CN111467089A - Interchangeable Unicondylar Femoral Prosthesis System and Knee Joint System - Google Patents

Abstract

The invention relates to an interchangeable unicondylar femoral prosthesis system and a knee joint system. Wherein the interchangeable unicondylar femoral prosthesis system includes at least two types of femoral prostheses, wherein each type of femoral prosthesis includes an osteotomy surface for connecting with the femur and an articular surface for matching with the tibial pad , the osteotomy surface is provided with a fixing piece, the articular surface includes the posterior condyle articular surface, and the maximum distance from the fixing piece to the posterior condyle articular surface is recorded as the first distance, and the first distances of different types of femoral prostheses are the same. The above-mentioned interchangeable unicondylar femoral prosthesis system preserves more bone mass in patients, simplifies surgical procedures, reduces operation time, and reduces the probability of infection.

Description

Interchangeable Unicondylar Femoral Prosthesis System and Knee Joint System

technical field

The invention relates to the technical field of medical devices, in particular to an interchangeable unicondylar femoral prosthesis system and a knee joint system.

Background technique

Unicondylar replacement surgery uses a micro-traumatic incision and can preserve the anterior and posterior cruciate ligaments of the knee joint. It has the advantages of less trauma, quick recovery, and good postoperative physiological activity. Therefore, unicondylar replacement surgery is widely used in single-compartment. in the treatment of osteoarthritis. Unicondylar replacement requires the replacement of the patient's diseased femoral articular surface with a femoral prosthesis and the patient's diseased tibial articular surface with a tibial pad, thereby allowing the patient to obtain a new knee joint.

Before performing unicondylar replacement, the patient's femur needs to be osteotomized and drilled so that the articular surface of the femur can be matched and fixed with the femoral prosthesis. In hospitals, there are generally a series of femoral prostheses of different specifications. Doctors can choose the appropriate femoral prosthesis from the unicondylar femoral prosthesis system according to the femoral size of different patients, so as to ensure that the replaced knee joint prosthesis can maximize the Approach the patient's native knee joint, thereby enhancing the patient's postoperative experience. However, when the doctor needs to replace the femoral prosthesis of different sizes during the operation, the femur needs to be re-cut and drilled, resulting in more bone destruction of the patient. At the same time, due to the existence of the old installation hole, the integrity of the new drill hole will be affected, thereby affecting the postoperative stability of the femoral prosthesis. In addition, repeated osteotomy and drilling will increase the operation time and increase the probability of infection.

SUMMARY OF THE INVENTION

Based on this, it is necessary to provide an interchangeable unicondylar femoral prosthesis system and a knee joint system in order to avoid the problem of re-osteotomy and drilling of the patient when changing the prosthesis model during the operation.

An interchangeable unicondylar femoral prosthesis system comprising at least two types of femoral prostheses, each type of said femoral prosthesis including an osteotomy surface for connection with the femur and for mating with a tibial pad The articular surface, the osteotomy surface is provided with a fixing member, the articular surface includes the posterior condyle articular surface, and the maximum distance from the fixing member to the posterior condyle articular surface is recorded as the first distance. The first distances of the femoral prostheses are the same.

The above interchangeable unicondylar femoral prosthesis system maintains the same maximum distance between the fixator of different types of femoral prosthesis and the articular surface of the posterior condyle. The position is guaranteed to remain unchanged, so that when replacing different types of femoral prosthesis during the operation, there is no need to additionally perform osteotomy on the posterior condyle section and distal section of the femur, and no new drilling is required for the femoral installation hole. In order to preserve more bone mass in patients, simplify surgical procedures, reduce operation time, and reduce the probability of infection.

In one of the embodiments, each type of the femoral prosthesis is provided with at least two of the fixing pieces, and the distance between two adjacent fixing pieces is recorded as the second distance. The second distance of the femoral prosthesis is the same.

In one embodiment, the osteotomy surface includes a distal osteotomy surface, a posterior oblique osteotomy surface and a posterior condyle osteotomy surface that are connected at an included angle in sequence, and the at least two fixing members are both arranged on the distal end osteotomy surface. end of the osteotomy surface.

