FR2501999A1 - Lower leg prosthesis with articulated knee, ankle and toe joints - has length of telescopic tibia element controlled by gas spring and knee joint spring biassed to unflexed position - Google Patents

Abstract

The prosthetic leg is articulated at the knee, ankle and toes with the overall length being variable using a gas spring. A second gas spring returns the knee joint to the unflexed position. The prosthesis is fitted to the femoral stump using a cup-shaped casing which has a silicone elastomer internal wall and a reinforced polyester resin outer wall. The tibia of the prosthesis is formed by a pair of tubes which slide telescopically within one another without play and with the min. possible friction. The lower end of the lower tube is connected to part of the ankle joint.

Description

The present invention concerns the manufacture of an articulated lower limb prosthesis
your lower limb prostheses commonly used today, whatever they are; fixing by straps or by suction cups, are fitted with a rigid socket made of wood, synthetic materials or metal, adjusted randomly on the stump. Some models have inflatable pockets or bladders helping to enclose the stump, it is not flush, however Ps guaranteed friction from walking especially at the edge of the socket.

 I, the knees are manual or automatic locking, the rannel in this case being provided by a metal or rubber spring sometimes paired with a friction or hydraulic shock absorber. Your ankle is re-read often fixed or with a slight rocking movement when walking is knee locked; the foot is a block of foam or felt; the aesthetics of the whole being only constituted by a reminder of the normal volumes.

 The production according to the invention allows adjustment of faithful Dlus between the stump and the internal tarty of the socket; made of sounle material going back beyond the rigid nartie of the socket and protecting the skin from any overheating.

 I, e knee is of automatic type, with return nar spring>, gas, associated n an integrated hydraulic shock absorber, a second gas spring lockable, continuously, in n'im norte such Position chosen, er permanence, by the user nermet, to vary the length of the leg nour better adapt to the Drofil of the ground; the ankle is soft tyne with a range of motion comparable to that of a normal limb; elasticity and the return to neutral noint ensures nar the mass of rubber constituting the aesthetic, the foot is removable and interchangeable by the user to allow to change the heel height; the aesthetics of the leg are made of silicone elastomer put in the cone put in the color individually, renewing the annarence of the member up to the fingerprints, the stuffing is made of soft foam ssrnthétioue.

The realization of said nrothesis is divided into several elements:
- The socket - the knee - the leg - the foot and the general esthetic.

 10) - The socket (pl 1 - fig 1): it is double-walled, the internal wall (1) is made of silicone elastomer of hardness approximately 35 schor, the external part (2) is a shell of reinforced polyester , the internal part can be either molded directly on the stump (on condition of having a silicone elastomer suitable for this kind of embodiment) or a reproduction of the stump produced by a faithful molding process. It is important that the stump be the longest possible, possible during this operation; the "sock" thus obtained don t be 2 to 3 mm thick and cover as far as possible the stump, it has at the end, an extra thickness (3) padded with soft foam to avoid pounding in the bottom. sock "the reinforced polyester is shaped without excess weight respecting a lip at the top which must remain flexible to prevent injuries caused nar the edge and by strengthening the seat of the nour patient to guarantee all risks of rupture during use these two pieces are then joined together using cold glue at the padding level only, the rest of the "sock" following the stump. in all its deformations (seated position) and remaining adherent to it, the polyester shell serving to guide the prosthesis. The quilting is traversed by an orifice (4) large enough to pull the tubular ierser used to lower the clear parts of the stump during threading; this orifice is then hermetically sealed na cap (5) comprising a rubber membrane valve (6) to evacuate the air which could accidentally slip between the stump and its protective neltu (1); outside the polyester shell is sealed at a determined location, nar the essesseage a ball joint (7) which will be blocked after correct alignment of the stump with respect to the entire anDareillage, a lever controlling the blocking the tibial spring is glued and sealed in the polyester shell at a height such that it can be operated with the fingertips while standing.

20) - The knee (p1 Il - fig 4): connects to the tail of the patella with round tubular forceps and to the broken tube of the tibia By a scabbard (9) the lower niece carries on its face.posterrière and horizontally a round sheath (îo) containing two needle bearings, its upper part is closed and flat. The sunpiece wraps the lower part on the side and front faces; the axis of the bearings of the lower part passes through and is fixed on the lateral faces of the upper part, the
Tubular pliers (10) holding the socket, is fixed dusus and in front of this upper part, the interior of which is furnished with a nylon stop (11), these two parts are connected to part of welded e + shaped sheet plates, thicknesses will be determined to provide maximum strength for minimum weight based on the weight of the user.

