The present disclosure relates generally to orthopaedic prostheses, and particularly to orthopaedic prostheses for use in knee replacement surgery.
Joint arthroplasty is a well-known surgical procedure by which a diseased and/or damaged natural joint is replaced by a prosthetic joint. One type of knee prosthesis includes a tibial tray, a femoral component, and a polymer insert or bearing positioned between the tibial tray and the femoral component. Depending on the severity of the damage to the patient's joint, orthopaedic prostheses of varying mobility may be used. For example, the knee prosthesis may include a “fixed” tibial bearing in cases wherein it is desirable to limit the movement of the knee prosthesis, such as when significant soft tissue damage or loss is present. Alternatively, the knee prosthesis may include a “mobile” tibial bearing in cases wherein a greater degree of freedom of movement is desired. Additionally, the knee prosthesis may be a total knee prosthesis designed to replace the femoral-tibial interface of both condyles of the patient's femur or a uni-compartmental (or uni-condylar) knee prosthesis designed to replace the femoral-tibial interface of a single condyle of the patient's femur.
The knee prosthesis may also include a patella component that is secured to the patient's natural patella such that its posterior surface articulates with the femoral component during extension and flexion of the knee. Types of patella components include a dome-shaped polymer bearing and a conforming or anatomic bearing that is designed to conform with the bearing surfaces of the femoral component.
The type of orthopedic knee prosthesis used to replace a patient's natural knee may also depend on whether the patient's posterior cruciate ligament is retained or sacrificed (i.e., removed) during surgery. For example, if the patient's posterior cruciate ligament is damaged, diseased, and/ or otherwise removed during surgery, a posterior stabilized knee prosthesis may be used to provide additional support and/or control at later degrees of flexion. Alternatively, if the posterior cruciate ligament is intact, a cruciate retaining knee prosthesis may be used.
According to one aspect of the disclosure, an orthopaedic knee prosthesis assembly is disclosed. The orthopaedic knee prosthesis assembly includes a plurality of femoral components, and each component includes a medial condyle and a lateral condyle. When each component is viewed in a transverse plane extending through a distal-most point of the medial condyle and a distal-most point of the lateral condyle, the medial condyle has a medial distal-most surface that is curved and includes the distal-most point of the medial condyle, and a medial inner surface connected to the medial distal-most surface and extending proximally away from the medial distal-most surface. The medial distal-most surface has a radius of curvature. When each component is viewed in a transverse plane extending through a distal-most point of the medial condyle and a distal-most point of the lateral condyle, the lateral condyle has a lateral distal-most surface that includes the distal-most point of the lateral condyle, and a lateral inner surface connected to the lateral distal-most surface and extending proximally away from the lateral distal-most surface. An angle is defined between the medial inner surface and the lateral inner surface. The plurality of femoral components include a first component, a second component, and a third component, and the angles of the first, second, and third components are equal in magnitude. The radius of the first component is greater than the radius of the second component by a scale factor, and the radius of the second component is greater than the radius of the third component by the scale factor.
In some embodiments, the scale factor may be equal to approximately 1.041. In some embodiments, when each component is viewed in the transverse plane, the lateral distal-most surface may be curved and may have a radius of curvature that is equal to the radius of curvature of the medial distal-most surface.
In some embodiments, the scale factor may be a first scale factor. When each component is viewed in the transverse plane, a width may be defined between the distal-most point of the medial condyle and the distal-most point of the lateral condyle. The width of the first component may be greater than the width of the second component by a second scale factor different from the first scale factor, and the width of the second component may be greater than the width of the third component by the second scale factor. In some embodiments, the second scale factor is equal to approximately 1.024.
In some embodiments, the magnitude of each of the angles of the first, second, and third components may be approximately 130 degrees. Additionally, in some embodiments, when each component is viewed in the transverse plane, the medial condyle may have a medial rounded edge surface that is connected to the medial inner surface and extend proximally away from the medial inner surface, the lateral condyle may have a lateral rounded edge surface that is connected to the lateral inner surface and extend proximally away from the lateral inner surface, and an arced imaginary line may extend between the medial condyle and the lateral condyle and have a radius of curvature. The arced imaginary line may define a first tangent point at the transition between the medial rounded edge surface and the medial inner surface and a second tangent point at the transition between the lateral rounded edge surface and the lateral inner surface. The radii of curvature of the arced imaginary lines of the first, second, and third components may be equal.
In some embodiments, the radius of curvature of the arced imaginary line of each of the first, second, and third components may be equal to approximately 14 millimeters. In some embodiments, when each component is viewed in the transverse plane, the medial condyle may have a medial flat surface that is connected to the medial rounded edge surface and extend proximally away from the medial rounded edge surface, the lateral condyle have a lateral flat surface that is connected to the lateral rounded edge surface and extend proximally away from the lateral rounded edge surface, and each component may include an intercondylar notch defined between the medial flat surface and the lateral flat surface.