In one embodiment, in the direction away from the posterior condyle osteotomy surface, the heights of the two adjacent fixing pieces in the direction perpendicular to the distal osteotomy surface have an increasing trend.

In one of the embodiments, the direction of the center line of each of the fixing pieces forms an included angle with the direction of the vertical line of the distal osteotomy surface.

In one embodiment, the osteotomy surface includes a distal osteotomy surface, a posterior oblique osteotomy surface, and a posterior condyle osteotomy surface connected at an angle in sequence, and the articular surface further includes a distal articular surface and a posterior oblique surface. articular surface, the distal osteotomy surface is opposite to the distal articular surface, the posterior oblique osteotomy surface is opposite to the posterior oblique articular surface, and the posterior condylar osteotomy surface is opposite to the posterior condyle articular surface , the thickness from the distal osteotomy surface to the distal articular surface is recorded as the first thickness, and the thickness from the posterior condyle osteotomy surface to the posterior condyle articular surface is recorded as the second thickness. The first thickness of the femoral prosthesis is the same, and the second thickness of the femoral prosthesis of different sizes is the same.

In one of the embodiments, the second thickness is greater than the first thickness.

In one embodiment, the length of the posterior oblique osteotomy surface on the midsagittal plane is recorded as the first length, and the first lengths of the femoral prostheses of different sizes are the same.

In one embodiment, the osteotomy surface includes a distal osteotomy surface, a posterior oblique osteotomy surface, and a posterior condyle osteotomy surface that are connected at an angle in sequence, wherein the plane where the distal osteotomy surface is located is the same as the The plane on which the osteotomy surface of the posterior condyle is located is vertical or approximately vertical, and the angle between the posterior oblique osteotomy surface and the distal osteotomy surface and the angle between the posterior oblique osteotomy surface and the distal end The included angles between the osteotomy surfaces are equal.

A knee joint system includes the interchangeable unicondylar femoral prosthesis system as described above and a tibial pad, the tibial pad being matched with the femoral prosthesis.

The above-mentioned knee joint system keeps the same maximum distance from the fixator of different types of femoral prosthesis to the articular surface of the posterior condyle. When replacing different types of femoral prostheses during surgery, there is no need to perform additional osteotomy on the posterior condyle section and distal section of the femur, and there is no need to make new drilling for the femoral installation hole, thus saving more bone in the patient. It can simplify the operation steps, reduce the operation time, and reduce the probability of infection.

Description of drawings

The accompanying drawings constituting a part of the present application are used to provide further understanding of the present invention, and the exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention.

In order to illustrate the technical solutions in the embodiments of the present invention more clearly, the following briefly introduces the accompanying drawings used in the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained from these drawings without creative effort.

1 is a schematic structural diagram of a type of unicondylar femoral prosthesis of an interchangeable unicondylar femoral prosthesis system according to an embodiment;

2 is a schematic diagram of the comparison of different types of femoral prostheses of an interchangeable unicondylar femoral prosthesis system according to an embodiment;

FIG. 3 is a cross-sectional comparison diagram of different types of femoral prostheses shown in FIG. 2;

4 is a schematic cross-sectional view of a femur of an embodiment;

5 is a schematic diagram of the cooperation between a femoral prosthesis and a femur according to an embodiment;

6 is a schematic diagram of the cooperation between the femoral prosthesis and the femur according to another embodiment;

7 is a schematic diagram of the cooperation between the femoral prosthesis and the femur according to another embodiment;

FIG. 8 is a cross-sectional comparison view of different types of femoral prostheses according to another embodiment.

Description of reference numbers:

10, osteotomy surface; 11, distal osteotomy surface; 12, posterior oblique osteotomy surface; 13, posterior condyle osteotomy surface; 20, articular surface; 21, distal articular surface; 22, posterior oblique articular surface; 23 , articular surface of posterior condyle; 30, fixing piece; 31, first fixing piece; 32, second fixing piece; 40, femur; 41, distal section; 42, posterior oblique section; 43, posterior condyle section; 44, installation hole.

Detailed ways

In order to make the above objects, features and advantages of the present invention more clearly understood, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", " Back, Left, Right, Vertical, Horizontal, Top, Bottom, Inner, Outer, Clockwise, Counterclockwise, Axial , "radial", "circumferential" and other indicated orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying the indicated device or Elements must have a particular orientation, be constructed and operate in a particular orientation and are therefore not to be construed as limitations of the invention.

