Patent Application
20090088862
The present disclosure relates generally to orthopaedic implant devices and more particularly to stem extensions for use with orthopaedic implant devices for knees.
Movement (e.g., flexion and extension) of the natural human knee involves movements of the femur and the tibia. Specifically, during flexion and extension, the distal end of the femur and the proximal end of the tibia articulate relative to one another through a series of complex movements. Damage (e.g., trauma) or disease can deteriorate the bones, articular cartilage, and/or ligaments of the knee, which can ultimately affect the ability of the natural knee to function in such a manner. As a result, orthopaedic implant devices have been developed to replace the natural knees of patients.
The longevity of an orthopaedic implant is dependent on a number of factors. One such factor is the proper matching of the implant with the patient's anatomy. Due to the large variation in human anatomy, the surgeon may use orthopaedic implants of various sizes and configurations to ensure proper matching of the implant with the anatomy of the patient.
According to one aspect, an orthopaedic implant may include a knee prosthetic component configured to be coupled to a surgically prepared surface of a bone of a patient and an adaptor that connects the knee prosthetic component with a stem extension. The adaptor may include a first mounting end that is coupled with the knee prosthetic component and a second mounting end that is coupled with the stem extension. The first mounting end may define a first axis and the second mounting end may define a second axis. The second axis may be offset from and parallel to the first axis when viewed in a first anatomical plane. Additionally, the first axis and the second axis may define an angle therebetween greater than zero degrees when viewed in a second anatomical plane substantially orthogonal to the first anatomical plane. In some embodiments, the second mounting end may comprise an aperture that receives a tapered end of the stem extension. Additionally, in some embodiments, the second mounting end may be movable relative to the first mounting end.
In some embodiments, the knee prosthetic component may be embodied as a tibial tray. The tibial tray may include a platform and a stem extending downwardly from a bottom surface of the platform. The stem may have an aperture defined at the distal end. The first mounting end of the adaptor may be tapered such that the aperture of the stem may receive the first mounting end of the adaptor. The first anatomical plane may be the medial/lateral plane, and the second anatomical plane may be the anterior/posterior plane. For example, the second axis of the second mounting end of the adaptor may be offset from and parallel to the first axis of the first mounting end of the adaptor when viewed in the medial/lateral plane. Additionally, the first axis of the first mounting end of the adaptor and the second axis of the second mounting end of the adaptor may define an angle therebetween greater than zero degrees when viewed in the anterior/posterior plane.
In other embodiments, the knee prosthetic component may be embodied as femoral component. The femoral component may include a pair of condyles and a platform defined between the condyles. The platform may include an aperture defined in an upper surface. The first mounting end of the adaptor may be tapered such that the aperture of the platform may receive the first mounting end of the adaptor. The first anatomical plane may be the anterior/posterior plane, and the second anatomical plane may be the medial/lateral plane. For example, the second axis of the second mounting end of the adaptor may be offset from and parallel to the first axis of the first mounting end of the adaptor when viewed in the anterior/posterior plane. Additionally, the first axis of the first mounting end of the adaptor and the second axis of the second mounting end of the adaptor may define an angle therebetween greater than zero degrees when viewed in the medial/lateral plane.
In some embodiments, the adaptor may be formed from two pieces. The first piece may include the first mounting end and a first mounting surface. The second piece may include the second mounting end and a second mounting surface. In some embodiments, the second mounting surface may be movable relative to the first mounting surface to change the angle defined between the first axis and the second axis when viewed in the second anatomical plane. Additionally, in some embodiments, the first mounting surface may include a first number of teeth and the second mounting surface may include a second number of teeth. The second number of teeth may be interdigitated with the first number of teeth of the first mounting surface.
According to another aspect of the invention, an implantable orthopaedic device may include a stem extension. The stem extension may include a mounting end and an elongated shaft that extends from the mounting end. The mounting end may be configured to be coupled with a knee prosthetic component such as a tibial tray or a femoral component. The mounting end may define a first axis and the elongated shaft may define a second axis. In some embodiments, the second axis may be offset from and parallel to the first axis when viewed in a first anatomical plane. In some embodiments, the first anatomical plane may be the medial/lateral plane. In other embodiments, the first anatomical plane may be the anterior/posterior plane. For example, the second axis may be offset from and parallel to the first axis by a distance of about two millimeters to about eight millimeters when viewed in the medial/lateral plane in some embodiments. In other embodiments, the second axis may be offset from and parallel to the first axis when viewed in the anterior/posterior plane.
