Predictability of sub-bandage pressure in compression therapy based on material properties

The pressure developed beneath any compression system is governed by the tension in the compression fabric. Depending on the type of material – cotton or elastomer – compression systems may react differently under the same stress. The previous work of our group and experience related to compression systems showed that classification of bandage materials is required for manufacturers who want to create products with specific compression levels. One of the mathematical descriptions of the expected pressure due to a tensile force in the fabric is the modified Young–Laplace equation. However, the pressure achieved by real compression systems hardly matches with the estimated values. Two groups of elastic bandages – short stretch and long stretch – were selected and investigated within this work. The tensile forces were measured using a dynamometer, and the pressures deduced at a given maximal load (3 N/cm) were compared with the pressures measured beneath the bandage on living subjects. The results show that the interface pressure can be predicted from the tensile force at the inflexion point of the hysteresis curves. Calculated pressures were in a therapeutic range but were significantly different from practically applied pressures, indicating large differences between calculated and real pressures on the leg.