Load and gap balance system in knee joint replacement surgery

Abstract

The invention relates to the technical field of balance systems, in particular to a load and gap balance system in a knee joint replacement operation. Mainly aiming at the problems that a doctor realizes symmetrical gap balance and ligament stress by virtue of a manual technology and subjective evaluation, an unsatisfactory result can be caused, and complications, such as instability, limited movement range and premature wear of an artificial knee joint prosthesis, are possibly caused, the following technical scheme is provided: the artificial knee joint comprises a knee joint, the knee joint comprises a femur and a tibia, and a medial collateral ligament and an lateral collateral ligament are connected between the femur and the tibia; the first osteotomy guider is used for cutting off the thighbone, the thighbone part of the first osteotomy guider is cut off to form a far-end osteotomy plane, and a thighbone prosthesis is installed at the position of the far-end osteotomy plane. According to the invention, the gap can be accurately measured, the ligament can be accurately tensioned, personalized alignment is realized, prosthesis selection is optimized, and the surgical effect of knee joint replacement, the satisfaction degree of a patient and the long-term durability of the prosthesis are effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of balancing systems, and in particular to a load and gap balancing system in knee replacement surgery. Background Art

[0002] Knee replacement surgery is a common procedure used to relieve pain and improve mobility in patients with severe knee degeneration. However, due to the complexity of balancing the extension and flexion gaps and tissue stresses (loads) of the medial / lateral collateral ligaments, posterior cruciate ligament and patellar ligament of the knee during surgery, achieving optimal results can be challenging. For example, the stress (load) of the medial collateral ligament MCL and the lateral collateral ligament LCL is different for each patient. Traditionally, doctors rely on manual techniques and subjective assessments to achieve symmetrical gap balance and ligament stress. These methods often lead to undesirable results and may cause complications such as instability, limited range of motion and premature wear of artificial knee prostheses. In view of this, the present invention proposes a load and gap balancing system in knee replacement surgery. Summary of the invention

[0003] The purpose of the present invention is to propose a load and gap balancing system in knee replacement surgery to address the problem in the background art that doctors rely on manual techniques and subjective evaluation to achieve symmetrical gap balance and ligament stress, which may lead to undesirable results and may cause complications such as instability, limited range of motion and premature wear of artificial knee prostheses.

[0004] The technical solution of the present invention is as follows: a load and gap balancing system in knee replacement surgery, comprising a knee joint, wherein the knee joint comprises a femur and a tibia, wherein the femur and the tibia are connected with a medial collateral ligament and a lateral collateral ligament; a first osteotomy guide for resecting the femur, wherein the first osteotomy guide resects the femur portion to form a distal osteotomy plane, wherein a femoral prosthesis is installed at the distal osteotomy plane; a second osteotomy guide for resecting the tibia, wherein the second osteotomy guide resects the tibia portion to form a proximal osteotomy plane, wherein a tibial prosthesis is installed at the proximal osteotomy plane; the resected portion of the femur comprises a first inner compartment and a first outer compartment, the resected portion of the tibia comprises a second inner compartment and a second outer compartment, the distal osteotomy plane and the proximal osteotomy plane form a rectangular extension gap, wherein the rectangular extension gap comprises an extension medial gap and an extension lateral gap; a first tensioning device, Used to tension the ligament to measure the gap and load; in the 90-degree flexion state of the knee joint, the two groups of the first reference holes establish a rotation reference line to assist in resecting the posterior condyle to form a posterior condyle osteotomy surface, a flexion gap is formed between the posterior condyle osteotomy surface and the proximal osteotomy plane, the flexion gap includes a medial flexion gap and a lateral flexion gap, and a second tensioning device is arranged between the posterior condyle osteotomy surface and the proximal osteotomy plane; the second tensioning device is used to measure the flexion gap of the inner and outer compartments separately; a tensioning mechanism is used to tension the ligament to measure the gap and load; multiple groups of mechanical tensioners; a rotation adjustment device installed on the femur to ensure the precise positioning of the femoral prosthesis; a patellar trial mold used to replace the patella, used to measure and adjust the shape and size of the patellar prosthesis to achieve the best knee joint balance; a gap balancer used to balance the extension gap of the medial compartment, used to calculate the best prosthesis position and orientation.

[0005] Optionally, the first osteotomy guide includes a first positioning plate mounted on the femur, two groups of first drill bits are arranged on the first positioning plate, the first drill bits are fixedly connected to the distal end of the femur, the distal end of the femur is provided with a first reference hole matching with the first drill bit, a first guide plate is mounted on the first positioning plate, a first guide groove is arranged on the first guide plate, two groups of first pins are arranged in the first guide plate, the first pins are fixedly connected to the femur, and the distal osteotomy plane and the two groups of first reference holes are used to determine three positions and three rotations of the femoral prosthesis.

[0006] Optionally, the second osteotomy guide includes a second positioning plate mounted on the tibia, two groups of second drill bits are provided on the second positioning plate, the second drill bits are fixedly connected to the proximal end of the tibia, the proximal end of the tibia is provided with a second reference hole matching with the second drill bit, a second guide plate is mounted on the second positioning plate, a second guide groove is provided on the second guide plate, two groups of second pins are provided in the second guide plate, the second pins are fixedly connected to the tibia, and the proximal tibial osteotomy plane and the two groups of second reference holes are used to determine three positions and three rotations of the tibial prosthesis.

[0007] Optionally, the first tensioning device includes two groups of first support rods rotatably connected, one end of the first support rod is fixedly connected to the first handle, and the end of the first support rod away from the first handle is fixedly connected to a support plate, and the two groups of support plates are located between the distal osteotomy plane and the proximal osteotomy plane.

[0008] Optionally, the first tensioning device further includes a first distance sensor installed near the first handle, first load sensors are installed on both groups of the first support rods, and a locking mechanism is also provided between the two groups of the handles.

[0009] Optionally, the second tensioning device includes two groups of second support rods rotatably connected, one end of the second support rod is fixedly connected to a second handle, one group of the second support rods is fixedly connected to a right-angle support plate at one end away from the second handle, and a visual mark is provided on the right-angle support plate, and the other group of the second support rods is fixedly connected to a parallel support plate at one end away from the second handle, the horizontal part of the right-angle support plate and the parallel support plate are inserted into the flexion gap, the right-angle support plate is fixed to the distal osteotomy plane by a fixing nail passing through the first reference hole, and the parallel support plate is fixed to the proximal osteotomy plane by a fixing nail passing through the second reference hole.

[0010] Optionally, the tensioning mechanism includes a first thin plate, two groups of first fixing nails are installed on the first thin plate, the first fixing nails are installed in the first reference hole, a rotating hinge is provided at the center position of the first thin plate, an angle sensor is installed at the rotating hinge position, a T-shaped plate is connected to the rotating hinge, the T-shaped plate includes a vertical plate rotatably connected to the rotating hinge, the end of the vertical plate away from the rotating hinge is fixedly connected to a horizontal plate, and also includes a second thin plate, two groups of second fixing nails are installed on the second thin plate, the second fixing nails are installed in the second reference hole, and a second distance sensor is installed at the first fixing nail position.

