RU2121823C1 - Method and device for forced releasing knee joint prosthesis fixable in rest reaction occurred - Google Patents

Abstract

FIELD: medical engineering. SUBSTANCE: method involves providing forced release of knee joint at the moment femur stump moves backward at the back push phase to prepare and realize transfer phase. The knee joint has rest, cantilever, rope with coating shell, belt with valve and lift unit. Lever axis is the rotation axis of the rest and cantilever. The lever is attached to receiving socket of femur prosthesis so that lever axis coincides with invalid person hip joint rotation axis. One end of the lever is placed between the belt and the valve and the other end has rope attached to it. The other end of the rope is attached to the lift hingedly connected to the hip joint unit. Pusher rests on the lift and the shell is attached to the rest with one end and to the hip joint unit with the other end. EFFECT: enabled fast walking and slow running; high reliability and safety. 2 cl, 2 dwg

Description

 The present invention relates to the field of medical technology, namely to prosthetics and prosthetics.

 A known method of forced fixation of the knee node of the prosthesis, implemented during the operation of the so-called Podrezkov prosthesis [1].

 This prosthesis contains wooden femoral and lower leg parts, connected by cranks to a friction element (rubber roller). In the support phase, when the disabled person operating this prosthesis is standing, the thigh stump, being in the receiving sleeve, puts pressure on the friction element (roller) and, therefore, on the lower leg of the prosthesis and artificial foot. The prosthesis is "fixed." During the transition to the “backward” phase, the hip stump with the prosthesis put on it is pushed back, as a result, gaps are formed between the shaft and the femoral and lower leg parts of the prosthesis, which allow the prosthesis to “unlock” and bend at the knee site of the prosthesis during the transfer phase.

 The disadvantage of this method is that it does not always provide a clear unlocking of the knee joint at the right time, since various factors can affect the fixation individually or in combination, namely: the well-being of the disabled person, meteorological conditions and the terrain where the disabled person moves , the pace of his walk, the "mechanical" state of the individual parts of the prosthesis, the step width of the disabled person associated with the angle of the abduction of the stump of the thigh with the prosthesis put on it (since the angle of abduction of the stump is backward connected with blowing back, and that with the release of the knee node to ensure the implementation of the transfer phase).

There are also various devices for implementing this method - currently there are several types (types) of knee assemblies that provide automatic stepless fixation (locking, jamming, locking) of the knee joint when the set reference reaction value is exceeded in a wide range of the knee angle and its wedging when the value of the reference reaction is less than the specified value. All of these knee nodes have the following drawback - the magnitude of the support reaction locking the knee joint should not exceed 30% of the weight of the disabled person for reasons of bracing and walking safety. This allows the disabled person to walk at a speed of no more than 2.5 - 3 km / h, since at a faster pace of walking, as well as when walking normally (see Fig. 1), in the phase of the back push, the knee joint should begin to bend when ~ 40% of the double-step period, that is, when the support reaction P ^{y is} above 100% of the weight of the disabled person and continues to grow, and the value of M $\genfrac{}{}{0ex}{}{\text{z}}{\text{c.p.}}$ maximizes and extends the knee joint. When walking fast and running slowly on the prosthesis with the “sending” of the thigh stump forward, the disabled person begins to bend the knee joint. Then the phase of the support follows, by diverting the thigh stump back, the knee joint begins to be unblocked and it is bent and transferred to the corresponding phase. Analysis of the walking parameters is normal (see Fig. 1) showed that the most suitable parameter for generating a command to open the knee joint in the support phase is the angle between the trunk and thigh -φ _TBS . It is difficult to come up with, besides the supporting phase of walking, a situation vital for a disabled person when he has to rest on a prosthesis with his hip thrown back relative to the body, this is very rare even for an ordinary person (gymnastics).

 For example, a hip prosthesis with an automatic fixation mechanism in the knee hinge is known, the knee hinge of the prosthesis is biaxial, one axis is mounted on the shin sleeve, and the second on the hip sleeve, the axes are connected by a movable link, a buffer made of material with high frictional properties, a crown with an arched bridge is welded to the tubular part of the calf frame, a spring is fixed to the axis of the knee hinge with one end, its second end is attached to the thigh sleeve, under the load the thigh sleeve repent, overcoming the action of the spring, the movable link rotates and the buffer is pressed against the jumper of the lower leg crown. The dimensions and arrangement of the links of the mechanism are selected in such a way that when trying to bend the prosthesis in the knee joint under load, jamming of the buffers and the bridge of the crown occurs, eliminating the possibility of bending the hip relative to the lower leg [2].

 Also known is the kinematic joint of the knee node of the prosthesis of the lower limb, which has a similar effect [3].

 All these devices (analogues) have a common drawback: they do not have devices for forced fixation.

 The closest analogue of the claimed device for implementing the claimed method is a device containing a lever mounted on an axis and a pusher [4].

 A disadvantage of the known method and device is that they do not provide increased comfort and speed of walking on hip prostheses with knee nodes with automatic stepless fixation of the knee joint provided by the support reaction of a given value by neutralizing the support reaction and fixing the knee joint in the backward push phase the account of the abduction of the thigh stump back relative to the body of the disabled person and the issuance at this moment of a command for forced release.

 The objective of the invention is to increase the comfort and speed of walking on hip prostheses with knee nodes with automatic stepless fixation of the knee joint provided by the support reaction of a given value by neutralizing the support reaction G • n and unlocking the knee joint in the back shock phase by moving the hip stump back relative to torso of a disabled person and filing at this moment a command for forced release.

