A planarized patellofemoral prosthesis

Abstract

This invention relates to the field of medical prosthesis technology, and discloses a planarized patellofemoral joint prosthesis, comprising a femoral prosthesis and a patellar prosthesis. The patellar prosthesis is used to connect to the posterior side of the patella and has a first mounting surface and a first joint movable contact surface, which are arranged opposite to each other along the thickness direction of the patellar prosthesis. The femoral prosthesis is used to connect to the anterior side of the femur and has a second mounting surface and a second joint movable contact surface, which are also arranged opposite to each other along the thickness direction of the femoral prosthesis. The second joint movable contact surface slides with the first joint movable contact surface, and the mating surface is at least partially planar. In this invention, the joint movable contact surface is at least partially planar, resulting in a good matching effect between the two. This reduces the stress concentration caused by groove mismatch and unbalanced contact between the patellar prosthesis and the femoral prosthesis, which helps to alleviate joint prosthesis wear and problems such as knee flexion and extension dysfunction and knee pain.

Description

Technical Field

[0001] This invention relates to the field of medical prosthesis technology, specifically to a planarized patellofemoral joint prosthesis. Background Technology

[0002] The patellofemoral joint, composed of the patella and the patellar surface at the lower end of the femur, is an important component of the knee joint. The patella, located within the quadriceps tendon, acts as a lever, increasing the torque of the quadriceps and transmitting force to the tibia via the patellar ligament. When patellofemoral pain syndrome or patellofemoral osteoarthritis occurs and conservative treatment is ineffective, surgical intervention is usually performed, such as knee replacement or patellofemoral joint replacement.

[0003] The knee joint, a natural structure of the human body, is the junction of the femur and patella, such as... Figure 1 As shown in the cross-section, the femur 4 has a concave structure in the middle, also called the trochlear groove 41 or femoral condyle. The patella 3 has an outward convex structure in the middle of its posterior side, forming a cone-shaped protrusion, referred to here as the clasp 31. The clasp 31 of the patella 3 slides in the trochlear groove 41 of the femur 4, which helps maintain the stability of the knee joint and makes the movement smoother. In related technologies, patellofemoral joint prostheses all adopt a biomimetic design, retaining the matching structure of the clasp 31 and trochlear groove 41 of the patellar side prosthesis and the femoral side prosthesis. However, the above structure has the problem of poor matching degree between the clasp 31 and the trochlear groove 41. During knee flexion and extension, stress concentration is prone to occur at the matching position of the clasp 31 and the trochlear groove 41. As a result, during patellofemoral joint movement, wear and tear of the patellofemoral joint is easily caused by the mismatch or unevenness of the grooves. In fact, the patellar side prosthesis may even dislodge from the groove of the femoral side prosthesis, increasing wear and making reduction more difficult. Summary of the Invention

[0004] To address the shortcomings of the prior art, this invention provides a planarized patellofemoral joint prosthesis that improves the matching effect between the femoral and patellar prostheses, avoids stress concentration at the contact point between the femoral and patellar prostheses, reduces prosthesis wear, increases the service life of the prosthesis, and alleviates problems such as difficulty in knee flexion and extension and knee pain in patients.

[0005] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows:

[0006] A planarized patellofemoral joint prosthesis includes a femoral side prosthesis and a patellar side prosthesis;

[0007] The patellar prosthesis is used to connect to the posterior side of the patella and has a first mounting surface and a first joint movable contact surface. The first mounting surface and the first joint movable contact surface are arranged opposite to each other along the thickness direction of the patellar prosthesis. The first mounting surface is used to be mounted on the patella, and the first joint movable contact surface is used to cooperate with the femoral prosthesis.

[0008] The femoral prosthesis is used to connect to the anterior side of the femur and has a second mounting surface and a second joint movable contact surface. The second mounting surface and the second joint movable contact surface are arranged opposite to each other along the thickness direction of the femoral prosthesis. The second mounting surface is used to mount on the femur. The second joint movable contact surface slides with the first joint movable contact surface and the mating surface is at least partially planar.

