CN113616392A

CN113616392A - Total knee joint prosthesis

Info

Publication number: CN113616392A
Application number: CN202110840551.9A
Authority: CN
Inventors: 丁涛
Original assignee: Hangzhou Lanxin Medical Technology Co ltd
Current assignee: Hangzhou Lanxin Medical Technology Co ltd
Priority date: 2021-07-24
Filing date: 2021-07-24
Publication date: 2021-11-09

Abstract

The invention provides a total knee joint prosthesis which comprises a femoral prosthesis and a patellar prosthesis mounted on the femoral prosthesis, wherein the femoral prosthesis comprises an anterior condyle surface provided with a trochlear groove, and the patellar prosthesis is matched with the trochlear groove. The projection of the connecting line of the lowest points of the sliding grooves on the frontal plane is an S-shaped curve. The knee joint prosthesis disclosed by the invention can better improve the motion stability of the patella prosthesis, the patella track is closer to the natural knee joint track, the dislocation probability of the patella after operation is reduced, the abrasion of the patella prosthesis is reduced, and the service life of the knee joint prosthesis is effectively prolonged.

Description

Total knee joint prosthesis

Technical Field

The invention relates to the field of knee joint prostheses, in particular to a total knee joint prosthesis.

Background

Knee Osteoarthritis (OA) is a common chronic irreversible knee joint disease characterized by degenerative changes in articular cartilage and secondary hyperosteogeny, a chronic damage to articular cartilage and surrounding soft tissues characterized by pain, stiffness, and loss of joint function. OA has a very high incidence among the population, and data studies have shown that 9.6% of men and 18% of women in older people over the age of 60 worldwide have a certain degree of OA symptoms, and the incidence of OA will be higher as the aging process is accelerated, and the pace of life becomes faster.

Knee replacement is the primary treatment at the end of OA of the knee joint. The knee joint replacement is to replace the diseased knee joint bone tissue with a knee joint prosthesis to relieve or relieve pain of a patient and recover and reconstruct the function of a natural knee joint, and with the continuous design improvement of the knee joint prosthesis and the continuous improvement of the operation technology, the knee joint replacement becomes a mature operation technology, and the survival rate of 10 to 15 years can reach more than 90 percent.

The unstable patella, the dislocation of the patella and the abrasion of the patella prosthesis are important reasons for the replacement and the renovation of the knee joint, the unstable patella, the dislocation of the patella and the abrasion of the patella prosthesis are related to the design of the femoral prosthesis and the patella prosthesis, the too shallow pulley groove and the unreasonable pulley Q angle easily cause the dislocation of the patella in the buckling process of the knee joint, the unreasonable matching degree of the femoral prosthesis and the patella prosthesis can cause the excessive abrasion of the femoral prosthesis and the patella prosthesis, and finally the renovation of the prosthesis is caused.

Disclosure of Invention

The invention aims to provide a total knee joint prosthesis which can reduce the probability of dislocation of patella after operation, reduce the abrasion of a patella prosthesis and effectively prolong the service life of the knee joint prosthesis.

According to one aspect of the present invention, there is provided a total knee prosthesis comprising a femoral prosthesis and a patellar prosthesis mounted to the femoral prosthesis, the femoral prosthesis comprising an anterior condylar surface provided with a trochlear groove, the patellar prosthesis cooperating with the trochlear groove. The projection of the connecting line of the lowest points of the sliding grooves on the frontal plane is an S-shaped curve.

Preferably, the "S" shaped curve is first biased laterally, then laterally, and then laterally from the distal end to the proximal end.

Preferably, the "S" shaped curve includes a first turning point, a second turning point and a third turning point sequentially arranged from the distal end to the proximal end, the femoral prosthesis further includes a posterior condylar surface, and angles of the first turning point, the second turning point and the third turning point are respectively 0 degree, 8 degrees and 20 degrees with a sagittal plane curvature center of the posterior condylar surface and a plane parallel to the cross section as a positioning reference.

Preferably, from the frontal plane, the S-shaped curve includes a first curve segment located below the first turning point, a second curve segment located between the first turning point and the second turning point, and a third curve segment located above the third turning point, the first curve segment is deviated from the lateral side, the included angle between the tangent of the first curve segment and the sagittal plane is 5-12 degrees, the included angle between the tangent of the second curve segment and the sagittal plane is 10-20 degrees, and the included angle between the tangent of the third curve segment and the sagittal plane is the same as the included angle between the tangent of the first curve segment and the sagittal plane.