Additionally, in some embodiments, when each femoral component is viewed in the transverse plane, the arced imaginary line, the medial inner surface, and the lateral inner surface may define a trochlear groove of the component. The trochlear groove has a depth, and the depth of the trochlear groove of the first component may be greater than the depth of the trochlear groove of the second component. The depth of the trochlear groove of the second component may be greater than the depth of the trochlear groove of the third component.
In some embodiments, when each femoral component is viewed in the transverse plane, the arced imaginary line has an apex, and the depth of the trochlear groove may be defined between the distal-most point of the medial condyle and the apex of the arced imaginary line.
According to another aspect, an orthopaedic knee prosthesis assembly includes a plurality of femoral components, and each component includes a medial condyle and a lateral condyle. When each component is viewed in a transverse plane extending through a distal-most point of the medial condyle and a distal-most point of the lateral condyle, the medial condyle has a medial distal-most surface that is curved and includes the distal-most point of the medial condyle, and a medial inner surface extending proximally away from the medial distal-most surface. The medial distal-most surface has a radius of curvature. When each component is viewed in a transverse plane extending through a distal-most point of the medial condyle and a distal-most point of the lateral condyle, the lateral condyle has a lateral distal-most surface that includes the distal-most point of the lateral condyle, and a lateral inner surface extending proximally away from the lateral distal-most surface. An arced imaginary line has a first tangent point on the medial inner surface and a second tangent point on the lateral inner surface, a first imaginary line extends through the first tangent point of the arced imaginary line and a third tangent point that is defined at a transition between the medial inner surface and the medial distal-most surface, and a second imaginary line extends through the second tangent point of the arced imaginary line and a fourth tangent point that is defined at a transition between the lateral inner surface and the lateral distal-most surface. An angle is defined between the first imaginary line and the second imaginary line.
The plurality of femoral components includes a first component, a second component, and a third component. The angles of the components are equal in magnitude, the radius of the first component is greater than the radius of the second component by a scale factor, and the radius of the second component is greater than the radius of the third component by the scale factor.
In some embodiments, the scale factor may be equal to approximately 1.041. Additionally, in some embodiments, when each component is viewed in the transverse plane, a width may be defined between the distal-most point of the medial condyle and the distal-most point of the lateral condyle. The width of the first component may be greater than the width of the second component by a second scale factor, and the width of the second component may be greater than the width of the third component by the second scale factor.
In some embodiments, each arced imaginary line may have a radius of curvature, and the radii of curvature of the arced imaginary lines of the first, second, and third components may be equal. In some embodiments, the magnitude of each of the angles of the plurality of femoral components may be approximately 130 degrees, and the radii of curvature of each of the arced imaginary lines of the plurality of femoral components may be approximately 14 millimeters.
According to another aspect, an orthopaedic knee prosthesis assembly includes a plurality of femoral components, and each component includes a medial condyle and a lateral condyle. When each component is viewed in a transverse plane extending through a distal-most point of the medial condyle and a distal-most point of the lateral condyle, the medial condyle has a medial curved distal-most surface that includes the distal-most point, and the medial curved distal-most surface has a radius of curvature. A width is defined between the distal-most points of the medial condyle and the lateral condyle. The plurality of femoral components include a first, second, and third component, and the radius of the first component is greater than the radius of the second component by a first scale factor. The radius of the second component is greater than the radius of the third component by the first scale factor. The width of the first component is greater than the width of the second component by a second scale factor that is less than the first scale factor, and the width of the second component is greater than the width of the third component by the second scale factor.
In some embodiments, the first scale factor may be equal to 1.041. Additionally, in some embodiments, the second scale factor may be equal to 1.024. In some embodiments, when each femoral component is viewed in the transverse plane, the medial condyle may have a medial inner surface extending proximally away from the medial curved distal-most surface and a medial rounded edge surface extending proximally away from the medial inner surface. An arced imaginary line may have a first tangent point at a transition between the medial rounded edge surface and the medial inner surface. The arced imaginary line may have a radius of curvature. The radii of curvature of the arced imaginary lines of the first, second, and third components may be equal.
According to one aspect, an implantable orthopaedic knee prosthesis assembly is disclosed. The implantable orthopaedic knee prosthesis assembly includes a femoral component including an articular surface configured to engage a tibial bearing and a trochlear groove defined in the articular surface. The trochlear groove is angled laterally when the femoral component is viewed in an anterior elevation view. The implantable orthopaedic knee prosthesis assembly also includes a patella component received in the trochlear groove, and the patella component is positioned at a first location in the trochlear groove at a first degree of flexion, and a second location in the trochlear groove at a second degree of flexion. The second degree of flexion is greater than the first degree of flexion and in a range of about 0 degrees to about 30 degrees. An arced imaginary line defines a central section of the trochlear groove. When the femoral component is viewed in a first transverse plane extending through the first location, the arced imaginary line has a first radius of curvature, and when the femoral component is viewed in a second transverse plane extending through the second location, the arced imaginary line has a second radius of curvature that is less than the first radius of curvature.
In some embodiments, the second radius of curvature may be greater than 15.5 millimeters. Additionally, in some embodiments, the first radius of curvature may be equal to approximately 27 millimeters.