In addition, the terms "first" and "second" are only used for descriptive purposes, and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, a feature delimited with "first", "second" may expressly or implicitly include at least one of that feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise expressly and specifically defined.

In the present invention, unless otherwise expressly specified and limited, the terms "installed", "connected", "connected", "fixed" and other terms should be understood in a broad sense, for example, it may be a fixed connection or a detachable connection , or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between the two elements, unless otherwise specified limit. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

In the present invention, unless otherwise expressly specified and limited, a first feature "on" or "under" a second feature may be in direct contact between the first and second features, or the first and second features indirectly through an intermediary touch. Also, the first feature being "above", "over" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is level higher than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature has a lower level than the second feature.

It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or an intervening element may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for the purpose of illustration only and do not represent the only embodiment.

Specifically, referring to FIGS. 1-3 , an interchangeable unicondylar femoral prosthesis system according to an embodiment includes at least two types of femoral prostheses, wherein each type of femoral prosthesis includes a cross section for connecting with the femur 40 . The bone surface 10 and the articular surface 20 for cooperating with the tibial pad, the osteotomy surface 10 is provided with a fixing member 30, the articular surface 20 includes the posterior condyle articular surface 23, and the maximum distance from the fixing member 30 to the posterior condyle articular surface 23 Denoted as the first distance A, the first distance A of different types of femoral prostheses is the same. Different types of femoral prostheses refer to femoral prostheses with different lengths viewed from the sagittal plane (ie, femoral prostheses corresponding to different knee joint sizes), see Figures 2 and 3 . If there is only one fixing member 30, the first distance A refers to the maximum distance from the fixing member 30 to the posterior condyle articular surface 23; if there are more than two fixing members 30, the first distance A refers to the farthest distance from the posterior condyle joint The maximum distance from the fixator 30 of the face 23 to the articular face 23 of the posterior condyle.

Specifically, the osteotomy surface 10 includes a distal osteotomy surface 11 , a posterior oblique osteotomy surface 12 and a posterior condyle osteotomy surface 13 that are connected at an angle in sequence, and the articular surface 20 further includes a distal articular surface 21 , a posterior oblique articular surface 22 and the posterior condyle articular surface 23, the distal osteotomy surface 11 is opposite to the distal articular surface 21, the posterior oblique osteotomy surface 12 is opposite to the posterior oblique articular surface 22, and the posterior condyle osteotomy surface 13 is opposite to the posterior condyle articular surface 23. Further, the distal osteotomy surface 11, the posterior oblique osteotomy surface 12 and the posterior condyle osteotomy surface 13 are all flat surfaces, and the posterior condyle articular surface 23, the posterior oblique articular surface 22 and the distal articular surface 21 are all convex towards the distal end. out surface. As shown in FIG. 5 , the distal osteotomy surface 11 , the posterior oblique osteotomy surface 12 and the posterior condylar osteotomy surface 13 are used to cooperate with the distal section 41 , the posterior oblique section 42 and the posterior condyle section 43 on the femur 40 respectively, The articular surface 20 is used to replace the diseased femoral articular surface of the patient, and cooperates with the concave surface of the tibial pad (not shown) to form a joint. Further, the fixing member 30 is a columnar structure, and the fixing member 30 is used to pass through the installation hole 44 of the femur 40 (as shown in FIG. 4 ), thereby positioning and fixing the femoral prosthesis.

Specifically, the maximum distance (ie, the first distance A) from the fixing member 30 to the posterior condyle articular surface 23 refers to the vertical distance from the intersection of the centerline of the fixing member 30 and the distal osteotomy surface 11 to the rearmost end of the posterior condyle articular surface 23 . Specifically, Fig. 1 shows the sagittal plane (ie, the midsagittal plane) passing through the mid-axial plane of the femoral prosthesis. From the perspective of the orientation in which it is implanted into the human body, the left side is the back of the human body, and the right side is the front of the human body. A straight line in the vertical direction (that is, the direction perpendicular to the distal osteotomy surface 11 ) is drawn through its rearmost point, then the intersection of the centerline of the most anterior fixator and the distal osteotomy surface 11 is perpendicular to the straight line The distance is the first distance A.

