CN212438950U - Interchangeable type single-condyle femoral prosthesis system and knee joint system - Google Patents

Abstract

The utility model relates to an exchange type unicondylar femoral prosthesis system and knee joint system. The interconversion type single-condyle femoral prosthesis system comprises at least two types of femoral prostheses, wherein each type of femoral prosthesis comprises a resection surface used for being connected with a femur and a joint surface used for being matched with a tibia liner, a fixing piece is arranged on the resection surface, the joint surface comprises a posterior condyle joint surface, the maximum distance from the fixing piece to the posterior condyle joint surface is recorded as a first distance, and the first distances of the femoral prostheses of different types are the same. The interchangeable unicondylar femoral prosthesis system keeps more bone mass of a patient, simplifies operation steps, reduces operation time and reduces infection occurrence probability.

Description

Interchangeable type single-condyle femoral prosthesis system and knee joint system

Technical Field

The utility model relates to the technical field of medical equipment, especially, relate to interchange type unicondylar femoral prosthesis system and knee joint system.

Background

The unicondylar replacement adopts a minimally invasive incision, can keep anterior and posterior cruciate ligaments of knee joints of patients, and has the advantages of small wound, quick recovery, good physiological activity of the patients after operation and the like, so the unicondylar replacement is widely applied to the treatment of unicompartmental osteoarthritis. Unicondylar replacement requires replacement of the patient's diseased femoral articular surface with a femoral prosthesis and replacement of the patient's diseased tibial articular surface with a tibial insert to provide the patient with a new knee joint.

Before the unicondylar replacement is performed, the femur of a patient needs to be cut and drilled, so that the femoral articular surface can be matched with and fixed to the femoral prosthesis. Generally have the thighbone prosthesis of a series of different specification models in the hospital, the doctor can select suitable thighbone prosthesis from the unicondylar thighbone prosthesis system according to different patients ' thighbone size to guarantee that the knee joint prosthesis after the replacement can be close patient's native knee joint by furthest, and then improve patient's postoperative experience. However, when a surgeon needs to intraoperatively replace a femoral prosthesis of a different size, the femur needs to be re-osteotomized and drilled, resulting in more bone mass being destroyed for the patient. Meanwhile, due to the existence of the old mounting hole, the integrity of the new drilling hole can be influenced, and the postoperative stability of the femoral prosthesis is further influenced. In addition, re-osteotomy and drilling can increase the surgical time and increase the incidence of infection.

SUMMERY OF THE UTILITY MODEL

In view of the above, there is a need for an interchangeable unicondylar femoral prosthesis system and knee joint system that avoids the problem of re-osteotomy and drilling of the patient when intraoperatively replacing the prosthesis model.

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 mating with a tibial insert, the resected surface having a fixation thereon, the articular surface comprising a posterior condylar articular surface, and the maximum distance of the fixation to the posterior condylar articular surface being noted as a first distance, the first distances being the same for different types of femoral prostheses.

The interchangeable single-condyle femoral prosthesis system keeps the same maximum distance from the fixing parts of the femoral prostheses of different models to the posterior condyle articular surface, in other words, the relative positions of the fixing parts of the femoral prostheses of different models are ensured to be unchanged, so that when the femoral prostheses of different models are replaced in an operation, the posterior condyle section and the distal section of the femur do not need to be cut additionally, and new drilling is not needed to be carried out on the mounting hole of the femur, thereby keeping more bone mass of a patient, simplifying the operation steps, reducing the operation time and reducing the infection occurrence probability.

In one embodiment, at least two fixing parts are arranged on each model of the femoral prosthesis, the distance between two adjacent fixing parts is recorded as a second distance, and the second distances of different models of the femoral prosthesis are the same.

In one embodiment, the osteotomy surface comprises a distal osteotomy surface, a posterior oblique osteotomy surface and a posterior condylar osteotomy surface which are sequentially connected in an included angle, and the at least two fixing pieces are arranged on the distal osteotomy surface.

In one embodiment, the height of two adjacent fasteners in a direction perpendicular to the distal osteotomy face increases in a direction away from the posterior condylar osteotomy face.

