Circular or flat-knit compression stockings?
Compression stockings, which are intended for the treatment of vein disorders, are produced using the circular knitting method and are therefore similar to conventional stockings. Lymph patients with edema are treated with flat-knitted compression stockings. But what exactly is the difference between the two?
Circular-knitted stockings are produced seamlessly and spirally, while flat-knitted compression stockings have a suture and can exert a high flat pressure on the leg using robust materials. In contrast to circular-knitted stockings, flat-knitted ones are suitable for the treatment of larger circumferences and difficult anatomic conditions, as they are less elastic and hold the edema together like a wall.
In the manufacturing process, the two different variants are mainly evident in the use of special machines. Circular knitting machines work with a round cylinder that contains between 300 and 520 needles. The compression stockings are knitted seamlessly from the lace to the cuff. The number of needles remains constant throughout the entire knitting process, whereas the stitch sizes vary and different circumferences can be knitted for one stocking.
For example, the meshes on the thigh are larger and therefore the pressure is lower than on the lower leg. Depending on the machine and manufacturer, the impressive number of over 3,000 stitches per second can be achieved. Depending on the design, a stocking is ready within four and a half minutes. For example, about eight kilometers of yarn is processed in a thigh stocking. Circular-knitted stockings are characterized by a higher elasticity than their flat-knitted counterparts.
The industry has succeeded in producing very fine and transparent stockings as well as in dyeing them in various trendy colours thanks to the continuous further development of the materials. As a result, medical compression stockings are hardly distinguishable from ordinary stockings, yet they continue to fulfil their medical purpose.
Flat-knitted stockings are produced with a flat-knitting machine. With the same stitch size, the different circumferences are created on the flat needle bed by changing the number of needles per row. Smaller circumferences, such as on the ankle, require fewer stitches than larger ones at the thigh or belly. At the end of the process, the two side ends are sewn together so that a seam is created. The variable number of stitches in the stockings means that even very different body shapes and sizes can be made to fit perfectly. Compared to circular-knitted stockings, flat-knitted products are less elastic but form a stable barrier thanks to the fixed stitch size.
Support and thrombosis stockings are not considered medical compression stockings.