Textiles: knitting – Fabrics or articles – Articles
Reexamination Certificate
1999-05-13
2001-04-17
Worrell, Danny (Department: 3741)
Textiles: knitting
Fabrics or articles
Articles
C066S17800A, C602S063000, C002S239000
Reexamination Certificate
active
06216495
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a support stocking designed for sports and sportsmen.
The elastic compression has proven its effectiveness in the-treatment of venous insufficiency, particularly in the early stages. It also makes it possible to slow the development into chronic venous insufficiency which occurs progressively and most often over several years.
Sport is theoretically beneficial to venous return, but only under certain conditions, which are rarely encountered in routine or competitive practice. For example, the type of sport, its intensity, its duration, the level of physical conditioning of the sportsmen, lack of training and insufficient recovery time may have an effect on the venous condition and be responsible for a loss of performance or the occurrence of injuries, such as strains, torn muscles, periostitis, chronic tendinitis or torn Achilles tendons.
There are few studies on the role of sport and compression on the venous system, and the results sometimes disagree. Nevertheless, the physical principles and hemodynamic effects of compression demonstrate its beneficial results when it is applied to sportsmen during and after physical activity.
The elastic supports currently available, with a measurable pressure, are reserved only for patients suffering functional or organic venous insufficiency. The pressures have been adapted as a function of parameters relating to the venous insufficiency. However, all these parameters and the hemodynamic conditions are different for sportsmen without venous insufficiency.
SUMMARY OF THE INVENTION
The object of the present invention is to adapt the support stockings obtained by various knitting methods to obtain pressures specific to sportsmen and to the practice of sport, while accommodating their specific physiology.
The supports intended to correct venous insufficiency consist of stockings, leg stockings or knee-high stockings, thigh supports and knitted tights, comprising textile yarns combined with covered or uncovered elastic yarns of natural or synthetic origin. The tension imparted to the elastic yarns during knitting determines the compressive pressure, that is to say the radial force of retention on the leg. The knitting may be circular or linear and the elasticity may be in one or more directions. These support stockings can be manufactured in standard sizes or to measure.
In practice, the compression provided by the stocking is defined by a blood pressure measured in mm of mercury, according to the French standards (A.F.N.O.R.), and distinction is made, amongst other things, between a force I, generating a pressure of between 10 and 15 mm of mercury, a force II, generating a pressure of between 15.1 and 20 mm of mercury, and a force III, generating a pressure of between 20.1 and 36 mm of mercury. In the other European countries, these values differ and are 13 to 22 mm of mercury for class I, 23 to 33 mm of mercury for class II and 34 to 47 mm of mercury for class III.
In stockings or knee-high stockings correcting venous insufficiency, the compression force in a maximum on the foot and the ankle and decreases up to the calf or thigh. This is the case with the stockings described in U.S. Pat. No. 4,745,917. The impetus for this principle is that, whatever the etiology or the mechanisms responsible for the venous insufficiency reflux, stasis, hypertension, etc.), the effect on the veins is always localized primarily at the ankle, the foot or the lower third of the leg. FR-A-1,124,593 describes a stocking which, specifically, provides maximum compression over the lower third of the leg.
It is difficult to calculate therapeutic compressive pressures because a number of factors are involved: the position of the body, the anatomical and biomechanical condition of the muscles, joints, tissues, the anatomical state of the venous and perivenous structures, the force of gravity, the tissue pressures, the hemodynamics and the venous pressures when changing position, under exertion, according to the variations in cardiac and abdominal pressures, the venous flow and reflux rates (deep, superficial, intermediate, etc.). Only some of the above factors are measurable.
Prior work has established a principle of graduating the compressive pressures in the downward direction, the maximum pressure being level with the ankle and the minimum pressure (=0) level with the heart. This maximum pressure at the ankle is calculated on the basis of data relating to the physiology of the venous insufficiency accompanied by venous reflux and hyperdiatension. This may not be applicable to sportsmen without venous insufficiency, whose physiology is different and specific.
This is why the applicants have tried to define new blood pressures and new gradients from studying the physiology of venous return and compression in sportsmen without venous insufficiency, during and following exertion.
An overview of physiopathology would seem essential for explaining the decisive elements of the present invention.
The main physiological parameters involved with sportsmen in the practice of sport are represented by venous hyperdistension with an increase in the oxygen-depleted residual volume (up to 50% of the basic volume) an increase in the caliber of the veins (30 to 40% for prolonged or intense exertion), and by an increase in the tranamural venous pressure. The results from the literature relating to measurments of the venous pressures and pressure variations during or following exertion disagree depending on the methodology because, most often, the measurements are taken at the ankle level. This may not correspond to the maximum pressure because sportsmen without venous insufficiency do not exhibit valvular reflux, have good articulation and an efficient plantar and muscular venous pump. The venous filling and dilation will firstly affect the muscles of the calf and have the superficial venous network, then the perforans and the deep network. Venous hypertension will therefore tend to be a maximum at the calf level.
It is also of interest to examine plantar vein physiology, applied to sportsmen.
The plantar venous axes are directly connected to the posterior tibial veins and also communicate with the superficial veins of the back of the foot through the perforans, some of which are of large caliber. The plantar venous reservoir ejected on each step can be estimated at between 30 and 40 ml. During the diastole, three antireflex mechanisms are involved: the valvules, of which there are many on the confluences and the collectors; a plexal device of the venous confluences which form a substantial barrier and a fibrous tunnel which surrounds the veins most highly exposed to the reflux.
This antireflux device is thus effective in sportsmen without venous insufficiency due to valvular incontinence. There is therefore no need to compress the foot and the malleolar region too much in sportsmen. This is of benefit both in physical terms Laplace's law) and in terms of tolerance to the support, since compression of the foot and the malleoli is hardest to endure. It should be added to this that, with the improvement in the podological characteristics of most sports shoes, the ejection conditions of the plantar venous reservoir are optimal.
The support stocking for the practice of sports, according to the invention, is composed of a sheet, elastically deformable in at least one direction, which is configured, when the stocking is being made, for example by stitching its edges or circular knitting, so as to exert on the body, that is to say at least on the foot and the leg, compressive pressures which are different between the foot and the leg.
According to the invention, the part of the stocking that extends from the end of the foot to just above the malleoli and sheaths the foot and the ankle is structured so as to exert a compressive pressure P1 with a value less than that of the compressive pressure P2 exerted by the part of the stocking sheathing the calf.
With this stocking, the compression exerted on a sportsman is therefore mo
Couzan Serge
Prufer Michael
BV Sport
Oliff & Berridg,e PLC
Worrell Danny
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