[0011] Optionally, the rotation adjustment device includes a fixed arm, two groups of third pins are installed on the fixed arm, the third pins are installed in the first reference hole, the fixed arm is L-shaped, and a third drill bit is also provided on the fixed arm, the third drill bit is inserted into the inner side of the femur parallel to the distal osteotomy plane, and a distal compensation is provided on the side of the fixed arm close to the femur. A mounting block is installed on the third drill bit, a screw is threaded on the mounting block, a splint is rotatably connected to the screw, a robot is installed on the side of the splint, a locator is connected to the robot, and a knife groove is opened on the locator.

[0012] Optionally, a triaxial load sensor is provided in the patella test mold, the patella test mold includes a dome-shaped surface, a substrate and at least two groups of positioning pins, a PCB board is provided inside the patella test mold, the triaxial load sensor is composed of a plurality of variable beams, the center of the variable beam is a round block, at least one group of load sensors is installed on each beam, a shell is provided on the outer side of the plurality of groups of variable beams, at least one group of pillars is installed on the shell.

[0013] Optionally, the gap balancer includes an electric actuator, an output end of the electric actuator is fixedly connected to a vertical lead screw, and the vertical lead screw is used to drive a set of mechanical tensioners.

[0014] In summary, the present application includes at least one of the following beneficial technical effects:

[0015] The present invention takes the form of a gap / load force balance device that measures the medial, lateral and patellofemoral compartments of the knee joint throughout the entire range of motion. Sensor equipment installed in the trial prosthesis measures load and gap, and tissue analysis is performed based on the prosthesis design, bone morphology and knee alignment to determine the optimal size, thickness and shape of the femoral, tibial and patellar components. Based on real-time data, soft tissue analysis can be used to recommend the best combination of prosthesis size and shape to achieve the desired therapeutic effect;

[0016] Further, by utilizing technologies such as Bluetooth, cellular or Wi-Fi, the system can achieve seamless wired or wireless data transmission between sensor devices and computers and robotic surgical systems, ensuring efficient and reliable data exchange and enhancing the overall surgical experience;

[0017] In summary, the present invention can accurately measure the gap, accurately tighten the ligament, achieve personalized alignment, optimize the prosthesis selection, and effectively improve the surgical effect of knee replacement, patient satisfaction and the long-term durability of the prosthesis. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A cross-sectional view of femoral osteotomy with a custom osteotomy guide Figure 1 ;

[0019] Figure 2 A cross-sectional view of a custom osteotomy guide for the femur Figure 2 ;

[0020] Figure 3 Oblique view of tibial osteotomy with custom osteotomy guide Figure 1 ;

[0021] Figure 4 Oblique view of tibial osteotomy with custom osteotomy guide Figure 2 ;

[0022] Figure 5 Schematic diagram of the initial reference of the gap balance device after initial osteotomy Figure 1 ;

[0023] Figure 6 Schematic diagram of the initial reference of the gap balance device after initial osteotomy Figure 2 ;

[0024] Figure 7 Flowchart of gap and load balancing steps for knee replacement surgery;

[0025] Figure 8 Balanced knee joint for extension gap Figure 1 ;

[0026] Fig. 9 Balanced knee joint for extension gap Figure 2 ;

[0027] Fig.10 Transverse view of the knee joint with flexion gap balance Figure 1 ;

[0028] Fig.11 Transverse view of the knee joint with flexion gap balance Figure 2 ;

[0029] Fig.12 View of the knee joint using a manual tensioner to balance the gap Figure 1 ;

[0030] Fig.13 View of the knee joint using a manual tensioner to balance the gap Figure 2 ;

[0031] Fig.14 This is the lateral view of the knee joint;

[0032] Fig.15 This is a transverse view of the knee joint using the sensor device;

[0033] Fig.16 Transverse axial view of the knee with a tensioner for the external compartment;

[0034] Fig.17This is the front view of the robot's femur;

[0035] Fig.18 This is the robot's transverse view of the femur;

[0036] Fig.19 The robot's horizontal axis Figure 1 ;

[0037] Fig. 20 The robot's horizontal axis Figure 2 ;

[0038] Fig.21 This is the external view of the robot;

[0039] Fig. 22 This is the anatomy of the knee joint;

[0040] Fig.23 is a cross-sectional view of a patellar component with a load sensor;

[0041] Fig.24 The knee joint with the prosthesis installed Figure 1 ;

[0042] Fig.25 The knee joint with the prosthesis installed Figure 2 ;

[0043] Fig.26 is a view of an electric linear actuator;

[0044] Reference numerals:

[0045] 1. Knee joint; 11. Femur; 12. Tibia; 13. Medial collateral ligament; 14. Lateral collateral ligament;

[0046] 110, first osteotomy guide; 111, first positioning plate; 112, first drill bit; 113, first reference hole; 114, first guide plate; 115, first guide groove; 116, first pin; 119, distal osteotomy plane; 1000, femoral prosthesis;

[0047] 120, second osteotomy guide; 121, second positioning plate; 122, second drill bit; 123, second reference hole; 124, second guide plate; 125, second guide groove; 126, second pin; 129, proximal osteotomy plane; 2000, tibial prosthesis;

[0048] 2. Mechanical tensioner;

[0049] 200, stretch gap; 201, stretch inner gap; 202, stretch outer gap; 211, first inner chamber; 212, first outer chamber; 221, second inner chamber; 222, second outer chamber;

[0050] 3. Rotate the reference line;

[0051] 300, flexion gap; 301, medial flexion gap; 302, lateral flexion gap; 309, posterior condylar osteotomy surface;

[0052] 4. First tensioning device; 41. First support rod; 42. First handle; 43. Support plate; 44. First distance sensor; 45. Load sensor; 46. Locking mechanism;

[0053] 5. Second tensioning device; 51. Second support rod; 52. Second handle; 53. Right-angle support plate; 54. Parallel support plate; 55. Visual mark;

[0054] 6. tensioning mechanism; 61. first thin plate; 62. first fixing nail; 63. rotating hinge; 64. vertical plate; 65. horizontal plate; 66. second thin plate; 67. second fixing nail; 68. second distance sensor;

[0055] 7. Rotation adjustment device; 71. Fixed arm; 72. Third pin; 73. Third drill bit; 74. Remote compensation; 75. Mounting block; 76. Screw; 77. Clamp; 78. Robot; 79. Positioner; 710. Tool groove;

[0056] 8. Gap balancer; 81. Electric actuator; 82. Vertical lead screw;

[0057] 9. Patella test mold; 91. Triaxial load sensor; 92. Dome-shaped surface; 93. Base plate; 94. Positioning pin; 95. PCB board; 96. Round block; 97. Shell; 98. Pillar. DETAILED DESCRIPTION

[0058] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0059] The components of the embodiments of the present invention generally described and shown in the drawings herein may be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention.

[0060] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without making any creative work shall fall within the scope of protection of the present invention.