The compression spring (13), of the compression type, is a gas spring damped at the end of the return stroke; it is placed laterally with respect to the leg, so as not to limit the stroke of the leg thus authorizing the wearer to sit on his heels, his sun head (14) furnished with a needle socket, is articulated on an axis (12) fixed behind the knee in the same plane, the spring nied is fixed on a pin (15) resting on the body of the "tibial" spring the position of the pirce will terminate the place where on the return of the leg the shock-absorbing effect will be felt, the adjustment takes into account the vitality of the sleeper, the length of the lever briefs on the knee joint and the nominal force of the spring; raised the clamp accelerates the movement, lowered the idle this adjustment is not commonly accessible.

ssO) - Your leg or "tibia" (pl Il - fig F): is formed by two square tubes sliding one inside the other without play. The upper tube engages in the socket of the lower part of the knee where it is held in place by mechanical pins. The lower nozzle engages in the socket of the removable foot where it is screwed at the end (16). These two tubes are joined by a gas spring (14) which can be blocked at any point in its stroke by the release of the plunger (18) located at the end of the rod. This control is carried out by the handle sealed in the polyester carcass of the socket by means of a cabal acting on a lever (19), when adjusting the lengths the spring will be blocked at mid-stroke rour have a possibility of more or less a half-stroke in each direction , the force of the spring will be such that the weight of the user can compress it completely by explaining it on the Prosthesis (pl 3 - fig 5). The articulation on the ring is located at the rear third of the foot; this slight offset on the front does not cause the swaying of a fixed foot, but allows to lock the knee in the stretched position S it is indeed essential that the vertical of the fulcrum of the foot passes in front of the axis of the knee and behind weary of the ankle, otherwise the knee would slip away; the metal sole (22) of the foot stops before the metatarsal heads, the entire metal part of the niez is made of welded sheet metal formwork like the knee, this articulated metal assembly is then sealed in the aesthetic block made of silicone elastomer, this block ensures progressive elasticity and return to neutral of the joint, the toes benefit
H e their own elasticity, the external shape is given by n molding performed on a donor of neighboring morphology, the color is carried out in agreement with the donor, in the mass. The mass of the esthetician is stopped dead close to the top of the gusset (230) for adaptation to the leg; it is obvious that the fixing by an easily accessible screw prevents the easy replacement of the foot and authorizes in particular the user (trice) to wear different heights of heels with the same leg.

 The rest of the aesthetics of the leg is made up of a block of low density polyurethane foam, hollowed out for the passage of the skeleton sculpted or molded into shape and covered with a retroduction of leg skin, as for the foot. to a donor, it remains possible to deposit it, in denial, for maintenance or adjustment of the mechanism.

Claims (6)

 10) wahrication of lower limb prosthesis characterized by the fact that it is articulated at the knee, ankle and toes.  20) Lower limb prosthesis according to claim I characterized in that the knee and the ankle are mounted on needle bearings.  30) Lower limb prosthesis according to claim I, characterized in that the length of the leg can be modified at any time by the user thanks to a continuously lockable gas spring.  40) Lower limb prosthesis according to claim I characterized in that the return of the knee is effected by a gas spring located laterally in order to allow the complete movement of the knee.  50) Lower limb prosthesis according to claim I, characterized in that the adhesion to the stump is effected by a skin of silicone elastomer adhering to the bottom of a shell of reinforced polyester resin, the skin of silicone elastomer being clearly More long than the shell to protect the flesh from overheating.  60) Lower limb prosthesis according to claim I characterized in that the socket is connected to the rest of the leg by a ro + .ule blocked after correcting the alignment of the assembly.  70) Prosthesis of lower limb according to claim I characterized par.le the fact that the orifice used to pass the tumble jersey necessary for the establishment deschairs is closed by a hermetic cap comprising a membrane valve permanently evacuating the air can slip inside the socket.  80) Lower limb prosthesis according to claim I characterized by the fact that it comprises an interchangeable articulated aesthetic foot in order to allow the norator to vary the height of his heels.