In view of the shortcomings of the traditional femoral prosthesis, our research and development personnel were surprised to find that the posterior condyle offset PCO of the knee joint (that is, the No. A distance A) does not correlate with the size of the knee joint. By keeping the maximum distance between the fixator 30 of different types of femoral prosthesis and the posterior condyle articular surface 23 the same, in other words, the relative position of the fixator 30 of different types of femoral prosthesis is kept unchanged, so that during surgery When replacing a different type of femoral prosthesis, there is no need to additionally perform osteotomy on the posterior condyle section 43 and distal section 41 of the femur 40, and there is no need to make new drilling for the installation hole 44 of the femur 40, so that the patient is preserved. More bone volume, simplified operation steps, reduced operation time, and reduced probability of infection. At the same time, it can avoid the impact of the installation holes punched later by the installation holes punched first, and the fixation ability will decrease.

Further, in this embodiment, when replacing different types of femoral prostheses during the operation, only the posterior oblique osteotomy surface 42 of the femur 40 needs to be reprocessed. Specifically, as shown in FIG. 6 , when a larger size is selected, the length L of the posterior oblique osteotomy surface 12 of the large femoral prosthesis in the sagittal plane is greater than the length L of the posterior oblique osteotomy surface 42 of the femur 40 in the sagittal plane. Because of the length in the sagittal plane, the posterior oblique osteotomy surface 42 of the femur 40 needs to be added, so that the large-sized femoral prosthesis can be completely matched with the femur 40. As shown in FIG. 7 , when a smaller size model is selected, the length L of the posterior oblique osteotomy surface 12 of the small size femoral prosthesis in the sagittal plane is smaller than that of the posterior oblique cross-section 42 of the femur 40 in the sagittal plane. If the femoral prosthesis is directly installed, there will be a certain gap between the posterior oblique osteotomy surface 12 of the femoral prosthesis and the posterior oblique section 42 of the femur 40. Therefore, it is necessary to add bone at the posterior oblique osteotomy surface 12 of the femoral prosthesis. cement thickness to fill the gap. In this embodiment, although the posterior oblique section 42 of the femur 40 also needs to be processed to a certain extent, compared with the traditional intraoperative replacement of the femoral prosthesis, each osteotomy surface of the femur 40 and the installation hole 44 need to be processed. The operation method of the interchangeable unicondylar femoral prosthesis system of the present application still simplifies the operation steps, reduces the operation time, and reduces the probability of infection.

It should be noted that, if the femoral prosthesis has many specifications and the size span of the femoral prosthesis is large, if the same first distance is used for different types of femoral prosthesis, for the femoral prosthesis of small size, the first The first distance will be too large, and the first distance will be too small for large size femoral prostheses. Therefore, in this case, for example, the smallest femoral prostheses that are not commonly used can also be used as a femoral prosthesis system, and the same relatively small first distance A can be used. Several commonly used intermediate models of femoral prosthesis are used as another femoral prosthesis system, and the same moderate first distance A is used, for example, the range of the first distance A is 30mm-50mm, preferably 36-46mm. Similarly, the femoral prostheses of the largest models that are not commonly used can be converted into a femoral prosthesis system with a larger first distance. In this embodiment, the interchangeable unicondylar femoral prosthesis systems of several common intermediate models that can be interchanged are taken as examples for detailed description.

Further, each type of femoral prosthesis is provided with at least two fixing parts 30, and the distance between two adjacent fixing parts 30 is recorded as the second distance B, and the second distance B of different types of femoral prosthesis same. Specifically, the second distance B refers to the straight-line distance between the intersection of the centerlines of the two fixing members 30 and the distal bone surface 11 on the midsagittal plane.