[0061] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0062] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0063] Example

[0064] like Figures 1 to 6 As shown, a load and gap balancing system in a knee replacement surgery proposed by the present invention comprises a knee joint 1, wherein the knee joint 1 comprises a femur 11 and a tibia 12, wherein a medial collateral ligament 13 and a lateral collateral ligament 14 are connected between the femur 11 and the tibia 12;

[0065] Specifically, the gap balancing system includes a first osteotomy guide 110 for resecting the femur 11, the first osteotomy guide 110 resecting a portion of the femur 11 to form a distal osteotomy plane 119, and a femoral prosthesis 1000 is installed at the distal osteotomy plane 119; the first osteotomy guide 110 includes a first positioning plate 111 installed on the femur 11, and two sets of first drill bits 112 are arranged on the first positioning plate 111, and the first drill bits 112 are fixedly connected to the distal end of the femur 11 The distal end of the femur 11 is provided with a first reference hole 113 that matches the first drill bit 112, a first guide plate 114 is installed on the first positioning plate 111, a first guide groove 115 is provided on the first guide plate 114, two groups of first pins 116 are provided in the first guide plate 114, the first pins 116 are fixedly connected to the femur 11, the distal osteotomy plane 119 and the two groups of first reference holes 113 are used to determine three positions and three rotations of the femoral prosthesis 1000. It also includes a second osteotomy guide 120 for removing the tibia 12, the second osteotomy guide 120 removes part of the tibia 12 to form a proximal osteotomy plane 129 of the tibia 12, and the proximal osteotomy plane 129 is installed with a tibial prosthesis 2000; the second osteotomy guide 120 includes a second positioning plate 121 installed on the tibia 12, two groups of second drill bits 122 are arranged on the second positioning plate 121, the second drill bits 122 are fixedly connected to the proximal end of the tibia 12, and the proximal end of the tibia 12 is provided with a second reference hole 123 matching the second drill bit 122, a second positioning plate 121 is installed with a second guide plate 124, the second guide plate 124 is provided with a second guide groove 125, two groups of second pins 126 are arranged in the second guide plate 124, and the second pins 126 are fixedly connected to the tibia 12, the proximal osteotomy plane 129 of the tibia 12 and the two groups of second reference holes 123 are used to determine three positions and three rotations of the tibial prosthesis 12. It is used to help doctors remove the ends of the femur 11 and the tibia 12 to install a total knee prosthesis. For more detailed descriptions of the first osteotomy guide 110 and the second osteotomy guide 120 of the knee joint, refer to patent application US20160038245A1 "Method for creating a customized joint osteotomy guide using two-dimensional imaging", which will not be described in detail here.

[0066] The first positioning plate 111 and the second positioning plate 121 customized based on the patient's preoperative imaging scan can establish the position and orientation of the prosthesis. The first guide plate 114 is mounted on the first positioning plate 111 to form the first osteotomy guide 110 of the femur 11; the second guide plate 124 is mounted on the second positioning plate 121 to form the second osteotomy guide 120 of the tibia 12. The first guide groove 115 and the second guide groove 125 provide guidance for the oscillating saw osteotomy. The pin 112 that fixes the first positioning plate 111 provides two first reference holes 113 after osteotomy, and the proximal second drill bit 122 that fixes the second positioning plate 121 provides two second reference holes 123 after osteotomy, with a hole diameter of about 3.2 mm. The distal osteotomy plane 119 of the femur 11 and the two first reference holes 113 are sufficient to determine the three positions of all femoral 11 prostheses, namely, internal and external rotation M / L, anterior and posterior A / P and proximal and distal P / D, and the three rotations of internal and external rotation V / V, flexion and extension F / E, and internal and external rotation I / E. Fig.21 Similarly, the proximal osteotomy plane 129 of the tibia 12 and the second reference hole 123 are sufficient to determine three positions and three rotations of the tibial prosthesis 2000 .

[0067] Furthermore, Figure 8 and Fig. 9It is shown that after the initial osteotomy of the knee joint 1 is completed using a customized osteotomy guide, the initial position and orientation of the femoral 11 and tibial 12 prostheses are determined. As above, the distal osteotomy plane 119 and the proximal osteotomy plane 129 can determine the P / D, F / E and V / V of the femoral 11 and tibial 12 components, respectively, and the first reference hole 113 and the second reference hole 123 can determine the I / E, M / L and AP positions of the femoral 11 and tibial 12 components, respectively. The medial and posterior condyles are often affected by arthritis, and the cartilage and subchondral bone have been worn. Using arthritic bones as a reference will result in inaccurate measurements of the true gap of the physiological knee joint. By using the osteotomy plane and the reference lines formed by drilling, the correlation between the position and orientation of the prosthesis relative to the physiological knee joint can be established. One of the goals of gap balancing is to ensure that the medial collateral ligament 13 and the lateral collateral ligament 14 are properly tensioned after the prosthesis is implanted to obtain the best effect. The second goal is to ensure that sufficient bone is removed according to the design and specifications of the prosthesis. For example, the thickness of the femoral 11 component at the distal and posterior portion ranges from 8 to 10 mm, and the thickness of the tibial 12 component ranges from 8 to 18 mm, with the thickness increasing by 1 or 2 mm. For a femoral 11 component with a thickness of 8 mm and a tibial 12 component with a thickness of 8 mm, the extension and flexion gaps should be at least 16 mm to fit the soft tissue envelope of the knee joint. In addition, the extension and flexion gaps of the native knee joint vary depending on the joint compartment. For example, under physiological conditions, with a force of 100 Newtons applied to each compartment, the extension gap 200 of the knee joint is approximately 6 mm medially and approximately 7 mm laterally. In addition, as part of a total knee replacement surgery, the anterior cruciate ligament ACL and / or the posterior cruciate ligament PCL are resected, which increases the extension and flexion gaps by 2-5 mm. Typically, the gap in the outer compartment is larger than the inner compartment due to the specifications of length, width and thickness and the bone morphology of the epicondyle.

[0068] Furthermore, if Figure 22-24 As shown in Figure 1, one of the goals of total knee surgery is to achieve equal and symmetrical extension and flexion gaps. In standard TKA, the goal is to achieve a neutral knee mechanical alignment of 0° in the frontal plane when the knee is extended, as shown in Figure 1. Figure 5The resected portion of the femur 11 shown includes a first inner compartment 211 and a first outer compartment 212, the resected portion of the tibia 12 includes a second inner compartment 221 and a second outer compartment 222, the distal osteotomy plane 119 and the proximal osteotomy plane 129 form a rectangular extension gap 200, and the rectangular extension gap 200 includes an extension inner gap 201 and an extension outer gap 202. X-ray / MRI / CT is used to establish a reference line from the center of the hip joint to the center of the knee joint to the center of the ankle joint. The distal osteotomy plane 119 and the proximal osteotomy plane 219 are perpendicular to the mechanical reference line in the neutral position. When determining the distal osteotomy plane 119 and the proximal osteotomy plane 129, the thickness of the prosthesis should be considered. The amount of osteotomy of the first inner compartment 211, the first outer compartment 212, the second inner compartment 221, and the second outer compartment 222 must be equal to or greater than the thickness of the prosthesis to achieve the rectangular extension gap 200. In most prosthesis designs, the combined prosthesis thickness in the extension gap 200 and the flexion gap is the same. Thus, the desired ligament balance of the medial collateral ligament 13 and the lateral collateral ligament 14 is achieved while symmetry of the extension medial gap 201 and the extension lateral gap 202 is desired. The extension gap 200 can be evaluated using a spacer of the same thickness as the combined prosthesis.

