JP6505985B2 - Knee balancer - Google Patents

Description

  The present invention relates to improvement of a knee balancer for inserting a joint between a tibia and a femur in artificial joint surgery to check balance of left and right ligaments and adjust bone resection.

  The conventional knee balancer is configured to measure the distance between the joints and the inclination by applying tension to the joints with a torque wrench in a state in which the movement of the joints is at rest. Because the structure is designed on the premise that measurement is performed at the limb position, measurement can not be performed continuously over the entire range of motion of the joint. As a knee balancer that solves such a problem, there is an apparatus described in Patent Document 1 below. This is provided with a compression coil spring between the lower and upper members, and is configured to apply a tension between the tibia and the femur by its tension. The upper member can be moved up and down with respect to the lower member by a compression coil spring, and can be tilted back and forth and right and left.

JP, 2008-183083, A

  However, in the background art described above, since the lower member and the upper member are inserted together with the compression coil spring between the tibia and the femur, the overall thickness is increased. For this reason, the knee balancer can not be installed in a limited joint space before completion of bone resection. In addition, it is not used only for the purpose of measuring the distance between the joints and the alignment inclination using the knee balancer after completing the bone resection, but installing the knee balancer to complete the joint space distance before completing the bone resection After measuring the ligament balance and determining the bone resection amount and angle to perform osteotomy, the thickness is too large to use.

  In addition, since the compression coil spring strictly reduces the tension applied to the joint when the gap distance between the joints is extended, the compression coil spring is always and continuously constant corresponding to the joint gap which changes over the entire movable range of the joint. There is also a problem that it is not possible to apply

  The present invention focuses on the above points, and its object is to provide a thin structure that can be placed in a narrow joint space before completing bone resection. Another object is to provide a structure capable of continuously applying a constant pressure to the knee joint portion in response to the joint gap changing throughout the range of motion of the joint. Still another purpose is to adjust the amount and angle of bone excision after confirming changes in balance, alignment, and joint space of the left and right ligaments throughout the range of motion of the joint according to their structures. To make the treatment possible.

The present invention is a knee balancer that is inserted into a knee joint to check the degree of balance of the ligament when performing artificial joint replacement, and the lower paddle in contact with the tibial side, the upper paddle in contact with the femur side, gas pressure or using the liquid pressure, moving means for moving the upper paddle up and down relative to the lower paddle, said on paddle, holding means for tiltably held in the left-right direction, and wherein the lower paddle A rib is formed on the periphery of the plate, and the upper paddle is shaped to include the plate housed in a concave surface formed between the plate and the rib .

One of the main forms is to prepare the paddles with an offset for the right knee for avoiding the ligament and an offset for the left knee, respectively, and replace them according to the left and right knees. It features. One of the other modes is characterized in that the upper paddle has a shape that can be applied to both the right knee and the left knee by turning over. In still another embodiment, the moving means uses fluid pressure, in this embodiment nitrogen gas pressure. Furthermore, one of the other modes is characterized in that measuring means is provided for electronically measuring the moving amount of the upper paddle by the moving means and the tilting amount of the upper paddle. The above and other objects, features and advantages of the present invention will be apparent from the following detailed description and the accompanying drawings.

  According to the present invention, the upper paddle is formed such that the upper paddle is housed in the concave surface of the lower paddle, so that the thickness is small and insertion into the knee joint is facilitated before completing the bone resection. it can. In addition, since a constant pressure is applied by gas pressure or liquid pressure to move the upper paddle in the vertical direction with respect to the lower paddle, the tension balance between the left and right ligaments and the distance of the joint space can be moved. The measurement can be continuously performed over the entire region, and the treatment for adjusting the amount of bone excision and the angle according to the tension balance of the ligament can be favorably performed.

It is the perspective view which looked at one Example of the knee balancer of this invention from upper direction. It is the perspective view which looked at the Example of the said FIG. 1 from the back direction of arrow F2. It is the side view which looked at the Example of the said FIG. 1 from the direction of arrow F3. FIG. 2 shows the air supply and sensor part of the embodiment of FIG. 1; It is a figure which expands and shows the paddle in the said Example. It is a figure which shows the use condition of the said Example. (A) shows the knee in the extended position, and (B) shows the knee in the flexed position. It is a figure which shows the other Example which applied this invention.

  Hereinafter, modes for carrying out the present invention will be described in detail based on examples.