In some embodiments, the femoral component may include a patellar surface that defines the trochlear groove. The patellar surface may extend between a medial edge connected to the articular surface and a lateral edge connected to the articular surface. When the femoral component is viewed in the first transverse plane, a first imaginary line may extend through a point on the medial edge and may be tangent to the arced imaginary line, a second imaginary line may extend through a point on the lateral edge and is tangent to the arced imaginary line, and a first angle may be defined between the first imaginary line and the second imaginary line. When the femoral component is viewed in the second transverse plane, a third imaginary line may extend through a point on the medial edge and is tangent to the arced imaginary line, a fourth imaginary line may extend through a point on the lateral edge and may be tangent to the arced imaginary line, and a second angle may be defined between the third imaginary line and the fourth imaginary line. The second angle may have a magnitude less than the first angle.
In some embodiments, the magnitude of the second angle may be greater than or equal to 132 degrees. Additionally, in some embodiments, the first angle may have a magnitude equal to approximately 152 degrees.
In some embodiments, the patella component may be positioned at a third location in the trochlear groove at a third degree of flexion that is greater than or equal to 45 degrees. When the femoral component is viewed in a third transverse plane extending through the third location, the arced imaginary line defining the central section of the trochlear groove may have a third radius of curvature that is less than the second radius of curvature.
In some embodiments, the patella component may be positioned at a fourth location in the trochlear groove at a fourth degree of flexion that is greater than the third degree of flexion and less than 90 degrees. When the femoral component is viewed in a fourth transverse plane extending through the fourth location, the arced imaginary line may have a fourth radius of curvature that is equal to the third radius of curvature. In some embodiments, the third radius may be equal to approximately 14 millimeters.
Additionally, in some embodiments, when the femoral component is viewed in the fourth transverse plane, a fifth imaginary line may extend through a point on the medial edge and is tangent to the arced imaginary line, a sixth imaginary line may extend through a point on the lateral edge and may tangent to the arced imaginary line, and a third angle may be defined between the fifth imaginary line and the sixth imaginary line. The third angle may have a magnitude less than the second angle. In some embodiments, the third angle may have a magnitude equal to approximately 130 degrees.
In some embodiments, when the femoral component is viewed in a sagittal plane, a second arced imaginary line may define the central section of the trochlear groove. The second arced imaginary line may have a constant radius of curvature.
According to another aspect, an implantable orthopaedic knee prosthesis assembly includes a plurality of femoral components. Each femoral component includes an articular surface configured to engage a tibial bearing, a trochlear groove defined in the articular surface, the trochlear groove having a longitudinal axis, and a pair of medial and lateral condyles. When each femoral component is viewed in a transverse plane extending through a distal-most point of the medial condyle and a distal-most point of the lateral condyle, the medial condyle includes a medial inner surface that partially defines the trochlear groove, the lateral condyle includes a lateral inner surface that partially defines the trochlear groove, a sulcus angle is defined between the medial inner surface and the lateral inner surface, and a width is defined between the distal-most point of the medial condyle and the distal-most point of the lateral condyle. When each femoral component is viewed in an anterior elevation view, the distal-most point of the medial condyle and the distal-most point of the lateral condyle are positioned in a distal plane, an imaginary axis extends orthogonal to the distal plane, and a trochlear angle is defined between the longitudinal axis and the imaginary axis. The sulcus angles of the each of the plurality of femoral components are equal in magnitude, the width of each femoral component is different from the width of each of the other femoral components, and the magnitudes of the trochlear angles vary inversely with the widths of the femoral components.
In some embodiments, the implantable orthopaedic knee prosthesis assembly may further include a patella component received in the trochlear groove of at least one of the femoral components. The patella component may be positioned at a first location in the trochlear groove of the femoral component at a first degree of flexion, and a second location in the trochlear groove of the femoral component at a second degree of flexion. The second degree of flexion may be greater than the first degree of flexion and in a range of about 0 degrees to about 30 degrees. A curved surface may define a central section of the trochlear groove at the first degree of flexion and the second degree of flexion. When the femoral component is viewed in a first transverse plane extending through the first location, the curved surface may have a first radius of curvature, and when the femoral component is viewed in a second transverse plane extending through the second location, the curved surface may have a second radius of curvature that is less than the first radius of curvature.
In some embodiments, the first radius may be equal to approximately 27 millimeters. The second radius may be equal to approximately 15.5 millimeters.
Additionally, in some embodiments, When each femoral component is viewed in the transverse plane extending through the distal-most point of the medial condyle and the distal-most point of the lateral condyle, the medial condyle may have a medial distal-most surface that includes the distal-most point of the medial condyle, and the medial distal-most surface may be curved and may have a radius of curvature. The radius of curvature each of the femoral components may increase proportionally with the width of each of the femoral components.