[0069] As above, see Fig.10 as well as Fig.11 In the ninety-degree flexion state of the knee joint 1, the two groups of first reference holes 113 establish a rotation reference line 3, which is used to assist in the resection of the posterior condyle of the femur to form a posterior condyle osteotomy surface 309, and a flexion gap 300 is formed between the posterior condyle osteotomy surface 309 and the proximal osteotomy plane 129. The flexion gap 300 includes a medial flexion gap 301 and a lateral flexion gap 302. A second tensioning device 5 is provided between the posterior condyle osteotomy surface 309 and the proximal osteotomy plane 129. Most doctors want to achieve equal or symmetrical flexion and extension gaps 200. After the initial osteotomy is completed, the distal osteotomy plane 119 and the proximal osteotomy plane 129 are formed, and the knee joint 1 is in ninety-degree flexion. The rotation reference line 3 can be established using the two first reference holes 113 of the femur 11. The first reference hole 113 is then used as a reference to assist the doctor in performing the posterior condyle osteotomy surface 309 of the femur 11. The initial rotation alignment can be determined using various existing surgical techniques, such as the posterior condylar axis or transcondylar axis represented by the dotted line. Alternatively, the medial collateral ligament 13 and the lateral collateral ligament 14 are tensioned using a tensioning device and the flexion gap is measured before adjusting the femur 11 to rotate about the center of the knee joint. Typical angle adjustment range: 0°-+3° internal rotation clockwise, -3°-0° external rotation counterclockwise. The flexion gap 300 can be checked using a spacer of the same thickness as the combined prosthesis. In this example, the medial flexion gap 301 and the lateral flexion gap 302 are symmetrical.

[0070] Generally speaking, establishing the reference plane and rotation of the femur 11 can be achieved using various surgical instruments such as manual instruments, computer navigation systems, robotic 78 systems, customized osteotomy guides and intelligent instruments, and various knee alignment methods such as mechanical, kinematic, functional, personalized, etc.

[0071] Most modern knee prosthesis components are designed to be symmetrical both medially and laterally to match the symmetrical rectangular gaps of extension and flexion. However, there are also some asymmetric physiological prosthesis designs in which the medial and lateral gaps are unequal. In addition, some clinical studies have found that if the gap is slightly asymmetric and the lateral gap is slightly larger than the medial gap to mimic the physiological knee joint, the clinical effect will be slightly better. Unicompartmental knee replacement improves clinical results and prosthesis survival rate by restoring the knee joint line and balancing the ligament stress on the undamaged side. Gap and ligament balance are more critical. Therefore, in order to achieve the best clinical effect, the gap balancing system must be able to accurately measure the knee extension and flexion gaps, transmit the data to the robot78-assisted system, and combine with the prosthesis design to perform precise osteotomy.

[0072] It is worth mentioning that Figures 12 to 15 As shown, the gap balancing system includes a first tensioning device 4, and the manual tensioner includes two groups of first support rods 41 that are rotatably connected, one end of the first support rod 41 is fixedly connected to a first handle 42, and one end of the first support rod 41 away from the first handle 42 is fixedly connected to a support plate 43, and the two groups of support plates 43 are located between the distal osteotomy plane 119 and the proximal osteotomy plane 129. The first tensioning device 4 also includes a first distance sensor 44 installed near the first handle 42, and first load sensors 45 are installed on both groups of first support rods 41, and a locking mechanism 46 is also provided between the two groups of handles. Fig.12 and Fig.13The use of the first tensioning device 4 to balance the extension gap 200 is shown. The first tensioning device 4 acts like a lamina spreader. When the doctor squeezes the upper and lower first handles 42, the distance between the first handles 42 is reduced, and the support plate 43 is inserted between the distal osteotomy plane 119 and the proximal osteotomy plane 129 from the outside and the inside in turn, thereby tightening the lateral collateral ligament 14 and the medial collateral ligament 13. The amount of force or load applied depends largely on the doctor's experience and preference. The extension lateral gap 202 can be measured manually using a certain thickness of pads, calipers, rulers or any linear measuring tool, and the measurement of the extension medial gap 201 is similar. There are several advantages to measuring the extension medial gap 201 and the extension lateral gap 202 independently. First, each compartment can be measured independently, such as a unicompartmental knee replacement surgery. Second, since the medial and lateral gaps can be measured separately, the doctor can obtain an asymmetric extension gap 200 as desired. The support plate 43 of the first tensioning device 4 can also be placed near the middle of the knee joint 1 to measure rectangular and symmetrical gaps. This has an impact on both the extension gap 200 and the ligament balance.

[0073] At the same time, the above-mentioned gap balancing system also includes a second tensioning device 5, which includes two groups of second support rods 51 that are rotatably connected, one end of the second support rod 51 is fixedly connected to the second handle 52, one end of one group of second support rods 51 away from the second handle 52 is fixedly connected to a right-angle support plate 53, and a visual mark 55 is provided on the right-angle support plate 53, and the other end of the second support rod 51 away from the second handle 52 is fixedly connected to a parallel support plate 54, the horizontal part of the right-angle support plate 53 and the parallel support plate 54 are inserted into the flexion gap 300, the right-angle support plate 53 is fixed to the distal osteotomy plane 119 by passing the first reference hole 113 with a fixing nail, and the parallel support plate 54 is fixed to the proximal osteotomy plane 129 by passing the second reference hole 123 with a fixing nail. Fig.14It is a side view when the knee joint is flexed 90 degrees. The second tensioning device 5 is composed of a right-angle gusset 53 and a parallel gusset 54, instead of being composed of two parallel support plates 43 like the first tensioning device 4. The fixing pin passes through the first reference hole 113 to fix the right-angle gusset 53 on the distal osteotomy plane 119. In addition, the right-angle gusset 53 is provided with a visual mark 55, which represents the distance mm from the distal fixing pin to the parallel gusset 54. The horizontal part of the right-angle gusset 53 is inserted into the flexion gap 300 and may or may not contact the posterior condyle. When the gap of the second handle 52 is reduced, the medial collateral ligament 13 and the lateral collateral ligament 14 are tensioned, and part of the right-angle gusset 53 provides support for the femur 11. In knee replacement surgery, since the anterior cruciate ligament ACL is sacrificed during the proximal osteotomy of the tibia 12, the flexion gap is affected by tension, which may cause the anterior part of the tibia 12 to be subluxated, thereby causing inaccurate flexion gap measurement. In order to prevent the anterior tibia 12 from being subluxated, the fixing pin passes through the second reference hole 123 to fix the parallel support plate 54 on the proximal osteotomy plane 129. The measurement of the flexion gap involves the distance from the first reference hole 113 to the parallel support plate 54, and the gap between the right-angle support plate 53 and the parallel support plate 54. The thickness of the right-angle support plate 53 and the parallel support plate 54 can be measured with a pad, a caliper, a ruler or any linear measuring tool. The distance from the first reference hole 113 to the parallel support plate 54 is provided by a visual mark 55 in increments of 1 mm or 2 mm. The manual tensioner can measure the flexion gap of the inner and outer compartments separately. If the rectangular gap of the inner and outer compartments is to be measured at the same time, a wider right-angle support plate 53 can be used to accommodate the inner and outer condyles and the two distal holes at the same time.

