A knee flexion-extension gap measuring balancer

Abstract

This invention provides a knee joint flexion-extension gap measuring and balancing device, including a base, a pressure measuring mechanism, and a gap measuring mechanism. The base includes a lower support arm and a measuring part. The pressure measuring mechanism includes a pressure measuring block mounted on the measuring part, with two symmetrically arranged pressure measuring sections. A pressure scale is provided on the front surface of each pressure measuring section. The upper support arm is inserted into and movable within the pressure measuring section. The lower and upper support arms are respectively attached to the tibial osteotomy surface and the femoral osteotomy surface, allowing observation of the pressure values ​​on the inner and outer sides of the knee joint. A gap scale is provided on the front surface of each measuring section. An eccentric adjustment mechanism is inserted into the measuring part and the pressure measuring block from the front surface of the measuring section. Rotation of the eccentric adjustment mechanism causes the pressure measuring block to move up and down, allowing observation of the knee joint flexion-extension gap value. This device can directly read the pressure values ​​on both sides of the knee joint and the knee joint gap value, providing accurate values ​​for surgeons and simplifying surgical procedures.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and in particular to a knee joint flexion-extension gap measuring and balancing device. Background Technology

[0002] Knee replacement surgery is a procedure that replaces all or part of a patient's damaged natural knee joint with a knee prosthesis. Today, knee replacement surgery has developed into a mature orthopedic procedure. In total knee replacement surgery, the osteotomy of the femur and tibia must not only consider the accuracy of the osteotomy angle, but also fully consider the balance of the soft tissues on the medial and lateral sides of the knee joint and the appropriate tension. Imbalance in the soft tissues around the knee joint can cause postoperative joint instability, postoperative joint dislocation, and abnormal joint stress, leading to premature and excessive wear of the knee prosthesis and ultimately surgical failure. The information disclosed in the background section is only for the purpose of helping to understand the background of the present invention, and therefore may include information that does not constitute prior art known to those skilled in the art.

[0003] In current techniques, when performing proximal tibial osteotomies and distal femoral osteotomies, attending physicians generally need to assess the extension gap to determine whether the medial and lateral soft tissue tension is appropriate and whether the osteotomy angle is accurate. The current practice involves the attending physician inserting a shim of fixed thickness between the femoral and tibia osteotomy surfaces to stabilize the femur. By swaying the tibia from side to side, the physician observes the size of the opening between the medial and lateral joints and feels the amount of force applied, thereby determining whether the medial and lateral soft tissues are balanced. If it is deemed inappropriate, the attending physician will generally replace the shim with one of a different thickness or loosen the medial or lateral collateral ligaments to achieve final soft tissue balance and obtain an appropriate gap value. The assessment steps are essentially the same when assessing the knee flexion gap.

[0004] Current methods for measuring the knee flexion-extension gap rely heavily on the surgeon's intuition. The attending physician lacks a quantifiable and readable tension value to assess the appropriateness of the tension in the medial and lateral soft tissues, depending solely on their personal experience. This introduces significant inaccuracies in the assessment of medial and lateral soft tissue tension. Similarly, when measuring the knee extension gap, surgeons previously relied on repeated trials with different thicknesses of pads to arrive at a final value, resulting in repetitive surgical steps and prolonged operation time. Therefore, current methods for measuring the knee flexion-extension gap are entirely based on the surgeon's experience and are inherently inaccurate. Summary of the Invention

[0005] This invention provides a knee joint flexion-extension gap measuring balancer. Existing devices have the following problems: relying solely on a doctor's personal experience to assess the pressure between knee flexion and extension cannot measure the pressure value between the knee joint flexion and extension; measuring the knee joint gap by changing different sized pads cannot obtain the knee joint gap value, resulting in inaccurate measurements.

