CN209790099U - Unicondylar femoral prosthesis and tibial insert - Google Patents

Abstract

the utility model relates to a unicondylar femoral prosthesis and shin bone liner, unicondylar femoral prosthesis including be used for with the thighbone be connected cut the bone face and be used for with the articular surface of shin bone butt, wherein the articular surface includes distal end articular surface and posterior condylar articular surface, distal end articular surface has first radius of curvature on the sagittal plane, posterior condylar articular surface has second radius of curvature on the sagittal plane, first radius of curvature is greater than second radius of curvature, the articular surface has third radius of curvature on the coronal plane, third radius of curvature equals with first radius of curvature. The single-condyle femoral prosthesis is more matched with the anatomical structure of the femoral articular surface of a human body, the problems of insufficient coverage of the femoral distal surface and excessive osteotomy are solved, and the bearing performance and the joint stability of the articular surface are improved.

Description

Unicondylar femoral prosthesis and tibial insert

Technical Field

The utility model relates to the technical field of medical equipment, especially, relate to a single condyle femoral prosthesis and shin bone liner.

background

Unicondylar replacement is widely used in the treatment of unicompartmental osteoarthrosis due to its small wound, quick recovery, etc. Unicondylar prostheses used in unicondylar replacement procedures can be divided into medial femoral prostheses for replacing the medial compartment, medial tibial prostheses, and lateral femoral and lateral tibial prostheses for replacing the lateral compartment.

In order to ensure that the contact area between the femoral component and the tibial component is not changed in the whole flexion and extension range, the joint surface of the traditional unicondylar femoral prosthesis is designed to be a single-radius spherical surface. Because the shape of the articular surface of the femoral posterior condylar part is closer to the spherical surface, the single-radius spherical design mainly covers the femoral posterior condylar part, namely, the contour of the articular surface of the posterior condylar part is taken as the standard for fitting, so the distal femur cannot be well matched. Meanwhile, when the bone is cut, a concave area is formed at the far end of the femur, and the far end is cut too much. The distal femur is the main bearing surface for the joint to walk and stand in daily physiological activities, and this mismatch increases the probability of loosening of the femoral condyle prosthesis after implantation. Or some unicondylar femoral prostheses adopt a multi-center design that the curvature radius is gradually reduced from the distal joint surface to the posterior condylar joint surface, and ligament tissues of knee joints can be loosened in the buckling process of the femoral prostheses, so that the joint stability is reduced, the postoperative proprioception of patients is poor, and the dislocation risk of the prostheses is high.

SUMMERY OF THE UTILITY MODEL

In view of the above, there is a need to provide a unicondylar femoral prosthesis and a tibial insert that address the above problems.

A unicondylar femoral prosthesis comprising a osteotomy surface for coupling with a femur and an articular surface for abutment with a tibial insert, the articular surface comprising a distal articular surface having a first radius of curvature in the sagittal plane and a posterior condylar articular surface having a second radius of curvature in the sagittal plane, the first radius of curvature being greater than the second radius of curvature.

The single-condyle femoral prosthesis adopts the joint surfaces with double radii on the sagittal plane, namely the distal joint surface with the first curvature radius and the posterior condyle joint surface with the second curvature radius on the sagittal plane, and the first curvature radius is larger than the second curvature radius, so that the single-condyle femoral prosthesis is more matched with the anatomical structure of the femoral joint surface of a human body, and the problems of insufficient coverage of the distal surface of the femur and excessive osteotomy of the traditional spherical single-radius prosthesis are solved.

In one embodiment, the articular surface has a third radius of curvature on the coronal plane, the third radius of curvature being equal to the first radius of curvature.

In one embodiment, the osteotomy surface comprises a posterior condylar osteotomy surface, a posterior oblique osteotomy surface and a distal osteotomy surface which are connected in sequence, the posterior condylar osteotomy surface, the posterior oblique osteotomy surface and the distal osteotomy surface are all planes, and the posterior condylar osteotomy surface and the distal osteotomy surface are perpendicular to each other.

In one embodiment, the osteotomy surfaces include a posterior condylar osteotomy surface that is planar and a distal osteotomy surface that is spherical and concentric with the distal articular surface.