For example, as shown in FIG. 1 , each type of femoral prosthesis is provided with two fixing pieces 30 , and the two fixing pieces 30 are the first fixing piece 31 and the second fixing piece 32 respectively. The second distance B between the fixing piece 31 and the second fixing piece 32 is the same, preferably, the second distance B between the first fixing piece 31 and the second fixing piece 32 is in the range of 10mm-28mm, preferably 16-20mm. It should be noted that, in other embodiments, three, four or more fixing members 30 may also be provided on the femoral prosthesis. By arranging at least two fixing pieces 30 on the femoral prosthesis, the installation stability of the femoral prosthesis is increased, and the problem of postoperative loosening of the femoral prosthesis is avoided. Further, by keeping the same distance between the two adjacent fixing parts 30 of different types of femoral prostheses, the relative positions of the fixing parts 30 of different types of femoral prostheses are guaranteed to be the same, so that the replacement during the operation is possible. When the femoral prosthesis is used, there is no need to perform additional osteotomy or drilling of the femur 40 , which further simplifies the operation steps, reduces the operation time, and reduces the probability of infection.

Further, at least two fixing pieces 30 are arranged on the distal osteotomy surface 11 . Issued through finite element analysis, compared to the traditional femoral prosthesis with two fixators 30 placed on the posterior oblique osteotomy surface 12 and the distal osteotomy surface 11 respectively, the femoral prosthesis of the present application is achieved by placing both the fixators 30 on the femoral prosthesis. The distal osteotomy surface 11 has better stability, especially rotational stability.

Further, in the direction away from the posterior condyle osteotomy surface 13 , the heights of the two adjacent fixing pieces 30 in the direction perpendicular to the distal osteotomy surface 11 tend to increase. For example, as shown in FIG. 1 , the height H1 of the first fixture 31 relatively far from the posterior condyle osteotomy surface 13 in the direction perpendicular to the distal osteotomy surface 11 is higher, and the second fixture relatively close to the posterior condyle osteotomy surface 13 The height H2 of 32 in the direction perpendicular to the distal osteotomy surface 11 is low. The first fixing member 31 which is relatively far away from the posterior condyle osteotomy surface 13 is closer to the load-bearing area when the knee joint is extended, and the use of a longer fixing member 30 in this area helps to improve the stability of the femoral prosthesis. Preferably, H2 is 1-5mm smaller than H1, and H1 ranges from 10mm-25mm, preferably 17-20mm.

Continuing to refer to FIG. 1 , the direction of the center line of each fixing member 30 forms an included angle with the direction of the vertical line of the distal osteotomy surface 11 . For example, as shown in the figure, the included angles between the first fixing member 31 and the second fixing member 32 and the vertical direction of the distal osteotomy surface 11 are equal. The included angle of the vertical direction of the end osteotomy surface 11 is greater than 0° and less than 30°, preferably 5-15°. The finite element analysis shows that, compared with the traditional fixator 30 and the femoral prosthesis perpendicular to the distal osteotomy surface 11 , the femoral prosthesis of the present application is obtained by placing the fixator 30 and the vertical line of the distal osteotomy surface 11 in a vertical line. A certain inclination angle setting can increase the installation stability of the femoral prosthesis.

Further, referring to FIG. 1 , the thickness from the distal osteotomy surface 11 to the distal articular surface 21 is denoted as the first thickness W1, and the thickness from the posterior condyle osteotomy surface 13 to the posterior condyle articular surface 23 is denoted as the second thickness W2. The first thickness W1 of the femoral prostheses of different sizes is the same, and the second thickness W2 of the femoral prostheses of different sizes is the same. The thickness referred to here refers to, on the midsagittal plane of the femoral prosthesis, a plane parallel to a certain osteotomy plane is translated toward the articular surface, when the plane is translated to only one intersection with the articular surface, the The vertical distance between the intersection point and the cut surface. Keeping the first distance A, the second distance B, the first thickness W1 and the second thickness W2 unchanged, it can ensure that when changing the prosthesis model, there is no need to re-drill and cut the bone, which is conducive to maximizing the preservation of the patient's bone volume. Simplify surgical operations and improve the stability of prosthesis installation.

Specifically, in unicondylar replacement, in order to evaluate the accuracy of the distal osteotomy of the femur 40, the thickness W1 of the distal osteotomy surface 11 to the distal articular surface 21 of different femoral prostheses needs to be equipped with different extension gaps In the same way, in order to evaluate the accuracy of the osteotomy of the posterior condyle of the femur 40, the posterior condyle thickness W2 of different types of femoral prosthesis needs to be measured with different flexion gap measuring instruments. Therefore, by using the same first thickness W1 and the same second thickness W2 for different types of femoral prostheses, the number of extension gap measurers and flexion gap measurers can be effectively reduced, further simplifying the operation and reducing the operation time. , reduce the probability of infection.

