RU208436U1 - Knee prosthesis - Google Patents

Abstract

The utility model relates to medical equipment, namely to prostheses, and can be used in lower limb prosthetics. To facilitate the design of the knee joint prosthesis, to simplify the manufacture of attachment points for the pyramid adapter to the upper support and the lower leg prosthesis to the lower part of the central support of the knee joint prosthesis, to reduce the cost of manufacturing, the knee joint prosthesis contains a central support 1, an upper support 2, an adapter "pyramid" 3 , small lever 4, large levers 5, 6, bushing 7, bushing 8, lower axle 9, upper axle 10, pneumatic damper 11, clamp 12, tightening screw 13, screw 14, self-locking washer 15, washer 16, nut 17. 3 ill.

Description

The utility model relates to medical technology, namely to prostheses, and can be used in prosthetics of the lower extremities.

Known polycentric knee joint containing an upper support platform for attaching the sleeve of the thigh, a lower bracket for attaching the shin tube, interconnected by the front and rear links using four rotational kinematic pairs, and the distance between the axes of the rotational kinematic pairs of links on the upper support platform is made greater than the distance between the axes of the rotary kinematic pairs on the lower bracket (see RF patent for invention No. 2294715, IPC A61F 2/64, publ. 03/10/2007, bull. No. 7).

The disadvantages of the known polycentric knee joint are the complexity of manufacture, high cost due to the design features of the upper support platform for attaching the thigh sleeve and the lower bracket for attaching the shin tube.

Known knee module, containing in the upper articulation a built-in pyramid for attaching the hip prosthesis, in the lower articulation a clamp for attaching the prosthetic leg, connected to each other by means of a middle articulation, and in the upper articulation built-in brake hydraulic unit (see RF patent for invention No. 2380061, IPC A61F 2/64, publ. 27.01.2010, bull. No. 3).

The disadvantages of the known knee module are the complexity of manufacture, high cost due to the design features of the lower articulation with the clamp and the upper articulation with the pyramid and the brake hydraulic unit.

The closest solution in terms of the technical essence and the achieved result to the proposed utility model is a knee joint prosthesis containing an upper support with a "pyramid" adapter installed on it for attaching a hip prosthesis and a central support with a bracket for attaching a lower leg prosthesis. The "pyramid" adapter is attached to the upper support by fitting the pyramid head into the pyramid base with an interference fit and tightening it with a spherical head screw and a washer with a spherical recess, while the pyramid base and the surface of the upper support are grooved for tight fixation of the pyramid on the upper support. The bracket consists of two lugs with a gap between them for tightening and a tightening screw (see RF patent for invention No. 2592248, IPC A61F 2/64, publ. 10.04.2016, bull. No. 10).

The disadvantages of the known knee joint prosthesis are the complexity of manufacture, high cost due to the design features of the central support and the attachment point of the "pyramid" adapter to the upper support of the knee joint prosthesis; the use of a central support with a bracket of two ears and a gap between them for tightening, with a lag screw for attaching the lower leg prosthesis complicates the process of its manufacture; the presence of complex elements in the attachment point of the “pyramid” adapter to the upper support, in particular, the interference fit of the pyramid head into the pyramid base, corrugations in the lower part of the pyramid base and the upper support of the knee prosthesis, washers with a spherical recess and a spherical head screw contribute to increase of these indicators.

The objective of the proposed utility model is the development of a device of a simple design - a knee joint prosthesis and its creation with the possibility of convenient assembly and low cost.

The technical result of the utility model is to create a knee joint prosthesis with the possibility of lightening the structure; simplifying the manufacture of attachment points for the hip prosthesis to the upper part and the lower leg prosthesis to the lower part of the knee prosthesis; reducing the cost of manufacturing.

The specified technical result is achieved by the fact that in a knee joint prosthesis containing a central support, an upper support, a pyramid adapter, a small lever, two large levers mirrored on both sides of the central support, a pneumatic damper, a bracket of two lugs with a lag screw the central support, according to the utility model, the adapter "pyramid" is made as part of the head of the pyramid and the base of the pyramid, fixed to the upper support, and the head of the pyramid is inserted into the base of the pyramid and fixed on the upper support of the knee joint prosthesis using a screw and self-locking washer, and the bracket is made as part of a removable clamp with a tightening gap, with a lag screw, a washer and a cylindrical nut, and the clamp is inserted in the lower part of the central support of the knee joint prosthesis.