In one embodiment, the radius of curvature of the distal osteotomy face is between 4mm and 7mm less than the first radius of curvature.

in one embodiment, the side of the unicondylar femoral prosthesis near the center of the knee joint is formed with an arc surface that is offset from the direction of the center of the knee joint.

In one embodiment, the arc extends from a point in the anterior half of the unicondylar femoral prosthesis on a side proximal to the center of the knee joint to a point at the anterior end of the unicondylar femoral prosthesis.

In one embodiment, the osteotomy surface is provided with at least one fixation post for assisting in fixation of the unicondylar femoral prosthesis.

In one embodiment, the transition angle between the distal articular surface and the posterior condylar articular surface ranges from 10 ° to 25 °, and the transition angle is the angle formed by a line on the sagittal plane passing through the center of curvature of the distal articular surface and through the distal-most point of the distal articular surface and a line passing through the center of curvature of the posterior condylar articular surface and through the intersection of the distal articular surface and the posterior condylar articular surface.

In one embodiment, the unicondylar femoral prosthesis is a medial femoral prosthesis for replacement of the medial compartment of a femur, the medial femoral prosthesis having a first radius of curvature in a range of 30mm to 55mm and a ratio of the first radius of curvature to the second radius of curvature in a range of 1.4 to 2.1.

In one embodiment, the medial femoral prosthesis has a lateral side and a medial side, both of which include curved surfaces that curve toward the center of the knee joint.

In one embodiment, the lateral side is projected in cross-section as an arc having a tangent at a midpoint in the arc in a range of 15 ° to 30 ° from the sagittal plane.

In one embodiment, the unicondylar femoral prosthesis is a lateral femoral prosthesis for replacement of a lateral compartment of a femur, the lateral femoral prosthesis having a first radius of curvature in a range of 30mm to 60mm and a ratio of the first radius of curvature to the second radius of curvature in a range of 1.4 to 2.1.

In one embodiment, the lateral femoral prosthesis has a lateral side and a medial side, the lateral side including a first straight side and a second straight side offset toward the center of the knee joint. The medial surface includes a third straight surface and a fourth straight surface that are biased toward the center of the knee joint.

in one embodiment, the first straight surface is parallel to the third straight surface, and the first straight surface and the third straight surface are angled from the sagittal plane by an angle in the range of 0 ° -6 °; the second straight surface is parallel to the fourth straight surface, and the included angle between the second straight surface and the sagittal plane ranges from 7 degrees to 14 degrees.

A tibial insert for cooperation with the unicondylar femoral prosthesis, the tibial insert having a proximal articular surface abutting the distal articular surface, the proximal articular surface being spherical, the ratio of the first radius of curvature to the radius of curvature of the proximal articular surface being in the range of 0.95-1.

The tibia liner can be matched with the unicondylar femoral prosthesis, so that the abrasion of the unicondylar femoral prosthesis can be reduced, and the service life of the unicondylar femoral prosthesis is prolonged.

drawings

FIG. 1 is a schematic view of various anatomical surfaces of a human body;

FIG. 2 is a sagittal view of a knee joint;

FIG. 3 is a coronal view of a knee joint;

FIG. 4 is a side view of an embodiment of a unicondylar femoral prosthesis;

FIG. 5 is a top view of the unicondylar femoral prosthesis shown in FIG. 4;

FIG. 6 is a side view of another embodiment of a unicondylar femoral prosthesis;

FIG. 7 is a top view of the unicondylar femoral prosthesis shown in FIG. 6;

FIG. 8 is a side view of a medial femoral prosthesis according to an embodiment;

FIG. 9 is a top view of the medial femoral prosthesis shown in FIG. 8;

FIG. 10 is a schematic view of the installation of the medial femoral prosthesis shown in FIG. 8;

FIG. 11 is a side view of an embodiment of a lateral femoral prosthesis;

FIG. 12 is a top view of the lateral femoral prosthesis shown in FIG. 11;

FIG. 13 is a schematic view of the installation of the lateral femoral prosthesis shown in FIG. 11;

FIG. 14 is a top view of another embodiment of a medial femoral prosthesis;

FIG. 15 is a top view of another embodiment of a lateral femoral prosthesis;

FIG. 16 is a schematic view of a tibial prosthesis according to an embodiment;

Fig. 17 is a cross-sectional view of the tibial prosthesis shown in fig. 16 at section a-a.