Further, the second thickness W2 is greater than the first thickness W1. The posterior condyle articular surface 23 of the femoral prosthesis is the main load-bearing area in the flexed state of the knee joint. By making the second thickness W2 greater than the first thickness W1 of the femoral prosthesis, the strength of the posterior condyle articular surface 23 of the femoral prosthesis can be increased, and the Femoral prosthesis life. In addition, the second thickness W2 of the femoral prosthesis is slightly larger, which is beneficial to slow down the curvature of the posterior and superior articular surface 20 of the femoral prosthesis, avoid the generation of edge loads during high flexion, improve the stress condition of the femoral prosthesis and the tibial pad, and at the same time make the patient Easier to achieve high buckling. Preferably, the range of the second thickness W2 is 5mm-8mm, preferably 6-7mm, and the range of the first thickness W1 is 4mm-7mm, preferably 5-6mm. Further, the thickness from the posterior oblique osteotomy surface 12 to the posterior oblique articular surface 22 is denoted as the third thickness W3, and the third thickness W3 is substantially the same as the first thickness W1.

As shown in Figures 2 and 3, in this embodiment, the lengths of the distal osteotomy surface 11, the posterior oblique osteotomy surface 12 and the posterior condyle osteotomy surface 13 of the different types of femoral prostheses, the lengths of their corresponding articular surfaces The curvature and the third thickness W3 are different, while the first distance A, the second distance B, the first thickness W1 and the second thickness W2 remain the same for different models. In other words, in one embodiment, by adjusting the lengths of the distal osteotomy surface 11 , the posterior oblique osteotomy surface 12 and the posterior condylar osteotomy surface 13 , the curvature of the respective articular surfaces and the third thickness W3 to ensure the first The distance A, the second distance B, the first thickness W1 and the second thickness W2 remain unchanged. In this embodiment, the replacement of the prosthesis model does not require re-drilling, but only needs to slightly process the posterior oblique osteotomy surface, and the mechanical strength of the prosthesis is basically not affected.

Further, the plane where the distal osteotomy surface 11 is located is perpendicular or approximately perpendicular to the plane where the posterior condyle osteotomy surface 13 is located, and the angle between the posterior oblique osteotomy surface 12 and the distal osteotomy surface 11 and the posterior The angle between the oblique osteotomy surface 12 and the distal osteotomy surface 11 is equal, that is, the angle between the posterior oblique osteotomy surface 12 and the distal osteotomy surface 11 is 135°, and the posterior oblique osteotomy surface 12 and the distal The included angle between the end osteotomy surfaces 11 is also 135°.

Referring to FIG. 8 , in another embodiment of the present application, another interchangeable unicondylar femoral prosthesis system is provided. In this embodiment, the posterior oblique osteotomy surface 12 of the femoral prosthesis is in the sagittal plane. The length L is recorded as the first length L, and the first length L is also the same for different types of femoral prostheses on the basis that the first distance A, the second distance B, the first thickness W1, and the second thickness W2 remain unchanged. Keeping the first length L unchanged can ensure that osteotomy is completely avoided when changing models, and no treatment is required to the posterior oblique osteotomy surface 12 . In this embodiment, in different types of femoral prostheses, the first distance A and the The second distance B is unchanged, and the first thickness W1 , the second thickness W2 and the first length L of the posterior oblique osteotomy 12 in the sagittal plane are unchanged. Therefore, when replacing different types of femoral prostheses in unicondylar replacement, there is no need to perform any osteotomy or drilling, which preserves the patient's bone mass, further simplifies the operation steps, and reduces the operation time. Different from the previous embodiment, in order to keep the first length L of the posterior oblique osteotomy surface 12 unchanged, the thickness W3 of the large-sized posterior oblique osteotomy surface 12 will be greatly reduced, and the mechanical strength will be slightly lower. in the previous embodiment.