A distinctive feature of the utility model is the implementation of the attachment point of the "pyramid" adapter to the upper support without complex elements, namely, the head of the "pyramid" is inserted into the base of the pyramid and fixed on the upper support of the knee joint prosthesis using a self-locking screw and washer, as well as simplification of the central support due to the implementation of a removable clamp with a lagging screw in the lower part of the central support of the knee joint prosthesis.

The main distinguishing features of the claimed utility model - "Knee joint prosthesis" are:

- implementation of the “pyramid” adapter as part of the pyramid head, pyramid base, screw and self-locking washer allows to reduce the number of manufactured parts for the hip prosthesis attachment to the upper part of the knee prosthesis;

- installation of the head of the pyramid into the base of the pyramid and fastening it to the upper support of the knee joint prosthesis using a screw and self-locking washer simplifies the assembly of the “pyramid” adapter;

- execution of a removable clamp with a clearance for tightening, with a lag screw, washer and a cylindrical nut, installation of the clamp in the lower part of the central support of the knee joint prosthesis, followed by tightening with a washer and nut, will simplify the manufacture and reduce the weight of the central support.

The proposed utility model "Knee joint prosthesis" has improved performance in comparison with the known technical solutions. Distinctive features of the design of the attachment points for the "pyramid" adapter and the removable clamp with the lag screw relative to the prototype allow to lighten the structure, simplify the production process, and also reduce the manufacturing cost.

The essence of the proposed utility model "Knee joint prosthesis" is illustrated by drawings, where:

- fig. 1 - shows a knee joint prosthesis in a lateral section;

- fig. 2 - shows the axis of the lower knee joint prosthesis in cross section;

- fig. 3 - shows the lower part of the knee joint prosthesis in cross section.

The knee joint prosthesis contains the following structural elements (see Fig. 1, 2, 3): central support 1, upper support 2, adapter "pyramid" 3, small lever 4, two large levers 5 and 6, located mirrored on both sides of the central supports 1, bushing 7, bushing 8, lower axle 9, upper axle 10, pneumatic damper 11, removable clamp 12, lag screw 13, screw 14, self-locking washer 15, washer 16, nut 17.

The central support 1 from the lower end has a receiving hole with a typical diameter of 30 mm for attaching the lower leg prosthesis. The fixation of the lower leg prosthesis is carried out by clamping the lower part of the central support 1, a removable clamp 12, which is tightened with a screw 13. The removable clamp 12 has a longitudinal slot of a small length to ensure free movement of the lower leg prosthesis during its installation. In the central support 1 there are four seats for needle bearings (not shown in Figs. 1, 2, 3), on which large levers 5, 6 and a small lever 4. The holes are made in pairs, in two axes 9, 10, the location of which determines the kinematics of the knee joint prosthesis.

The upper support 2 of the knee joint prosthesis also has two pairs of holes in which needle bearings are installed (not shown in Figs. 1, 2, 3) for mating with levers: small 4 and large 5, 6.

The upper part of the support 2 is flat and serves to install the “pyramid” adapter 3, with the help of which the knee joint prosthesis is securely, rigidly and quickly attached to the receiving bowl of the leg stump.

The adapter "pyramid" 3 is made as a part of the head of the pyramid and the base of the pyramid, fixed to the upper support 2. The head of the pyramid is inserted into the base of the pyramid and fixed on the upper support 2 of the knee joint prosthesis using a screw 14 and a self-locking washer 15 to prevent self-unscrewing of the thread.

The removable clamp 12 is made with a tightening gap, with a tightening screw 13, a washer 16 and a nut 17 of a cylindrical shape. The removable collar 12 is located at the bottom of the central support 1 of the knee joint prosthesis.

