 MPa and 2.01 MPa, respectively When torsional force was applied, it was found as 0.008 MPa and 0.16 MPa, respectively.
Discussion: In SH type 2 distal femoral fractures, the cross-pinning method is superior to the two parallel screw methods placed from the metaphyseal part
in bending, torsion and axial loads.