Sensitivity of the properties of the graduated compression stocking and soft tissues on the lower limb-stocking...

Graduated compression stocking (GCS) plays an important role in the treatment of venous disease in the lower limb. However, the effect of the variation in the mechanical properties of the GCS and the soft tissues on the treatment of the venous disease in the lower limb remains unclear. The aim of the present study was to investigate the influence of the material properties of the GCS and soft tissues on the lower limb-stocking interfacial pressure using the orthogonal simulation test. A three-dimensional finite element (FE) model of the lower limb was established using the MRI dataset of a 40-year-old volunteer. The bones, the skin, the veins and the skeletal muscles were reconstructed in the FE model. The FE model of the GCS was generated using the information provided by the manufacturer. Then the parameter sensitivity analysis was performed using a two-step orthogonal simulation test. The first-step orthogonal test showed that the variation in the Young's modulus in the wale direction of the GCS induced a change of 0.37 mmHg in the lower limb-stocking interfacial pressure in the ankle section. The second-step orthogonal test showed that the variations in the Young's modulus in the wale direction of the GCS in the knee section induced the changes of 0.05 mmHg, 0.15 mmHg and 0.60 mmHg in the interfacial pressure in the ankle, the calf and the knee, respectively. In conclusion, the Young's modulus in the wale direction of the GCS and the Poisson's ratio of the GCS are the parameters significantly influencing the lower limb-stocking interfacial pressure. The interfacial pressure in the ankle is not sensitive to the Young's modulus in the wale direction of the GCS in the knee section. However, the interfacial pressures in the calf and knee are sensitive to the Young's modulus in the wale direction of the GCS in the knee section. These data provide important information for the design of GCS.