In one embodiment, the direction of the center line of each of the fixing members is at an angle to the perpendicular to the distal osteotomy surface.

In one embodiment, the osteotomy surfaces include a distal osteotomy surface, a posterior oblique osteotomy surface and a posterior condylar osteotomy surface which are sequentially connected in an included angle, the articular surfaces further include a distal articular surface and a posterior oblique 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, the posterior condylar osteotomy surface is opposite to the posterior condylar articular surface, the thickness from the distal osteotomy surface to the distal articular surface is recorded as a first thickness, the thickness from the posterior condylar osteotomy surface to the posterior condylar articular surface is recorded as a second thickness, the first thicknesses of different types of the femoral prosthesis are the same, and the second thicknesses of different types of the femoral prosthesis are the same.

In one embodiment, the second thickness is greater than the first thickness.

In one embodiment, the length of the posterior oblique osteotomy plane in the median sagittal plane is taken as a first length, and the first lengths of different models of the femoral prosthesis are the same.

In one embodiment, the osteotomy surface comprises a distal osteotomy surface, a posterior oblique osteotomy surface and a posterior condylar osteotomy surface which are sequentially connected in an included angle manner, wherein a plane where the distal osteotomy surface is located is perpendicular or approximately perpendicular to a plane where the posterior condylar osteotomy surface is located, and an included angle between the posterior oblique osteotomy surface and the distal osteotomy surface is equal to an included angle between the posterior oblique osteotomy surface and the distal osteotomy surface.

A knee joint system comprising an interchangeable unicondylar femoral prosthesis system as described above and a tibial insert that mates with the femoral prosthesis.

Above-mentioned knee joint system all keeps the same through the biggest distance that makes the femoral prosthesis's of different models mounting to posterior condylar articular surface, in other words, make the relative position of the femoral prosthesis's of different models mounting guarantee unchangeably, thereby when changing the femoral prosthesis of different models in the art, need not additionally to the femoral posterior condylar cross-section again, the distal end cross-section cuts the bone, also need not to carry out new drilling at the mounting hole to the thighbone, thereby more bone mass of remaining patient, simplify the operation step, reduce the operating time, reduce the infection probability of occurrence.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification.

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

FIG. 1 is a schematic view of a unicondylar femoral prosthesis of one version of an embodiment of an interchangeable unicondylar femoral prosthesis system;

FIG. 2 is a comparative schematic view of different models of femoral prostheses of an embodiment of an interchangeable unicondylar femoral prosthesis system;

FIG. 3 is a cross-sectional comparison view of a different model of femoral prosthesis shown in FIG. 2;

FIG. 4 is a schematic cross-sectional view of a femur, according to an embodiment;

FIG. 5 is a schematic view of an embodiment of a femoral prosthesis mated to a femur;

FIG. 6 is a schematic view of another embodiment of a femoral prosthesis mated to a femur;

FIG. 7 is a schematic view of a femoral prosthesis according to yet another embodiment in cooperation with a femur;

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

Description of reference numerals:

10. cutting bone surface; 11. a distal osteotomy face; 12. a posterior oblique osteotomy face; 13. a posterior condylar osteotomy face; 20. a joint surface; 21. a distal articular surface; 22. posterior oblique articular surface; 23. the posterior condylar articular surface; 30. a fixing member; 31. a first fixing member; 32. a second fixing member; 40. the femur; 41. a distal cross-section; 42. a rear oblique cross section; 43. posterior condylar cross-section; 44. and (7) installing holes.

Detailed Description

In order to make the above objects, features and advantages of the present invention more comprehensible, embodiments of the present invention are 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. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, as those skilled in the art will be able to make similar modifications without departing from the spirit and scope of the present invention.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", and the like, indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore, should not be construed as limiting the present invention.

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

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," and "fixed" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.

In the present application, unless expressly stated or limited otherwise, the first feature may be directly on or directly under the second feature or indirectly via intermediate members. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or intervening elements 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 the like as used herein are for illustrative purposes only and do not denote a unique embodiment.