  FIG. 1 shows the knee balancer of this embodiment, which is as shown in FIG. 2 when viewed in the direction of arrow F2 in FIG. 1 and as FIG. 3A when viewed from arrow F3. In these figures, the knee balancer 10 is configured centering on a main body 20, and an elevating body 30 capable of moving up and down is provided on the upper part thereof. An actuator 40 is provided on the front side of the main body 20, whereby the elevating body 30 is moved up and down. Further, a paddle 50 is provided on the front side of the main body 20 and the elevating body 30. The paddle 50 is configured by a lower paddle 52 connected to the main body 20 and an upper paddle 54 connected to the elevating body 30, and as shown in FIG. As the body 30 moves up and down, the upper paddle 54 moves up and down with respect to the lower paddle 52.

  The actuator 40 described above uses, for example, gas pressure. For example, nitrogen gas is contained in the gas cylinder 42 through the tube 61, the switch valve 62 and the tube 63 from the nitrogen supply outlet prepared in the operating room. It is supplied. The nitrogen gas supplied into the gas cylinder 42 is partially released from the degassing valve 64, and the nitrogen gas pressure in the gas cylinder 42 is adjusted by the balance between the supply amount of nitrogen gas and the degassing amount. The piston rod 44 moves up and down at a constant pressure. Guide rods 45 are provided in parallel to the piston rod 44, and the elevating bar 31 is moved up and down by the piston rod 44 and the guide rod 45, and the elevating body 30 installed thereon is also moved up and down. .

  A sensor rod 72 of a piston structure is provided on the rear side of the main body 20 and supports the rods 44 and 45 so as to move up and down in parallel by relieving resistance against the stress applied to the upper paddle 54 by the bearing inside the piston. ing. A distance sensor 70 is provided at the tip of the sensor rod 72. The distance sensor 70 has, for example, a solenoid coil structure, and by moving the sensor rod 72 therein, the amount of movement of the elevating body 30, that is, the elevation distance can be electronically measured. There is. In addition, since the piston rod 44, the guide rod 45, and the sensor rod 72 are provided in parallel, the elevating operation of the elevating body 30 can be stably performed. A distance scale 74 is provided on the back side of the distance sensor 70, and this also makes it possible to know the elevation distance.

  FIG. 4 shows the connection of various sensors described above and the gas supply path. A control console 100 is provided in the operating room, and a display panel 110 is supported by a pillar 104 with a caster 102. The display panel 110 is supplied with nitrogen gas from the nitrogen supply source 60, which is an outlet for supplying nitrogen, through the regulator 65 so that the pressure can be detected and adjusted by the pressure sensor 80 and the precision pressure control valve 82. It has become. The regulator 65 is for adjusting the nitrogen gas pressure of the nitrogen supply source 60 to a predetermined value in advance, and is provided as necessary. The nitrogen gas whose pressure has been adjusted by the pressure sensor 80 and the precision pressure adjustment valve 82 is supplied to the above-described tube 61.

  Detection signals of the angle encoder 34, the distance sensor 70, and the pressure sensor 80 are also supplied to the display panel 110, and the detection results thereof are displayed. That is, the nitrogen gas pressure 112, the distance 116, and the angle 118 are displayed on the display panel 110, and the operator operates the knee balancer 10 while referring to these.

  Next, the lower paddle 52 of the paddle 50 is attached to the upper portion on the front side of the main body 20 described above, and the upper paddle 54 is attached to the front side of the elevating body 30. FIG. 5 shows those parts in an enlarged manner, in which (A) shows the lower paddle 52 and the upper paddle 54 separated and (B) shows the lower paddle 52 and the upper paddle 54 overlapped. Indicates Moreover, the plane and side surface of each paddle 52, 54 are shown to (C)-(F), respectively.

  First, to explain from the lower paddle 52 side, the lower paddle 52 includes a substantially heart-shaped plate 52A along the shape of the cutting surface at the proximal end of the tibia and a rib 52B provided around the plate 52A for increasing strength. ing. At the base of the plate 52A, a downwardly extending thick arm 52C is provided in a substantially U-shape so as to form an offset 52D. A mounting piece 52E is formed at the tip of the arm 52C. The mounting piece 52E is inserted into the mounting groove 22A of the main body 20 described above, and is fixed by the screw 22B.

  On the other hand, the upper paddle 54 is shaped to fit within the rib 52B of the lower paddle 52, and includes a plate 54A shaped to correspond to the medial and lateral condyles of the distal end of the femur, A thick arm 52C extending horizontally is provided substantially in a U-shape to form an offset 54D. A mounting piece 54E is formed at the tip of the arm 54C. The mounting piece 54E is inserted into the mounting groove 32A provided in the inclined portion 32 of the elevating body 30 described above, and is fixed by the screw 32B.