Further, the present application also provides a knee joint system. The knee joint system includes the interchangeable unicondylar femoral prosthesis system of any of the above-mentioned embodiments, and a tibial pad that matches the femoral prosthesis.

The above-mentioned knee joint system maintains the same maximum distance from the fixator 30 of the femoral prosthesis of different models to the articular surface 23 of the posterior condyle. Therefore, when replacing different types of femoral prosthesis during the operation, there is no need to additionally perform osteotomy on the posterior condyle section 43 and the distal section 41 of the femur 40, and there is no need to perform new drilling for the installation hole 44 of the femur 40. , thereby preserving more bone mass in patients, simplifying surgical procedures, reducing operation time, and reducing the probability of infection.

The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity, all possible combinations of the technical features in the above-described embodiments are not described. However, as long as there is no contradiction between the combinations of these technical features, All should be regarded as the scope described in this specification.

The above-mentioned embodiments only represent several embodiments of the present invention, and the descriptions thereof are specific and detailed, but should not be construed as a limitation on the scope of the invention patent. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can also be made, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention should be subject to the appended claims.

Claims (10)

1. An interchangeable unicondylar femoral prosthesis system comprising at least two types of femoral prostheses, each type of femoral prosthesis comprising a resected surface for attachment to a femur and an articular surface for engagement with a tibial insert, the resected surface having a fixation thereon, the articular surface comprising a posterior condylar articular surface, and the maximum distance from the fixation to the posterior condylar articular surface being designated as a first distance, the first distances being the same for different types of femoral prostheses.

2. The interchangeable unicondylar femoral prosthesis system of claim 1, wherein each size of said femoral prosthesis is provided with at least two of said fasteners and the distance between two adjacent fasteners is designated as a second distance, said second distance being the same for different sizes of said femoral prosthesis.

3. The interchangeable unicondylar femoral prosthesis system of claim 2, wherein said osteotomy surfaces comprise a distal osteotomy surface, a posterior oblique osteotomy surface, and a posterior condylar osteotomy surface, angularly connected in sequence, said at least two fixation elements each being disposed on said distal osteotomy surface.

4. The interchangeable unicondylar femoral prosthesis system of claim 3, wherein adjacent two of said fasteners exhibit an increasing height in a direction perpendicular to said distal osteotomy face in a direction away from said posterior condylar osteotomy face.

5. The interchangeable unicondylar femoral prosthesis system of claim 3, wherein the centerline direction of each said fastener is angled from perpendicular to said distal osteotomy surface.

6. The interchangeable unicondylar femoral prosthesis system of claim 1, wherein said osteotomy surfaces comprise a distal osteotomy surface, a posterior oblique osteotomy surface, and a posterior condylar osteotomy surface, said articular surfaces further comprising a distal articular surface opposite said distal articular surface and a posterior oblique articular surface opposite said posterior oblique articular surface, said distal osteotomy surface having a thickness to said distal articular surface designated a first thickness, said posterior condylar osteotomy surface having a thickness to said posterior condylar articular surface designated a second thickness, said first thicknesses of different models of said femoral prosthesis being the same, and said second thicknesses of different models of said femoral prosthesis being the same.

7. The interchangeable unicondylar femoral prosthesis system of claim 6, wherein the second thickness is greater than the first thickness.

8. The interchangeable unicondylar femoral prosthesis system of claim 6, wherein the length of the posterior oblique osteotomy plane in the median sagittal plane is designated as a first length, the first length being the same for different models of the femoral prosthesis.

9. The interchangeable unicondylar femoral prosthesis system of claim 1, wherein said osteotomy surfaces comprise a distal osteotomy surface, a posterior oblique osteotomy surface, and a posterior condylar osteotomy surface, sequentially joined at an included angle, wherein said distal osteotomy surface lies in a plane perpendicular or approximately perpendicular to a plane in which said posterior condylar osteotomy surface lies, and wherein the included angle between said posterior oblique osteotomy surface and said distal osteotomy surface is equal to the included angle between said posterior oblique osteotomy surface and said distal osteotomy surface.

10. A knee joint system comprising the interchangeable unicondylar femoral prosthesis system of any of claims 1-9 and a tibial insert, the tibial insert being mated with the femoral prosthesis.

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