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 can be embodied in many different forms other than those specifically described herein, and it will be apparent to those skilled in the art that similar modifications can be made without departing from the spirit and scope of the invention, and it is therefore not to be limited to the specific embodiments disclosed below.

It will be understood that when an element is referred to as being "secured to" 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.

unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

To better explain the technical solution of the present invention, the orientation names involved in the embodiments are first explained, as shown in fig. 1 to 3:

sagittal plane 101: the longitudinal section divides the human body or joints into left and right parts from the front and back, wherein the sagittal plane passing through the center of the human body is the central sagittal plane, and the sagittal plane divides the human body into two equal parts.

Coronal plane 102: this means a longitudinal section which divides the body or joint into two parts, front and rear, from the left and right, and is perpendicular to the sagittal plane.

Horizontal plane 103: also called transverse plane, is a plane parallel to the ground plane and dividing the body or joint into upper and lower parts, which are perpendicular to the coronal and sagittal planes.

a far end: the end of the body or joint relatively distant from the head.

Proximal end: the human body or joint is relatively close to one end of the head.

Inner side: relatively close to the midsagittal plane of the human body.

Outside: relatively far from the median sagittal plane of the human body.

front side: on the sagittal plane, relatively near the side of the abdomen.

Rear side: on the sagittal plane, relatively near the side of the back.

Referring to fig. 4 and 5, embodiments of the present application provide a unicondylar femoral prosthesis 100 for replacing the medial compartment or the lateral compartment of a knee joint. Specifically, the unicondylar femoral prosthesis 100 of an embodiment includes an articular surface 110 and a osteotomy surface 120. The osteotomy surface 120 is used to interface with the femur to secure the unicondylar femoral prosthesis 100. The articular surface 110 is intended to abut the tibia in place of the diseased femoral articular surface. The joint surface 110 is a distally convex curved surface, and the joint surface 110 includes a distal joint surface 111 for replacing the distal femur and a posterior condylar joint surface 112 for replacing the posterior femur. The distal articular surface 111 has a first radius of curvature Rd in the sagittal plane and the posterior condylar articular surface 112 has a second radius of curvature Rp in the sagittal plane. The first radius of curvature Rd is greater than the second radius of curvature Rp so that the articular surface 110 forms a curved surface with a double radius on the sagittal plane to better match the distal end of the femur with the posterior condyles. Further, the articular surface 110 has a third radius of curvature Rc on the coronal plane, and the third radius of curvature Rc is equal to the first radius of curvature Rd such that the distal articular surface 111 forms a spherical surface having a radius of the first radius of curvature Rd. The spherical surface has better bearing capacity, so that the far-end joint surface 111 serving as a main bearing surface has better bearing capacity in daily walking and standing.

The unicondylar femoral prosthesis 100 described above employs a bi-radial articular surface 110 in the sagittal plane, i.e., a distal articular surface 111 having a first radius of curvature Rd in the sagittal plane and a posterior condylar articular surface 112 having a second radius of curvature Rp. Because the curvature radius of the distal end joint surface 111 of the human femur is larger than that of the posterior condylar joint surface 112, the first curvature radius Rd is set to be larger than the second curvature radius Rp, so that the joint surface 110 can be more matched with the anatomical structure of the femoral joint surface of the human femur, and the problems of insufficient coverage of the distal end surface of the femur and excessive osteotomy of the traditional spherical single-radius prosthesis are solved. Further, the curvature radius of the joint surface 110 of the unicondylar femoral prosthesis 100 on the coronal plane is equal to the first curvature radius Rd, so that the distal joint surface 111 forms a spherical surface, the problem of unstable knee joint flexion caused by the femoral prosthesis of the traditional multi-center design is solved, and the force bearing performance and the joint stability of the distal joint surface 111 are improved.