[0009] As a preferred technical solution, the plane of the second joint movable contact surface of the femoral prosthesis and the plane of the first joint movable contact surface of the patellar prosthesis are inclined planes with a lower inner surface and a higher outer surface, and the angle Q with the coronal plane of the human body is 5~10°.

[0010] As a preferred technical solution, the femoral prosthesis and the patellar prosthesis are provided in three specifications. Among the three specifications of femoral prosthesis and patellar prosthesis, the angle Q between the plane of the second joint contact surface and the plane of the first joint contact surface and the coronal plane of the human body are 5°, 8° and 10° respectively.

[0011] As a preferred technical solution, the first joint movable contact surface includes a first plane, a first guide surface and a second guide surface. The first guide surface, the first plane and the second guide surface are smoothly connected in sequence from top to bottom. The first guide surface gradually extends towards the patella from bottom to top, and the second guide surface gradually extends towards the patella from top to bottom.

[0012] As a preferred technical solution, both the first guide surface and the second guide surface are inclined surfaces, with the lower side of the first guide surface smoothly transitioning to the first plane and the upper side of the second guide surface smoothly transitioning to the first plane.

[0013] As a preferred technical solution, the second joint movable contact surface of the femoral prosthesis includes a second plane, a third guide surface and a fourth guide surface. The third guide surface is located on the upper side of the second plane and smoothly transitions with the second plane. The third guide surface gradually extends in an inclined direction away from the patellar prosthesis from bottom to top. The fourth guide surface is located on the lower side of the second plane and smoothly transitions with the second plane. The fourth guide surface gradually extends in an inclined direction away from the patellar prosthesis from top to bottom.

[0014] As a preferred technical solution, the patellar prosthesis includes a first body and a first wing. The first wing is smoothly connected to the outer periphery of the first body. The first wing and the first body form a first mounting cavity for covering the patella. The first mounting surface is located inside the first mounting cavity, the first joint movable contact surface is located outside the first mounting cavity, and the outer surface of the first body is planar.

[0015] As a preferred technical solution, the first side wing includes a first inner wing and a first outer wing, the first inner wing and the first outer wing are respectively arranged on the left and right sides of the first main body, and at least one of the first inner wing and the first outer wing is provided with a first fixing hole; the first side wing also includes a first upper wing and a first lower wing, the first upper wing and the first lower wing are respectively arranged on the upper and lower sides of the first main body, and at least one of the first upper wing and the first lower wing is provided with a second clearance notch.

[0016] As a preferred technical solution, the femoral prosthesis includes a second body and a second wing. The second wing is smoothly connected to the outer edge of the second body, and the second wing and the second body form a second mounting cavity for covering the femur. The second mounting surface is located inside the second mounting cavity, and the second joint movable contact surface is located outside the second mounting cavity. The outer surface of the second body is planar. The second wing includes a second inner wing and a second outer wing, which are respectively arranged on the left and right sides of the second body. The second inner wing and the second outer wing are respectively provided with second fixing holes, and the second fixing holes on the second inner wing and the second outer wing are positioned opposite each other. The second wing also includes a second upper wing and a second lower wing, with the second upper wing located on the upper side of the second body and the second lower wing located on the lower side of the second body.

[0017] As a preferred technical solution, the femoral prosthesis further includes a liner, which is embedded on the side of the second body and the second wing away from the second mounting cavity, and the liner covers the movable contact surface of the second joint; the second body and the second wing are made of metal material, and the liner is made of ultra-high molecular weight polyethylene material.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] The planarized patellofemoral joint prosthesis of the present invention has at least a partial planar mating surface between the first joint movable contact surface of the patellar prosthesis and the second joint movable contact surface of the femoral prosthesis. Compared with the traditional bionic structure in which the patellofemoral prosthesis and the femoral prosthesis use a grooving groove and a trolley groove for mating, the two have a better matching effect. This can reduce the stress concentration problem at the contact position of the patellar prosthesis and the femoral prosthesis caused by groove mismatch and unbalanced contact, which is beneficial to alleviate joint prosthesis wear and knee flexion and extension pain.

[0020] The planarized patellofemoral joint prosthesis of the present invention has a second joint movable contact surface and a first joint movable contact surface mating plane that is an inclined plane with a lower inner surface and a higher outer surface, with an angle Q of 5~10° with the coronal plane of the human body, and is externally rotated to ensure postoperative symmetry of the knee flexion gap and balance of the medial and lateral collateral ligaments.

