Positioning module for assisting distal femur extramedullary positioning

Abstract

A positioning module for assisting in extramedullary positioning of the distal femur is characterized in that the positioning module at least comprises an extension rod, the extension rod is provided with a positioning groove, the positioning groove is slidably connected with a positioning block, the positioning block is telescopically connected with a positioning rod, and the bottom surface of the positioning rod is a plane. The positioning module for assisting in extramedullary positioning of the distal femur is easy to manufacture, low in cost and convenient and fast to operate.

Description

Technical Field

[0001] The utility model relates to the technical field of medical devices, in particular to a positioning module used for assisting the extramedullary positioning of the distal femur in orthopedic total knee replacement surgery. Background Art

[0002] Total knee arthroplasty (TKA) is an effective method for treating end-stage knee osteoarthritis (KOA). Before the operation, the valgus and valgus angles of the joint will be carefully measured based on conventional X-ray anteroposterior and lateral knee joint films to provide a basis for osteotomy during the operation. During the operation, osteotomy will be performed on the distal femur and tibial plateau at the knee joint to maintain or reconstruct the normal force line of the lower limb, so that the stress distribution of the prosthesis fixation interface can be uniform and the physiological balance of the knee ligament force can be restored. During the operation, tibial plateau osteotomy is relatively easy to perform. Therefore, the success or failure of distal femoral osteotomy is one of the important factors determining the postoperative effect.

[0003] Figure 1 is a schematic diagram of the structural principle of the femoral reference line; see Figure 1 As shown, the femoral anatomical axis is the line A running through the center of the femoral medullary cavity. The femoral mechanical axis (usually collinear with the femoral force line) is the line M running from the center of the femoral head to the midpoint of the distal femur (it can also be defined as the line running from the intersection of the femoral anatomical axis and the intercondylar notch to the center of rotation of the femoral head). Figure 2 is a schematic diagram of the side view of the femur, see Figure 2 As shown, although the femoral anatomical axis A itself has a certain curvature, the femoral anatomical axis A near the distal end of the femur is approximately a straight line, so existing distal femoral osteotomies all utilize this feature. Figure 3 This is a schematic diagram of the structural principle after distal femoral osteotomy; AM in the figure represents the plane where the femoral mechanical axis and femoral anatomical axis are located near the distal femur. Figures 1 to 3 As shown in the figure, during the distal femoral osteotomy, the femoral intramedullary positioning osteotomy method is routinely used, which usually includes three main steps:

[0004] Step 1: Preoperative imaging planning: obtain the femoral valgus angle data through anteroposterior X-ray measurement; obtain the angle between the femoral mechanical axis in the sagittal plane and the anatomical axis of the distal femur through lateral X-ray measurement.

[0005] The second step is to determine the distal femoral valgus angle according to the femoral valgus angle obtained before surgery, that is, Figure 1 and Figure 3 The position of the distal femoral osteotomy surface is shown in the figure, and the osteotomy is performed using the intramedullary positioning osteotomy tool.

[0006] The third step is to refer to the angle between the femoral mechanical axis and the distal femoral anatomical axis obtained from the sagittal plane X-ray before surgery, and the position of the anterior femoral cortex (usually a positioning needle is used to achieve point positioning at the cortex), and determine the distal femoral flexion and extension osteotomy angle, that is, Figure 3 The positional relationship of the four osteotomy surfaces (i.e., the anterior femoral condyle, posterior femoral condyle and anterior and posterior chamfers) connected to the distal femoral osteotomy surface is determined, and the distal femoral osteotomy surface is used as the installation positioning reference, and osteotomy is performed using the osteotomy plate.

[0007] It can be seen from the above steps that the key to the success of the distal femoral osteotomy operation using conventional intramedullary positioning osteotomy tools lies in whether the distal femoral osteotomy surface meets the accuracy requirements. On the one hand, whether the distal femoral osteotomy surface is perpendicular to the plane where the femoral mechanical axis and the femoral anatomical axis are located, and on the other hand, whether the distal femoral osteotomy surface is perpendicular to the femoral force line (when using the intramedullary positioning method, it is to ensure that the distal femoral osteotomy surface is perpendicular to the femoral mechanical axis).

[0008] Femoral osteotomy methods in knee replacement surgery include intramedullary positioning and extramedullary positioning. The intramedullary positioning method requires that the intramedullary positioning rod be inserted into the femoral medullary cavity (ensuring that the positioning base is coaxial with the femoral anatomical axis) and that the medullary cavity be expanded, which will also destroy the medullary cavity structure and increase medullary cavity bleeding. The adipose tissue in the medullary cavity may enter the blood vessels due to increased pressure, and there is a risk of embolism and pulmonary embolism after circulation. The tools used in the common extramedullary positioning method need to refer to the proximal end of the femur during use, such as a knee replacement femoral extramedullary positioning device provided by Chinese patent CN104027190B, and a knee replacement intramedullary extramedullary positioning device provided by Chinese patent CN111904616B. Therefore, the intraoperative positioning process is still relatively cumbersome.