[0006] To solve the above-mentioned technical problems, embodiments of the present invention provide the following solutions:

[0007] A knee joint flexion-extension gap measuring balancer includes a base, the base including a lower support arm and a measuring part;

[0008] A pressure measuring mechanism includes a pressure measuring block disposed on the measuring part. The pressure measuring block includes two symmetrically arranged pressure measuring parts. A pressure scale is provided on the front end face of the pressure measuring part. An upper support arm is inserted into the pressure measuring part and can move within the pressure measuring part. The lower support arm and the upper support arm are respectively attached to the tibial osteotomy surface and the femoral osteotomy surface, and the pressure values ​​on the inner and outer sides of the knee joint can be observed.

[0009] The gap measuring mechanism has a gap scale on the front end face of the measuring part. The eccentric adjustment mechanism is inserted into the measuring part and the pressure measuring block from the front end face of the measuring part. The rotation of the eccentric adjustment mechanism can drive the pressure measuring block to move up and down, and the gap value of knee joint flexion and extension can be observed.

[0010] The measuring part is provided with a vertically arranged guide groove, the pressure measuring part is inserted into the guide groove, and can move up and down within the guide groove;

[0011] The measuring part is provided with a through hole, and an eccentric adjustment mechanism is installed in the through hole. The front end face of the measuring part is provided with a gap scale on the circumferential side of the through hole.

[0012] The pressure measuring block further includes a connecting part that connects the two pressure measuring parts. The connecting part is inserted into the guide groove and has a through groove. The eccentric adjustment mechanism is inserted into the through groove.

[0013] The eccentric adjustment mechanism includes an adjustment knob, which has an eccentrically set eccentric shaft and a scale line on its front end face.

[0014] The adjustment knob is inserted into the through hole of the measuring part, and the eccentric shaft is inserted into the through groove on the pressure measuring block. When the adjustment knob is rotated, the eccentric shaft can drive the pressure measuring block to move in the guide groove. The gap value of knee joint flexion and extension can be observed through the gap scale and the scale line on the adjustment knob.

[0015] The pressure measuring part is provided with a mounting hole, and the front end face of the pressure measuring part is provided with an observation hole that communicates with the mounting hole. The front end face of the pressure measuring part is provided with a pressure scale at the observation hole. A spring is provided in the mounting hole, and the upper support arm is inserted into the mounting hole and presses the spring.

[0016] The connecting part of the pressure measuring block and the pressure measuring part are stepped, so that after the connecting part is inserted into the guide groove, the end face of the pressure measuring part connected to the connecting part contacts the left and right end faces of the measuring part.

[0017] The adjustment knob has multiple holes on its outer circumference, and damping springs and ball bearings are installed in the holes. The ball bearings rest on the inner circumference of the through hole of the measuring part.

[0018] The adjustment knob has a rotating groove at one end of the gap scale.

[0019] The upper support arm is provided with a long groove, and the pressure measuring part is provided with a limiting through hole that connects to the mounting hole. After the limiting pin passes through the limiting through hole, it is inserted into the long groove to restrict the movement of the pressure measuring block under the guidance of the limiting pin.

[0020] The pressure measuring part has an inner hole at its bottom end, and a spring is installed inside the inner hole. The spring rests between the inner hole and the mounting hole.

[0021] The above-described solution of the present invention has at least the following beneficial effects:

[0022] The above-described solution of the present invention allows the knee joint flexion-extension gap measuring balancer to directly read the pressure values ​​on both the inner and outer sides of the knee joint. The gap measuring mechanism facilitates convenient and rapid measurement of the knee joint gap value. Driving the gap measuring mechanism opens the upper and lower support arms, allowing for direct measurement of the flexion-extension gap and pressure values, enabling doctors to accurately apply pressure to the knee joint. By analyzing the pressure values ​​on the inner and outer sides of the knee joint, the balance between the inner and outer sides can be directly and accurately determined, providing accurate values ​​for the surgeon, simplifying surgical procedures, saving surgical time, and reducing the risk of surgical infection. Attached Figure Description

[0023] Figure 1 This is an exploded view of the knee joint flexion-extension gap measuring balancer of the present invention;

[0024] Figure 2 This is a schematic diagram of the knee joint flexion-extension gap measuring balancer of the present invention;

[0025] Figure 3 This is a front view of the knee joint flexion-extension gap measuring balancer of the present invention;

[0026] Figure 4 This is a left view of the knee joint flexion-extension gap measuring balancer of the present invention;

[0027] Figure 5 This is a top view of the knee joint flexion-extension gap measuring balancer of the present invention.