Additionally, the first axis and the second axis may define an angle therebetween greater than zero degrees when viewed in a second anatomical plane. In some embodiments, the angle defined between the first axis and the second axis may be greater than or equal to one degree when viewed in the second anatomical plane. In some embodiments, the second anatomical plane may be the anterior/posterior plane. In other embodiments, the second anatomical plane may be the medial/lateral plane. For example, the angle defined between the first axis and the second axis may be about one degree to about five degrees when viewed in the anterior/posterior plane. In other embodiments, the angle defined between the first axis and the second axis may be about one degree to about nine degrees when viewed in the medial/lateral plane. In some embodiments, the angle defined between the first axis and the second axis may also be adjustable when viewed in the second anatomical plane. For example, the elongated shaft may be movable relative to the mounting end to adjust the angle defined between the first axis and the second axis when viewed in the anterior/posterior plane.
According to still another aspect of the invention, an implantable orthopaedic device may include an adaptor. The adaptor may include a first mounting end configured to be coupled with a knee prosthetic component and a second mounting end configured to be coupled with a stem extension. The first mounting end may define a first axis, and the second mounting end may define a second axis. The second axis may be offset from and parallel to the first axis when viewed in a first plane. Additionally, the first axis and the second axis may define an angle therebetween greater than zero degrees when viewed in a second plane substantially orthogonal to the first plane. In one particular embodiment, the first plane may be embodied as the medial/lateral plane and the second plane may be embodied as the anterior/posterior plane.
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 shown 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.
Referring to
The knee prosthetic component 12 may be embodied as any type of knee prosthetic component configured to receive a stem extension. For example, as illustrated in
The tibial tray 18 is configured to be coupled with a tibial bearing (not shown) such as a polymer tibial bearing. As such, the upper surface 24 of the platform 20 may be configured to receive the tibial bearing. For example, the platform 20 may include any number of rails, tracks, openings, and/or the like configured to receive or otherwise be coupled with a portion of the tibial bearing. Additionally, the tibial tray 18 may be configured to be coupled to any type of tibial bearing, including, for example, a mobile tibial bearing and/or a fixed tibial bearing.
As discussed above, the adaptor 14 is configured to be coupled with the tibial tray 18 and the stem extension 16. As such, the adaptor 14 includes a mounting end 28 configured to be coupled to the tibial tray 18. The mounting end 28 may include any number of apertures, protrusions, grooves, and/or other structures necessary to facilitate the securing of adaptor 14 to the tibial tray 18. For example, in the embodiment illustrated in
In other embodiments, the mounting end 28 of the adaptor 14 may include other or additional structures to facilitate the coupling of the adaptor 14 to the tibial tray 18. For example, in some embodiments, the mounting end 28 may include a threaded stud extending therefrom. In such embodiments, the distal end 34 of the stem 22 may include a corresponding threaded aperture configured to receive the threaded stud of the mounting end 28. Alternatively, the distal end 34 of the stem 22 may be threaded and configured to be received in a threaded aperture defined in the mounting end 28 of the adaptor 14.
The adaptor 14 also includes a mounting end 40 configured to be coupled with the stem extension 16. Similar to the mounting end 28, the mounting end 40 may include any number of apertures, protrusions, grooves, and/or other structures necessary to facilitate the securing of adaptor 14 to the stem extension 16. For example, in the embodiments illustrated in
The adaptor 14 is configured such that the position of the stem extension 16 relative to the tibial tray 18 is altered when the adaptor 14 is coupled therebetween. As illustrated in
The adaptor 14 may be configured such that the axis 48 is offset from and angled relative to the axis 46 by any amount suitable for implantation. For example, in one particular embodiment, the axis 48 is offset from the axis 46 by a distance 50 of about two millimeters to about eight millimeters when the axes 46, 48 are viewed in medial/lateral plane (see
It should be also appreciated that, in use, an orthopaedic surgeon may select an adaptor 14 having a desirable offset and angulation for the particular patient. For example, as illustrated in
It should be also appreciated that the adaptor 14 may be used with any one of a number of knee prosthetic components and stem extensions to offset the stem extension 16 in a first anatomical plane and angle the stem extension 16 in a second anatomical plane, which is orthogonal to the first anatomical plane. That is, in some embodiments, the adaptor 14 may be used to offset the stem extension 16 in the medial/lateral plane and angle the stem extension 16 in the anterior/posterior plane (see
Although the knee prosthetic component 12 is embodied as a tibial tray in the embodiment of
The femoral component 60 is configured to be coupled to a surgically prepared surface of the distal end of a patient's femur (not shown). When the femoral component 60 is coupled to the patient's femur, the adaptor 14 and the stem extension 16 are embedded in the patient's femur to thereby secure the femoral component 60 to the patient's bone. In use, the condyles 62, 64 replace the natural condyles of the patient's femur and are configured to articulate on the proximal end of the patient's natural or surgically prepared tibia.