[0009] In view of the shortcomings of the above-mentioned existing positioning methods, the inventor team submitted a utility model patent application with application number 202210141523.2 and utility model name "Extramedullary Positioning Tool and Positioning System for Distal Femur" on February 16, 2022. In this technical solution, refer to the record in paragraph

[0041] of its public text, by adjusting the fourth rod and the fifth rod to contact the two sides of the femur respectively, and ensuring that the first rod is located between the fourth rod and the fifth rod, it can be determined that the first rod 1 is coaxial with the anatomical axis of the distal femur, thereby facilitating the determination of the precise osteotomy angle. However, since this technical solution requires the fourth rod and the fifth rod to contact the two sides of the femur respectively, the wound during the operation must be large enough to provide sufficient operating space, which will also have a certain impact on the patient's postoperative wound recovery.

[0010] Through long-term surgical practice, the inventor team found that the cortex of the femoral condyle trochlear cartilage that migrates to the femoral shaft area (that is, the outer surface of the femoral shaft near the end of the trochlear cartilage) is approximately flat, and the cortex of the femoral condyle trochlear cartilage that migrates to the femoral shaft area is similar to the Figure 3 The plane formed by the mechanical axis of the femoral shaft and the anatomical axis of the femoral shaft is parallel. According to the surgical principle, artificial knee replacement surgery requires that the distal femoral osteotomy surface is parallel to the plane formed by the mechanical axis of the femoral shaft and the anatomical axis of the femoral shaft. Figure 3 The plane formed by the mechanical axis of the femoral shaft and the anatomical axis of the femoral shaft is vertical and perpendicular to the femoral force line, but in the existing surgical techniques, it is impossible to accurately locate the plane formed by the mechanical axis of the femoral shaft and the anatomical axis of the femoral shaft during the operation. Therefore, the inventor team took into account the characteristics of using the part of the cortex of the femoral condylar trochlear cartilage that migrates to the femoral shaft area to be parallel to the plane formed by the mechanical axis of the femoral shaft and the anatomical axis of the femoral shaft to determine the correct sagittal plane for distal femoral osteotomy. And in the invention application "A device for positioning the distal femur and a method of use" submitted on the same day as the present application, a complete set of new devices for positioning the distal femur extramedullary is provided. Since the entire set of surgical operation ideas and devices are newly designed by the inventor team, in order to better protect the product, the inventor team focuses on the "positioning module", one of the innovative points of the aforementioned entire set of devices, in this utility model application to explain and protect it. Utility Model Content

[0011] The technical problem to be solved by the utility model is to provide a positioning module for assisting the extramedullary positioning of the distal femur, so as to reduce or avoid the above-mentioned problems.

[0012] The utility model provides a positioning module for assisting the extramedullary positioning of the distal femur, which comprises at least one extension rod, the extension rod is provided with a positioning groove, the positioning groove is slidably connected to a positioning block, the positioning block is telescopically connected to a positioning rod, and the bottom surface of the positioning rod is a plane.

[0013] Preferably, the positioning block is an integrally formed rectangular block that can be sleeved on the extension rod and slide, and the positioning block and the extension rod are clearance-fitted.

[0014] Preferably, the positioning block is assembled by a first positioning portion and a second positioning portion rotatably connected to the first positioning portion, the first positioning portion is provided with a first connecting groove for sleeved on the extension rod and a vertical side wall portion for connecting to the second positioning portion, the second positioning portion includes a raised connecting portion and a flat plate portion, the raised connecting portion and the vertical side wall portion are connected by a pin shaft with an interference fit.

[0015] Preferably, the positioning block is provided with a limiting guide hole for limiting and guiding the positioning rod, and the positioning rod and the limiting guide hole are clearance-fitted.

[0016] Preferably, the cross-sectional shape of the positioning rod matches the limiting guide hole, and is rectangular, circular or waist-shaped, and the area of ​​the bottom surface of the positioning rod is 1 square centimeter.

[0017] Preferably, the positioning module is provided with a door-shaped connecting rod perpendicular to the extension rod.

[0018] Preferably, the positioning module is provided with a mounting plate connected to the extension rod, the bottom surface of the mounting plate and the bottom surface of the extension rod are in the same plane, and a connecting pin for connecting to the rotating platform is provided at the bottom of the mounting plate.

[0019] Preferably, the positioning module is provided with a vertical insert connected to the extension rod for inserting into the osteotomy knife guide groove of the osteotomy module.