[0028] Figure label:

[0029] 1. Upper support arm L; 2. Spring; 3. Pressure measuring block; 31. Pressure measuring part; 311. Pressure scale; 312. Mounting hole; 313. Observation hole; 32. Connecting part; 321. Through groove; 4. Limiting pin; 5. Base; 51. Lower support arm; 52. Measuring part; 521. Guide groove; 522. Through hole; 6. Adjustment knob; 7. Eccentric shaft; 8. Ball bearing; 9. Damping spring; 12. Upper support arm R; 13. Rotating shaft. Detailed Implementation

[0030] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0031] like Figure 1-5As shown, this embodiment provides a knee flexion-extension gap measuring balancer, including a base 5, a pressure measuring mechanism, and a gap measuring mechanism. The base 5 includes a lower support arm 51 and a measuring part 52. The lower support arm 51 is used to fit closely to the tibial osteotomy surface. The measuring part 52 is used to install the pressure measuring mechanism and the gap measuring mechanism to realize pressure value measurement and gap value measurement. The pressure measuring mechanism includes a pressure measuring block 3 disposed on the measuring part 52. The pressure measuring block 3 includes two symmetrically arranged pressure measuring parts 5231. A pressure scale 311 is provided on the front end surface of the pressure measuring part 5231. The upper support arm is inserted into the pressure measuring part 5231 and can move within the pressure measuring part 5231. The gap measuring mechanism includes an eccentric adjustment mechanism. A gap scale is provided on the front end surface of the measuring part 52. The eccentric adjustment mechanism is inserted into the measuring part 52 and the pressure measuring block 3 from the front end surface of the measuring part 52. The rotation of the eccentric adjustment mechanism can drive the pressure measuring block 3 to move up and down, and the gap value of knee flexion-extension can be observed. The lower support arm 51 and the upper support arm are respectively attached to the tibial osteotomy surface and the femoral osteotomy surface. The pressure values ​​on the inner and outer sides of the knee joint can be observed through the pressure scale 311. The upper support arm is divided into upper support arm L1 and upper support arm R12. The two upper support arms are used to measure the pressure values ​​on the inner and outer sides of the knee joint. When the pressure values ​​on the inner and outer sides are not the same, it indicates that the knee joint is not balanced. Therefore, the knee joint flexion-extension gap measuring balancer of this embodiment also has the function of judging whether the knee joint is balanced by the pressure values ​​on the inner and outer sides. To judge the tension on the inner and outer sides of the knee joint, when the attending physician expects the tension on the inner and outer sides to be 70N, the pressure values ​​on both sides usually need to reach the 70N scale. If the tension value on one side is too high, appropriate measures should be taken, such as releasing the collateral ligament on that side to reduce the tension value on that side to about 70N, so that the pressure values ​​on both sides are basically the same and achieve balance. The knee joint flexion-extension gap measuring balancer in this embodiment can directly read the pressure values ​​on both the inner and outer sides of the knee joint. Through the gap measuring mechanism, the knee joint gap value can be measured conveniently and quickly to determine whether the knee joint is balanced. This provides doctors with accurate values ​​for surgery, simplifies surgical procedures, saves surgical time, and reduces the risk of surgical infection.

[0032] In this embodiment, the knee joint flexion-extension gap measuring balancer is used after osteotomy of the distal femur and proximal tibia. The knee joint is placed in either an extended or flexed position, and the femur and tibia are pulled to create a gap. The balancer is then placed within this gap, with the lower support arm 51 resting against the tibial osteotomy surface and the upper support arm against the femoral osteotomy surface. The eccentric adjustment mechanism is then adjusted, causing the pressure measuring block 3 to move upwards, widening the gap between the upper and lower support arms 51. This allows the upper support arm to support the femoral osteotomy surface. The pressure scale 311 and the gap scale are observed to obtain the current medial and lateral pressure values ​​of the knee joint, and thus the current knee joint flexion-extension gap value, which is either the gap value in the extended or flexed position. The medial and lateral pressure value measurement and the knee joint flexion-extension gap value measurement of this application complement each other, facilitating doctors in measuring the medial and lateral pressure and gap values ​​and determining whether the medial and lateral sides of the knee joint are balanced.