Preferably, the included angle between the tangent line of the first curve section and the sagittal plane is 7 degrees, and the included angle between the second curve section and the sagittal plane is 15 degrees.

Preferably, a projection of a connecting line of the lowest points of the sliding grooves on a sagittal plane is a first arc line segment, the first arc line segment comprises a proximal curve segment and a distal curve segment, and the curvature radius of the distal curve segment is smaller than that of the proximal curve segment.

Preferably, the radius of curvature of the proximal curved section ranges from 35mm to 100mm and the radius of curvature of the distal curved section ranges from 35mm to 45 mm.

Preferably, the projections of the different sections of the slideway onto the cross section are all circular.

Preferably, the femoral prosthesis further comprises a posterior condylar surface, and three sections are respectively taken from the proximal end, the middle section and the distal end by taking a sagittal curvature center of the posterior condylar surface and a plane parallel to the cross section as positioning references, wherein the curvature radiuses of the three sections are respectively R3, R4 and R5, and the relationship of the three sections is R3 > R4 > R5.

Preferably, the patella prosthesis comprises a proximal face and a distal articular face, the proximal face comprising a groove and a post disposed within the groove.

The knee joint prosthesis disclosed by the invention can better improve the motion stability of the patella prosthesis, the patella track is closer to the natural knee joint track, the dislocation probability of the patella after operation is reduced, the abrasion of the patella prosthesis is reduced, and the service life of the knee joint prosthesis is effectively prolonged.

Drawings

Fig. 1 is an illustration of the orientation of a human body in the present invention.

Fig. 2 is a schematic view of a femoral prosthesis of the present invention.

Fig. 3 is a schematic view of another angle of the femoral prosthesis of the present invention.

Fig. 4 is a front view of a femoral prosthesis of the present invention with a hinge point.

Fig. 5 is a front view of a femoral prosthesis of the present invention without a hinge point.

Fig. 6 is a sectional view of "1-1" in fig. 5.

Fig. 7 is a cross-sectional view of "2-2" in fig. 5.

Fig. 8 is a cross-sectional view of "3-3" in fig. 5.

Fig. 9 is a front view of a patella prosthesis.

Fig. 10 is a cross-sectional view of a patella prosthesis.

Fig. 11 is a top view of a patella prosthesis.

Fig. 12 is a schematic view of a femoral prosthesis and a patellar prosthesis combined together.

Fig. 13 is a sectional view taken along the line "a-a" in fig. 12.

Fig. 14 is a schematic view of another position of a femoral prosthesis and a patellar prosthesis when combined together.

Fig. 15 is a sectional view taken along the line "B-B" in fig. 14.

Fig. 16 is a schematic view of another position of a femoral prosthesis and a patellar prosthesis when combined together.

Fig. 17 is a cross-sectional view taken along the line "C-C" in fig. 16.

Fig. 18 is a schematic view showing the same radius of curvature of the distal surface of patella prostheses of different specifications.

Detailed Description

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

To better explain the technical solutions of the present invention, the terms of orientation in the embodiments are explained first. Referring to fig. 1, the directions are explained as follows:

sagittal plane: longitudinally cutting the human body or the joint into a section formed by a left part and a right part from the front and back directions;

frontal plane: from the left and right direction, the human body or the joint is divided into a front section and a rear section, and the section is vertical to the sagittal plane;

cross section: from the up-down direction, the section divides the human body or the joint into an upper section and a lower section, and the section is vertical to the frontal plane and the sagittal plane;

a far end: the end of the body or joint relatively far 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 sagittal plane of a human body;

outside: relatively deviated from the sagittal plane of the human body;

front: deviated from the frontal plane and close to the face of the human body;

rear: deviated from the frontal plane and close to the back of the human body.

Referring to fig. 2 to 18, the present invention relates to a total knee prosthesis, which includes a femoral prosthesis 100 and a patella prosthesis 200, and the patella prosthesis 200 and the femoral prosthesis 100 are combined together.