[0020] The positioning module for assisting the extramedullary positioning of the distal femur provided by the utility model has a simple structure, is easy to manufacture, has a low cost, and is convenient and quick to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The following drawings are only intended to illustrate and explain the present invention, and do not limit the scope of the present invention.

[0022] Figure 1 It is a schematic diagram of the structural principle of the femoral reference line;

[0023] Figure 2 is a schematic diagram of the side view of the femur;

[0024] Figure 3 This is a schematic diagram of the structural principle after distal femoral osteotomy;

[0025] Figure 4 It is a schematic diagram of the principle of three-dimensional decomposition structure of a positioning module for assisting the extramedullary positioning of the distal femur according to a specific embodiment of the utility model;

[0026] Figure 5 for Figure 4 Schematic diagram of the three-dimensional decomposition structure principle of the positioning block;

[0027] Figure 6 for Figure 5 A schematic diagram of the B-direction structural principle of the first positioning portion;

[0028] Figure 7 for Figure 4 Schematic diagram of the enlarged structural principle of the rotating platform;

[0029] Figure 8 for Figure 7 Schematic diagram of the C-direction structural principle of the positioning slider;

[0030] Fig. 9 for Figure 7 A schematic diagram of the structural principle of a rotating platform of an improved embodiment based on the present invention;

[0031] Fig.10 for Figure 4 A schematic diagram of a partially exploded structural principle of an improved embodiment based on the present invention;

[0032] Fig.11 for Figure 4 A schematic diagram of the partial three-dimensional decomposition structure principle of another improved embodiment based on the present invention. DETAILED DESCRIPTION

[0033] In order to have a clearer understanding of the technical features, purposes and effects of the present utility model, the specific implementation methods of the present utility model are now described with reference to the accompanying drawings.

[0034] Figure 1 It is a schematic diagram of the structural principle of the femoral reference line; Figure 1 The circle in the figure indicates the location where the femoral condylar trochlear cartilage migrates to the cortex of the femoral shaft area. Figure 2 is a schematic diagram of the side view of the femur; Figure 3 This is a schematic diagram of the structural principle after distal femoral osteotomy; Figure 4 FIG. 1 is a schematic diagram of a three-dimensional decomposition structure principle of a positioning module for assisting the extramedullary positioning of the distal femur according to a specific embodiment of the utility model; see Figures 1 to 4 As shown, the inventor team provided a distal femoral extramedullary positioning device in the technical proposal of the invention application "A distal femoral extramedullary positioning device and use method" submitted on the same day as the present application, which includes a base 1, and a rotating platform 2 detachably connected to the base 1, an osteotomy module 3 and a positioning module 4.

[0035] The base 1 includes a reference plate 11 and a support plate 12 perpendicular to the reference plate 11. The planes where the central axis (i.e., symmetry axis) of the reference plate 11 and the central axis (i.e., symmetry axis) of the support plate 12 are located are perpendicular to the reference plate 11 and the support plate 12 respectively. The reference plate 11 is used to fit with the distal end of the femur, and after adjusting the position, it can ensure that the side of the reference plate 11 that fits with the distal end of the femur can coincide with the plane perpendicular to the plane formed by the femoral mechanical axis and the femoral anatomical axis where the femoral condyle tangent is located, so that a reference for intercepting the distal femoral osteotomy surface can be provided to the osteotomy module 3. The base 1 can be modified on the basis of the existing intramedullary positioning module, that is, the base 1 only needs to provide the reference plate 11 and the support plate 12 perpendicular to the reference plate 11. The function of the support plate 12 is to provide a connection foundation with the rotating platform 2, the osteotomy module 3 and the positioning module 4.

[0036] When the reference plate 11 is made of a metal material with good hardness, a smaller thickness (e.g., 2-3 mm) can be set. The reference plate 11 can be a rectangular plate with four corners at rounded transition angles, or a U-shaped plate similar to the existing commonly used intramedullary osteotomy tools, as long as it can ensure that the side that fits the distal end of the femur has sufficient coverage. The support plate 12 is used to connect with other modules, so it needs to have a certain thickness to ensure that there is enough space to set the connection structure. For example, Figure 4 In the illustrated embodiment, the support plate 12 designed by the inventor's team is provided with a pin hole 121 for rotatably connecting with the rotating platform 2 via a pin 122. That is to say, in the case of only one connecting hole structure, the thickness of the support plate 12 only needs to ensure the verticality and connection stiffness of the pin 122.

[0037] The rotating platform 2 is used to provide a rotatable platform coaxial with the supporting plate 12 of the base 1 (the axis of rotation is on the central axis of the supporting plate 12), see Figure 4 As shown, in Figure 4 In the embodiment, the rotating platform 2 is a newly designed structure by the inventor team, which can be made of a steel plate with a thickness of 10 mm, so that the heavier weight can ensure the fit with the support plate 12. It is rotatably connected to the support plate 12 through a pin 122, so that the rotation angle of the rotating platform 2 and the support plate 12 can be adjusted relatively easily (that is, the angle that can make the distal femoral osteotomy surface and the femoral force line form a perpendicular relationship), and the rear end of the support plate 12 is provided with an arc-shaped protrusion 123 corresponding to the pin hole 121, and the arc-shaped protrusion 123 is provided with a plurality of scale grooves spaced one degree apart from each other.