[0021] The planarized patellofemoral joint prosthesis of the present invention has a first fixation hole on the first inner wing and / or the first outer wing and the first upper wing of the patellar side prosthesis, and a second fixation hole on the second inner wing and the second outer wing of the femoral side prosthesis. This facilitates the fixation of the patellar side prosthesis to the patella and the femoral side prosthesis to the femur, without affecting the normal contact between the first joint movement contact surface and the second joint movement contact surface, thus ensuring normal knee flexion and extension. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the connection between the femur and patella in the knee joint, a natural structure of the human body.

[0024] Figure 2 This is a side view of the assembled embodiment of the present invention;

[0025] Figure 3 yes Figure 2 A bottom view;

[0026] Figure 4 This is a three-dimensional schematic diagram of the patellar prosthesis in this invention;

[0027] Figure 5 This is a three-dimensional schematic diagram of the femoral prosthesis in this invention;

[0028] Figure 6 This is a schematic diagram of the patellar prosthesis.

[0029] Figure 7 This is a schematic diagram of the femoral prosthesis.

[0030] Figure label:

[0031] 1-Patronic side prosthesis; 2-Femoral side prosthesis; 3-Patron; 31-Cardiac protrusion; 4-Femur; 41-Pulley groove; 101-First mounting surface; 102-First joint contact surface; 1021-First plane; 1022-First guide surface; 1023-Second guide surface; 103-First mounting cavity; 11-First main body; 12-First lateral wing; 121-First inner wing; 122-First outer wing; 123-First upper wing; 124-First lower wing; 201-First fixing hole; 1202-First clearance notch; 1203-Second clearance notch; 201-Second joint movable contact surface; 202-Second mounting surface; 2011-Second plane; 2012-Third guide surface; 2013-Fourth guide surface; 21-Second main body; 22-Second side wing; 23-Pad; 221-Second inner wing; 222-Second outer wing; 223-Second upper wing; 224-Second lower wing; 2201-Second fixing hole. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0033] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0034] In the fields of anatomy and medical devices, directions and planes such as internal, external, anterior, posterior, distal, proximal, sagittal, coronal, and cross-section have specific meanings and are well known to those skilled in the art. Unless otherwise specified, these terms refer to the meanings generally accepted by those skilled in the art.

[0035] Typically, when describing the human body, joints, or prostheses, three types of cross-sections are involved: the sagittal plane, the coronal plane, and the cross-section. The sagittal plane is a longitudinal section that divides the human body or joint into left and right parts along the anterior-posterior direction. The median sagittal plane, passing through the center of the human body, divides the body into two equal parts. The coronal plane is a longitudinal section that divides the human body or joint into anterior and posterior parts along the lateral direction. The coronal plane is perpendicular to the sagittal plane. The cross-section is a plane parallel to the ground that divides the human body or joint into upper and lower parts. The cross-section is perpendicular to both the coronal and sagittal planes.

[0036] Understandably, when describing a knee joint or knee prosthesis, the sagittal, coronal, and cross-sectional planes refer to the views taken when a person is standing upright normally, at which point the knee flexion angle is 0°. These views can change as the knee joint or prosthesis flexes or extends, or as the body's posture adjusts.

[0037] Typically, when describing the human body, joints, or prostheses, three different directions are involved: distal, medial, and posterior. The distal end refers to the end of the body or joint relatively far from the torso. The proximal end refers to the side of the body or joint relatively close to the torso, specifically the side relatively close to the midsagittal plane. The lateral end refers to the side relatively far from the midsagittal plane. The anterior end refers to the end in the sagittal plane relatively close to the abdomen. The posterior end refers to the end in the sagittal plane relatively close to the back.

