CN219700215U - Knee joint balancer - Google Patents

Abstract

The utility model discloses a knee joint balancer, which belongs to the technical field of medical appliances, and comprises a balancer housing, wherein the balancer housing comprises two cylinders which are arranged in parallel, and a pushing piece is connected in each cylinder in a sliding way, wherein: the upper end of the balancer housing is provided with a lower abutting plate which is used for being placed between the inner condyle and the outer condyle of the knee joint and abutting against the upper surface of the lower condyle; the upper end of each cylinder body is respectively provided with a condylar support which is used for being placed between the inner condyle and the outer condyle of the knee joint and is used for abutting against the lower surface of the upper condyle, and a pushing piece in each cylinder body is respectively connected with the corresponding condylar support; and each cylinder body is provided with a pressure sensor for measuring the bearing pressure of the corresponding condylar support. The utility model can accurately measure the pressure of the knee joint and ensure the pressure to be consistent when the knee joint gaps are equal.

Description

Knee joint balancer

Technical Field

The utility model relates to the technical field of medical appliances, in particular to a knee joint balancer.

Background

Successful total knee arthroplasty (total knee arthroplasty, TKA) depends in part on reestablishing normal lower limb alignment, proper implant design and positioning, safe implant fixation, and adequate soft tissue balance and stability. It is widely believed that soft tissue imbalance and bone alignment of TKA can lead to dysfunction and failure. The knee balancer is intended to assist the surgeon in achieving good balance and successful total knee replacement by a simple, repeatable method. The goal is to obtain the same rectangular gap when flexed and stretched under the same ligament tension.

Knee balancers are mainly used in knee arthroplasty. The method is mainly applied to a gap balance method in clinical operation, and compared with a traditional measurement osteotomy method, the gap balance method is divided into straightening gap balance and buckling gap balance, the method is more focused on the balance of soft tissues, does not depend on anatomical marks, is more suitable for repairing and curing femoral condyle defects, and has certain advantages for improving the patella track.

The existing knee joint balancer on the market cannot measure the straightening and buckling gaps accurately or even cannot measure the buckling gaps; and the pressure uniformity when the gaps are equal cannot be ensured, and the gaps are possibly changed due to the inconsistent pressure; the thickness of the tibial plateau pad cannot be obtained by measuring the buckling clearance, so that the operation difficulty is increased while the stock quantity is increased.

Disclosure of Invention

The utility model aims to provide the knee joint balancer which can accurately measure the pressure of the knee joint and ensure the pressure to be consistent when the knee joint gaps are equal.

In order to solve the technical problems, the utility model provides the following technical scheme:

the knee joint balancer comprises a balancer housing, wherein the balancer housing comprises two cylinders which are arranged in parallel, each cylinder is internally and slidably connected with a pushing piece, and the pushing piece is arranged in the cylinder, wherein:

the upper end of the balancer housing is provided with a lower abutting plate which is used for being placed between the inner condyle and the outer condyle of the knee joint and abutting against the upper surface of the lower condyle;

the upper end of each cylinder body is respectively provided with a condylar support which is used for being placed between the inner condyle and the outer condyle of the knee joint and is used for abutting against the lower surface of the upper condyle, and a pushing piece in each cylinder body is respectively connected with the corresponding condylar support;

and each cylinder body is provided with a pressure sensor for measuring the bearing pressure of the corresponding condylar support.

Further, the lower abutting plate is a condylar support accommodating groove, and the condylar support on each cylinder body is located in the condylar support accommodating groove.

Further, each cylinder and the pushing piece thereof are provided with a scale for displaying the gap size at the corresponding condyle of the knee joint, and the other cylinder is provided with a scale line for reading the scale.

Further, each pushing piece in the cylinder body comprises an upper pushing piece and a lower pushing piece, the upper pushing piece is a first sleeve extending along the length direction of the cylinder body, the lower pushing piece is a second sleeve which is connected to the lower portion of the inner side of the first sleeve in a sliding mode, and a first compression screw which is used for being matched with the lower end of the second sleeve in a blocking mode is arranged at the opening of the lower end of the first sleeve.

Further, the lower end of each barrel is provided with a driving piece in driving connection with a corresponding lower pushing piece, the driving piece is a rotating shaft which is axially fixed and circumferentially rotatable and is connected with the barrel, the upper part of the rotating shaft is provided with a screw rod section, the inside of the second sleeve is provided with an axial threaded hole, the screw rod section of the rotating shaft is in threaded connection with the axial threaded hole of the second sleeve, and the lower end of the rotating shaft is provided with a driving handle;

and/or the section of the second sleeve is D-shaped, and the part of the first sleeve matched with the second sleeve is a D-shaped hole.