Specifically, referring to fig. 1-3, an embodiment of an interchangeable unicondylar femoral prosthesis system includes at least two types of femoral prostheses, wherein each type of femoral prosthesis includes a resected surface 10 for coupling with a femur 40 and an articulating surface 20 for mating with a tibial insert, the resected surface 10 has a fixation element 30 thereon, the articulating surface 20 includes a posterior condylar articulating surface 23, and the maximum distance from the fixation element 30 to the posterior condylar articulating surface 23 is designated as a first distance a, and the first distances a for the different types of femoral prostheses are the same. Different types of femoral prostheses refer to femoral prostheses of different lengths when viewed from the sagittal plane (i.e., femoral prostheses that correspond to different sizes of knee joints), see fig. 2 and 3. If there is only one fastener 30, the first distance A refers to the maximum distance of that fastener 30 from the posterior condylar articular surface 23; if there are more than two fixtures 30, the first distance A refers to the greatest distance from the fixture 30 furthest from the posterior condylar articular surface 23 to the posterior condylar articular surface 23.

Specifically, the osteotomy surface 10 includes a distal osteotomy surface 11, a posterior oblique osteotomy surface 12 and a posterior condylar osteotomy surface 13 which are sequentially connected in an included angle, the joint surface 20 further includes a distal joint surface 21, a posterior oblique joint surface 22 and a posterior condylar joint surface 23, the distal osteotomy surface 11 is opposite to the distal joint surface 21, the posterior oblique osteotomy surface 12 is opposite to the posterior oblique joint surface 22, and the posterior condylar osteotomy surface 13 is opposite to the posterior condylar joint surface 23. Further, the distal osteotomy surface 11, the posterior oblique osteotomy surface 12 and the posterior condylar osteotomy surface 13 are all planar surfaces, and the posterior condylar articular surface 23, the posterior oblique articular surface 22 and the distal articular surface 21 are all distally convex curved surfaces. As shown in FIG. 5, the distal facet 11, the posterior chamfer facet 12, and the posterior condylar facet 13 are adapted to mate with a distal facet 41, a posterior chamfer facet 42, and a posterior condylar facet 43, respectively, on a femur 40, and the articular facet 20 is adapted to replace the diseased femoral articular facet of the patient, which mates with the concavity of a tibial insert (not shown) to form a joint. Further, the fixing member 30 is a cylindrical structure, and the fixing member 30 is used to penetrate through the mounting hole 44 of the femur 40 (as shown in fig. 4), so as to fix the position of the femoral prosthesis.

Specifically, the maximum distance of the fixture 30 from the posterior condylar articular surface 23 (i.e., the first distance A) refers to the perpendicular distance from the intersection of the centerline of the fixture 30 with the distal facet 11 to the posterior-most end of the posterior condylar articular surface 23. Specifically, fig. 1 is a sagittal plane (i.e., the median sagittal plane) passing through the medial axis of the femoral prosthesis, and the left side is the posterior side of the human body and the right side is the anterior side of the human body, as viewed from the orientation in which the femoral prosthesis is implanted in the human body. A straight line in the vertical direction (i.e., the direction perpendicular to the distal osteotomy face 11) is drawn through the rearmost point, and the perpendicular distance from the intersection of the center line of the forward-most fastener and the distal osteotomy face 11 to the straight line is the first distance a.

In view of the shortcomings of conventional femoral prostheses, I have surprisingly discovered that the posterior condylar offset PCO (i.e., the first distance A in this embodiment) of the knee joint is independent of the size of the knee joint, through studies and statistical analysis of anatomical data of the human knee joint. By keeping the maximum distances from the fixing parts 30 of the femoral prostheses of different models to the posterior condylar articular surface 23 the same, in other words, the relative positions of the fixing parts 30 of the femoral prostheses of different models are ensured to be unchanged, so that when the femoral prostheses of different models are replaced in an operation, the posterior condylar section 43 and the distal section 41 of the femur 40 do not need to be cut additionally, and new drilling is not needed to be carried out on the mounting hole 44 of the femur 40, so that more bone mass of a patient is reserved, the operation steps are simplified, the operation time is shortened, the infection occurrence probability is reduced, meanwhile, the problem that the mounting hole which is drilled later is influenced by the mounting hole which is drilled first is avoided, and the fixing capacity is reduced.