According to another aspect, an implantable orthopaedic knee prosthesis is disclosed. The implantable orthopaedic knee prosthesis includes a femoral component including an articular surface configured to engage a tibial bearing and a laterally-angled trochlear groove defined in the articular surface. The trochlear groove of the femoral component is configured to receive a patella component in a first location at a first degree of flexion and a second location at a second degree of flexion that is greater than the first degree of flexion and in a range of about 0 degrees to about 30 degrees. An arced imaginary line defines a central section of the trochlear groove. When the femoral component is viewed in a first transverse plane extending through the first location, the arced imaginary line has a first radius of curvature, and when the femoral component is viewed in a second transverse plane extending through the second location. The arced imaginary line has a second radius of curvature that is less than the first radius of curvature.
In some embodiments, the trochlear groove may be defined between a medial edge and a lateral edge. When the femoral component is viewed in the first transverse plane, a first imaginary line may extend through a point on the medial edge and may be tangent to the arced imaginary line. A second imaginary line may extend through a point on the lateral edge and is tangent to the arced imaginary line, and a first angle may be defined between the first imaginary line and the second imaginary line. When the femoral component is viewed in the second transverse plane, a third imaginary line may extend through a point on the medial edge and may be tangent to the arced imaginary line, a fourth imaginary line may extend through a point on the lateral edge and may be tangent to the arced imaginary line, and a second angle may be defined between the third imaginary line and the fourth imaginary line. The second angle may have a magnitude less than the first angle.
In some embodiments, the trochlear groove may be configured to receive a patella component in a third location at a third degree of flexion that is greater than or equal to 45 degrees. When the femoral component is viewed in a third transverse plane extending through the third location, the arced imaginary line defining the central section of the trochlear groove may have a third radius of curvature that is less than the second radius of curvature.
In some embodiments, when the femoral component is viewed in a sagittal plane, a second arced imaginary line may define the central section of the trochlear groove. The second arced imaginary line may have a constant radius of curvature.
The detailed description particularly refers to the following figures, in which:
While the concepts of the present disclosure are susceptible to various modifications and alternative forms, specific exemplary embodiments thereof have been illustrated by way of example in the drawings and will herein be described in detail. It should be understood, however, that there is no intent to limit the concepts of the present disclosure to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.
Terms representing anatomical references, such as anterior, posterior, medial, lateral, superior, inferior, etcetera, may be used throughout the specification in reference to the orthopaedic implants and surgical instruments described herein as well as in reference to the patient's natural anatomy. Such terms have well-understood meanings in both the study of anatomy and the field of orthopaedics. Use of such anatomical reference terms in the written description and claims is intended to be consistent with their well-understood meanings unless noted otherwise.
Referring now to
As described in more detail below, the femoral component 12 is configured to articulate with the tibial bearing 14, which is configured to be coupled with the tibial tray 16. As illustrated in
The tibial tray 16 is configured to be secured to a surgically-prepared proximal end of a patient's tibia (not illustrated). The tibial tray 16 may be secured to the patient's tibia via use of bone cement or other attachment means. The tibial tray 16 includes a platform 18 having a top surface 20 and a bottom surface 22. Illustratively, the top surface 20 is generally planar and, in some embodiments, may be highly polished. The tibial tray 16 also includes a stem 24 extending downwardly from the bottom surface 22 of the platform 18. A locking buttress 26 extends upwardly from the top surface 20. The buttress 26 is sized and shaped to receive a number of complimentary locking tabs of the tibial bearing 14, as described in greater detail below. An example of a tibial tray is described in U.S. Patent App. Pub. No. 2012/0109325 entitled “Tibial Component Having an Angled Cement Pocket” by Christel M. Wagner et al., which was filed on Sep. 30, 2011 and is expressly incorporated herein by reference.
As described above, the tibial bearing 14 is configured to be coupled with the tibial tray 16. The tibial bearing 14 includes a platform 30 having an upper bearing surface 32 and a bottom surface 34. As illustrated in
The upper bearing surface 32 of the tibial bearing 14 includes a medial bearing surface 42 and a lateral bearing surface 44. The bearing surfaces 42, 44 are configured to receive or otherwise contact corresponding medial and lateral condyles of the femoral component 12, as described in greater detail below. As such, each of the bearing surface 42, 44 has a concave contour that is shaped to receive one of the condyles of the femoral component 12.
The femoral component 12 is configured to be coupled to a surgically-prepared surface of the distal end of a patient's femur (not illustrated). The femoral component 12 may be secured to the patient's femur via use of bone cement or other attachment means. The femoral component 12 includes an anterior flange 50, a medial condyle 52, and a lateral condyle 54. The condyles 52, 54 are spaced apart to define an intercondylar notch 56 therebetween. An example of a femoral component is described in U.S. Patent App. Pub. No. 2012/0083894 entitled “Femoral Component of a Knee Prosthesis Having an Angled Cement Pocket” by Christel M. Wagner et al., which was filed on Sep. 30, 2010 and is expressly incorporated herein by reference.