[0038] A planarized patellofemoral joint prosthesis, such as Figures 2-7 As shown, the device includes a patellar prosthesis 1 and a femoral prosthesis 2: the patellar prosthesis 1 is used to connect to the posterior side of the patella 3, and has a first mounting surface 101 and a first articulated contact surface 102. The first mounting surface 101 and the first articulated contact surface 102 are arranged opposite to each other along the thickness direction of the patellar prosthesis 1. The first mounting surface 101 is used to mount on the patella 3, and the first articulated contact surface 102 is used to mate with the femoral prosthesis 2; the femoral prosthesis 2 is used to connect to the anterior side of the femur 4, and has a second mounting surface 202 and a second articulated contact surface 201. The second mounting surface 202 and the second articulated contact surface 201 are arranged opposite to each other along the thickness direction of the femoral prosthesis 2. The second mounting surface 202 is used to mount on the femur 4, and the second articulated contact surface 201 slides in engagement with the first articulated contact surface 102 of the patellar prosthesis 1; the mating surfaces of the first articulated contact surface 102 and the second articulated contact surface 201 are at least partially planar.

[0039] According to an embodiment of the present invention, when the patellar prosthesis 1 is implanted into the patella 3, the first mounting surface 101 is fitted with the patella 3. When the femoral prosthesis 2 is implanted into the femur 4, the second mounting surface is fitted with the femur 4. The first joint movable contact surface 102 of the patellar prosthesis 1 and the second joint movable contact surface 201 of the femoral prosthesis 2 are connected by planar sliding connection. Compared with the scheme in bionic prostheses where the patellar prosthesis and the femoral prosthesis are fitted with a cam and a trochlear groove, this method can reduce the stress concentration at the contact position of the patellar prosthesis and the femoral prosthesis caused by groove mismatch or unevenness, which is beneficial to slow down the wear of the joint prosthesis.

[0040] This invention, by designing the first joint movable contact surface 102 of the patellar-side prosthesis and the second joint movable contact surface 201 of the femoral-side prosthesis as planar surfaces, eliminates the need for the patellar-side prosthesis 1 to be as... Figure 1 The limitation shown is not within the trochlear groove 41, but rather sliding is achieved using a plane, which increases the contact area between the patellar prosthesis 1 and the femoral prosthesis 2, which helps to reduce the pressure on the patella 3 and avoid stress concentration.

[0041] Understandably, before implanting the patellar prosthesis 1, it is necessary to modify the conical protrusion structure, namely the locking protrusion 31 (i.e., the structure that mates with the trochlear groove 41 of the femur 4) in the posterior region of the patella 3. Figure 1 The patellar prosthesis 1 is processed to accommodate the patellar prosthesis 2, wherein the plane of the first joint contact surface 102 corresponds to the processed area of ​​the patellar 3's locking protrusion 31. Before installing the femoral prosthesis 2, the trochlear groove 41 of the femur 4 (as shown) needs to be processed. Figure 1 The femoral prosthesis 2 is processed (as shown) to install the femoral side prosthesis 2, wherein the plane of the second joint movable contact surface 201 corresponds to the processed area of ​​the trochlear groove 41 of the femur 4.

[0042] Therefore, the design of the patellofemoral joint prosthesis in this embodiment of the invention differs from the original patellofemoral joint structure. The patellofemoral joint prosthesis in this embodiment of the invention is an anti-biomimetic design. The planar contact of the first joint contact surface 102 and the second joint contact surface 201 can reduce the patellofemoral joint wear problem caused by groove mismatch or unevenness during patellofemoral joint movement, which is beneficial to reduce the pressure on the patella 3 and avoid stress concentration.

[0043] Furthermore, such as Figure 3As shown, the plane of the second joint movable contact surface 201 of the femoral prosthesis 2 and the plane of the first joint movable contact surface 102 of the patellar prosthesis 1 are inclined planes with a lower inner surface and a higher outer surface, forming an angle Q with the human coronal plane of 5-10°. It can be understood that the inclined plane of the femoral prosthesis 2 and the patellar prosthesis 1, with a lower inner surface and a higher outer surface, means that the plane tends to move away from the human coronal plane from the medial side of the femoral prosthesis 2 or the patellar prosthesis 1 to the lateral side. The inclined setting of the mating plane is used to ensure postoperative symmetry of the knee flexion gap and balance of the medial and lateral collateral ligaments. Preferably, the femoral prosthesis 2 and the patellar prosthesis 1 are available in three sizes, with the angle Q between the plane of the second joint movable contact surface and the plane of the first joint movable contact surface and the human coronal plane being 5°, 8°, and 10° respectively, to accommodate the external rotation needs of different patients.