 The task in terms of the method is solved by the fact that in the method of forced fixation of the knee node of the prosthesis, fixed when a support reaction occurs, which involves the abstraction of the thigh stump with the prosthesis on it back when moving from the support phase of the prosthetic limb to the backward push phase, a distinctive feature is that that at the time of the abduction of the thigh stump back to ensure and implement the phase of transfer of the prosthesis, the knee node is forcibly unlocked (forced release is performed).

 In terms of the device, the task is solved in that in the device for implementing the method, comprising a lever mounted on an axis and a pusher, a distinctive feature is that an emphasis, an arm, a cable with a bowden (sheath), a belt with a valve and a lift are introduced into it moreover, the axis of the lever is the axis of rotation of the stop and the bracket, which is attached to the receiving sleeve of the hip of the prosthesis so that the axis of the lever coincides with the axis of rotation of the hip joint of the disabled person, and the lever is inserted at one end between the belt and the valve, and a cable is attached to its other end, the second end of the cable is attached to the lift, pivotally connected to the knee assembly, the pusher rests on the lift, the bowden (sheath) is attached to the stop by one end, and to the knee assembly by the other.

 The totality of the above characteristics, providing the neutralization of the support reaction and the fixation of the knee hinge in the phase of the back push due to the removal of the thigh stump back relative to the body of the disabled person, was not found in science and technology until the filing date of the application, which meets the requirement of "novelty." Thus, the claimed technical solution meets the criterion of "positive effect". In addition, the authors have not found such solutions, therefore, the set of essential features meets the criteria of the invention "significant differences".

 The essence of the invention is illustrated by the drawing, where in FIG. 2 schematically shows a device for forcing the knee assembly to be locked when a support reaction occurs.

The device comprises a lever 1, an axis of the lever 2, an emphasis 3, an arm 4, a cable 5, a bowden (sheath) 6, a belt 7, a valve 8, a lift 9 and a pusher 10. The lever 1, an emphasis 3 and an arm 4 are interconnected by an axis of the lever 2 The bracket 4 is attached to the receiving sleeve of the thigh so that the axis of the lever 1 coincides with the axis of rotation of the hip joint of the disabled person. A lever 1 is inserted at one end between the belt 7 and the valve 8, and a cable 5 is attached to its other end, the second end of the cable is attached to the lift 9, pivotally connected to the knee assembly, and the pusher 10 is supported on the lift. Bowden 6 is attached to the stop 3 with one end and the other to the knee node. The sizes l _G , l _n , l _p and h _p must be selected so that the force P _p does not exceed 1 kg.

 A device for forced release of the knee node, fixed when a support reaction occurs, operates as follows.

 When a disabled person moves with a prosthesis on the thigh stump with a receiving sleeve and an arm 4 attached to it, forward relative to the body of the disabled person, a gap is formed between the stop 3 and the bracket 4, and when moving backward, the bracket 4 comes into contact with the stop 3 and, turning the stop 3 relative to the lever 1, pulls the cable 5 out of Bowden 6, as a result of this, the second end of the cable rotates the hoist 9 around its axis of rotation and moves the pusher 10, overcoming the support reaction G • n and thus breaking the knee joint.

;
принимаем l_G = 0,8 мм, тогда усилие на тросик

и соответственно:

Такая величина силы на поясе инвалида вполне приемлема и не внесет дискомфорта при его быстрой ходьбе. Если же Δ_T = 0,15 мм, то P_p = 0,26 кг.Typically, in the knee nodes that are fixed when a support reaction occurs, very small strokes in the range of Δ _T = 0.1 - 0.3 mm are needed to fix them. Given acceptable values for the sizes α, l _n , l _p , h _p , G and "n", we estimate the value of P _p . If the weight of the disabled person is G = 100 kg, the dynamic coefficient is n = 1.3, α = 25 ^o , l _n = l _p = 50 mm, h _p ~ 200 mm for a person of average height (1700 mm), then

;
take l _G = 0.8 mm, then the force on the cable

and correspondingly:

This amount of strength on the belt of a disabled person is quite acceptable and will not bring discomfort when walking fast. If Δ _T = 0.15 mm, then P _p = 0.26 kg.

An example of a specific implementation of the method
A disabled person Jin with a hip stump has been using a lower limb prosthesis with a knee node with automatic fixation for many years. The prosthesis during its operation has repeatedly given "failures": sometimes the knee node was unblocked during the phase of the back push. When the prosthesis was equipped with the proposed device for forced fixation, the effectiveness of using the prosthesis increased sharply - almost always the fixation is clear and on time.

 The application of the method of forced fixation of the knee node of the prosthesis fixed when a support reaction occurs, and the device for its implementation provides the disabled person with the ability to quickly walk and run slowly on the hip prostheses with knee nodes fixed when the support reaction occurs, and also provides increased safety, comfort and anthropomorphic walking and running.

Claims (2)

 1. The method of forced fixation of the knee node of the prosthesis, fixed when a support reaction occurs, which consists in diverting the thigh stump with the prosthesis on it back when moving from the phase of the prosthetic limb support to the backward jolt phase, characterized in that when the thigh stump is pulled back to the phase the back push for the preparation and implementation of the transfer phase, the knee assembly is forcibly unlocked (forced release is performed).  2. The device for implementing the method according to claim 1, comprising a lever mounted on an axis and a pusher, characterized in that a stop, an arm, a cable with a bowden (sheath), a belt with a valve and a lift are introduced into it, the axis of the lever being the axis rotation of the stop and the bracket, which is attached to the receiving sleeve of the hip of the prosthesis so that the axis of the lever coincides with the axis of rotation of the hip joint of the disabled person, with the lever at one end inserted between the belt and the valve, and a cable attached to its other end, the second end of the cable attached to the lifter pivotally connected to the knee assembly, the pusher rests on the lift, the bowden (shell) is attached to the stop at one end and the knee assembly to the other.

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