The osteotomy face 120 of the unicondylar femoral prosthesis 100 matches the femoral osteotomy face formed in a unicondylar replacement. In one embodiment, the osteotomy face 120 includes a posterior condylar osteotomy face 121, a posterior oblique osteotomy face 122, and a distal osteotomy face 123, all connected in series. The posterior condylar facet 121, the posterior chamfer facet 122, and the distal facet 123 are all planar, and the posterior condylar facet 121 and the distal facet 123 are perpendicular to each other. Further, the posterior oblique osteotomy face 122 is angled 130-140, preferably 135, from the posterior condylar osteotomy face 121 and the distal osteotomy face 123. The posterior condylar osteotomy surface 121, the posterior oblique osteotomy surface 122 and the distal osteotomy surface 123 are arranged to be planes, so that the osteotomy surface 120 is easy to process, and the process difficulty is reduced.

referring to fig. 6 and 7, in another embodiment, the distal osteotomy surface 123 may be replaced by a spherical surface, and specifically, the osteotomy surface 120 of one embodiment includes a posterior condylar osteotomy surface 121 and a distal osteotomy surface 123. Wherein the posterior condylar osteotomy surface 121 is planar. The distal osteotomy surface 123 is spherical and the distal osteotomy surface 123 is concentric with the distal articular surface 111, i.e., the center of curvature of the distal osteotomy surface 123 coincides with the center of curvature of the distal articular surface 111. Further, the radius of curvature of the distal osteotomy surface 123 is between 4mm and 7mm, preferably between 4.5 and 6.5mm, most preferably 6mm, smaller than the radius of curvature of the distal articular surface 111. Within this range, the thickness of the prosthesis can satisfy the requirement of mechanical strength, and the amount of bone grafting can be controlled as much as possible to prevent excessive bone cutting. The above numerical ranges are inclusive of the endpoints, and the following is the same. The spherical structure of the distal osteotomy surface 123 can retain more cortical bone of the femur, so that the original cancellous bone structure of the femur can be better maintained during osteotomy, the force bearing performance after femoral operation is better, and the loosening probability of the postoperation unicondylar femoral prosthesis 100 is reduced.

With continued reference to fig. 4, in one embodiment, at least one fixation post 124 is disposed on the osteotomy surface 120 of the unicondylar femoral prosthesis 100. Specifically, referring to fig. 4, two fixation posts 124 are provided on the osteotomy face 120. The fixation post 124 is cylindrical to assist in fixation of the unicondylar femoral prosthesis 100. Specifically, in the replacement of the unicondylar femoral prosthesis 100, a mounting hole is formed on the femoral resection surface, and the fixing post 124 is disposed in the mounting hole, so as to fix the unicondylar femoral prosthesis 100.

The unicondylar femoral prosthesis 100 may be divided into a medial femoral prosthesis for replacing the medial compartment of the femur and a lateral femoral prosthesis for replacing the lateral compartment of the femur, depending on the replacement location. When the unicondylar femoral prosthesis 100 is a medial femoral prosthesis, the first radius of curvature Rd ranges from 30mm to 55mm, preferably from 36mm to 46mm, and most preferably 41 mm. The first curvature radius Rd is in the numerical range, and the shape of the far-end joint surface of the prosthesis is more matched with the original physiological structure of the far-end joint surface of the human body. The ratio of the first radius of curvature Rd to the second radius of curvature Rp ranges from 1.4 to 2.1, preferably from 1.6 to 2.0, and most preferably 1.7, thereby making the medial femoral prosthesis more closely match the medial femoral compartment. Further, the transition angle β of the distal articular surface 111 to the posterior condylar articular surface 112 ranges from 10 ° to 25 °, preferably from 15 ° to 20 °, and most preferably is 20 °. The transition angle can better balance the joint mobility and the friction performance in the range. The transition angle β is defined as the angle formed, in the sagittal plane, by a line passing through the center of curvature of the distal articular surface 111 and through the distal-most point a of the distal articular surface 111 and a line passing through the center of curvature of the posterior condylar articular surface 112 and through the intersection b of the distal articular surface 111 and the posterior condylar articular surface 112.

When the unicondylar femoral prosthesis 100 is a lateral femoral prosthesis, the first radius of curvature Rd ranges from 30mm to 60mm, preferably from 41mm to 51mm, and most preferably 46 mm. The first curvature radius Rd is in the numerical range, and the shape of the far-end joint surface of the prosthesis is more matched with the original physiological structure of the far-end joint surface of the human body. The ratio of the first radius of curvature Rd to the second radius of curvature Rp ranges from 1.4 to 2.1, preferably from 1.6 to 2.0, and most preferably 1.7, thereby making the lateral femoral prosthesis more closely match the lateral femoral compartment. Further, the transition angle β between the distal articular surface 111 and the posterior condylar articular surface 112 is in the range of 10-25 °, and the transition angle provides better balance between joint motion and frictional properties within this range.