[0044] Optionally, such as Figure 4 As shown, the first joint movable contact surface 102 includes a first plane 1021, a first guide surface 1022, and a second guide surface 1023. The first guide surface 1022, the first plane 1021, and the second guide surface 1023 are smoothly connected sequentially from top to bottom. The first guide surface 1022 gradually extends towards the patella 3 from bottom to top, and the second guide surface 1023 gradually extends towards the patella 3 from top to bottom. It can be understood that the first guide surface 1022 is located above the first plane 1021, and the second guide surface 1023 is located below the first plane 1021. When the patellar prosthesis 1 slides downward, the contact area between the patellar prosthesis 1 and the femoral prosthesis 2 can gradually transition from the first plane 1021 to the first guide surface 1022. When the patellar prosthesis 1 moves downward to its limit position, the first guide surface 1022 of the patellar prosthesis 1 contacts the femoral prosthesis 2. As the patellar prosthesis 1 slides upward, the contact area between the patellar prosthesis 1 and the femoral prosthesis 2 can gradually transition from the first plane 1021 to the second guide surface 1023. When the patellar prosthesis 1 moves upward to its limit position, the second guide surface 1023 of the patellar prosthesis 1 contacts the femoral prosthesis 2.

[0045] Therefore, the patellar prosthesis 1 of the present invention, by providing a first guide surface 1022 and a second guide surface 1023, can satisfy the smooth movement of the patellofemoral joint over a wide range, which is beneficial to increasing the contact area between the patellar prosthesis 1 and the femoral prosthesis 2 and reducing stress concentration.

[0046] For example, both the first guide surface 1022 and the second guide surface 1023 are inclined surfaces. The lower side of the first guide surface 1022 smoothly transitions to the first plane 1021, and the upper side of the second guide surface 1023 smoothly transitions to the first plane 1021. This can reduce the movement resistance of the patellar prosthesis 1 and make the contact stress between the patellar prosthesis 1 and the femoral prosthesis 2 change evenly, thereby reducing stress concentration.

[0047] It is understandable that the first joint movable contact surface 102 is similar in shape to the ski surface, that is, the middle position of the first joint movable contact surface 102 is a plane, and the extreme positions at both ends of the first joint movable contact surface 102 are inclined curved surfaces. This can ensure the smoothness of the patella 3 when sliding and reduce the movement resistance of the patellar side prosthesis 1.

[0048] Optionally, such as Figure 5 As shown, the second joint movable contact surface 201 of the femoral prosthesis 2 includes a second plane 2011, a third guide surface 2012 and a fourth guide surface 2013. The third guide surface 2012 is located on the upper side of the second plane 2011 and smoothly transitions with the second plane 2011. The third guide surface 2012 gradually extends in an inclined direction away from the patellar prosthesis 1 from bottom to top. The fourth guide surface 2013 is located on the lower side of the second plane 2011 and smoothly transitions with the second plane 2011. The fourth guide surface 2013 gradually extends in an inclined direction away from the patellar prosthesis 1 from top to bottom. Understandably, as the patellar prosthesis 1 slides upward, the contact area between the femoral prosthesis 2 and the patellar prosthesis 1 gradually transitions from the second plane 2011 to the third guide surface 2012. When the patellar prosthesis 1 moves upward to its extreme position, the third guide surface 2012 of the femoral prosthesis 2 contacts the patellar prosthesis 1. Similarly, as the patellar prosthesis 1 slides downward, the contact area between the femoral prosthesis 2 and the patellar prosthesis 1 gradually transitions from the second plane 2011 to the fourth guide surface 2013. When the patellar prosthesis 1 moves downward to its extreme position, the fourth guide surface 2013 of the femoral prosthesis 2 contacts the patellar prosthesis 1.