[0033] Specifically, the pressure scale 311 includes two scales, one of which is the pressure value and the other is the gap value. The gap scale shows the gap value, and the gap value of knee flexion and extension is equal to the value on the gap scale minus the gap value on the pressure scale 311.

[0034] Furthermore, the upper and lower support arms 51 are provided with protruding ridge structures to increase friction and make the support arms fit more firmly against the osteotomy surface.

[0035] In this embodiment, the measuring part 52 is provided with a vertically arranged guide groove 521. The pressure measuring part 5231 is inserted into the guide groove 521 and can move up and down within the guide groove 521. The measuring part 52 is provided with a through hole 522. An eccentric adjustment mechanism is installed in the through hole 522. The front end face of the measuring part 52 is provided with a gap scale on the circumferential side of the through hole 522.

[0036] The pressure measuring block 3 in this embodiment includes two symmetrically arranged pressure measuring parts 5231 and a connecting part 32. The connecting part 32 connects the two pressure measuring parts 5231 and is inserted into a guide groove 521, allowing it to move up and down within the guide groove 521. Specifically, the connecting part 32 and the pressure measuring parts 5231 are stepped, such that after the connecting part 32 is inserted into the guide groove 521, the end face of the pressure measuring part 5231 connected to the connecting part 32 contacts the left and right end faces of the measuring part 52. This stepped structure design ensures the stability of the pressure measuring block 3's up and down movement and prevents deviation. The connecting part 32 is provided with a through groove 321, and an eccentric adjustment mechanism is inserted into the through groove 321. Adjusting the eccentric mechanism allows the pressure measuring block 3 to move up and down. The pressure measuring unit 5231 has a mounting hole 312, and an observation hole 313 communicating with the mounting hole 312 is provided on the front end face of the pressure measuring unit 5231. A pressure scale 311 is provided on the front end face of the pressure measuring unit 5231 at the observation hole 313. A spring 2 is provided inside the mounting hole 312, and the upper support arm is inserted into the mounting hole 312 and presses the spring 2. Specifically, the bottom end of the pressure measuring unit 5231 has an inner hole, and the spring 2 is installed in the inner hole, with the spring 2 pressing against the inner hole and the mounting hole 312. Specifically, the upper support arm has a scribe line. When the upper support arm is in a certain position, the pressure value can be observed by looking at the scribe line and the pressure scale 311 on the upper support arm through the observation hole 313. Furthermore, the pressure measuring unit 5231 is also provided with a limiting through hole that connects to the mounting hole 312, and the upper support arm is provided with a long groove. After the limiting pin 4 passes through the limiting through hole, it is inserted into the long groove, which restricts the pressure measuring block 3 from moving under the guidance of the limiting pin 4, thus playing a guiding role and preventing the upper support arm from rotating.

[0037] The eccentric adjustment mechanism of this embodiment includes an adjustment knob 6, on which an eccentric shaft 7 is provided. The front end face of the adjustment knob 6 has graduated lines. The adjustment knob 6 is inserted into the through hole 522 of the measuring part 52, and the eccentric shaft 7 is inserted into the through groove 321 of the pressure measuring block 3. Rotating the adjustment knob 6 causes the eccentric shaft 7 to move the pressure measuring block 3 within the guide groove 521, causing the upper support to move up and down relative to the lower support. The gap value of knee flexion and extension can be observed through the gap scale and the graduated lines on the adjustment knob 6. Further, the outer circumference of the adjustment knob 6 has multiple holes, in which damping springs 9 and ball bearings 8 are installed. The ball bearings 8 rest on the inner circumference of the through hole 522 of the measuring part 52. The design of the ball bearings 8 and the damping springs 9 provides appropriate damping for the adjustment knob 6. Further, a rotating groove is provided at one end of the adjustment knob 6 located on the gap scale. The adjustment knob 6 is rotated using the rotating groove. The rotating groove is preferably hexagonal and preferably located in the center of the adjustment knob 6. Furthermore, the eccentric adjustment mechanism also includes a rotating shaft 13, which is mounted on the eccentric shaft 7 and located within the through hole 522 of the measuring section 52.