The present application further provides an asymmetric unicondylar femoral prosthesis, and in particular, referring to fig. 8-10, taking medial femoral prosthesis 200 of a right side knee joint as an example, a side of medial femoral prosthesis 200 near knee joint center 500 is medial side 231 of medial femoral prosthesis 200, and a side of medial femoral prosthesis 200 away from knee joint center 500 is lateral side 232 of medial femoral prosthesis 200. The medial surface 231 of the medial femoral prosthesis 200 is formed with an arc surface 2311 that is offset from the knee joint center 500. Specifically, the cambered surface 2311 extends from a point a located in the anterior half of the medial side 231 of the medial femoral prosthesis 200 to a point B located at the anterior end of the medial femoral prosthesis 200. Preferably, point A is located on the anterior 35% to 45% of medial side 231, and most preferably point A is located on the anterior 40% of medial side 231. Wherein "located at the front 35% to 45% of the medial side 231" means: the distance L1 from point a to point B in the anterior-posterior direction accounts for 35% to 45% of the anterior-most to posterior-most distance L2 of the medial femoral prosthesis 200. Preferably, point B is located at the anterior midpoint of the medial femoral prosthesis 200. The medial femoral prosthesis 200 with the cambered surface 2311 can reduce the probability of collision between the patella and the medial femoral prosthesis 200 during the flexion and extension of the postoperative knee joint, and reduce postoperative pain and the probability of looseness of the medial femoral prosthesis 200. Further, the medial femoral prosthesis 200 of the right knee joint is mirrored by using the midsagittal plane as a mirror plane, so that the medial femoral prosthesis applied to the medial compartment of the left knee joint can be obtained.

Referring to fig. 11-13, taking lateral femoral prosthesis 300 of the right side knee joint as an example, the side of lateral femoral prosthesis 300 near knee joint center 500 is medial side 331, and the side of medial femoral prosthesis 200 away from knee joint center 500 is lateral side 332. The medial surface 331 of the lateral femoral prosthesis 300 has an arcuate surface 3311 formed thereon in a direction away from the knee joint center 500. Specifically, the contour 3311 extends from a point a located in the anterior half of the medial side 331 of the lateral femoral prosthesis 300 to a point B located at the anterior end of the lateral femoral prosthesis 300. Preferably, point A is located on the anterior 35% to 45% of medial side 331, and most preferably point A is located on the anterior 40% of medial side 331. Wherein "located at the front 35-45% of the medial side 331" means: the distance L1 from point a to point B in the anterior-posterior direction accounts for 35% to 45% of the distance L2 from the most anterior end to the most posterior end of the lateral femoral prosthesis 300. The lateral femoral prosthesis 300 with the cambered surface 3311 can reduce the probability of collision between the patella and the lateral femoral prosthesis 300 during flexion and extension of the postoperative knee joint, and reduce postoperative pain and the probability of looseness of the lateral femoral prosthesis 300. Further, the lateral femoral prosthesis 300 of the right knee joint is mirrored by taking the median sagittal plane as a mirror image plane, so that the lateral femoral prosthesis applied to the lateral compartment of the left knee joint can be obtained.

in one embodiment, the present application is further modified with respect to medial 231 and lateral 232 sides of medial femoral prosthesis 200. Specifically, referring to fig. 14, taking the medial femoral prosthesis 200 of the right knee joint as an example, the lateral surface 232 and the medial surface 231 of the medial femoral prosthesis 200 are curved surfaces that curve toward the center of the knee joint. Optionally, the medial surface 231 of the medial femoral prosthesis 200 is further formed with an arc 2311 offset from the direction of extension of the medial surface 231, the arc 2311 extending from a point on the anterior half of the unicondylar femoral prosthesis on the side closer to the center of the knee joint to a point on the anterior end of the unicondylar femoral prosthesis. Two end point position ranges refer to the embodiment shown in fig. 9. Further, as shown in FIG. 14, the projection of lateral side 232 onto a horizontal plane can form an arc having a tangent at the midpoint C that is at an angle α 1 to the sagittal plane in the range of 15 to 30, preferably 23 to 27, and most preferably 25. The included angle alpha 1 is within the range, the anatomical shapes of the medial femoral prosthesis 200 and the medial condyle of the femur are more matched, interference between the front overhang projection of the medial femoral prosthesis 200 and the medial ligament tissue of the knee joint is avoided, and the postoperative pain occurrence probability of the patient is reduced. Further, the medial femoral prosthesis 200 of the right knee joint is mirrored by using the midsagittal plane as a mirror plane, so that the medial femoral prosthesis applied to the medial compartment of the left knee joint can be obtained.