[0038] Figure 7 for Figure 4 Schematic diagram of the enlarged structural principle of the rotating platform; Figure 8 for Figure 7 Schematic diagram of the C-direction structure principle of the positioning slider; see Figure 7 and Figure 8As shown, the rotating platform 2 is provided with a positioning slider 21 that can be connected by a spring (not shown in the figure). Specifically, the positioning slider 21 can be prepared from a metal rod with a rectangular cross-section. The rotating platform 2 is provided with a U-shaped guide frame 22. The U-shaped guide frame 22 is provided with a guide hole 221. The rotating platform 2 is provided with a limiting hole 222 corresponding to the guide hole 221. The positioning slider 21 is provided with a wedge-shaped portion 211 for engaging with the scale groove, and an assembly through hole 212 for inserting a pin (not shown in the figure). During assembly, the end of the positioning slider 21 provided with the assembly through hole 212 is first inserted into the guide hole 221, and then a spring (not shown in the figure) is inserted into the positioning slider 21 from the inner side of the U-shaped guide frame 22, and then a pin is inserted into the assembly through hole 212. The elastic force of the spring between the pin and the U-shaped guide frame 22 can be utilized so that the wedge-shaped portion 211 can be inserted into the scale groove of the arc-shaped protrusion 123 when no external force is applied. When the rotation angle needs to be adjusted, the positioning slider 21 can be pulled outward, adjusted to the right position, and then released. The wedge-shaped portion 211 can be inserted into the corresponding scale groove under the action of the spring force to fix the rotation angle. In this way, the rotation angle of the rotating platform 2 relative to the reference plate 11 can be accurately set by the positioning slider 21.

[0039] Of course, the rotating platform 2 can also be modified using an existing intramedullary or extramedullary angle adjustment device, as long as the rotating part of the rotating platform 2 can accurately rotate relative to the support plate 12 after the modification. For example, the rotating structure in the prior application 202210141523.2 of the inventor team mentioned in the background technology. Those skilled in the art should understand that when using an existing intramedullary or extramedullary angle adjustment device for modification, the existing angle adjustment device will generally also include a fixed part and a rotating part, such as the femoral intramedullary positioning valgus angle adjustment device of Johnson & Johnson (China) Medical Devices Co., Ltd. Then, it is only necessary to connect the fixed part of the existing angle adjustment device to the support plate 12, and then ensure that the rotation axis of the rotating part of the existing angle adjustment device is located in the plane where the central axis of the reference plate 11 and the central axis of the support plate 12 are located, so as to ensure accurate adjustment of the rotation angle.

[0040] The osteotomy module used to cut the "distal femoral osteotomy surface" in the existing intramedullary tool set has mature technologies in its osteotomy knife guide groove, positioning hole and other structures, such as the distal femoral osteotomy module of Johnson & Johnson (China) Medical Devices Co., Ltd. Therefore, the osteotomy module 3 in the technical solution of the present utility model can be modified on the basis of the existing osteotomy module. Generally speaking, the existing osteotomy modules mostly use a two-link structure to connect with the rotating platform. Then the osteotomy module 3 in the present application can be that only the connecting rod part of the osteotomy module in the common tool set is shortened, and it can only be connected to the rotating platform 2 in a pluggable or fixed manner. After the reference plate 11 is positioned by the positioning module 4, it can be ensured that the plane guided by the osteotomy knife guide groove is the plane formed by the mechanical axis of the femoral shaft and the anatomical axis of the femoral shaft (that is, Figure 1 and Figure 3 The AM plane shown in the figure shall be perpendicular to the AM plane.

[0041] Fig. 9 for Figure 7 A schematic diagram of the structural principle of a rotating platform of an improved embodiment based on FIG. Fig. 9 As shown, in an improved embodiment, the front end surface of the rotating platform 2' can be set to an arc shape, which can better avoid interference with the patient's femur during use. In addition, the hole of the rotating platform 2' used to connect with the support table 12 can be closer to the front end surface, which can maintain more structural setting space for connection structure settings with other modules, such as the osteotomy module 3 or the positioning module 4.