Further, in this embodiment, only the posterior chamfer facet 42 of the femur 40 needs to be treated again when intraoperatively replacing a different model of femoral prosthesis. Specifically, as shown in FIG. 6, when a larger size is selected, the posterior oblique facet 42 of the femur 40 needs to be resected in order for the large size femoral prosthesis to completely match the femur 40, since the length L of the posterior oblique facet 12 of the large size femoral prosthesis in the sagittal plane is greater than the length of the posterior oblique facet 42 of the femur 40 in the sagittal plane. As shown in fig. 7, when a smaller size is selected, since the length L of the posterior oblique section 12 of the femoral prosthesis in the sagittal plane is smaller than the length L of the posterior oblique section 42 of the femur 40 in the sagittal plane, if the femoral prosthesis is directly installed, a certain gap exists between the posterior oblique section 12 of the femoral prosthesis and the posterior oblique section 42 of the femur 40, and therefore, the cement thickness needs to be increased at the posterior oblique section 12 of the femoral prosthesis to fill the gap. Although a certain treatment is required for the posterior oblique section 42 of the femur 40 in this embodiment, compared to the conventional way in which the osteotomy surfaces and the mounting holes 44 of the femur 40 are required to be treated when the femoral prosthesis is replaced during the operation, the operation method using the interchangeable unicondylar femoral prosthesis system of the present application simplifies the operation steps, reduces the operation time, and reduces the occurrence probability of infection.

It should be noted that if the size of the femoral prosthesis is larger, the size span of the femoral prosthesis is larger, and if the same first distance is adopted for different sizes of femoral prostheses, the first distance will be too large for a very small size of femoral prosthesis, and too small for a very large size of femoral prosthesis. In this case, therefore, for example, the smallest several types of femoral prostheses which are less common can also be used as a femoral prosthesis system, using the same, relatively small, first distance a. Several intermediate-sized femoral prostheses commonly used are used as another femoral prosthesis system, using the same moderate first distance a, for example in the range of 30mm to 50mm, preferably 36 to 46 mm. Similarly, the largest of the several models of femoral prostheses that are not commonly used can be replaced with a femoral prosthesis system that uses a larger first distance. In the present embodiment, several interchangeable unicondylar femoral prosthesis systems of common medial size that are interchangeable are exemplified for the detailed description.

Further, at least two fixing pieces 30 are arranged on each type of femoral prosthesis, the distance between two adjacent fixing pieces 30 is marked as a second distance B, and the second distances B of different types of femoral prostheses are the same. Specifically, the second distance B is the linear distance between the intersection of the centerlines of the two anchors 30 and the distal bone-joining face 11 in the midsagittal plane.

For example, as shown in fig. 1, each type of femoral prosthesis is provided with two fixing elements 30, the two fixing elements 30 are a first fixing element 31 and a second fixing element 32, and the second distance B between the first fixing element 31 and the second fixing element 32 of the femoral prostheses of different types is the same, preferably, the second distance B between the first fixing element 31 and the second fixing element 32 is in the range of 10mm-28mm, and preferably 16-20 mm. It should be noted that in other embodiments, three, four or more fixation elements 30 may be provided on the femoral prosthesis. Through set up two at least fixings 30 on femoral prosthesis, increased femoral prosthesis's installation stability, avoided femoral prosthesis's not hard up problem of postoperative. Further, the distance between two adjacent fixing parts 30 of the femoral prostheses of different models is kept the same, so that the relative positions of the fixing parts 30 of the femoral prostheses of different models are ensured to be the same, and when the femoral prostheses are replaced in an operation, the femur 40 does not need to be cut or drilled additionally, so that the operation steps are further simplified, the operation time is shortened, and the infection occurrence probability is reduced.