Further, the lower part of the rotating shaft is provided with a limiting boss, the lower end of the cylinder body is provided with a second compression screw which is in stop fit with the lower surface of the limiting boss, and the upper end of the driving handle is provided with a limiting ring which is in stop fit with the lower surface of the second compression screw.

Further, a first opening window is formed in the cylinder body, scales are arranged on the edge of the first opening window, and the scribing lines are arranged on the first sleeve.

Further, a baffle is arranged at the upper end of the inner side of the first sleeve, and an elastic piece is arranged between the baffle and the second sleeve in the first sleeve.

Further, a second window is arranged at the part of the first sleeve, which is positioned in the first window, the edge of the second window is provided with a scale for displaying the pressure of the corresponding condyle of the knee joint, and the second sleeve is provided with a scale line for reading the scale;

and/or the elastic member is a spring and externally silvered;

and/or the pressure sensor is arranged in the first sleeve and between the baffle table and the second sleeve.

Further, the pressure sensor is arranged on the condylar support;

and/or a transverse link rod is arranged between the cylinder bodies;

and/or the pressure sensor is a wireless sensor for communicating with an external terminal device.

The utility model has the following beneficial effects:

the knee joint balancer comprises a balancer shell, wherein the balancer shell comprises two cylinders which are arranged in parallel, a pushing piece is connected in each cylinder in a sliding manner, a lower abutting plate which is used for being placed between an inner condyle and an outer condyle of a knee joint and is used for abutting against the upper surface of a lower condyle is arranged at the upper end of the balancer shell, a condyle support which is used for being placed between the inner condyle and the outer condyle of the knee joint and is used for abutting against the lower surface of the upper condyle is arranged at the upper end of each cylinder, the pushing piece in each cylinder is connected with a corresponding condyle support, and a pressure sensor which is used for measuring the bearing pressure of the corresponding condyle support is arranged on each cylinder. Therefore, the utility model can accurately measure the pressure of the knee joint and ensure the pressure to be consistent when the knee joint gaps are equal.

Drawings

FIG. 1 is a schematic view of the overall structure of a knee balancer of the present utility model;

FIG. 2 is a schematic elevational view of the knee balancer of FIG. 1, with an enlarged view of the middle portion additionally shown;

FIG. 3 is a schematic top view of the knee balancer of FIG. 1;

FIG. 4 is a schematic side cross-sectional view of the knee balancer of FIG. 1;

FIG. 5 is an exploded view of the knee balancer of FIG. 1;

FIG. 6 is a schematic view of the second sleeve of FIG. 1, wherein (a) is a front view, (b) is a top view, and (c) is a perspective view;

fig. 7 is a schematic structural diagram of the pressure sensor in fig. 1.

Detailed Description

In order to make the technical problems, technical solutions and advantages to be solved more apparent, the following detailed description will be given with reference to the accompanying drawings and specific embodiments.

The utility model provides a knee joint balancer, as shown in figures 1-7, comprising a balancer housing 1, wherein the balancer housing 1 comprises two cylinders 10 which are arranged in parallel, each cylinder 10 is internally and slidably connected with a pushing piece, and the pushing piece comprises:

the upper end of the balancer housing 1 is provided with a lower abutting plate which is used for being placed between the inner condyle and the outer condyle of the knee joint and abutting against the upper surface of the lower condyle;

the upper end of each cylinder 10 is respectively provided with a condylar support 11 (namely, above a lower abutting plate; only one of the condylar supports 11 is shown in fig. 1, and the other condylar support 11 is omitted) which is used for being placed between the inner and outer condyles of the knee joint and is used for abutting against the lower surface of the upper condyle, and a pushing piece in each cylinder 10 is respectively connected with the corresponding condylar support 11;

each cylinder 10 is provided with a pressure sensor 13 for measuring the pressure borne by the corresponding condylar support 11.

When the knee joint balancer is used, the knee joint balancer is firstly placed at the knee joint to be detected, the lower abutting plate is positioned between the inner condyle and the outer condyle of the knee joint and abuts against the upper surface of the lower condyle, the condylar support 11 is respectively positioned between the inner condyle and the outer condyle of the knee joint and abuts against the lower surface of the upper condyle, then the pushing piece is driven to move upwards, the condylar support 11 is pushed upwards, in the process, the gap size (namely the gap between the femoral tibia) at the corresponding condyle of the knee joint can be observed, and the pressure size at the corresponding condyle of the knee joint can be obtained through the pressure sensor 13.