in another embodiment, the present application further improves medial 331 and lateral 332 surfaces of lateral femoral prosthesis 300, and specifically, referring to fig. 15, for example, lateral femoral prosthesis 300 of the right knee joint, lateral surface 332 of lateral femoral prosthesis 300 includes a first straight surface 3321 and a second straight surface 3322 that are offset toward the center of the knee joint. The medial side 331 includes a third straight side 3312 and a fourth straight side 3313 that are offset toward the center of the knee joint. Optionally, medial surface 331 of lateral femoral prosthesis 300 is further formed with an arc 3311 offset from the direction in which fourth straight surface 3313 extends, said arc 3311 extending from a point in the anterior half of the unicondylar femoral prosthesis on a side proximal to the center of the knee joint to a point at the anterior end of the unicondylar femoral prosthesis. Two end point location ranges refer to the embodiment shown in fig. 12. Wherein the first straight surface 3321 is parallel to the third straight surface 3312 and the first straight surface 3321 and the third straight surface 3312 each include an angle α 2 with the sagittal plane in the range of 0 ° to 6 °, preferably 3 ° to 5 °, most preferably 3 °. The second straight surface 3322 is parallel to the fourth straight surface 3313 and the angle α 3 between the second straight surface 3322 and the fourth straight surface 3313 and the sagittal plane is in the range 7 ° to 14 °, preferably 7 ° to 11 °, and most preferably 9 °. The included angles α 2 and α 3 are within the above ranges, so that the anatomical shapes of the lateral femoral prosthesis 300 and the lateral condyle of the femur are more matched, interference between the front-end overhang of the lateral femoral prosthesis 300 and the lateral ligament tissue of the knee joint is avoided, and the postoperative pain occurrence probability of the patient is reduced. Further, the lateral femoral prosthesis 300 of the right knee joint is mirrored by taking the median sagittal plane as a mirror image plane, so that the lateral femoral prosthesis applied to the lateral compartment of the left knee joint can be obtained.

Referring to fig. 16-17, the present application further provides a tibial insert 400 for use with any of the above-described embodiments of the unicondylar femoral prosthesis, such as the unicondylar femoral prosthesis 100. Specifically, tibial insert 400 of one embodiment includes a distal surface 410 and a proximal articular surface 420. Distal surface 410 is planar for attachment to the tibia. The proximal articular surface 420 is adapted to abut the distal articular surface 111 of the unicondylar femoral prosthesis 100 described above. Further, the proximal articular surface 420 is spherical, and the radius of curvature SR of the proximal articular surface 420 is similar to the first radius of curvature Rd of the distal articular surface 111 with which it is engaged. Specifically, the ratio of the first radius of curvature Rd to the radius of curvature SR of the proximal articular surface 420 ranges from 0.95 to 1.

When the tibial insert 400 is in the knee extension state, i.e., when the tibial insert 400 is in contact with the distal articular surface 111 of the unicondylar femoral prosthesis 100, the proximal articular surface 420 and the distal articular surface 111 can be highly matched because the radius of curvature SR of the proximal articular surface 420 is similar to both the sagittal curvature radius Rd and the coronal curvature radius Rc of the distal articular surface 111. At this time, the posture of the human body is standing walking and the like, and is a posture with a large bearing pressure of the knee joint, and the height matching of the tibial gasket 400 and the unicondylar femoral prosthesis 100 can ensure that the tibial gasket 400 and the unicondylar femoral prosthesis 100 have better contact friction performance, reduce the abrasion of the unicondylar femoral prosthesis 100 and prolong the service life of the unicondylar femoral prosthesis 100.