Large levers 5, 6 experience a slight load during the operation of the knee joint prosthesis and therefore have a lightweight design, slightly curved in shape, which are located on the outer side of the central 1 and upper 2 supports. The small lever 4 is one-piece, symmetrical, located in the central part of the support 1 and takes on the main load of the knee joint prosthesis. It has a special platform (not shown in Figs. 1, 2, 3), with which the small lever 4 rests against the upper support 2, thereby limiting the extension movement of the knee joint prosthesis, performs the function of a geometric lock. The limitation of flexion of the knee joint prosthesis is provided by the emphasis of the large levers 5, 6 in special stops (not shown in Figs. 1, 2, 3), made in the central support 1. These stops are made on the largest levers 5, 6, and in the central support 1 for them there are provided mating platforms (not shown in Figs. 1, 2, 3), into which additional locking devices can be installed.

The pneumatic damper 11 in the knee joint prosthesis is a separate purchased item. It has two adjustment screws (not shown in Figs. 1, 2, 3): one controls the compression force, the other controls the rate of extension of the knee joint prosthesis in the transfer phase. The pneumatic damper 11 itself has a classic design and contains a movable piston (not shown in Figs. 1, 2, 3) with a sealing collar and a rod (not shown in Figs. 1, 2, 3) connected to the upper support 2 of the knee prosthesis joint. When the knee prosthesis is flexed, the rod pushes against the piston and moves it downward, creating air pressure under the piston. Part of the air is vented through the first adjusting screw (not shown in Figs. 1, 2, 3), facilitating the flexion of the knee joint prosthesis. The reverse movement of the knee joint propels the piston upward, creating a vacuum under the piston. Through the second adjusting screw (not shown in Figs. 1, 2, 3), outside air enters the cavity under the piston, allowing it to rise upward under the action of a spring (not shown in Figs. 1, 2, 3) located inside the pneumatic damper 11.

Inside the pneumatic damper 11 there is a spring (not shown in Figs. 1, 2, 3) to fix the prosthesis in extreme positions. Air cavities - rod (above the piston) and working (under the piston) communicate with each other through channels (not shown in Figs. 1, 2, 3), the flow area of which can be changed using two adjusting screws "FLEXION" - bending and "EXTENSION "-extension. Clamping the overflow channel (not indicated in Figs. 1, 2, 3) from the working cavity to the rod, when bending the knee joint prosthesis in the air cavity under the piston, excessive pressure is formed, increasing the compression force (flexion resistance) of the pneumatic damper 11.

In both bypass channels (not indicated in Figs. 1, 2, 3) of the pneumatic damper 11 at the very bottom, technological holes with a diameter of about 1.5 mm are made for air penetration from the working cavity into the bypass channels. Outside the cylinder, these holes are plugged with special aluminum rivets.

In the design of the knee joint prosthesis there are two shafts (not shown in Figs. 1, 2, 3), which are fixed with locking screws (not shown in Figs. 1, 2, 3). These screws at the end have a recess for a hexagonal wrench, which are protected from contamination by special mushroom-shaped rubber plugs (not shown in Figs. 1, 2, 3).

The proposed utility model "Knee joint prosthesis" works as follows.

The knee joint prosthesis with a pneumatic damper 11 to control the transfer phase with separate adjustment of the flexion and extension resistance, is used in hip prostheses at different levels of amputations above the knee, as well as for isolation in the hip joint.

The proposed polycentric kinematics knee joint prosthesis with a geometric lock provides increased safety, with control of the stance phase, and is intended for use in conditions of both low and medium and high levels of activity: sitting, standing, walking, brisk walking. Due to the use of a pneumatic damper 11, the knee joint prosthesis precisely adapts to changes in the pace of walking in an extended range of movement speeds - from slow to accelerated strides without changing the initial adjustments. In addition, the knee joint prosthesis can be retrofitted with an additional locking device (not indicated in Figs. 1, 2, 3), which ensures complete safety and excludes falling when moving over rough terrain or during primary prosthetics at the first level of activity.