The illustrative orthopaedic knee prosthesis 10 of
Other examples of orthopaedic knee prostheses are described in U.S. Patent App. Pub. No. 2011/0178605 entitled “Knee Prosthesis System” by Daniel D. Auger et al., which was filed on Jan. 21, 2010, U.S. Patent App. Pub. No. 2011/0178606 entitled “Tibial Components for a Knee Prosthesis System” by Daren L. Deffenbaugh et al., which was filed on Jan. 21, 2010, U.S. Patent App. Pub. No. 2011/0029090 entitled “Prosthesis with Modular Extensions” by Anthony D. Zannis et al., which was filed on Oct. 14, 2010, U.S. Patent App. Pub. No. 2011/0035017 entitled “Prosthesis with Cut-off Pegs and Surgical Method” by Daren L. Deffenbaugh et al., which was filed on Oct. 14, 2010, U.S. Patent App. Pub. No. 2010/0036500 entitled “Orthopaedic Knee Prosthesis Having Controlled Condylar Curvature” by Mark A. Heldreth et al., which was filed on Jun. 19, 2009, U.S. Patent App. Pub. No. 2010/0016979 entitled “Knee Prosthesis With Enhanced Kinematics” by Joseph G. Wyss et al., which was filed on Jul. 16, 2008, U.S. Patent App. Pub. No. 2009/0326666 entitled “Posterior Stabilized Orthopaedic Knee Prosthesis” by Joseph G. Wyss et al., which was filed on Jun. 30, 2008, U.S. Patent App. Pub. No. 2009/0326665 entitled “Posterior Stabilized Orthopaedic Knee Prosthesis Having Control Condylar Curvature” by Joseph G. Wyss et al., which was filed on Jun. 30, 2008, U.S. Patent App. Pub. No. 2009/0326664 entitled “Posterior Cructiate Retaining Orthopaedic Knee Prosthesis Having Control Condylar Curvature” by Joseph G. Wyss et al., which was filed on Jun. 30, 2008, U.S. patent application Ser. No. 13/534,469 entitled “Posterior Stabilized Orthopaedic Knee Prosthesis Having Control Condylar Curvature” by Joseph G. Wyss et al., which was filed on Jun. 27, 2012, U.S. patent application Ser. No. 13/481,943 entitled “Positioning of Femoral Cam and Tibial Bearing Post to Reduce Anterior Sliding” by Joseph G. Wyss et al., which was filed on May 28, 2012, U.S. patent application Ser. No. 13/527,758 entitled “Posterior Stabilized Orthopaedic Prosthesis Assembly” by Joseph G. Wyss et al., which was filed on Jun. 20, 2012, U.S. patent application Ser. No. 13/534,459 entitled “Posterior Stabilized Orthopaedic Knee Prosthesis Having Control Condylar Curvature” by Joseph G. Wyss et al., which was filed on Jun. 27, 2012, U.S. patent application Ser. No. 13/487,990 entitled “Posterior Stabilized Orthopaedic Knee Prosthesis Having Control Condylar Curvature” by Christel M. Wagner et al., which was filed on Jun. 4, 2012, U.S. patent application Ser. No. 13/540,177 entitled “Orthopaedic Knee Prosthesis Having Controlled Condylar Curvature” by Christel M. Wagner et al., which was filed on Jul. 2, 2012, U.S. Patent App. Pub. No. 2008/0088860 entitled “Hinged Orthopaedic Prosthesis” by Alan Ritchie et al., which was filed on Sep. 30, 2007, and U.S. Patent App. Pub. No. 2008/0004708 entitled “Hinged Orthopaedic Prosthesis” by Joseph G. Wyss et al., which was filed on Jun. 30, 2006, each of which is expressly incorporated herein by reference. Cross-reference is also made to U.S. patent application Ser. No. 13/470,415 entitled “Prosthesis Kit with Finned Sleeve” by John Bonitati, which was filed on May 14, 2012 and is expressly incorporated herein by reference.
As illustrated in
The femoral component 12 also includes a trochlear groove 66 that is defined in the articular surface 60. The trochlear groove 66 is configured to receive the patient's patella and is defined by a patellar surface 68, as described in greater detail below. In the illustrative embodiment, the prosthesis 10 includes a patella component 70 that is configured to be received in the trochlear groove 66 and articulate with the femoral component 12 during extension and flexion of the patient's knee. The patella component 70 is embodied as a monolithic polymer body constructed with a material that allows for smooth articulation between the patella component 70 and the femoral component 12. One such polymeric material is polyethylene such as ultrahigh molecular weight polyethylene (UHMWPE). It should be appreciated that in other embodiments the patella component 70 may be omitted from the prosthesis 10 such that the patient's natural patella is received in the trochlear groove 66 and articulates with the femoral component 12 during use.
As illustrated in
As illustrated in
It should be appreciated that the illustrative orthopaedic knee prosthesis 10 is configured to replace a patient's right knee; as such, the bearing surface 42 and the condyle 52 are referred to as being medially located, and the bearing surface 44 and the condyle 54 are referred to as being laterally located. However, in other embodiments, the orthopaedic knee prosthesis 10 may be configured to replace a patient's left knee. In such embodiments, it should be appreciated that the bearing surface 42 and the condyle 52 may be laterally located and the bearing surface 44 and the condyle 54 may be medially located. Regardless, the features and concepts described herein may be incorporated in an orthopaedic knee prosthesis configured to replace either knee joint of a patient.