Specifically, two using modes can be adopted: 1. applying the same tension, if the gaps between the cavities at the medial condyle and the lateral condyle of the knee joint are different, for example, the outer side is 24mm and the inner side is 26mm, ligament release is needed to be carried out on one side with smaller gaps so as to balance the two cavities reaching the same gaps, and the ligament release can be carried out by using standard technology in the prior art; 2. the same cavity gap is applied, and at the moment, if the pressure values measured by the pressure sensors 13 at the medial and lateral condyles of the knee joint are different, ligament release is needed on the side with larger pressure values.

The knee joint balancer comprises a balancer shell, wherein the balancer shell comprises two cylinders which are arranged in parallel, a pushing piece is connected in each cylinder in a sliding manner, a lower abutting plate which is used for being placed between an inner condyle and an outer condyle of a knee joint and is used for abutting against the upper surface of a lower condyle is arranged at the upper end of the balancer shell, a condyle support which is used for being placed between the inner condyle and the outer condyle of the knee joint and is used for abutting against the lower surface of the upper condyle is arranged at the upper end of each cylinder, the pushing piece in each cylinder is connected with a corresponding condyle support, and a pressure sensor which is used for measuring the bearing pressure of the corresponding condyle support is arranged on each cylinder. Therefore, the utility model can accurately measure the pressure of the knee joint and ensure the pressure to be consistent when the knee joint gaps are equal.

In the present utility model, the lower abutment plate may be variously configured, as shown in fig. 1 and 3-4, and may specifically be a condylar-holder accommodating groove 14, in which case the condylar-holder 11 on each cylinder 10 is located in the condylar-holder accommodating groove 14.

For precisely measuring the knee joint gap size, it is preferable that, as shown in fig. 2, each cylinder 10 and its pushing member are provided with a scale 101 for displaying the knee joint gap size at the corresponding condyle, and the other is provided with a score line 151 for reading the scale 101.

Thus, in use, the scale 101 may be read according to the score line 151 to obtain the gap size at the corresponding condyle of the knee joint, and the tibial plateau pad thickness may also be calculated according to the gap size, for example, the gap size may be subtracted by the corresponding posterior condyle thickness of the femoral prosthesis to obtain the tibial plateau pad thickness required in surgery. Therefore, the present utility model also enables accurate measurement of knee joint gap size and gives tibial plateau pad thickness.

In the present utility model, the pushing member may take various structural forms, such as a cylindrical block, etc., which are easily conceived by those skilled in the art, however, in order to improve the compactness between the components and the accuracy of the reading, the following structural forms are preferably adopted:

as shown in fig. 4 to 5, the pushing members in each cylinder 10 include an upper pushing member and a lower pushing member, the upper pushing member is a first sleeve 15 extending along the length direction of the cylinder 10, the lower pushing member is a second sleeve 16 slidably connected to the lower portion of the inner side of the first sleeve 15, and a first compression screw 152 for being in blocking fit with the lower end of the second sleeve 16 is disposed at the opening of the lower end of the first sleeve 15 so as to prevent the second sleeve 16 from being separated.

At this time, the upper pushing members (i.e., the first sleeves 15) are respectively connected to the corresponding condylar rests 11, and the connection between the first sleeves 15 and the condylar rests 11 may be performed by various manners, such as welding, clamping, etc., and in the embodiment shown in the drawings, the connection is performed by using screws 111. As shown in fig. 1-2, the balancer housing 1 may be made of metal, and serves to protect internal components; a cross link 19 may be provided between the cylinders 10 to integrate the two cylinders 10 and enhance the overall firmness of the balancer housing 1. In addition, the whole product can be symmetrically designed on the left side and the right side so as to be convenient to process and manufacture.

Furthermore, a blocking table 153 may be disposed at the upper end of the inner side of the first sleeve 15, and an elastic member 12 may be disposed between the blocking table 153 and the second sleeve 16 in the first sleeve 15, so that the first sleeve 15 has a certain movement margin, so as to avoid damage to the knee joint caused by excessive rigidity in use.

