The Structure and Compression of Medical Compression Stockings

Abstract

This paper lays out standards of compression stockings and their classification into classes. The analysis of knitted fabric structure parameters, elongation and compression of moderate- and high-compression stockings was conducted. Stocking compression on specific parts of the stocking leg was measured on three sizes of a wooden leg model. For moderate-compression stockings, compression above the ankle was 32 hPa. For high-compression stockings, compression above the ankle was 60 hPa. Both groups of the analyzed compression stockings were made on modern one-cylinder hosiery automats. The legs of the stockings were made in single inlaid jersey 1 + 1. Both yarns were elastane covered. The finer yarn formed loops and its knitting into a course was significantly larger than in the other yarn, which was much coarser and does not form loops but "lay the weft in a bent way". The smallest elongation of knitted fabric was above the ankle, where the highest compression was achieved, while the largest elongation was under the crotch, where the stocking leg exerted the smallest compression on the surface. The leg of the compression stocking acted as a casing that imposed compression on the leg and often reinforced it to be able to sustain compression loads.

Keywords: compression; compression stocking; elastane; elongation.

Figure 1

Positions for leg measurements: (a) for height and circumference; (b) marks on the wooden leg model when measuring compression.

Figure 2

Force–elongation diagrams for the double-covered elastane yarns used to make compression stockings, measured without preload: (a) nominal yarn count of 52 dtex for the yarn used to make loops; (b) nominal yarn count of 232 dtex for the yarn that did not make loops but “lay the weft in a bent way”.

Figure 3

Yarns and structure of knitted fabric in women’s moderate-compression pantyhose: (a) the appearance of pantyhose; (b) double-covered elastane yarn with a nominal count of 52 dtex, which was used to make loops; (c) double-covered elastane yarn with a nominal count of 232 dtex, which was not used to make loops but to “lay the weft in a bent way” in rapport 1 + 1; (d) structure, jersey, single inlaid 1 + 1 used to make the largest part of the stocking; T—ground yarn, P—“bent weft“.

Figure 4

Medical compression stockings with the foot, heel and panties with a high compression of 60 hPa (45 mmHg) above the ankle: (a) the appearance of the pantyhose; (b) ground single-covered elastane yarn with a total count of 120 dtex, which was used to make loops in each course; (c) double-covered elastane yarn with a total count of 700 dtex, which laid the weft in a bent way and exerted high compression; (d) front side of the knitted fabric; (e) backside of the knitted fabric.

Figure 5

The relation of the length of the ground yarn knitted into a course (L_oc) and the compression (K_c) at a specific position on the wooden leg model of size M9 for moderate compression.

Figure 6

The relation of the length of the ground yarn knitted into a course (L_oc) and the average compression (K_c) at specific parts of the wooden leg model of size M9 for high compression.