[0049] In embodiments of the present invention, the femoral prosthesis 2, by providing a second plane 2011, can increase the contact area between the femoral prosthesis 2 and the patellar prosthesis 1, reduce stress concentration, and thus slow down the wear of the patellofemoral joint prosthesis. Furthermore, by providing a third guide surface 2012 and a fourth guide surface 2013, and smoothly transitioning to the second plane 2011, the femoral prosthesis 2 can allow for smooth movement of the patellofemoral joint over a wide range of motion. This facilitates increasing the contact area between the patellar prosthesis 1 and the femoral prosthesis 2, resulting in a more uniform change in contact stress between them and reducing stress concentration.

[0050] In one specific embodiment, such as Figure 4 and Figure 6 As shown, the patellar prosthesis 1 includes a first body 11 and a first wing 12. The first wing 12 is smoothly connected to the outer periphery of the first body 11. The first wing 12 and the first body 11 form a first mounting cavity 103 for covering the patella 3. The first mounting surface 101 is located inside the first mounting cavity 103, and the first joint movable contact surface 102 is located outside the first mounting cavity 103. The outer surface of the first body 11 is planar. Since the first mounting cavity 103 can cover the patella 3, on the one hand, it can improve the firmness of the patellar prosthesis 1 after assembly with the patella 3; on the other hand, when the patella 3 moves to its extreme position, the first wing 12 can also contact the femoral prosthesis 2, thereby increasing the movable contact surface between the patellar prosthesis 1 and the femoral prosthesis 2 and reducing stress concentration.

[0051] Preferably, the first wing 12 includes a first inner wing 121 and a first outer wing 122, which are respectively arranged on the left and right sides of the first main body 11. At least one of the first inner wing 121 and the first outer wing 122 is provided with a first fixing hole 1201. It can be understood that the first inner wing 121 refers to the side of the patellar prosthesis 1 that is relatively close to the midsagittal plane of the human body, and the first outer wing 122 refers to the side of the patellar prosthesis 1 that is relatively far away from the midsagittal plane of the human body. Since at least one of the first inner wing 121 and the first outer wing 122 is provided with a first fixing hole 1201, it is convenient to fix the patellar prosthesis 1 and the patella 3, without affecting the normal contact between the patellar prosthesis 1 and the femoral prosthesis 2.

[0052] For example, there are two first fixation holes 1201, which are arranged at intervals along the vertical direction on the first inner wing 121 or the first outer wing 122. Bone screws can be inserted into the first fixation holes 1201 to connect the patellar prosthesis 1 to the patella 3.

[0053] Optionally, such as Figure 2 , Figure 6As shown, one of the first inner wing 121 and the first outer wing 122 is provided with a first fixing hole 1201, and the other is provided with a first clearance notch 1202. For example, the first inner wing 121 is provided with the first fixing hole 1201, and the first outer wing 122 is provided with the first clearance notch 1202. Another example is that the first outer wing 122 is provided with the first fixing hole 1201, and the first inner wing 121 is provided with the first clearance notch 1202. Since the first fixing hole 1201 is arranged on one side, it is beneficial to improve surgical efficiency and shorten surgical time. Furthermore, since the patella 3 is relatively small, fixing the patellar-side prosthesis 1 to the patella 3 on one side is sufficient to ensure the firmness of the connection between the patellar-side prosthesis 1 and the patella 3. Of course, as needed, two first fixing holes 1201 can also be provided on both the first inner wing 121 and the first outer wing 122, and a first clearance notch 1202 can be provided between the two first fixing holes 1201. Because the first inner wing 121 and / or the first outer wing 122 are provided with a first clearance notch 1202, the ligaments around the patella 3 (such as the patellar tendon) can be cleared, preventing the implantation of the patellar prosthesis 1 from having an adverse effect on the ligaments around the patella 3. This results in less trauma and is beneficial to improving the patient's postoperative recovery.