[0074] In this scheme, Fig.15 and Fig.16The figure shows a knee joint flexed 90 degrees, a tensioning mechanism 6, the tensioning mechanism 6 comprising a first thin plate 61, two groups of first fixing pins 62 are installed on the first thin plate 61, the first fixing pin 62 is installed in the first reference hole 113, a rotating hinge 63 is provided at the center of the first thin plate 61, an angle sensor is installed at the position of the rotating hinge 63, a T-shaped plate is connected to the rotating hinge 63, the T-shaped plate comprises a vertical plate 64 rotatably connected to the rotating hinge 63, a horizontal plate 65 is fixedly connected to one end of the vertical plate 64 away from the rotating hinge 63, and a second thin plate 66 is also included, two groups of second fixing pins 67 are installed on the second thin plate 66, the second fixing pin 67 is installed in the second reference hole 123, and a second distance sensor 68 is installed at the position of the first fixing pin 62. The two first fixing pins 62 pass through the distal first reference hole 113 to fix the rectangular first thin plate 612-4mm thick on the distal osteotomy plane 119 of the femur 11. The rotating hinge 63 is located at the center of the first thin plate 61 and is also the center of the femoral 11 component. The T-shaped plate is composed of a vertical plate 64 and a horizontal plate 65, which are connected to the rotating hinge 63. Two second fixing nails 67 pass through the second reference hole 123 of the tibia 12 to fix the second thin plate 66 2-4mm thick on the proximal osteotomy plane 129. In one embodiment, the second thin plate 66 is not fixed by the second fixing nails 67, and the doctor uses his hands to prevent the anterior subluxation of the tibia 12. The support plate 43 of the first tensioning device 4 is inserted between the horizontal plate 65 and the second thin plate 66 to tension the lateral collateral ligament 14. The horizontal plate 65 and the second thin plate 66 protect the soft cortical bone from damage caused by the support plate 43. When the first handle 42 is squeezed, the horizontal plate 65 rotates around the rotating hinge 63, and the horizontal plate 65 contacts the lateral posterior condyle near the lateral collateral ligament 14. The rotation angle around the hinge can be measured using a visual micrometer or a sensor, such as a potentiometer, an encoder, an accelerometer, etc. The measurement of the flexion lateral gap 302 involves the distance from the first fixing pin 62 to the horizontal plate 65, the thickness of the horizontal plate 65 and the second thin plate 66, and the gap of the support plate 43. The first tensioning device 4 also includes various sensors for measuring the gap mm and the load N of the ligament. The first distance sensor 44 is located near the handle and can be an optical visible light or infrared, ultrasonic or linear potentiometer. The distance sensed by the first distance sensor 44 is proportional to the flexion gap 300 because the size and geometry of the first tensioning device 4 have been defined. In addition, the first load sensor 45 is connected to the first handle 42 to measure the total load of the tensioned ligament. When the stress reaches the expected value, the first handle 42 can be locked with a locking mechanism 46. Similarly, the flexion medial gap 301 and the load can be measured by inserting the expander of the first tensioning device 4 from the inside between the horizontal plate 65 and the second thin plate 66 to tension the medial collateral ligament 13.

[0075] In this embodiment, the first tensioning device 4 is placed near the center of the knee joint 1 between the horizontal plate 65 and the second thin plate 66. When the load applied by squeezing the first handle 42 reaches the expected value, the lateral collateral ligament 14 and the medial collateral ligament 13 will reach a balance to form a flexion gap 300. The first distance sensor 44 can measure the flexion lateral gap 302, and the angle sensor can measure the rotation angle around the rotation hinge 63. These measured values ​​can be used to adjust the posterior condylar osteotomy surface 309 to obtain the expected flexion gap 300. Similarly, the extension gap 200 can be measured by inserting an expander between the horizontal plate 65 and the second thin plate 66, and the medial collateral ligament 13 and the lateral collateral ligament 14 can be balanced. If a symmetrical rectangular extension gap 200 and flexion gap 300 and balanced ligaments are to be obtained in total knee replacement surgery, the results are similar to those of measuring the two compartments separately.

[0076] Furthermore, Fig.16 A knee joint in 90 degrees of flexion is shown with a mechanical tensioner 2 for ligament and gap balancing. Second distance sensors 68 are located at the two first fixation pins 62 to measure the distance of the ligament tensioner from the rotation reference line 3 to the second medial compartment 221 and the second external compartment 222, respectively. In the second medial compartment 221, the mechanical tensioner 2 is spring loaded with a certain spring constant sufficient to tension the medial collateral ligament 13 with the expected load. The flexion medial gap 301 can be measured using any manual measurement tool or distance measurement sensor. The mechanical tensioner 2 is inserted between the medial posterior condyle of the femur 11 and the proximal osteotomy plane 129 of the tibia 12, with its top and bottom plates in contact with the bone. In the second external compartment 222, the mechanical tensioner 2 is raised and lowered like a jack by turning the screw manually or electrically until the expected load is reached. As above, various sensors can be used to measure load and distance. The situation of inserting the mechanical tensioner 2 between the medial posterior condyle of the femur 11 and the proximal osteotomy plane 129 of the tibia 12 is similar. The above only gives two examples of mechanical structures. There are many other electromechanical or non-mechanical actuators, such as air bags or water bags, hydraulic pistons, manual or electric linear actuators, etc. As above, the mechanical tensioner 2 can balance the medial collateral ligament 13 and the lateral collateral ligament 14 manually, and the mechanical tensioner 2 that accommodates the inner and outer condyles can measure the flexion gap 300 at the same time. Similarly, the extension gap 200 can be measured with one mechanical tensioner 2 alone, while the rectangular extension gap 200 must be measured using two mechanical tensioners 2 at the same time.

[0077] Clinical studies have shown that the extension gap 200 changes by less than 1mm for loads between 100N and 200N, regardless of whether the ACL or PCL is sacrificed. In contrast, when both the ACL and PCL are excised, the flexion gap changes by 4-6mm for loads between 100N and 200N, while the flexion gap changes by 1-2mm when only the ACL is excised. Therefore, adjusting the femoral 11 component rotation I / E and anteroposterior A / P to achieve the desired flexion gap and ligament balance is critical to achieving optimal clinical results.

[0078] Furthermore, in the above gap balancing system Fig.17 and Fig.18 It is a front view and an axial view of a mounting device for a two-axis robot 78 auxiliary system. The device can adjust the robot 78 rotationally to obtain the desired flexion gap and / or ligament balance.