[0042] The positioning module 4 is used to utilize Figure 1 The "femoral condylar trochlear cartilage migrates to the cortex of the femoral shaft area" shown in the figure ensures that the side of the reference plate 11 that fits the distal end of the femur can coincide with the plane perpendicular to the plane formed by the femoral mechanical axis and the femoral anatomical axis where the femoral condyle tangent is located. Specifically, the positioning module 4 includes at least one extension rod 41, and the extension rod 41 is provided with a positioning groove 42. The positioning groove 42 is slidably connected to a positioning block 43, and the positioning block 43 is telescopically connected to a positioning rod 44, and the bottom surface of the positioning rod 44 is a plane.

[0043] The biggest difference between the present invention and the prior art is that the inventor team found through long-term surgical practice that the cortex of the femoral condyle trochlear cartilage that migrates to the femoral shaft area (that is, the outer surface of the femoral shaft near the end of the trochlear cartilage) is approximately flat, and the cortex of the femoral condyle trochlear cartilage that migrates to the femoral shaft area is similar to the Figure 3 The plane formed by the mechanical axis of the femoral shaft and the anatomical axis of the femoral shaft is parallel. According to the surgical principle, artificial knee replacement surgery requires that the distal femoral osteotomy surface is parallel to the plane formed by the mechanical axis of the femoral shaft and the anatomical axis of the femoral shaft. Figure 3The plane formed by the mechanical axis of the femoral shaft and the anatomical axis of the femoral shaft is vertical and perpendicular to the femoral force line, but in existing surgical techniques, it is impossible to accurately locate the plane formed by the mechanical axis of the femoral shaft and the anatomical axis of the femoral shaft during surgery. Therefore, the inventor team took into account the characteristics of utilizing the part of the cortex of the femoral condyle trochlear cartilage that migrates to the femoral shaft area and is parallel to the plane formed by the mechanical axis of the femoral shaft and the anatomical axis of the femoral shaft to determine the correct sagittal plane for distal femoral osteotomy. The positioning module 4 is connected to the base 1 through the extension rod 41. By ensuring that the extension rod 41 is parallel to the support plate 12, it can be ensured that the extension rod 41 is perpendicular to the reference plate 11. In this way, as long as the positioning rod 44 can be ensured to be perpendicular to the extension rod 41, the degree of fit between the bottom surface of the positioning rod 44 and the "femoral condylar trochlear cartilage migration to the cortex of the femoral shaft area" can be observed to determine whether the side of the reference plate 11 that fits the distal end of the femur coincides with the plane where the femoral condyle tangent is located and is perpendicular to the plane formed by the femoral mechanical axis and the femoral anatomical axis.

[0044] The extension rod 41 is used to provide an operating space located at the "femoral condylar trochlear cartilage migration to the cortex of the femoral shaft area", and by ensuring the parallelism of the extension rod 41 and the support plate 12, the parallelism of the positioning groove 42 and the positioning block 43 and the support plate 12 is ensured. The positioning groove 42 provides the positioning rod 44 with sufficient span space above the "femoral condylar trochlear cartilage migration to the cortex of the femoral shaft area", and the positioning block 43 is provided with a limited guide hole 433 for limiting the positioning rod 44. The positioning rod 44 can be made of metal material or hard resin material, and the positioning rod 44 and the limited guide hole 433 can be clearance fit. The cross-sectional shape of the positioning rod 44 matches the limited guide hole 433, and can be rectangular, circular or waist-shaped, etc., as long as it can ensure that the axis of the positioning rod 44 is perpendicular to the plane of the extension rod 41. The bottom surface area of ​​the positioning rod 44 can be set to about 1 square centimeter, so that it can have a smaller size and weight under the premise of ensuring the contact area with the "femoral condylar trochlear cartilage migrating to the cortex of the femoral shaft area". The positioning block 43 can be an integrally formed rectangular block that can be sleeved and slid on the extension rod 41. The positioning block 43 and the extension rod 41 can also be clearance-fitted.

[0045] Figure 5 for Figure 4 Schematic diagram of the three-dimensional decomposition structure principle of the positioning block; Figure 6 for Figure 5 Schematic diagram of the B-direction structure principle of the first positioning part; see Figure 5 and Figure 6As shown, in order to better ensure the fitting stability of the positioning block 43 with the extension rod 41 when it moves into place, the positioning block 43 can be assembled by a first positioning portion 431 and a second positioning portion 432 rotatably connected to the first positioning portion 431, the first positioning portion 431 is provided with a first connecting groove 4311 for sleeved on the extension rod 41 and a vertical side wall portion 4312 for connecting to the second positioning portion 432, the second positioning portion 432 includes a raised connecting portion 4321 and a flat plate portion 4322, and the raised connecting portion 4321 and the vertical side wall portion 4312 are connected by a pin with an interference fit. When it is necessary to adjust the position of the positioning block 43, it is only necessary to rotate the second positioning portion 432 so that the flat plate portion 4322 does not contact the bottom surface of the extension rod 41. In this way, the positioning block 43 is only connected to the extension rod 41 through the first connecting groove 4311, and the position of the positioning block 43 can be easily slid. When it is adjusted to the right position, it is only necessary to rotate the second positioning portion 432 so that the flat plate portion 4322 is tightly fitted with the bottom surface of the extension rod 41. In this way, the position of the positioning block 43 on the extension rod 41 can be stabilized, and the axis of the positioning rod 44 can be effectively guaranteed to be perpendicular to the plane of the extension rod 41.