[0054] Optionally, the first wing 12 further includes a first upper wing 123 and a first lower wing 124, which are respectively arranged on the upper and lower sides of the first body 11. The first upper wing 123 and the first lower wing 124 are smoothly connected to the first body 11. The first upper wing 123 has a first fixing hole vertically provided for inserting a bone screw from top to bottom to fix the patellar prosthesis to the patella. At least one of the first upper wing 123 and the first lower wing 124 has a second clearance notch 1203, which is located on the side away from the first body 11. For example, the first upper wing 123 has a second clearance notch 1203. For example, the first lower wing 124 has a second clearance notch 1203. For yet another example, both the first upper wing 123 and the first lower wing 124 have a second clearance notch 1203. Because the first upper wing 123 and the first lower wing 124 are provided with a second avoidance notch 1203, the ligament tissues (such as the patellar tendon) around the patella 3 can be avoided, preventing the implantation of the patellar side prosthesis 1 from having an adverse effect on the ligament tissues around the patella 3. The trauma is smaller and it is beneficial to improve the patient's postoperative recovery.

[0055] More preferably, the first side wing 12 is inclined relative to the first main body 11, and the first side wing 12 is smoothly connected to the first main body 11 around its perimeter. The length of the first side wing 12 is 4mm.

[0056] In this embodiment, as Figure 5 , Figure 7As shown, the femoral prosthesis 2 includes a second body 21 and a second wing 22. The second wing 22 is smoothly connected to the outer edge of the second body 21, and the second wing 22 and the second body 21 form a second mounting cavity (not shown) for covering the femur 4. The second mounting surface is located inside the second mounting cavity, and the second joint movable contact surface 201 is located outside the second mounting cavity. The outer surface of the second body 21 is planar. Since the second mounting cavity can cover the femur 4, the firmness of the femoral prosthesis 2 after assembly with the femur 4 can be improved. The second wing 22 includes a second upper wing 223 and a second lower wing 224. The second upper wing 223 is smoothly connected to the upper side of the second body 21, and the second lower wing 224 is smoothly connected to the lower side of the second body 21. It also includes a second inner wing 221 and a second outer wing 222, which are respectively arranged on the left and right sides of the second main body 21. The second inner wing 221 and the second outer wing 222 are each provided with a second fixing hole 2201, and the second fixing holes 2201 on the second inner wing 221 and the second outer wing 222 are positioned opposite each other. It can be understood that the second inner wing 221 refers to the side of the femoral prosthesis 2 that is relatively closer to the midsagittal plane of the human body, and the second outer wing 222 refers to the side of the femoral prosthesis 2 that is relatively farther away from the midsagittal plane of the human body. Because the second inner wing 221 and the second outer wing 222 are provided with second fixing holes 2201, it is convenient to fix the femoral prosthesis 2 and the femur 4 without affecting the normal contact between the femoral prosthesis 2 and the patellar prosthesis 1.

[0057] For example, such as Figure 7 As shown, the second inner wing 221 and the second outer wing 222 are respectively provided with three second fixing holes 2201, which are evenly spaced along the outer contour of the second inner wing 221 or the second outer wing 222. Bone screws can be inserted into the second fixing holes 2201 to connect the femoral prosthesis 2 to the femur 4.

[0058] Optionally, the materials of the patellar prosthesis 1 and the femoral prosthesis 2 can be the same as those of traditional medical implants, such as metal alloys, or can be made of materials such as PEEK and Teflon. The elastic modulus and stiffness of the materials need to be sufficiently high, and they must meet the biocompatibility requirements of implant-grade materials to disperse stress and avoid prosthesis wear or failure caused by stress concentration. Preferably, the femoral prosthesis 2 also includes a liner 23, which is embedded on the side of the second body 21 and the second wing 22 away from the second mounting cavity. The liner 23 covers the second joint movable contact surface 201. The second body and the second wing are made of metal materials, and the liner 23 is preferably made of highly cross-linked ultra-high molecular weight polyethylene. Through the contact between the liner 23 and the patellar prosthesis 1, the wear between the patellar prosthesis 1 and the femoral prosthesis 2 is reduced, and the service life of the prosthesis is extended.

[0059] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the appended claims.