[0079] from Fig.17 Starting with a front view of the femur 11, Fig.13 The robot 78 auxiliary system shown has a mounting and rotation adjustment device 7, which is fixed on the femur 11. The rotation adjustment device 7 mounted on the femur 11 includes a fixed arm 71, on which two sets of third pins 72 are mounted, and the third pins 72 are mounted in the first reference hole 113. The fixed arm 71 is L-shaped, and a third drill 73 is also arranged on the fixed arm 71. The third drill 73 is inserted into the inner side of the femur 11 parallel to the distal osteotomy plane 119. A distal compensation 74 is arranged on the side of the fixed arm 71 close to the femur 11. A mounting block 75 is mounted on the third drill 73, and a screw 76 is threadedly connected to the mounting block 75. A splint 77 is rotatably connected to the screw 76. A robot 78 is mounted on the side of the splint 77, and a positioner 79 is connected to the robot 78. A knife groove 710 is opened on the positioner 79. Using the same distal osteotomy plane 119 and first reference hole 113 as the gap balancing system, two third pins 72 fix the fixation arm 71 to the distal osteotomy plane 119 position of the femur 11, and a third drill bit 73 with a diameter of about 4 mm is inserted into the inner side of the femur 11 parallel to the distal osteotomy plane 119, requiring a certain distal compensation 74. After the third drill bit 73 has been inserted into the femur 11, the fixation arm 71 and the third pin 72 are removed. Next, the rotation adjustment mechanism or mounting block 75 is attached to the third drill bit 73, and another part of the splint 77 is attached to the robot 78. The fixing screw 76 locks the splint 77 and the mounting block 75, fixing the mounting block 75 to form a friction lock. Note that only the robot 78 can rotate around the center of the hinge 76, and the third drill bit 73 fixed to the bone serves as an initial reference for the position and orientation of the prosthesis.

[0080] In this embodiment, Fig.18It is shown that the center of the rotation adjustment or hinge of the robot 78 is located at the screw 76, and can be rotated clockwise or counterclockwise to any angle. With the rotation reference line 3 as the reference, the rotation adjustment angle of the femur 11 is mostly in the range of -5° to +5°, with an increment of 1° or 2°. In order to prevent the third drill bit 73 from loosening or moving due to the vibration of the swing saw, the fixed arm 71 is fixed to one or two first reference holes 113 positions with nails. In addition, any A / P compensation between the center of the screw 76 and the center of the femur 11 component or the knee joint can be calculated using the length of the fixed arm 71 from the hinge screw 76 to the first reference hole 113. The calculated robot 78 A / P compensation generated due to the rotation angle adjustment, the A / P compensation varies according to the rotation angle. The total A / P compensation of the robot 78 includes any A / P compensation between the third drill bit 73 and the fixed arm 71, and the prosthesis A / P adjustment, to ensure the precise positioning of the femur 11 component.

[0081] Specific Figures 19 to 21 The robot 78 is shown with a positioner 79, and the upper blade groove 710 is used for navigation of the swing saw system. The initial setting of the rotation angle is 0°, and the rotation reference line 3 is used as the default reference line. Figure 7 Flowchart and Figure 5-10 A gap balancing system, a manual or power-driven knee balancer device can measure the extension and flexion gaps of the internal and external compartments simultaneously or separately. After the extension and flexion gaps are measured and recorded, the compensation formed by the prosthesis size, rotation angle, medial and lateral spacing, etc., can be adjusted using the forward motion trajectory of the hinge and two-axis robot 78, regardless of the expected flexion gap symmetry. Fig. 20 A 3° rotation adjustment is shown relative to the robot 78 hinge. The intended goal of this example is to obtain symmetrical and balanced extension and flexion gaps for the medial and lateral compartments. The A / P compensation of the robot 78 is calculated above, so the positioner 79 can help the surgeon to accurately resect the posterior condyle to form the posterior condyle osteotomy surface 309.

[0082] As described in the previous patent application for the dual-axis robot 78, Fig.21 is a side view of the knee joint, the robot 78 is rotated to adjust the mechanical device see Fig.17 Installed near the condylar line. The two rotation axes of the robot 78 define the workspace. By adjusting the rotation angle of the two axes, the positioner 79 can reach any angle within the workspace of the robot 78. For most modern prosthesis designs, the osteotomy planes such as distal, anterior condyle, posterior condyle, anterior oblique and posterior oblique can be defined by the 2-axis plane. The robot 78 can adapt to the prosthesis position and orientation adjustment based on the gap balance system and distance.

[0083] As mentioned above, one of the advantages of using the first reference hole 113 as the reference line for the rotation adjustment of the robot 78 and the prosthesis is that it is easy to calculate. Subsequently, the robot 78 can easily determine any A / P compensation based on the expected extension gap 200 and flexion gap 300. Another advantage of using the rotation reference line 3 as the reference is that the reference of some prosthesis designs is the front, not the back. For example, if the prosthesis design is based on the front reference system, the distance between the posterior condylar osteotomy surface 309 and the robot 78 rotation axis varies with the prosthesis specifications; if the prosthesis design is based on the back reference system, the distance between the posterior condylar osteotomy surface 309 and the robot 78 rotation axis is fixed. Since the gap balancer 8 and the prosthesis system use the same reference planes, the distal osteotomy plane 119 and the proximal osteotomy plane 129, and the reference lines, the connection line of the two first reference holes 113 and the connection line of the two second reference holes 123, the doctor can use any manual, robot 78 assisted surgical system and / or computer navigation system. The working method of robot 78 is existing technology. For details, please refer to US patent application US20210137613A1 "Method and system for robot 78-assisted surgery using customized osteotomy guide".

[0084] To date, gap balancing systems have focused on the extension / flexion gaps of the femoral 11 and tibial 12 components and the medial collateral ligament 13 / lateral collateral ligament 14. In addition, as part of total knee and patellofemoral replacement surgery, the patella is also osteotomized and replaced with a button-like polymer prosthesis that is similar in shape, thickness and size to the native bone. Fig. 22 and Fig.23 The patella trial 9 is shown with its various degrees of freedom, three translations and three rotations.

[0085] Finally, see Fig. 22 and Fig.23 The above-mentioned gap balancing system also includes a patellar test mold 9 for replacing the patella, a triaxial load sensor 91 is arranged in the patellar test mold 9, the patellar test mold 9 includes a dome-shaped surface 92, a base plate 93 and at least two groups of positioning pins 94, a PCB board 95 is arranged inside the patellar test mold 9, and the triaxial load sensor 91 is composed of a plurality of variable beams, the center of the variable beam is a round block 96, and at least one group of load sensors is installed on each beam, and a shell 97 is arranged on the outer side of the plurality of groups of variable beams, and at least one group of pillars 98 is installed on the shell 97. The balance of the patellofemoral joint is also crucial to eliminate patellar pain and looseness, and improve clinical efficacy and prosthesis survival rate. In order to balance the patellofemoral joint, a triaxial load sensor 91 is embedded in the patellar test mold 9 to provide load and gap information. The patellar test mold 9 includes a dome-shaped surface 92, a base plate 93 and two or more positioning pins 94. Resection Fig. 22After preparing the patella, one or more nail holes are drilled in the distal bone using a template. The position and depth of the nail holes are predetermined based on the osteotomy plane. The nails are passed through the patella trial mold 9 and inserted into the corresponding holes on the patella to provide a reference for position and direction, and then fixed with bone cement or non-bone cement.

