A skin flap is a segment of skin and subcutaneous tissue that is transferred from one body part to another. Among the many possible flap designs, the rhombic transposition flap is most popular. The first rhombic flap was described by Limberg. The classical Limberg flap is a transposition flap used to cover defects that have been excised as a rhombus with the apex angles of 60° and 120°. The optimal angles were derived by Limberg on paper models.
The aim of our contribution is to analyse Limberg’s theoretical results with regard to the simplicity of paper models. For these purposes a three dimensional finite element model with varying apex angles was built. The apex angles were varied from 40° to 80°. A non-linear relation for material behaviour of skin was used.
The maximal extrusion and distribution of stress along the sides of a closed defect were analysed. The height of extrusion increased with increasing the apex angle. The maximal extrusion of 2.8 mm appears for the angle of 80°. The maximal stress distribution is also valid for the case of the maximal apex angle.
The knowledge of precise geometry of the rhomboid flap is essential. Limberg supported this knowledge by an analysis based on a paper model, and his results are widely used. From our results it can be seen that the apex angle of 60° is not the optimal but the maximal angle for the rhomboid flap. With lower apex angles better results can be reached.
Conflict of interest: None declared.