As described above, the femoral component 12 includes an articular surface 60. Referring now to
The trochlear groove 66 is defined in the articular surface 60 by the patellar surface 68 between the edges 82, 84 thereof. The trochlear groove 66 also includes a central section 86 defined by a bowed surface 88 of the patellar surface 68. As described in greater detail below, the trochlear groove 66 is angled laterally and includes a longitudinal axis 90 that extends laterally along the central section 86.
The medial condyle 52 has a distal-most point 92 on the medial condyle surface 62. Similarly, the lateral condyle 54 has a distal-most point 94 on the lateral condyle surface 64. As shown in
A trochlear angle α of the trochlear groove 66 is defined between the longitudinal axis 90 and the imaginary line 98. In the illustrative embodiment, the trochlear angle α of the femoral component 12 has a magnitude of approximately 12.0 degrees. As such, the longitudinal axis 90 (and hence the trochlear groove 66) is angled laterally. It should be appreciated that in other embodiments the trochlear angle α may have a magnitude in the range of 10.1 degrees to 14.1 degrees, depending on, for example, the size of the femoral component.
As shown in
Referring now to
Additionally, as the orthopaedic knee prosthesis 10 is articulated through the middle degrees of flexion, the patella component 70 moves along the femoral component 12 to other locations in the trochlear groove 66. For example, as illustrated in
Referring now to
The bowed surface 88 defines an arced imaginary line 120, and the surface 88 and the line 120 define the central section 86 of the trochlear groove 66. The bowed surface 88 (and hence the arced imaginary line 120 and the central section 86) has a radius of curvature R1 equal to approximately 27 millimeters at the location 102. It should be appreciated that in other embodiments the radius of curvature may be greater than or less than 27 millimeters depending on, for example, the sizes of the femoral component 12 and the patella component 70.
As shown in
As shown in
Referring now to
As described above, the bowed surface 88 defines an arced imaginary line 120, and the bowed surface 88 has a radius of curvature R1 at the location 102. At the location 104, the bowed surface 88 (and hence the arced imaginary line 120) has a radius of curvature R2 that is less than the radius R1. In other words, the central section 86 of the trochlear groove 66 has a radius of curvature at the location 104 that is less than its radius of curvature at the location 102. In the illustrative embodiment, the radius of curvature R2 is equal to approximately 15.5 millimeters. It should be appreciated that in other embodiments the radius of curvature may be greater than or less than 15.5 millimeters depending on, for example, the relative size of the femoral component and the patella component.
The trochlear groove 66 defines a sulcus angle S2 at the location 104 that is less than the sulcus angle S1 defined at the location 102. As shown in
As shown in
Referring now to
As described above, the bowed surface 88 defines an arced imaginary line 120, and the bowed surface 88 has the radii of curvature R1, R2 at the locations 102, 104, respectively. At the location 106, the bowed surface 88 (and hence the arced imaginary line 120) has a radius of curvature R3 that is less than either the radius R1 or the radius R2. Thus, the central section 86 of the trochlear groove 66 has a radius of curvature at the location 106 that is less than its radii of curvature at the locations 102, 104. In the illustrative embodiment, the radius of curvature R3 is equal to approximately 14 millimeters. It should be appreciated that in other embodiments the radius of curvature may be greater than or less than 14 millimeters depending on, for example, the relative size of the femoral component and the patella component.
The trochlear groove 66 defines a sulcus angle S3 at the location 106 that is less than either the sulcus angle S1 or the sulcus angle S2 defined at the locations 102, 104, respectively. As shown in
As shown in
Referring now to
As shown in
The distal-most surface 210 is convexly curved in the plane 198 and has a medial-lateral radius of curvature 214 when viewed in cross-section as shown in
The medial inner surface 200 extends proximally away from the point 212. As shown in the cross-section of
As shown in
The distal-most surface 220 is convexly curved in the plane 198 and has a medial-lateral radius of curvature 224 when viewed in cross-section as shown in
The lateral inner surface 202 extends proximally away from the point 222. As shown in the cross-section of
An arced imaginary line 230 extends between the medial inner surface 200 and the lateral inner surface 202 at the location 108. The arced imaginary line 230 connects to a tangent point 232 defined at the transition of the medial inner surface 200 and the rounded medial edge surface 216. In that way, the tangent point 232 lies on the edge connecting the surfaces 200, 216. Similarly, the arced imaginary line 230 connects to another tangent point 234 defined at the transition of the lateral inner surface 202 and the rounded lateral edge surface 226.