As shown in fig. 2 to 4, the femoral prosthesis 100 has a proximal osteotomy face 6 and a distal face 7. The proximal osteotomy face 6 is intended to mate with a surgically created osteotomy face distal of a femur (not shown). The distal surface 7 includes a posterior condylar surface 8, an anterior condylar surface 10, and a connecting surface 9 connecting the posterior condylar surface 8 and the anterior condylar surface 10 together. The posterior condylar surface 8 and the connecting surface 9 are composed of a lateral articular surface 12 and a medial articular surface 13, and the anterior condylar surface 10 is provided with a trochlear groove 11. The posterior condylar surface 8 and the joint surface 9 are used to form an articular surface with a tibial prosthesis (not shown). The trochlear groove 11 is used to form a patellofemoral joint surface in cooperation with the patellar prosthesis 200. The projection of the connecting line of the lowest point of the sliding groove 11 on the frontal plane is an S-shaped curve 14, the trend from the far end to the near end is that the curve is firstly deviated outwards, then deviated inwards, and then deviated outwards, and the turning points are respectively a first turning point 15, a second turning point 16 and a third turning point 17. Through this setting, the motion stability of promotion patella false body 200 that can be better, the patella orbit that more is close natural knee joint, the dislocation probability takes place for the postoperative patella is lower, and patella false body wearing and tearing are still less, and knee joint false body life is higher.

The first, second and

third transition points

15, 16 and 17 are angled at about 0 °, 8 ° and 20 °, respectively, relative to the sagittal plane center of curvature 23 of the posterior condylar surface 8 and a plane 24 parallel to the transverse plane (as viewed from the sagittal plane). From the frontal plane, the "S" shaped curve includes, from the distal end, a first curve segment located below the first turning point 15, a second curve segment located between the first turning point 15 and the second turning point 16, and a third curve segment located above the third turning point 16. From the distal end, the first curved section is offset laterally outward. The tangent 18 to the first curved section has an angle in the range of 5 to 12, preferably 7, with the fixture α 1, α 1 of the sagittal plane 10. The second curve section is inwardly offset by an offset angle defined by the tangent to the clamp α 2 of the sagittal plane 10, the α 2 angle ranging from 10 ° to 20 °, preferably 15 °. The third curve segment is offset to the outside, and the offset angle of the third curve segment is the same as that of the first curve segment.

The projection of the line of the lowest point of the sliding groove 11 on the sagittal plane is an arc line which is composed of a proximal curve section 21 and a distal curve section 22. The curvature radius of the proximal curve section 21 is R1, the curvature radius of the distal curve section 22 is R2, R2 is smaller than R1, the range of R1 is 35mm-100mm, and the range of R2 is 35-45 mm. The intersection of the proximal curve segment 21 and the distal curve segment 22 approaches the turning point 16 of the S-curve 14.

As shown in fig. 5 to 8, the projections of the different sections of the chute 11 on the cross section are all circular. Taking a sagittal plane curvature center 19 of the posterior condylar surface 8 and a plane 20 parallel to the cross section as positioning references, respectively cutting 3 sections from a proximal end (about-35 degrees), a middle section (about 0 degrees) to a distal end (about 45 degrees), wherein the curvature radiuses of the three sections are R3, R4 and R5 respectively, the relationship of R3 > R4 > R5, and the range of R3 is 80-200 mm, preferably 100 mm; the range of R4 is 25-30 mm, and the preferred range is 27 mm; the range of R5 is 20-25 mm, preferably 23 mm. The trochlear groove 11 is circular in cross section, and the radius of curvature of the trochlear groove 11 gradually decreases from the proximal end to the distal end. The articular surface of the patella prosthesis 200 is a fixed sphere, and the spherical radius of the articular surface of the patella prosthesis with different specifications is kept unchanged. Adopt above-mentioned technical scheme's thighbone false body and patella false body, the motion stability of better promotion patella false body, the patella orbit is closer with natural knee joint orbit, reduces the probability that the dislocation takes place for the postoperative patella to reduce the wearing and tearing of patella false body, effectively improve knee joint false body's life.

As shown in fig. 9 to 11, the present invention also provides a patellar prosthesis 200, the patellar prosthesis 200 having a proximal end surface 30 and a distal articular surface 31. The proximal face 30 is provided with a post 32 recess 33 and the proximal face 30 is adapted to mate with an intraoperatively formed patellar osteotomy surface (not shown). The upright columns 32 are used for assisting in fixing the patella prosthesis 200, and the number of the upright columns 32 is more than 1, preferably 3; the groove 33 is used for containing bone cement and assisting in fixing the patellar prosthesis 200; the patella distal surface 31 is used for matching with the trochlear groove 11 of the femoral prosthesis 100 to form a patellofemoral joint surface; the distal articular surface 31 of the patellar prosthesis 200 has a spherical shape with a radius of curvature SR6, SR6 being slightly smaller than the radius of curvature R5 of the distal trochlear groove 11 of the femoral prosthesis 100, and the ratio R5/R6 being about 1.01-1.1, preferably 1.05.