During upright standing (standing), the knee joint prosthesis provides complete closure due to the geometric lock (not indicated in Figs. 1, 2, 3), which allows safe and even loading of both limbs, which significantly affects biomechanical stabilization in the standing position ... To bend the knee (squat), you need to load the toe of the prosthetic foot and bend the prosthetic knee. Thus, the support phase of the knee joint prosthesis is controlled. If there is an additional locking device, it must be unlocked before bending the knee and landing.

When walking, a knee joint prosthesis is required to provide a dynamic component so that walking is performed with minimal physical costs. The return of the knee joint prosthesis to a straight state due to the use of a pneumatic damper 11 from a bent to a straight one occurs smoothly, precisely adjusting to the pace of movement on the prosthesis. In addition, there is the possibility of adjusting the pneumatic damper 11 for the individual characteristics of the patient - speed, activity.

Installation and fixation of the knee joint prosthesis in the prosthesis is carried out through the "pyramid" adapter 3.

The pneumatic damper 11 in the knee joint prosthesis provides pneumatic control of the transfer phase with separate adjustment of the flexion and extension resistance. Inside the pneumatic damper 11 there is a spring (not shown in Figs. 1, 2, 3), the task of which is to fix the prosthesis in extreme positions. Air cavities - rod (above the piston) and working (under the piston) communicate with each other through channels (not shown in Figs. 1, 2, 3), the flow area of which can be changed using two adjusting screws "FLEXION" - bending and "EXTENSION "- extension. Thus, it is possible to vary the rate of return of the knee joint prosthesis from the bent position to the erect position (setting the pace of walking) and the flexion force of the prosthesis, adjusting to the mass of a particular person. Clamping the overflow channel (not indicated in Figs. 1, 2, 3) from the working cavity to the rod cavity, when the knee joint prosthesis is bent, excess pressure is formed in the air cavity under the piston, increasing the compression force (flexion resistance) of the pneumatic damper 11. In both bypass channels (not indicated in Figs. 1, 2, 3) of the pneumatic damper 11, at the very bottom, technological holes with a diameter of about 1.5 mm are made. Through these openings, air enters from the working cavity into the bypass channels. Outside the cylinder, these holes are plugged with special aluminum rivets.

In the design of the knee joint prosthesis there are two shafts (not shown in Figs. 1, 2, 3), which are fixed with locking screws (not shown in Figs. 1, 2, 3). These screws at the end have a recess for a hexagonal wrench, which are protected from contamination by special mushroom-shaped rubber plugs (not shown in Figs. 1, 2, 3).

The proposed utility model "Knee joint prosthesis" in comparison with the prototype (RF patent for invention No. 2592248, IPC A61F 2/64, publ. 10.04.2016, bull. No. 10) provides the following advantages:

- a simple and more convenient way of attaching the hip prosthesis to the upper part of the knee joint prosthesis by reducing the number of parts in the design of the "pyramid" adapter;

- a simple and more convenient way of attaching the lower leg prosthesis to the lower part of the knee joint prosthesis using a removable clamp with a lag screw;

- reducing the weight of the knee joint prosthesis;

- reduction in manufacturing costs;

- use in hip prostheses at various levels of amputation above the knee, as well as for isolation in the hip joint;

- increased safety with control of the stance phase using in conditions of both low, medium and high levels of activity: sitting, standing, walking, brisk walking;

- expansion of the range of speeds of movement - from slow to accelerated steps without changing the initial adjustments;

- retrofitting with an additional locking device for complete safety and prevention of falling when driving over rough terrain or during primary prosthetics at the first level of activity.

Claims (1)

A knee joint prosthesis containing a central support, an upper support, a pyramid adapter, a small lever, two large levers mirrored on both sides of the central support, a pneumatic damper, a lag screw bracket, characterized in that the pyramid adapter is made as a part of the head of the pyramid and the base of the pyramid, fixed to the upper support, while the head of the pyramid is inserted into the base of the pyramid and fixed to the upper support of the knee joint prosthesis using a screw and self-locking washer, and the bracket is made up of a removable clamp with a gap for tightening with a lag screw, washer and a nut of a cylindrical shape, and the removable clamp is located in the lower part of the central support of the knee joint prosthesis.

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