As described above and shown in
As described above, the central section 86 of the trochlear groove 66 has a radius of curvature R3 at the location 106 (i.e., a flexion of about 45 degrees). At the location 108 (i.e., a flexion of about 90 degrees), each of the medial inner surface 200 and the lateral inner surface 202 (and hence the central section 86) has the radius of curvature R4 at the tangent points 232, 234, respectively, that is equal to the radius of curvature R3. In the illustrative embodiment, the radius of curvature R4 is equal to approximately 14 millimeters. It should be appreciated that in other embodiments the radius of curvature may be greater than or less than 14 millimeters. It should be appreciated that in other embodiments the radius of curvature may be greater than or less than 14 millimeters depending on, for example, the relative size of the femoral component and the patella component.
The trochlear groove 66 defines a sulcus angle S4 at the location 108 that is equal to the sulcus angle S3 defined at location 106. As shown in
As described above, the arced imaginary line 230 indicates the boundary of the region occupied by the posterior bearing surface 72 of the patella component in the trochlear groove 66, with the point 252 indicating the maximum depth of the posterior bearing surface 72 at the location 108. The trochlear groove 66 of the femoral component 12 has a depth 250 at the location 108 that is equal to the depth of the groove 66 at the location 106. At the location 108, the trochlear depth 250, which is the maximum depth of the apex of posterior bearing surface 72 of the patella component at the location 108, is defined between the distal-most point 92 of the medial condyle 52 and the point 252 of the arced imaginary line 230. In the illustrative embodiment, the depth 250 is equal to approximately 6.623 millimeters. It should be appreciated that the depth 250 may be greater than or less than the 6.623 millimeters depending on, for example, the relative size of the femoral component and the patella component.
As shown in
Returning to
Referring now to
As shown in
The femoral component 300 has a trochlear groove 306 that is defined by the patellar surface 68 between the edges 82, 84 thereof. The trochlear groove 306 also includes a central section 86 defined by a bowed surface 88 of the patellar surface 68. The trochlear groove 306, like the groove 66, includes an open section between the condyles 52, 54. As described in greater detail below, the trochlear groove 306 has a laterally angled longitudinal axis 90 that extends through the central section 86.
The medial condyle 52 has a distal-most point 92 on the medial condyle surface 62. Similarly, the lateral condyle 54 has a distal-most point 94 on the lateral condyle surface 64. As shown in
A trochlear angle β is defined between the longitudinal axis 90 of the trochlear groove 306 and the imaginary line 98. In the illustrative embodiment, the trochlear angle β has a magnitude of approximately 11.6 degrees. As described above, the femoral component 12 has a trochlear angle α that has magnitude of approximately 12.0 degrees. As such, the trochlear groove 306 of the larger component 300 is angled less than the trochlear groove 66 of the smaller component 12. It should be appreciated that in other embodiments the trochlear angle may have a magnitude in the range of 10.1 degrees to 14.1 degrees depending on, for example, the size of the femoral component.
The femoral component 300, like the femoral component 12, may be articulated over a number of degrees of flexion. When positioned like the femoral component 12 in
The patellar surface 68 of the femoral component 300 includes a medial inner surface 200 of the medial condyle 52 and a lateral inner surface 202 of the lateral condyle 54. The posterior bearing surface 72 of the patella component is configured to contact one or more contact points (not shown) on the medial inner surface 200 and the lateral inner surface 202.
The medial condyle surface 62 of the medial condyle 52 has a distal-most surface 310 that is connected to the medial inner surface 200 at a point 212 on the medial edge 82. As shown in
As shown in the cross-section of
As shown in
As shown in the cross-section of
An arced imaginary line 230 extends between the medial inner surface 200 and the lateral inner surface 202 at the location 108. The arced imaginary line 230 connects to a tangent point 232 defined at the transition of the medial inner surface 200 and the rounded medial edge surface 216. Similarly, the arced imaginary line 230 connects to another tangent point 234 defined at the transition of the lateral inner surface 202 and the rounded lateral edge surface 226.
Like the femoral component 12, the apex of the posterior bearing surface 72 of the patella component is positioned at the point 252 when the patella component and the femoral component are articulated to the late degree of flexion. The point 252 cooperates with the points 232, 234 to define the arced imaginary line 230, which indicates the boundary of the region occupied by the posterior bearing surface 72 of the patella component in the trochlear groove 66 (and hence the intercondylar notch 56). As shown in
Each of the medial inner surface 200 and the lateral inner surface 202 (and hence the central section 86) of the femoral component 300 has radius of curvature R4 at the tangent points 232, 234, respectively. In the illustrative embodiment, the radius of curvature R4 is equal to approximately 14 millimeters. In other words, the radius of curvature R4 of the femoral component 300 is equal to the radius of curvature R4 of the smaller femoral component 12.
Additionally, the trochlear groove 66 defines a sulcus angle S4. As shown in
As described above, the arced imaginary line 230 indicates the boundary of the region occupied by the posterior bearing surface 72 of the patella component in the trochlear groove 66, with the point 252 indicating the maximum depth of the posterior bearing surface 72 at the location 108. The trochlear groove 66 of the femoral component 12 has a depth 350, which is the maximum depth of the apex of posterior bearing surface 72 of the patella component and is defined between the distal-most point 92 of the medial condyle 52 and the point 252 of the arced imaginary line 230. The femoral component 300 also has a radial width 360 defined between the distal-most point 92 of the medial condyle 52 and the distal-most point 94 of the lateral condyle 54. The femoral component 300 has a component width 362 defined between the outer side surface 264 of the medial condyle 52 and the outer side surface 266 of the lateral condyle 54.