  The offsets 52D, 54D formed on the arms 52C of the lower paddle 52 and the arms 54C of the upper paddle 54 are formed in the same direction to avoid the patella ligament. The paddle 50 in FIG. 5 is for the right foot, and the paddle 50 is inserted into the knee joint so as to avoid the patella ligament from the inside of the patient's right knee. In the paddle for the left knee, the direction of the offset is opposite to that in FIG. In the present embodiment, the shape of the upper paddle 54 is devised so that it can be applied to both the right knee and the left knee by reversing the front and back.

  Next, the inclined portion 32 on the front side of the elevating body 30 described above is a direction orthogonal to the elevating direction of the elevating body 30, and the upper paddle 54 can be inclined as the extending direction of the paddle 50 is the inclined shaft 32C. Holding the arm 54C. The angle of inclination of the upper paddle 54 is electronically detected by an angle encoder 34 (see FIG. 4) provided in the lift 30. A pointer 36A and a tilt angle scale 36B are provided at the end of the tilt shaft 32C on the back side of the lift 30. This also makes it possible to know the tilt angle of the upper paddle 54. There is.

  An unevenness 24A is provided on the front side of the main body 20 described above, and a recess 24B is provided on the back side. These irregularities 24A and 24B allow the operator to hold the main body 20 with good hand.

  Next, the operation of the embodiment will be described with reference to FIG. The figure (A) is a figure which looked at use condition when a knee is in extension position from a frontal plane, and (B) is a figure which looked at use condition when a knee was in flexion position from a sagittal plane . A tibial base plate BP is provided on the proximal end side of the tibia BT. The operator holds the asperities 24A and 24B of the main body 20 of the knee balancer 10 and inserts the paddle 50 into the knee joint. The paddle 50 of the knee balancer 10, with the upper paddle 54 housed in the concave formed between the plate 52A of the lower paddle 52 and the rib 52B, the tibial base plate BP and the medial condyle BFa at the distal end of the femur BF. And the lateral condyle BFb. According to the present embodiment, since there is no compression coil spring as in the background art and the whole is formed thin, insertion into the narrow joint space before completion of bone resection is easy.

  In this state, when the operator turns the switch valve 62 ON, compressed nitrogen at a constant pressure is sent from the nitrogen supply source 60 to the gas cylinder 42 of the actuator 40, the elevator 30 ascends, and the upper paddle 54 further To rise. The upper paddle 54 lifts in contact with the medial condyle BFa and the lateral condyle BFb at the distal end of the femur BF, but tilts under the influence of the tensile strength of the medial collateral ligament MLa and the lateral collateral ligament MLb Become. The distance or distance H between the lower paddle 52 and the upper paddle 54 at this time can be known by the distance sensor 70 or the distance scale 74. Further, the inclination θ of the lower paddle 52 and the upper paddle 54 can be known by the angle encoder 34 or the inclination angle scale 36B. Further, as described above, since the distance H and the inclination θ are displayed on the display panel 110 together with the pressure P, the operator can also know the distance H and the like by these. If necessary, the operator adjusts the pressure P with the precision pressure control valve 82. The operator measures the distance H and the inclination θ at the advanced position and the flexed position, respectively. The balance of the knee joint can be known from the distance H and the inclination θ, and based on this, the operator sets the cutting amount and cutting angle of the distal end of the femur.

  On the other hand, detection signals of the angle encoder 34 and the distance sensor 70 are transmitted to, for example, a computer system, and are used for data management of the amount of change in each flexion position from extension of the knee joint to maximum flexion. It is to be noted that an appropriate amount of cutting and a cutting angle of the distal end of the femur may be calculated from the distance H and the inclination θ.

Thus, according to the present embodiment, the following effects can be obtained.
(1) Since there is no compression coil spring between the lower paddle 52 and the upper paddle 54, the overall thickness of the paddle 50 is greatly reduced, so that the narrow joint space before the bone resection is completed. Insertion is easy.
(2) Since a constant pressure is constantly applied from the nitrogen source 60 to lift the upper paddle 54, the balance of the left and right ligaments over the entire range of movement from the extension to the maximum flexion of the knee joint The distance of the joint space can be measured continuously, and according to this, the treatment to adjust the amount of bone resection and the angle can be performed well.
(3) The paddle 50 provided with an offset for inserting into the knee joint, avoiding the patella ligament, has a structure that can be easily replaced with screws so that one can cope with the left and right knees.