The position of the pressure sensor 13 can be flexibly set as required, for example, can be directly set on the upper surface of the condylar tray 11, however, in order to avoid contact with internal tissues, it is preferable to set in the first sleeve 15 between the baffle 153 and the second sleeve 16. It will be appreciated that the pressure sensor 13 may be used alone or in combination with the resilient member 12 as shown in the embodiment of the figures, with better results.

The pressure sensor 13 is preferably a wireless sensor for communicating with an external terminal device (e.g. a mobile phone, tablet computer, etc.), and in use, the pressure sensor 13 can transmit a pressure value to the external terminal device, thereby obtaining a pressure value at a corresponding condyle of the knee joint. The wireless pressure sensor and the external terminal equipment are in a wireless connection mode, the type can be flexibly selected according to the needs, for example, the wireless pressure sensor can be M5600 (see figure 7), the M5600 is internally provided with WIFI, high-precision 24-bit ADC (Analog-to-digital converter) digital output can be provided, hard wiring is not needed, bluetooth connection is adopted, and the wireless pressure sensor has the advantages of being reliable in work, stable in performance, small in size, light in weight, convenient to install and detach and the like. It is understood that the wireless pressure sensor is not resistant to high temperature and high pressure, so the wireless pressure sensor can be disposable and not used repeatedly.

The elastic member 12 may be a spring as shown in the drawings, and the outside of the spring may be silver-plated to enhance transmission of signals between the wireless pressure sensor and an external terminal device.

Further, as shown in fig. 4-6, the lower end of each cylinder 10 may be provided with a driving member connected with the corresponding lower pushing member (the second sleeve 16) in a driving manner, the driving member is an axially fixed and circumferentially rotatable rotating shaft 17 connected with the cylinder 10, a screw section 171 is disposed at the upper part of the rotating shaft 17, an axial threaded hole 161 is disposed in the second sleeve 16, the screw section 171 of the rotating shaft 17 is in threaded connection with the axial threaded hole 161 of the second sleeve 16, and a driving handle 172 (may be a plum blossom handle specifically) is disposed at the lower end of the rotating shaft 17.

When in use, the rotating shaft 17 is rotated (in the direction indicated by the arrow of the arc line in fig. 1), the rotating shaft 17 is axially fixed, the rotating shaft 17 drives the second sleeve 16 to move upwards, the second sleeve 16 applies pressure to the elastic piece 12 and the pressure sensor 13, and then the first sleeve 15 and the condylar support 11 are jacked upwards (in the direction indicated by the arrow of the straight line in fig. 1), in the process, the scale 101 can be read according to the score line 151, the gap size of the corresponding condyle of the knee joint can be obtained, and the pressure size of the corresponding condyle of the knee joint can be obtained by utilizing the pressure sensor 13.

Further, the driving handle 172 is preferably detachably attached to the rotation shaft 17, and when the driving handle 172 is detached, the first sleeve 15 can be taken out directly from above the cylinder 10 of the balancer housing 1, thereby facilitating detachment and cleaning and sterilization. The first sleeve 15 and the second sleeve 16 can be detached through the first compression screw 152, and when the first compression screw 152 below the first sleeve 15 is unscrewed, the second sleeve 16, the elastic piece 12 (spring) and the pressure sensor 13 in the first sleeve can be taken out, so that the cleaning and the disinfection are convenient, and when an instrument has a problem (such as aging of the spring), the replacement and the repair are convenient.

In order to conveniently realize the connection barrel 10 with the axial fixing and circumferential rotation of the rotating shaft 17, a limiting boss 173 can be arranged at the lower part of the rotating shaft 17, a second compression screw 18 which is in stop fit with the lower surface of the limiting boss 173 is arranged at the lower end of the barrel 10, and a limiting ring 174 which is in stop fit with the lower surface of the second compression screw 18 is arranged at the upper end of the driving handle 172. Thus, by providing the stopper boss 173 and the stopper ring 174, the rotation shaft 17 and the driving handle 172 can be preferably prevented from moving up and down.

The second sleeve 16 may have a D-shaped cross section (see fig. 6), and the portion of the first sleeve 15 that mates with the second sleeve 16 may have a D-shaped hole, so that undesired rotation of the second sleeve 16 and the first sleeve 15 may be prevented during the up-and-down movement of the first sleeve 15 by the second sleeve 16.

As shown in fig. 2, to conveniently display the gap size at the corresponding condyle of the knee joint, a first window 102 may be provided on the barrel 10, the scale 101 is provided at the edge of the first window 102, and the score line 151 is provided on the first sleeve 15.