[0086] Inside the patella trial mold 9 is a triaxial load sensor 91 and an electronic component PCB board 95. The triaxial load sensor 91 consists of 4 or more deformable beams. The center of these beams is a round block 96, which is defined as the origin of the three axes x, y, and z. On each beam, along each axis x, y, and z, one or more load sensors are installed. The force F and inertia M can be calculated using the measurements of these sensors. Through the PCB board 95, these beams are attached to a rectangular or circular housing 97 on the base plate 93. One or more pillars 98 attached to the round block 96 can sense any load from the patella trial mold 9 prosthesis during the trial mold. The patella trial mold 9 prosthesis can be disposable or reusable and may or may not contain any battery power supply. Real-time measurement data from the load sensor is wirelessly transmitted to Fig.26 Based on real-time measurements and physician preference, the following knee motions can be optimized for each patient using a variety of patellar trial 9 prosthesis sizes and shapes.

[0087] Figure 24 to Figure 26 is an example of a total knee gap dynamic balancing system for all three compartments: medial, lateral, and patellofemoral. Similar balancing systems can also be developed for unicompartmental, bicompartmental, or patellofemoral replacement surgeries. Ideally, the shape and specifications of the trial prosthesis are identical to the design of the prosthesis that will be implanted. This will ensure that the measured data is as close as possible to the final data after the prosthesis is implanted. After all initial osteotomies including the patella are completed using the osteotomy guide, the first tensioning device 4 or the mechanical tensioner 2 can measure the gaps and loads of the ligaments of all compartments, either individually or together, with the aid of the knee gap dynamic balancing system. In one embodiment, the first thin plate 61 and the vertical plate 64, the horizontal plate 65, and the femoral component are replaced by a standard or customized approximate shape. The knee gap dynamic balancing system can be used to measure and adjust data in real time before subsequent osteotomies. Depending on the surgeon's preference, the expected position and orientation of the prosthesis can be recorded, wirelessly transmitted to the robot 78, or displayed on a computer monitor, such as Fig.26 As described above, the extension gap 200 and the flexion gap 300 may be symmetrical or asymmetrical, depending on the surgeon's preference and the prosthesis design. Fig.25The measurement of the medial flexion gap 301 and the lateral flexion gap 302 is shown separately when the internal and external rotation I / E is fixed at 0°. To obtain a symmetrical flexion gap 300, the mechanical tensioner 2 can rotate the femur 11 around the center while stretching the medial collateral ligament 13 and the lateral collateral ligament 14. At the same time, the extension and flexion of the femoral 11 component can be adjusted. Finally, the patellar trial mold 9 can be used to measure and adjust the shape and size of the patellar prosthesis to achieve optimal knee balance.

[0088] at last, Fig.26 A gap balancer 8 for balancing the extension gap 200 of the inner chamber is described. The gap balancer 8 includes an electric actuator 81. The output end of the electric actuator 81 is fixedly connected to a vertical lead screw 82. The vertical lead screw 82 is used to drive a set of mechanical tensioners 2 for balancing the extension gap 200 of the inner chamber. For simplicity, after pressing the button of the electric actuator 81, the vertical lead screw 82 and the mechanical tensioner 2 are driven. The mechanical tensioner 2 can be a hinged jack for adjusting the extension inner gap 201. The vertical lead screw 82 can be a planetary gear or a worm gear to increase the torque loaded on the jack. Fig.26 As shown, the measurement data can be displayed on a digital display on an LED or electric actuator 81, or can be transmitted to a computer via wired or wireless means such as Bluetooth, wireless network, cellular or serial communication. The surgical planning software can display the initial position and orientation of the prosthesis, the measured values ​​of the medial gap and the lateral gap, and the load data of the medial collateral ligament 13 and the lateral collateral ligament 14. Using a soft tissue analysis algorithm, the surgical planning software can calculate the optimal prosthesis position and orientation based on the surgeon's preference and the prosthesis design. The dual-axis robot 78 can adjust any position of the prosthesis in real time.

[0089] In this embodiment, Figure 7 As shown, the operation process of the present invention is: first, Figures 1 to 4 The custom osteotomy guides for the femur 11 and tibia 12 described in the foregoing are used to establish the distal osteotomy plane 119 and the proximal osteotomy plane 129, as well as the line from the two first reference holes 113. Then, using spacers of different thicknesses, such as prostheses or tissue tensioners for the femur 11 and tibia 12, a certain stress is applied, and the extension and flexion gaps are measured and recorded using the established initial reference. Next, using the same initial reference as the gap balancing system near the anteromedial side of the femur 11, the mounting fixture of the robot 78 is fixed to the bone, such as Fig.17 As shown. Using the same bone reference and measurement data as the gap balancing system, the robot 78 can adjust the osteotomy position, direction A / P, I / E, F / E and prosthesis specifications to obtain the desired extension and flexion gaps. The surgeon uses the robot 78 to assist the system in performing subsequent osteotomies on the femur 11, as shown. Fig.21As shown. In the final step, the physician verifies knee stability and range of motion using static or dynamic trial casts, with the goal of ensuring that extension and flexion gaps remain balanced throughout the knee's range of motion. Tibial 12 spacers of varying thickness can be used as tensioners to balance the medial collateral ligament 13 and lateral collateral ligament 14. In addition, patellar load sensors can be used to determine the forces acting on the patellofemoral joint, Fig.17 A more detailed description is given in .

[0090] The above specific embodiment is only an optional embodiment of the present invention. Based on the technical solution of the present invention and the relevant inspiration of the above embodiment, those skilled in the art can make various alternative improvements and combinations to the above specific embodiment.