[0038] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A knee joint flexion-extension gap measuring balancer, characterized in that, Includes a base, the base comprising a lower support arm and a measuring section; A pressure measuring mechanism includes a pressure measuring block disposed on the measuring part. The pressure measuring block includes two symmetrically arranged pressure measuring parts. A pressure scale is provided on the front end face of the pressure measuring part. An upper support arm is inserted into the pressure measuring part and can move within the pressure measuring part. The lower support arm and the upper support arm are respectively attached to the tibial osteotomy surface and the femoral osteotomy surface, and the pressure values ​​on the inner and outer sides of the knee joint can be observed. The gap measuring mechanism has a gap scale on the front end face of the measuring part. The eccentric adjustment mechanism is inserted into the measuring part and the pressure measuring block from the front end face of the measuring part. The rotation of the eccentric adjustment mechanism can drive the pressure measuring block to move up and down, and the gap value of the knee joint flexion and extension can be observed. The measuring part is provided with a vertically arranged guide groove, the pressure measuring part is inserted into the guide groove and can move up and down in the guide groove; the measuring part is provided with a through hole, an eccentric adjustment mechanism is installed in the through hole, and a gap scale is provided on the front end face of the measuring part on the circumferential side of the through hole; The pressure measuring block also includes a connecting part that connects the two pressure measuring parts. The connecting part is inserted into the guide groove. The connecting part is provided with a through groove, and the eccentric adjustment mechanism is inserted into the through groove. The eccentric adjustment mechanism includes an adjustment knob, on which an eccentric shaft is provided, and on the front end face of the adjustment knob are engraved lines. The adjustment knob is inserted into the through hole of the measuring part, and the eccentric shaft is inserted into the through groove on the pressure measuring block. When the adjustment knob is rotated, the eccentric shaft can drive the pressure measuring block to move in the guide groove. The gap value of knee joint flexion and extension can be observed through the gap scale and the scale line on the adjustment knob. The pressure measuring part is provided with a mounting hole, and the front end face of the pressure measuring part is provided with an observation hole communicating with the mounting hole. The front end face of the pressure measuring part is provided with a pressure scale located at the observation hole. A spring is provided in the mounting hole, and the upper support arm is inserted into the mounting hole and presses the spring. The upper support arm is provided with a long groove, and the pressure measuring part is provided with a limiting through hole that connects to the mounting hole. After the limiting pin passes through the limiting through hole, it is inserted into the long groove to restrict the pressure measuring block from moving under the guidance of the limiting pin.

2. The knee joint flexion-extension gap measuring balancer as described in claim 1, characterized in that, The connecting part of the pressure measuring block and the pressure measuring part are stepped, so that after the connecting part is inserted into the guide groove, the end face of the pressure measuring part connected to the connecting part contacts the left and right end faces of the measuring part.

3. The knee joint flexion-extension gap measuring balancer as described in claim 1, characterized in that, The adjustment knob has multiple holes on its outer circumference, and damping springs and ball bearings are installed in the holes. The ball bearings rest on the inner circumference of the through hole of the measuring part.

4. The knee joint flexion-extension gap measuring balancer as described in claim 1, characterized in that, The adjustment knob has a rotating groove at one end of the gap scale.

5. The knee joint flexion-extension gap measuring balancer as described in claim 1, characterized in that, An inner hole is provided at the bottom of the pressure measuring part, and a spring is installed in the inner hole. The spring presses against the inner hole and the mounting hole.

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