Further, at least two fixation members 30 are each provided on the distal osteotomy face 11. The femoral prosthesis of the present application has better stability, especially rotational stability, by placing both fixation members 30 on the distal osteotomy face 11, compared to the conventional femoral prosthesis with two fixation members 30 on the posterior osteotomy face 12 and the distal osteotomy face 11, respectively, issued by finite element analysis.

Further, the height of two adjacent fixtures 30 in the direction perpendicular to the distal osteotomy face 11 increases in a direction away from the posterior condylar osteotomy face 13. For example, as shown in FIG. 1, the first fastener element 31 relatively distal to the posterior condylar osteotomy face 13 has a higher height H1 in the direction perpendicular to the distal osteotomy face 11, and the second fastener element 32 relatively proximal to the posterior condylar osteotomy face 13 has a lower height H2 in the direction perpendicular to the distal osteotomy face 11. The first fastener 31, which is relatively far from the posterior condylar osteotomy face 13, is closer to the weight bearing area of the knee in extension, where the use of a longer fastener 30 helps to improve the stability of the femoral prosthesis. Preferably, H2 is 1-5mm smaller than H1, and H1 ranges from 10mm to 25mm, preferably 17-20 mm.

With continued reference to figure 1, the direction of the centerline of each fastener element 30 is angled from the perpendicular to the distal osteotomy face 11. For example, as shown in the figures, the first fixing element 31 and the second fixing element 32 are at the same angle with the perpendicular to the distal osteotomy face 11, and preferably, the angle between the first fixing element 31 and the second fixing element 32 with the perpendicular to the distal osteotomy face 11 is greater than 0 ° and less than 30 °, preferably 5-15 °. Finite element analysis shows that compared with the traditional fixing piece 30 and the femoral prosthesis vertical to the far-end osteotomy surface 11, the femoral prosthesis can increase the installation stability of the femoral prosthesis by arranging the fixing piece 30 at a certain inclination angle with the vertical line of the far-end osteotomy surface 11.

Further, referring to fig. 1, the thickness from the distal facet 11 to the distal articular surface 21 is designated as a first thickness W1, the thickness from the posterior condylar facet 13 to the posterior condylar articular surface 23 is designated as a second thickness W2, the first thickness W1 is the same for different models of femoral prostheses, and the second thickness W2 is the same for different models of femoral prostheses. Thickness is defined herein as the perpendicular distance from the plane of the femoral prosthesis when translated in the sagittal plane parallel to the plane of the osteotomy to the plane of the joint. The first distance A, the second distance B, the first thickness W1 and the second thickness W2 are guaranteed to be unchanged, the fact that holes are not needed to be punched again and the bone is not needed to be cut when the prosthesis model is replaced can be guaranteed, the maximum bone mass of a patient can be kept, the operation is simplified, and the prosthesis installation stability is improved.

Specifically, in the unicondylar replacement, in order to evaluate the accuracy of the distal resection of the femur 40, the thickness W1 from the distal resection surface 11 to the distal joint surface 21 of different femoral prostheses needs to be measured by different extension gap measuring devices, and similarly, in order to evaluate the accuracy of the posterior resection of the femur 40, the thickness W2 of the posterior condyles of different types of femoral prostheses needs to be measured by different flexion gap measuring devices. Therefore, different types of femoral prostheses are respectively provided with the same first thickness W1 and the same second thickness W2, so that the number of extension gap measurers and flexion gap measurers can be effectively reduced, the operation is further simplified, the operation time is reduced, and the infection occurrence probability is reduced.

Further, the second thickness W2 is greater than the first thickness W1. The posterior condylar articular surface 23 of the femoral prosthesis is a main bearing area of the knee joint in a flexion state, and the strength of the posterior condylar articular surface 23 of the femoral prosthesis can be improved and the service life of the femoral prosthesis can be prolonged by enabling the second thickness W2 to be larger than the first thickness W1. In addition, the second thickness W2 of the femoral component is slightly greater, which is beneficial to slowing down the curvature of the upper-posterior articular surface 20 of the femoral component, avoiding the generation of edge load during high flexion, improving the stress condition of the femoral component and the tibial gasket, and simultaneously making the patient more easily realize high flexion. Preferably, the second thickness W2 ranges from 5mm to 8mm, preferably from 6 to 7mm, and the first thickness W1 ranges from 4mm to 7mm, preferably from 5 to 6 mm. Further, the thickness from the posterior oblique osteotomy face 12 to the posterior oblique articular face 22 is noted as a third thickness W3, the third thickness W3 being substantially the same as the first thickness W1.