Claims

1. A load and gap balancing system for knee replacement surgery, characterized in that: include: A knee joint (1), the knee joint (1) comprising a femur (11) and a tibia (12), wherein a medial collateral ligament (13) and a lateral collateral ligament (14) are connected between the femur (11) and the tibia (12); A first osteotomy guide (110) for removing a femur (11), wherein the first osteotomy guide (110) removes a portion of the femur (11) to form a distal osteotomy plane (119), and a femoral prosthesis (1000) is installed at the distal osteotomy plane (119); A second osteotomy guide (120) for removing a tibia (12), wherein the second osteotomy guide (120) removes a portion of the tibia (12) to form a proximal osteotomy plane (129), and a tibial prosthesis (2000) is installed on the proximal osteotomy plane (129); The resected portion of the femur (11) includes a first inner compartment (211) and a first outer compartment (212), the resected portion of the tibia (12) includes a second inner compartment (221) and a second outer compartment (222), the distal osteotomy plane (119) and the proximal osteotomy plane (129) form a rectangular expansion gap (200), and the rectangular expansion gap (200) includes an expansion medial gap (201) and an expansion lateral gap (202); A first tensioning device (4) for tensioning the ligament to measure the gap and load; In a 90-degree flexion state of the knee joint (1), the two groups of the first reference holes (113) establish a rotation reference line (3) for assisting in the resection of the posterior condyle to form a posterior condyle osteotomy surface (309), a flexion gap (300) is formed between the posterior condyle osteotomy surface (309) and the proximal osteotomy plane (129), the flexion gap (300) comprising a flexion medial gap (301) and a flexion lateral gap (302), and a second tensioning device (5) is provided between the posterior condyle osteotomy surface (309) and the proximal osteotomy plane (129); A second tensioning device (5) for measuring the flexion gap (300) of the inner and outer compartments separately; A tensioning mechanism (6) for tensioning the ligament to measure the gap and load; Multiple sets of mechanical tensioners (2); A rotation adjustment device (7) mounted on the femur (11) for ensuring the accurate positioning of the femoral prosthesis (1000); A patellar trial mold (9) for replacing the patella, used for measuring and adjusting the shape and size of the patellar prosthesis to achieve an optimal knee joint balance; A gap balancer (8) for balancing the medial compartment extension gap (200) is used to calculate optimal prosthesis position and orientation.

2. A load and gap balancing system in knee replacement surgery according to claim 1, characterized in that: The first osteotomy guide (110) comprises a first positioning plate (111) mounted on the femur (11), two groups of first drill bits (112) are arranged on the first positioning plate (111), the first drill bits (112) are fixedly connected to the distal end of the femur (11), the distal end of the femur (11) is provided with a first reference hole (113) matching with the first drill bit (112), a first guide plate (114) is mounted on the first positioning plate (111), a first guide groove (115) is arranged on the first guide plate (114), two groups of first pins (116) are arranged in the first guide plate (114), the first pins (116) are fixedly connected to the femur (11), the distal osteotomy plane (119) and the two groups of first reference holes (113) are used to determine three positions and three rotations of the femoral prosthesis (1000).

3. A load and gap balancing system in knee replacement surgery according to claim 2, characterized in that: The second osteotomy guide (120) includes a second positioning plate (121) mounted on the tibia (12), two groups of second drill bits (122) are arranged on the second positioning plate (121), the second drill bits (122) are fixedly connected to the proximal end of the tibia (12), the proximal end of the tibia (12) is provided with a second reference hole (123) matching with the second drill bit (122), a second guide plate (124) is mounted on the second positioning plate (121), a second guide groove (125) is arranged on the second guide plate (124), two groups of second pins (126) are arranged in the second guide plate (124), the second pins (126) are fixedly connected to the tibia (12), the proximal osteotomy plane (129) of the tibia (12) and the two groups of second reference holes (123) are used to determine three positions and three rotations of the tibial prosthesis (2000).

4. A load and gap balancing system in knee replacement surgery according to claim 3, characterized in that: The first tensioning device (4) comprises two groups of first support rods (41) rotatably connected, one end of the first support rod (41) is fixedly connected to a first handle (42), and one end of the first support rod (41) away from the first handle (42) is fixedly connected to a support plate (43), and the two groups of support plates (43) are located between the distal osteotomy plane (119) and the proximal osteotomy plane (129).

5. A load and gap balancing system in knee replacement surgery according to claim 4, characterized in that: The first tensioning device (4) further comprises a first distance sensor (44) installed near the first handle (42), first load sensors (45) are installed on both sets of the first support rods (41), and a locking mechanism (46) is also provided between the two sets of handles.

6. A load and gap balancing system in knee replacement surgery according to claim 5, characterized in that: The second tensioning device (5) comprises two groups of second support rods (51) which are rotatably connected, one end of the second support rod (51) is fixedly connected to a second handle (52), one end of the second support rod (51) away from the second handle (52) is fixedly connected to a right-angle support plate (53), and a visual mark (55) is provided on the right-angle support plate (53), and the other end of the second support rod (51) away from the second handle (52) is fixedly connected to a parallel support plate (54), the horizontal part of the right-angle support plate (53) and the parallel support plate (54) are inserted into the flexion gap (300), the right-angle support plate (53) is fixed to the distal osteotomy plane (119) by a fixing nail passing through the first reference hole (113), and the parallel support plate (54) is fixed to the proximal osteotomy plane (129) by a fixing nail passing through the second reference hole (123).

7. A load and gap balancing system in knee replacement surgery according to claim 6, characterized in that: The tensioning mechanism (6) comprises a first thin plate (61), on which two groups of first fixing nails (62) are installed, and the first fixing nails (62) are installed in the first reference hole (113); a rotating hinge (63) is provided at the center of the first thin plate (61), and an angle sensor is installed at the position of the rotating hinge (63); a T-shaped plate is connected to the rotating hinge (63), and the T-shaped plate comprises a vertical plate (64) rotatably connected to the rotating hinge (63), and the end of the vertical plate (64) away from the rotating hinge (63) is fixedly connected to a horizontal plate (65); and a second thin plate (66) is also included, on which two groups of second fixing nails (67) are installed, and the second fixing nails (67) are installed in the second reference hole (123); and a second distance sensor (68) is installed at the position of the first fixing nail (62).

8. A load and gap balancing system in knee replacement surgery according to claim 7, characterized in that: The rotation adjustment device (7) comprises a fixed arm (71), on which two groups of third pins (72) are installed, and the third pins (72) are installed in the first reference hole (113). The fixed arm (71) is L-shaped, and the fixed arm (71) is also provided with a third drill bit (73), and the third drill bit (73) is inserted into the inner side of the femur (11) parallel to the distal osteotomy plane (119). A distal compensation (74) is provided on the side of the fixed arm (71) close to the femur (11). A mounting block (75) is installed on the third drill bit (73), and a screw (76) is threadedly connected to the mounting block (75). A splint (77) is rotatably connected to the screw (76). A robot (78) is installed on the side of the splint (77), and a positioner (79) is connected to the robot (78), and a knife groove (710) is provided on the positioner (79).

9. A load and gap balancing system in knee replacement surgery according to claim 8, characterized in that: A triaxial load sensor (91) is arranged in the patella test mold (9), the patella test mold (9) comprises a dome-shaped surface (92), a base plate (93) and at least two groups of positioning pins (94), a PCB board (95) is arranged inside the patella test mold (9), the triaxial load sensor (91) is composed of a plurality of variable beams, the center of the variable beams is a round block (96), at least one group of load sensors is installed on each beam, a shell (97) is arranged on the outer side of the plurality of groups of variable beams, and at least one group of pillars (98) is installed on the shell (97).

10. A load and gap balancing system in knee replacement surgery according to claim 9, characterized in that: The gap balancer (8) comprises an electric actuator (81), the output end of the electric actuator (81) is fixedly connected to a vertical lead screw (82), and the vertical lead screw (82) is used to drive a set of mechanical tensioners (2).

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