In knee flexion, i.e., when tibial insert 400 is in contact with the posterior condylar articular surface 112 of unicondylar femoral prosthesis 100, the radius of curvature SR of proximal articular surface 420 is not similar to the sagittal plane radius of curvature (i.e., third radius of curvature Rp) of posterior condylar articular surface 112, but because the radius of curvature SR of proximal articular surface 420 is similar to the coronal plane radius of curvature (i.e., third radius of curvature Rc) of posterior condylar articular surface 112, proximal articular surface 420 and posterior condylar articular surface 112 also maintain a high degree of matching in the coronal plane. When the knee joint is in the bucking state, the human body is mostly the position of sitting, and the knee joint pressure-bearing is little this moment, and the high matching of coronal plane is enough to guarantee better contact friction performance, reduces the wearing and tearing of unicondylar femoral prosthesis 100, improves unicondylar femoral prosthesis 100's life.

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 (14)

1. A unicondylar femoral prosthesis comprising a osteotomy surface for coupling with a femur and an articular surface for abutment with a tibial insert, said articular surface comprising a distal articular surface having a first radius of curvature in the sagittal plane and a posterior condylar articular surface having a second radius of curvature in the sagittal plane, said first radius of curvature being greater than said second radius of curvature.

2. The unicondylar femoral prosthesis of claim 1, wherein the articular surface has a third radius of curvature on the coronal surface, the third radius of curvature being equal to the first radius of curvature.

3. The unicondylar femoral prosthesis of claim 1, wherein the osteotomy surface comprises a posterior condylar osteotomy surface and a distal osteotomy surface, the posterior condylar osteotomy surface being planar, the distal osteotomy surface being spherical, and the distal osteotomy surface being concentric with the distal articular surface.

4. The unicondylar femoral prosthesis of claim 3, wherein the radius of curvature of the distal osteotomy face is between 4mm and 7mm less than the first radius of curvature.

5. The unicondylar femoral prosthesis of claim 1, wherein a side of the unicondylar femoral prosthesis near a center of a knee joint is formed with an arc that is offset from the center of the knee joint.

6. The unicondylar femoral prosthesis of claim 5, wherein the arc extends from a point in an anterior half of the unicondylar femoral prosthesis on a side proximal to a center of a knee joint to a point at an anterior end of the unicondylar femoral prosthesis.

7. The unicondylar femoral prosthesis of claim 1, wherein the transition angle of the distal articular surface to the posterior condylar articular surface ranges from 10 ° to 25 °.

8. The unicondylar femoral prosthesis of any of claims 1-7, wherein the unicondylar femoral prosthesis is a medial femoral prosthesis for replacement of the medial compartment of a femur, the medial femoral prosthesis having a first radius of curvature in the range of 30mm-55mm and a ratio of the first radius of curvature to the second radius of curvature in the range of 1.4-2.1.

9. The unicondylar femoral prosthesis of claim 8, wherein the medial femoral prosthesis has a lateral side and a medial side, each of the lateral side and the medial side including a curved surface that curves toward a location near the center of the knee joint.

10. The unicondylar femoral prosthesis of claim 9, wherein a projection of said lateral surface onto a horizontal plane forms an arc, a tangent at a midpoint of said arc subtending an angle with the sagittal plane in the range of 15 ° -30 °.

11. The unicondylar femoral prosthesis of any of claims 1-7, wherein the unicondylar femoral prosthesis is a lateral femoral prosthesis for replacement of a lateral femoral compartment, the lateral femoral prosthesis having a first radius of curvature in a range of 30mm-60mm and a ratio of the first radius of curvature to the second radius of curvature in a range of 1.4-2.1.

12. The unicondylar femoral prosthesis of claim 11, wherein the lateral femoral prosthesis has a lateral side and a medial side, the lateral side including a first straight side and a second straight side offset from a center of the knee joint, and the medial side including a third straight side and a fourth straight side offset from the center of the knee joint.

13. the unicondylar femoral prosthesis of claim 12, wherein said first straight surface is parallel to said third straight surface, and said first straight surface and said third straight surface are angled from the sagittal plane in the range of 0 ° -6 °; the second straight surface is parallel to the fourth straight surface, and the included angle between the second straight surface and the sagittal plane ranges from 7 degrees to 14 degrees.

14. A tibial insert for cooperation with the unicondylar femoral prosthesis of any of claims 1-13, wherein the tibial insert has a proximal articular surface abutting the distal articular surface, the proximal articular surface is spherical, and the ratio of the first radius of curvature to the radius of curvature of the proximal articular surface is in the range of 0.95-1.