As described above, the trochlear depth 350 of the femoral component 300 is greater than the trochlear depth 250 of the femoral component 12. Similarly, the radius of curvature 314 of the distal-most surface 310 of the medial condyle 52 of the femoral component 300 is greater than the radius 214 of the femoral component 12. In the illustrative embodiment, the radius 314 of the femoral component 300 is proportionally greater than the radius 214 of the femoral component 12 by a scale factor M that is equal to 1.041. As such, the radius 314 of the femoral component 300 is equal to approximately 25.321 millimeters.
Additionally, the widths 360, 362 of the femoral component 300 are greater than the widths 260, 262 of the femoral component 12. In the illustrative embodiment, the radial width 360 of the femoral component 300 is proportionally greater than the radial width 260 of the femoral component 12 by a scale factor N of 1.024. As such, the radial width 360 of the femoral component 300 is equal to approximately 49.398 millimeters. In the illustrative embodiment, the component width 362 of the femoral component 300 is proportionally greater than the component width 262 of the femoral component 12 by a scale factor 0 that is equal to 1.047. As such, the component width 362 of the femoral component 300 is equal to approximately 69.626 millimeters.
While the trochlear depth 350, widths 360, 362, and radius 314 of the femoral component 300 are greater than the corresponding trochlear depth 250, widths 260, 262, and radius 214 of the femoral component 12, the sulcus angle S4 of the femoral component 300 is equal in magnitude to the sulcus angle S4 of the femoral component 12. Additionally, the radii R4 of the central sections 86 of the trochlear grooves 66 of the components 12, 300 are also equal. As a result, the basic configuration of the patellar surfaces 68 of the femoral components 12, 300 remains the same, thereby permitting the use of the same patella component 70 with each of the femoral components 12, 300.
As shown in
Referring now to
As described above, the radius 314 of the femoral component 300 is proportionally greater than the radius 214 of the femoral component 12 by a scale factor M. In the table 600, the component 12 is illustratively identified as Size 5, and the component 300 is illustratively identified as Size 6. As shown in
Additionally, the widths of the femoral components also proportionally change with each change in size. As described above, the radial width 360 of the femoral component 300 is proportionally greater than the radial width 260 of the femoral component 12 by a scale factor N. Similarly, the radial width of the next-larger femoral component 400 (i.e., Size 7) is proportionally greater than the radial width of the femoral component 300 (i.e., Size 6) by the same scale factor N, while the radial width of the next-smaller size femoral component 500 (i.e., Size 4) is proportionally less than the radial width 260 of the femoral component 12 (i.e., Size 5) by the scale factor N. In the illustrative embodiment, the scale factor N is equal to 1.024. It should be appreciated that in other embodiments the scale factor N may be greater or less than 1.024 depending on the number of femoral component sizes in the component family, the variability in the size of the patients in the population, and so forth.
As described above, the component width 362 of the femoral component 300 is proportionally greater than the component width 262 of the femoral component 12 by a scale factor O. Similarly, the component width of the next-larger femoral component 400 is proportionally greater than the component width 362 of the femoral component 300 by the same scale factor 0. The component width of the next-smaller size femoral component 500 is proportionally less than the component width 262 of the femoral component 12 by the scale factor 0. In the illustrative embodiment, the scale factor 0 is equal to 1.047. It should be appreciated that in other embodiments the scale factor 0 may be greater or less than 1.047 depending on the number of femoral component sizes in the family, the expected variability in the sizes of the patients in the population, and so forth.
As shown in
While the disclosure has been illustrated and described in detail in the drawings and foregoing description, such an illustration and description is to be considered as exemplary and not restrictive in character, it being understood that only illustrative embodiments have been illustrated and described and that all changes and modifications that come within the spirit of the disclosure are desired to be protected.
There are a plurality of advantages of the present disclosure arising from the various features of the method, apparatus, and system described herein. It will be noted that alternative embodiments of the method, apparatus, and system of the present disclosure may not include all of the features described yet still benefit from at least some of the advantages of such features. Those of ordinary skill in the art may readily devise their own implementations of the method, apparatus, and system that incorporate one or more of the features of the present invention and fall within the spirit and scope of the present disclosure as defined by the appended claims.
This application claims priority under 35 U.S.C. §120 to U.S. patent application Ser. No. 13/683,683, which was filed on Nov. 21, 2012 and is expressly incorporated herein by reference. Cross-reference is made to U.S. patent application Ser. No. 13/683,630 entitled “Knee Prosthesis Assembly Having Proportional Coronal Geometry” by Abraham P. Wright et al., which was filed on Nov. 21, 2012 and is expressly incorporated herein by reference.
Number | Date | Country | |
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Parent | 13683683 | Nov 2012 | US |
Child | 15807254 | US |