As shown in fig. 12 to 17, the degree of matching between the articular surface 31 of the patella prosthesis 200 and the trochlear groove 11 of the femoral prosthesis gradually increases with the increase of the flexion angle. As the flexion angle increases, the contact pressure of the patellofemoral joint surface of the knee joint increases, so that the contact area between the patella prosthesis 200 and the femoral prosthesis 100 can be increased by gradually increasing the matching degree of the joint surface 31 and the pulley groove 11, the contact stress is reduced, and the wear of the patella prosthesis is reduced.

As shown in fig. 18, the radius of curvature R6 of the distal surface of the patella prosthesis 200 of different specifications remains the same, so that the patella prosthesis 200 of different specifications can be arbitrarily exchanged with the femoral prosthesis 100, thereby providing more surgical options for the surgeon and improving the knee joint replacement effect. The femoral prosthesis 100 and the patella prosthesis 200 adopting the design scheme have patella tracks close to natural knee joints, the patella stability is good, the dislocation rate is lower, the wear of the patella prosthesis 200 is less, and the service life of the prosthesis is longer.

It will be apparent to those skilled in the art that various modifications and variations can be made to the above-described exemplary embodiments of the present invention without departing from the spirit and scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

Claims

1. The total knee joint prosthesis comprises a femur prosthesis and a patellar prosthesis mounted on the femur prosthesis, wherein the femur prosthesis comprises an anterior condylar surface provided with a trochlear groove, the patellar prosthesis is matched with the trochlear groove, and the projection of a connecting line of the lowest points of the trochlear groove on a frontal plane is an S-shaped curve.

2. The total knee prosthesis of claim 1, wherein the "S" curve is oriented from the distal end to the proximal end with a first lateral deviation, then medial deviation, and then lateral deviation.

3. The total knee prosthesis of claim 2, wherein the "S" shaped curve includes a first inflection point, a second inflection point and a third inflection point arranged in sequence from a distal end to a proximal end, the femoral prosthesis further includes a posterior condylar surface, and the angles of the first inflection point, the second inflection point and the third inflection point are 0 degree, 8 degree and 20 degree, respectively, with reference to a sagittal plane curvature center of the posterior condylar surface and a plane parallel to the cross section.

4. The total knee prosthesis of claim 3, wherein the "S" -shaped curve includes, from a distal end as viewed from a frontal plane, a first curve segment located below the first inflection point, a second curve segment located between the first inflection point and the second inflection point, and a third curve segment located above the third inflection point, the first curve segment being laterally offset, a tangent of the first curve segment being at an angle in the range of 5 degrees to 12 degrees with respect to the sagittal plane, a tangent of the second curve segment being at an angle in the range of 10 degrees to 20 degrees with respect to the sagittal plane, and a tangent of the third curve segment being at the same angle with respect to the sagittal plane as the tangent of the first curve segment.

5. The total knee prosthesis of claim 4, wherein a tangent to the first curvilinear segment is at an angle of 7 degrees to the sagittal plane and the second curvilinear segment is at an angle of 15 degrees to the sagittal plane.

6. The total knee prosthesis of claim 1, wherein a line connecting the nadir of the trochlear groove is projected on a sagittal plane as a first arc segment, the first arc segment including a proximal curve segment and a distal curve segment, the distal curve segment having a radius of curvature less than the radius of curvature of the proximal curve segment.

7. The total knee prosthesis of claim 6, wherein the proximal curvilinear segment has a radius of curvature in the range of 35mm to 100mm and the distal curvilinear segment has a radius of curvature in the range of 35mm to 45 mm.

8. The total knee prosthesis of claim 1, wherein the projections of the different cross-sections of the trochlear groove in cross-section are all circular.

9. The total knee prosthesis of claim 8, wherein the femoral prosthesis further includes a posterior condylar surface, three sections being taken from proximal, medial and distal ends, respectively, based on a sagittal plane center of curvature of the posterior condylar surface and a plane parallel to the transverse plane, the three sections having radii of curvature R3, R4 and R5, respectively, in a relationship of R3 > R4 > R5.

10. The total knee prosthesis of claim 1, wherein the patellar prosthesis includes a proximal face and a distal articular face, the proximal face including a groove and a post disposed within the groove.