[0046] The positioning module 4 can be connected to the base station 1 in a variety of ways. Figure 4 As shown, in a preferred embodiment, the positioning module 4 is provided with a gate-shaped connecting rod 45 perpendicular to the extension rod 41, and the osteotomy module 3 is provided with an assembly guide hole 31 for guiding the gate-shaped connecting rod 45. Figure 4In the technical solution, when used in surgery, the base 1, the rotating platform 2, the osteotomy module 3 and the positioning module 4 are first assembled in sequence, but the positioning rod 44 is not inserted first. The rotating platform 2 can be adjusted according to the femoral valgus angle data obtained by measuring the anteroposterior X-ray before the operation, so that the central axis of the osteotomy module 3 and the angle between the central axis of the extension rod 41 and the reference plate 11 are equal to the femoral valgus angle, and then the reference plate 11 is fitted with the distal end of the femoral condyle, the osteotomy module 3 is fitted with the upper end of the femoral condyle, and the position of the positioning block 43 is adjusted along the positioning groove 42 so that the positioning block 43 is located above the "femoral condyle trochlear cartilage migrates to the cortex of the femoral shaft area", and then the positioning rod 44 is inserted so that the positioning rod 44 falls on the "femoral condyle trochlear cartilage migrates to the cortex of the femoral shaft area". After that, the position of the reference plate 11 can be fine-tuned along the distal end of the femur on the premise of ensuring that the reference plate 11 and the osteotomy module 3 are in close contact with the femur, and the degree of contact between the bottom surface of the positioning rod 44 and the "femoral condyle trochlear cartilage migrates to the cortex of the femoral shaft area" is observed. If it is completely in close contact, it means that the bottom surface of the positioning rod 44 is parallel to the plane formed by the mechanical axis of the femur and the anatomical axis of the femur, which means that the side of the reference plate 11 that is in close contact with the distal end of the femur coincides with the plane perpendicular to the plane formed by the femoral condyle tangent and the anatomical axis of the femur. At this time, the osteotomy module 3 can be punched and fixed, and then the positioning module 4, the base 1 and the rotating platform 2 are disassembled, and the osteotomy module 3 can be used to perform distal femoral osteotomy.

[0047] Fig.10 for Figure 4 A schematic diagram of the partial three-dimensional decomposition structure principle of an improved embodiment based on the present invention; see Fig.10As shown, in an improved embodiment, the reference plate 11 is further provided with a mounting hole 111 for fixed connection with the femur, the positioning module 4' is provided with a mounting plate 46 connected with the extension rod 41, the bottom surface of the mounting plate 46 is in the same plane as the bottom surface of the extension rod 41, and the bottom of the mounting plate 46 is provided with a connecting pin for connecting with the rotating platform 2. When used during surgery, the base 1 and the rotating platform 2 are first assembled in sequence, and then the positioning module 4' is assembled on the rotating platform 2 through the mounting plate 46, without inserting the positioning rod 44 first, and the rotating platform 2 can be adjusted according to the angle data of the femoral condyle tangent and the femoral mechanical axis M obtained by preoperative anteroposterior X-ray measurement, so that when the reference plate 11 is perpendicular to the plane formed by the femoral shaft mechanical axis and the femoral shaft anatomical axis, and the femoral condyle tangent is located in the plane of the reference plate 11, the central axis of the rotating platform 2 can be parallel to the femoral mechanical axis M, and then the reference plate 11 is aligned with the rotation platform 2. The distal end of the femoral condyle is fitted, and the mounting plate 46 extends out of the bottom of the rotating platform 2 and fits with the upper end of the femoral condyle. The position of the positioning block 43 is adjusted along the positioning groove 42 so that the positioning block 43 is located above the "femoral condyle trochlear cartilage migrates to the cortex of the femoral shaft area", and then the positioning rod 44 is inserted so that the positioning rod 44 falls on the "femoral condyle trochlear cartilage migrates to the cortex of the femoral shaft area". After that, the reference plate 11 and the mounting plate 46 can be ensured to fit with the femur. On the premise of being completely fitted, the position of the reference plate 11 is finely adjusted against the distal end of the femur, and the degree of fit between the bottom surface of the positioning rod 44 and the "femoral condyle trochlear cartilage migrating to the cortex of the femoral shaft area" is observed. If it is completely fitted, it means that the bottom surface of the positioning rod 44 is parallel to the plane formed by the mechanical axis of the femur and the anatomical axis of the femur, which means that the side of the reference plate 11 that fits the distal end of the femur coincides with the plane perpendicular to the plane formed by the mechanical axis of the femur and the anatomical axis of the femur where the tangent of the femoral condyle is located. Afterwards, the reference plate 11 can be fixed to the distal end of the femur through the mounting hole 111, and then the positioning module 4' can be removed and replaced with the osteotomy module 3. Because the bottom surface of the osteotomy module 3 will coincide with the top surface of the rotation module 2, it means that the bottom surface of the osteotomy module 3 will fit with the upper end of the femoral condyle. At this time, the osteotomy module 3 can be positioned, and then the reference plate 11 and the rotation module 2 can be removed, and the distal femoral osteotomy can be performed through the osteotomy module 3.