In this embodiment, as shown in fig. 2 and 3, the lengths of the distal osteotomy surface 11, the posterior oblique osteotomy surface 12 and the posterior condylar osteotomy surface 13, the curvatures of the respective articular surfaces and the third thickness W3 of the femoral prostheses of different models are different, and the first distance a, the second distance B, the first thickness W1 and the second thickness W2 of different models are kept the same. In other words, in one embodiment, the first distance a, the second distance B, the first thickness W1, and the second thickness W2 are maintained by adjusting the lengths of the distal facet 11, the posterior oblique facet 12, and the posterior condylar facet 13, the curvature of the respective articular surfaces, and the third thickness W3. In the embodiment, the model of the prosthesis is changed without re-punching, only the posterior oblique osteotomy surface is slightly processed, and the mechanical strength of the prosthesis is basically not influenced.

Further, the plane of the distal osteotomy surface 11 is perpendicular or approximately perpendicular to the plane of the posterior condylar osteotomy surface 13, and preferably the angle between the posterior oblique osteotomy surface 12 and the distal osteotomy surface 11 is equal to the angle between the posterior oblique osteotomy surface 12 and the distal osteotomy surface 11, i.e. the angle between the posterior oblique osteotomy surface 12 and the distal osteotomy surface 11 is 135 °, and the angle between the posterior oblique osteotomy surface 12 and the distal osteotomy surface 11 is also 135 °.

Referring to fig. 8, the present application provides, in another embodiment, another interchangeable unicondylar femoral prosthesis system, wherein the length L of the posterior oblique osteotomy 12 of the femoral prosthesis in the sagittal plane is denoted as the first length L, and the first length L is the same for different types of femoral prostheses while maintaining the first distance a, the second distance B, the first thickness W1, and the second thickness W2 constant. The invariance of the first length L ensures that osteotomy is completely avoided when changing models, without any treatment of the posterior oblique osteotomy face 12. In this embodiment, the first and second distances a, B and the first and second thicknesses W1, W2 and the first length L of the posterior oblique osteotomy face 12 in the sagittal plane are maintained constant in different models of femoral prostheses by varying the lengths of the posterior condylar and distal osteotomy faces 13, 11, the third thickness W3 and the curvature of the three articular faces. Therefore, when femoral prostheses of different models are replaced in the unicondylar replacement, no osteotomy or drilling treatment is needed, more bone mass of a patient is reserved, the operation steps are further simplified, and the operation time is shortened. Unlike the previous embodiment, in order to ensure that the first length L of the posterior oblique osteotomy face 12 is constant, the thickness W3 of the large-sized posterior oblique osteotomy face 12 is greatly reduced, and the mechanical strength is slightly lower than that of the previous embodiment.

Further, the present application also provides a knee joint system. The knee system includes the interchangeable unicondylar femoral prosthesis system of any of the embodiments described above and a tibial insert that mates with the femoral prosthesis.

In the knee joint system, the maximum distances from the fixing parts 30 of the femoral prostheses of different models to the posterior condylar articular surface 23 are kept the same, in other words, the relative positions of the fixing parts 30 of the femoral prostheses of different models are ensured to be unchanged, so that when the femoral prostheses of different models are replaced in an operation, the posterior condylar section 43 and the distal section 41 of the femur 40 do not need to be cut additionally, and a new drilling hole is not needed to be formed in the mounting hole 44 of the femur 40, so that more bone mass of a patient is reserved, the operation steps are simplified, the operation time is shortened, and the infection occurrence probability is reduced.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only represent some embodiments of the present invention, and the description thereof is specific and detailed, but not to be construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, without departing from the spirit of the present invention, several variations and modifications can be made, which are within the scope of the present invention. Therefore, the protection scope 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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