  A second embodiment of the present invention will now be described with reference to FIG. As shown in the figure, in the present embodiment, the posture sensor A (gyro sensor) 200 is provided on the femoral bone BF side, and the posture sensor B 210 is provided on the tibia BT side. Specifically, on the femoral bone BF side, the sensor attachment 202 is attached to the cutting guide pins PA and PB attached to the distal end side, and the posture sensor A 200 is attached thereto. On the other hand, on the tibia BT side, a posture sensor B210 is attached to the body 20 of the knee balancer 10 fixed on the proximal end side thereof via the tibia base plate BP and the lower paddle 52.

  Thereby, it is possible to measure the relative angle of the posture sensor A200 and the posture sensor B210 when the knee joint changes continuously from the extended position to the flexed position (see, for example, Japanese Patent Application No. 2014-105295). Furthermore, the knee bending angle can be known by performing electronic calculation. In addition, changes in the distance H and the angle θ by the knee balancer 10 can also be measured simultaneously, and more appropriate treatment can be performed by linking those measured values.

The present invention is not limited to the embodiments described above, and various modifications can be made without departing from the scope of the present invention. For example, the following are also included.
(1) In the above embodiment, the paddle was moved up and down using nitrogen gas pressure. However, liquid pressure such as oil pressure may be used.
.
(2) The mounting position of the posture sensor shown in the above embodiment is also an example, and in short, any position may be used as long as it can be fixed to either the femoral side or the tibial side. The fixing method may also be changed as appropriate.
(3) The structure and shape of each part shown in the above-described embodiment are merely an example, and various design changes can be made within the range of achieving the same function

  According to the present invention, the upper paddle is formed so as to be housed in the concave surface of the lower paddle, so that the thickness is small and insertion into a narrow joint space before completion of bone resection is facilitated. In addition, since the upper paddle is moved vertically with respect to the lower paddle using gas pressure or liquid pressure, a constant pressure is continuously applied to check the balance of the left and right ligaments. The distance of joint space can be measured continuously over the entire range of motion. Furthermore, the treatment for adjusting the amount and angle of bone resection can be favorably performed according to the tension balance of the ligament, and is suitable for knee joint replacement.

10: knee balancer 20: body 22A: mounting groove 22B: screw 24A, 24B: unevenness 30: elevator 31: elevator bar 32: inclined portion 32A: mounting groove 32B: screw 32C: inclined shaft 34: angle encoder 36A: pointer 36B: Tilt angle scale 40: Actuator 42: Gas cylinder 44: Piston rod 45: Guide rod 50: Paddle 52: Lower paddle 52A: Plate 52B: Rib 52C: Arm 52D: Offset 52E: Mounting piece 54: Upper paddle 54A: Plate 54C: Arm 54D: Offset 54E: Mounting piece 60: Nitrogen source 61: Tube 62: Switch valve 63: Tube 64: Degassing valve 65: Regulator 70: Distance sensor 72: Sensor rod 74: Distance scale 80: Pressure sensor 82: Precision Pressure control valve 100: control console 102: caster 1 4: post 110: Display panel 112: Nitrogen gas pressure 116: Distance 118: Angle 200: orientation sensor A
202: Attachment for sensor 210: Posture sensor B
BF: femur BFa: medial condyle BFb: lateral condyle BP: tibia base plate BT: tibia H: distance θ: tilt angle MLa: medial collateral ligament MLb: lateral collateral ligament PA, PB: pin for cutting guide

Claims (5)

When performing artificial joint replacement, it is a knee balancer that is inserted into the knee joint to check the degree of balance of the ligament,
Lower paddle, adjacent to tibial side,
Upper paddle touching the femur side,
Moving means for vertically moving the upper paddle relative to the lower paddle using gas pressure or liquid pressure;
Holding means for holding the upper paddle so as to be tiltable in the left and right direction,
Equipped with
The lower paddle has a shape in which ribs are formed around the plate,
The knee balancer is characterized in that the upper paddle includes a plate housed in a concave formed between the plate and the rib.   A paddle provided with an offset for the right knee for avoiding a ligament and a paddle provided with an offset for the left knee are respectively prepared as the paddles, and are changed according to the left and right knees. Knee balancer.   3. The knee balancer according to claim 2, wherein the upper paddle has a shape that can be applied to both the right knee and the left knee by reversing the front and back.   The knee balancer according to any one of claims 1 to 3, wherein the moving means uses nitrogen gas.   The knee balancer according to any one of claims 1 to 4, further comprising measuring means for electronically measuring an amount of movement of the upper paddle by the moving means and an amount of inclination of the upper paddle.

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