[0048] Fig.11 for Figure 4A schematic diagram of the partial three-dimensional decomposition structure principle of another improved embodiment based on the present invention. In another improved embodiment, the positioning module 4'' is provided with a vertical insert 47 connected to the extension rod 41 for inserting into the osteotomy knife guide groove of the osteotomy module 3. By inserting the vertical insert 47 into the osteotomy knife guide groove of the osteotomy module 3, the horizontality of the extension rod 41 and the support plate 12 can also be ensured. The process of positioning the reference plate 11 during the operation is the same as that in the above two embodiments, so it will not be repeated here.

[0049] The method for using the positioning module for assisting the extramedullary positioning of the distal femur provided by the utility model can be performed in the following steps:

[0050] Step 1, assembling the base 1, the rotating platform 2, the positioning module 4 (4', 4'') and / or the osteotomy module 3 together, without placing the positioning rod 44, and then making the reference plate 11 fit the medial condyle and lateral condyle of the patient's femur at the same time, adjusting the positions of the reference plate 11 and the positioning block 43, so that the positioning block 43 is located above the "femoral condylar trochlear cartilage migration to the femoral shaft area";

[0051] As mentioned above, when the base 1 and the rotating platform 2 are combined and assembled, the rotating platform 2 can be adjusted according to the angle data between the femoral condyle tangent and the femoral mechanical axis M obtained by preoperative AP X-ray measurement, so that when the reference plate 11 is perpendicular to the plane formed by the femoral shaft mechanical axis and the femoral shaft anatomical axis, and the femoral condyle tangent is located in the plane of the reference plate 11, the central axis of the rotating platform 2 can be parallel to the femoral mechanical axis M.

[0052] After the reference plate 11 is fitted to the medial condyle and lateral condyle of the patient's femur at the same time, it means that the reference plate 11 is located on a section plane of the medial condyle and the lateral condyle, but this section plane is not guaranteed to be the plane where the femoral condyle tangent obtained by the AP X-ray measurement is located. At this time, the position of the positioning block 43 can be roughly fixed so that the positioning block 43 is located above the "femoral condyle trochlear cartilage migrates to the cortex of the femoral shaft area".

[0053] Step 2, inserting the positioning rod 44 into the positioning block 43, adjusting the reference plate 11 and / or the rotating platform 2, so that the bottom surface of the positioning rod 44 contacts the "cortex of the femoral condylar trochlear cartilage migrating to the femoral shaft area".

[0054] For a more accurate description of the operation process, see Figure 1 and Figure 3 As shown, in Figure 1 The dashed straight lines with arrows in the figure represent the "inside" and "outside" directions of the distal femur, that is, the directions toward the medial condyle and lateral condyle, respectively. Figure 3 The “anterior” and “posterior” directions of the distal femur are indicated by the dashed arc line with an arrow, wherein the “anterior” direction refers to the direction toward the patella.

[0055] The positioning rod 44 is clearance-matched with the limiting guide hole 433 of the positioning block 43 , so that the positioning rod 44 can slide in the limiting guide hole 433 relatively easily.

[0056] Since the reference plate 11 of the present invention is only fitted with the medial condyle and lateral condyle of the patient's femur at the same time, it does not need to use an intramedullary positioning rod for positioning like the existing intramedullary positioning tools. Figure 1 As shown, it is only necessary to adjust the position of the reference plate 11 in the "inward" and "outward" directions so that the bottom surface of the positioning rod 44 can be in contact with the "cortex of the femoral condylar trochlear cartilage migrating to the femoral shaft area".

[0057] Step 3, adjust the reference plate 11 (see Figure 3 The dotted arc line with arrows as shown in the figure indicates the "front" and "back" directions of the distal end of the femur), so that the bottom surface of the positioning rod 44 is completely in contact with the "cortex of the femoral condyle trochlea cartilage migrating to the femoral shaft area",

[0058] When the osteotomy module 3 is not installed and the reference plate 11 is provided with the mounting hole 111 (for example Fig.10 In the embodiment shown in the figure), the reference plate 11 can be fixed first, and then the positioning module 4 can be removed and replaced with the osteotomy module 3, and then the osteotomy module 3 can be fixed.