As discussed above, the adaptor 14 is configured to be coupled with the femoral component 60 and the stem extension 16. As such, as described above in regard to
In other embodiments, the mounting end 28 of the adaptor 14 may include other or additional structures to facilitate the coupling of the adaptor 14 to the femoral component 60. For example, in some embodiments, the femoral component 60 may include a stem (not shown) extending upwardly from the upper surface 68 of the platform 66. In such embodiments, the mounting end 28 may be configured to be coupled to the stem of the femoral component 60. For example, in such embodiments, the mounting end 28 may be tapered and sized to be received in an aperture of the stem of the femoral component 60. In other embodiments, the mounting end 28 may include a threaded stud extending therefrom and configured to be received in a corresponding threaded aperture defined in the end of the stem of the femoral component 60. Alternatively, the distal end of the stem of the femoral component 60 may be threaded and configured to be received in a threaded aperture defined in the mounting end 28 of the adaptor 14.
As discussed above in regard to
The adaptor 14 may be configured such that the axis 48 is offset from and angled relative to the axis 46 by any amount suitable for implantation. For example, in one particular embodiment, the angle 76 defined between the axes 46, 48 is in the range of about one degree to about nine degrees (see
Although the adaptor 14 and the stem extension 16 are illustrated in
The stem extension 80 is configured such that the position of the elongated shaft 84 is altered relative to the knee prosthetic component 12. As illustrated in
Similar to the adaptor 14, the stem extension 80 may be configured such that the axis 88 is offset from and angled relative to the axis 86 by any amount suitable for implantation. For example, in one particular embodiment, the axis 88 is offset from the axis 86 by the distance 90 of about two millimeters to about eight millimeters when the axes 86, 88 are viewed in the medial/lateral plane (see
It should be appreciated, however, that other amounts of offset and angulation may be used in other embodiments based on the particular implementation, bone anatomy of the patient, and the like. It should also be appreciated that the stem extension 80 is configured to be used with a particular knee joint, either the left knee joint or right knee joint of the patient. A different embodiment of stem extension 80 may be required for use with the other knee joint such that the offset and angulation of the elongated shaft 84 is proper for the particular knee joint.
It should also be appreciated that the stem extension 80 can be used with any one of a number of knee prosthetic components to offset the elongated shaft 84 in a first anatomical plane and angle the elongated shaft 84 in a second anatomical plane, which is orthogonal to the first anatomical plane. That is, in some embodiments, the stem extension 80 may offset the elongated shaft 84 in the medial/lateral plane and angle the elongated shaft 84 in the anterior/posterior plane (see
In some embodiments, the adaptor 14 may be formed from multiple pieces. For example, as illustrated in
In such embodiments, the first piece 100 of the adaptor 14 includes the mounting end 28 and a mounting plate 103 having a mounting surface 104. The second piece 102 of the adaptor 14 includes the mounting end 40 and a mounting plate 105 having a mounting surface 106. When the pieces 100, 102 of the adaptor 14 are coupled together, the mounting surfaces 104, 106 confront or abut each other. As such, the mounting surfaces 104, 106 may include any number of apertures, protrusions, grooves, and/or other structures necessary to facilitate the securing of the first piece 100 to the second piece 102. For example, referring to
In some embodiments, the second piece 102 may be coupled to the first piece 100 at any one of a number of positions such that the angle 52 (see
Alternatively, as illustrated in
In some embodiments, the stem extension 120 may be coupled to the first piece 100 at any one of a number of positions such that an angle 132 (see
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 shown 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 apparatus, system, and method described herein. It will be noted that alternative embodiments of the apparatus, system, and method 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 apparatus, system, and method 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.