Considering that a doctor may not be convenient to view the pressure value transmitted by the pressure sensor 13 on the terminal device in time during operation, a scale can be additionally arranged on the knee joint balancer to display the pressure value at the corresponding condyle of the knee joint, namely: the portion of the first sleeve 15 located in the first window 102 may be provided with a second window 154, the edge of the second window 154 is provided with a scale 155 for displaying the pressure at the corresponding condyle of the knee joint, and the second sleeve 16 is provided with a scale 162 for reading the scale 155. Here, the scale 155 may be set according to the linear change of the length of the elastic member 12 after being stressed, so it can be understood that the scale 155 is for roughly displaying the pressure level at the corresponding condyle of the knee joint, rather than precisely providing the pressure level at the corresponding condyle of the knee joint as the pressure sensor 13.

While the foregoing is directed to the preferred embodiments of the present utility model, it will be appreciated by those skilled in the art that various modifications and adaptations can be made without departing from the principles of the present utility model, and such modifications and adaptations are intended to be comprehended within the scope of the present utility model.

Claims (10)

1. The utility model provides a knee joint balancer which characterized in that includes the balancer shell, the balancer shell includes two barrels that set up side by side, every in the barrel all sliding connection have the impeller, wherein:

the upper end of the balancer housing is provided with a lower abutting plate which is used for being placed between the inner condyle and the outer condyle of the knee joint and abutting against the upper surface of the lower condyle;

the upper end of each cylinder body is respectively provided with a condylar support which is used for being placed between the inner condyle and the outer condyle of the knee joint and is used for abutting against the lower surface of the upper condyle, and a pushing piece in each cylinder body is respectively connected with the corresponding condylar support;

and each cylinder body is provided with a pressure sensor for measuring the bearing pressure of the corresponding condylar support.

2. The knee balancer of claim 1, wherein the lower abutment plate is a condylar-tray receiving slot, and the condylar tray on each cylinder is located in the condylar-tray receiving slot.

3. The knee balancer of claim 1, wherein each of the cylinders and the pushing member thereof is provided with a scale for displaying the gap size at the corresponding condyle of the knee, and the other is provided with a score line for reading the scale.

4. The knee balancer of claim 3, wherein each pushing member in the barrel comprises an upper pushing member and a lower pushing member, the upper pushing member is a first sleeve extending along the length direction of the barrel, the lower pushing member is a second sleeve slidingly connected to the lower portion of the inner side of the first sleeve, and a first compression screw for being in blocking fit with the lower end of the second sleeve is arranged at the opening of the lower end of the first sleeve.

5. The knee joint balancer according to claim 4, wherein a driving member for driving and connecting the corresponding lower pushing member is arranged at the lower end of each barrel, the driving member is a rotating shaft which is axially fixed and circumferentially rotatable and is connected with the barrel, a screw rod section is arranged at the upper part of the rotating shaft, an axial threaded hole is arranged in the second sleeve, the screw rod section of the rotating shaft is in threaded connection with the axial threaded hole of the second sleeve, and a driving handle is arranged at the lower end of the rotating shaft;

and/or the section of the second sleeve is D-shaped, and the part of the first sleeve matched with the second sleeve is a D-shaped hole.

6. The knee joint balancer according to claim 5, wherein the lower part of the rotating shaft is provided with a limit boss, the lower end of the cylinder body is provided with a second compression screw in stop fit with the lower surface of the limit boss, and the upper end of the driving handle is provided with a limit ring in stop fit with the lower surface of the second compression screw.

7. The knee balancer of claim 4, wherein the barrel is provided with a first fenestration, the scale is provided on an edge of the first fenestration, and the score line is provided on the first sleeve.

8. The knee balancer of claim 7, wherein a blocking table is provided at an inner upper end of the first sleeve, and an elastic member is provided between the blocking table and the second sleeve in the first sleeve.

9. The knee joint balancer according to claim 8, wherein a second window is provided on a portion of the first sleeve located in the first window, a scale for displaying the pressure of the corresponding condyle of the knee joint is provided on an edge of the second window, and a score line for reading the scale is provided on the second sleeve;

and/or the elastic member is a spring and externally silvered;

and/or the pressure sensor is arranged in the first sleeve and between the baffle table and the second sleeve.

10. The knee balancer of claim 1, wherein the pressure sensor is disposed on the condylar tray;

and/or a transverse link rod is arranged between the cylinder bodies;

and/or the pressure sensor is a wireless sensor for communicating with an external terminal device.