[0059] When the osteotomy module 3 is installed on the rotating platform 2 during the positioning process (for example Figure 4 and Fig.11 In the embodiment shown in the figure), the osteotomy module 3 can be directly fixed.

[0060] In this way, the osteotomy module 3 can be accurately positioned, and then the osteotomy operation can be performed.

[0061] As mentioned above, when the bottom surface of the positioning rod 44 is completely in contact with the "cortex of the femoral condylar trochlear cartilage migrating to the femoral shaft area", it means that the bottom surface of the positioning rod 44 is parallel to the plane formed by the femoral mechanical axis and the femoral anatomical axis. It also means that the side of the reference plate 11 that is in contact with the distal end of the femur coincides with the plane perpendicular to the plane formed by the femoral mechanical axis and the femoral anatomical axis where the femoral condyle tangent is located. In addition, because the angle of the rotating platform 2 is adjusted according to the angle data of the femoral condyle tangent and the femoral mechanical axis M obtained by the preoperative anteroposterior X-ray measurement, this position can ensure that the osteotomy working surface of the osteotomy module 3 is perpendicular to the plane formed by the femoral shaft mechanical axis and the femoral shaft anatomical axis, and perpendicular to the femoral force line.

[0062] The positioning module provided by the utility model is used to assist in the extramedullary positioning of the distal femur. The "femoral condylar trochlear cartilage migrates to the cortex of the femoral shaft area" to ensure that the side of the reference plate that fits the distal femur can coincide with the plane perpendicular to the plane formed by the femoral mechanical axis and the femoral anatomical axis where the femoral condyle tangent is located, so that an accurate reference for cutting the distal femoral osteotomy surface can be provided to the osteotomy module. The positioning module provided by the utility model is easy to manufacture, low in cost, and quick and easy to operate.

[0063] Those skilled in the art should understand that although the present invention is described in the form of multiple embodiments, not every embodiment contains only one independent technical solution. Such description in the specification is only for the sake of clarity. Those skilled in the art should understand the specification as a whole and regard the technical solutions involved in each embodiment as being able to be combined into different embodiments to understand the scope of protection of the present invention.

[0064] The above description is only an illustrative embodiment of the present invention and is not intended to limit the scope of the present invention. Any equivalent changes, modifications and combinations made by any technician in the field without departing from the concept and principle of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A positioning module for assisting the extramedullary positioning of the distal femur, characterized in that: It at least comprises an extension rod, the extension rod is provided with a positioning groove, the positioning groove is slidably connected to a positioning block, the positioning block is telescopically connected to a positioning rod, and the bottom surface of the positioning rod is a plane.

2. The positioning module for assisting the extramedullary positioning of the distal femur according to claim 1, characterized in that: The positioning block is an integrally formed rectangular block that can be sleeved on the extension rod and slide, and the positioning block and the extension rod are clearance-matched.

3. The positioning module for assisting the extramedullary positioning of the distal femur according to claim 1, characterized in that: The positioning block is assembled by a first positioning portion and a second positioning portion rotatably connected to the first positioning portion, the first positioning portion is provided with a first connecting groove for sleeved on the extension rod and a vertical side wall portion for connecting to the second positioning portion, the second positioning portion includes a raised connecting portion and a flat plate portion, the raised connecting portion and the vertical side wall portion are connected by a pin shaft with an interference fit.

4. The positioning module for assisting the extramedullary positioning of the distal femur according to claim 1, characterized in that: The positioning block is provided with a limiting guide hole for limiting and guiding the positioning rod, and the positioning rod and the limiting guide hole are clearance-matched.

5. The positioning module for assisting the extramedullary positioning of the distal femur according to claim 4, characterized in that: The cross-sectional shape of the positioning rod matches the limiting guide hole and is rectangular, circular or waist-shaped, and the area of ​​the bottom surface of the positioning rod is 1 square centimeter.

6. The positioning module for assisting the extramedullary positioning of the distal femur according to claim 1, characterized in that: The positioning module is provided with a door-shaped connecting rod perpendicular to the extension rod.

7. The positioning module for assisting the extramedullary positioning of the distal femur according to claim 1, characterized in that: The positioning module is provided with a mounting plate connected to the extension rod, the bottom surface of the mounting plate and the bottom surface of the extension rod are in the same plane, and the bottom of the mounting plate is provided with a connecting pin for connecting to the rotating platform.

8. The positioning module for assisting the extramedullary positioning of the distal femur according to claim 1, characterized in that: The positioning module is provided with a vertical insert connected to the extension rod for inserting into the osteotomy knife guide groove of the osteotomy module.

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