Claims

1. A planarized patellofemoral joint prosthesis, comprising a femoral prosthesis and a patellar prosthesis; characterized in that: The patellar prosthesis is used to connect to the posterior side of the patella and has a first mounting surface and a first joint movable contact surface. The first mounting surface and the first joint movable contact surface are arranged opposite to each other along the thickness direction of the patellar prosthesis. The first mounting surface is used to be mounted on the patella, and the first joint movable contact surface is used to cooperate with the femoral prosthesis. The first joint movable contact surface includes a first plane. The femoral prosthesis is used to connect to the anterior side of the femur and has a second mounting surface and a second joint movable contact surface. The second mounting surface and the second joint movable contact surface are arranged opposite to each other along the thickness direction of the femoral prosthesis. The second mounting surface is used to be mounted on the femur. The second joint movable contact surface includes a second plane. The second plane of the second joint movable contact surface slides and engages with the first plane of the first joint movable contact surface. The second plane of the second joint contact surface of the femoral prosthesis and the first plane of the first joint contact surface of the patellar prosthesis are inclined planes with a lower inner surface and a higher outer surface, and the angle between the inclined plane and the coronal plane of the human body is 5~10°.

2. The planarized patellofemoral joint prosthesis according to claim 1, characterized in that: The femoral and patellar prostheses are available in three matching specifications. Within the same matching specification, the plane of the second joint contact surface and the plane of the first joint contact surface have the same angle with the coronal plane of the human body. The angles for the three matching specifications are 5°, 8°, and 10°, respectively.

3. The planarized patellofemoral joint prosthesis according to claim 1, characterized in that: The first joint movable contact surface also includes a first guide surface and a second guide surface. The first guide surface, the first plane and the second guide surface are smoothly connected in sequence from top to bottom. The first guide surface gradually extends towards the patella from bottom to top, and the second guide surface gradually extends towards the patella from top to bottom.

4. The planarized patellofemoral joint prosthesis according to claim 3, characterized in that: Both the first guide surface and the second guide surface are inclined surfaces. The lower side of the first guide surface smoothly transitions to the first plane, and the upper side of the second guide surface smoothly transitions to the first plane.

5. The planarized patellofemoral joint prosthesis according to claim 3, characterized in that: The second joint contact surface of the femoral prosthesis also includes a third guide surface and a fourth guide surface. The third guide surface is located on the upper side of the second plane and smoothly transitions with the second plane. The third guide surface gradually extends in an inclined direction away from the patellar prosthesis from bottom to top. The fourth guide surface is located on the lower side of the second plane and smoothly transitions with the second plane. The fourth guide surface gradually extends in an inclined direction away from the patellar prosthesis from top to bottom.

6. The planarized patellofemoral joint prosthesis according to claim 3, characterized in that: The patellar prosthesis includes a first body and a first wing. The first wing is smoothly connected to the outer periphery of the first body. The first wing and the first body form a first mounting cavity for covering the patella. The first mounting surface is located inside the first mounting cavity, and the first joint movable contact surface is located outside the first mounting cavity.

7. The planarized patellofemoral joint prosthesis according to claim 6, characterized in that: The first side wing includes a first inner wing and a first outer wing, which are respectively arranged on the left and right sides of the first main body. At least one of the first inner wing and the first outer wing is provided with a first fixing hole. The first side wing also includes a first upper wing and a first lower wing, which are respectively arranged on the upper and lower sides of the first main body. At least one of the first upper wing and the first lower wing is provided with a second clearance notch.

8. The planarized patellofemoral joint prosthesis according to claim 5, characterized in that: The femoral prosthesis includes a second body and a second wing. The second wing is smoothly connected to the outer edge of the second body, and the second wing and the second body form a second mounting cavity for covering the femur. The second mounting surface is located inside the second mounting cavity, and the second joint movable contact surface is located outside the second mounting cavity. The second wing includes a second inner wing and a second outer wing, which are respectively arranged on the left and right sides of the second body. The second inner wing and the second outer wing are respectively provided with second fixing holes, and the second fixing holes on the second inner wing and the second outer wing are positioned opposite each other. The second wing also includes a second upper wing and a second lower wing, with the second upper wing located on the upper side of the second body and the second lower wing located on the lower side of the second body.

9. The planarized patellofemoral joint prosthesis according to claim 8, characterized in that: The femoral prosthesis also includes a liner, which is embedded on the side of the second body and the second wing away from the second mounting cavity, and the liner covers the movable contact surface of the second joint; the second body and the second wing are made of metal material, and the liner is made of ultra-high molecular weight polyethylene material.

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