Patent Application
20060206211
Not Applicable.
1. The Field of the Invention
The present disclosure relates generally to prostheses used in hip surgical procedures, and more particularly, but not necessarily entirely, to the features that mechanically interconnect a femoral head component within a bipolar prosthesis forming at least a part of a hip joint.
2. Description of Related Art
The human hip joint acts mechanically as a ball and socket joint, wherein the ball-shaped head of the natural femur is positioned within the natural socket-shaped acetabulum of the pelvis. In a total hip joint replacement, both the natural femoral head and the natural surface of the acetabulum are replaced with prosthetic devices. A total hip replacement is typically used when both the natural femoral head and natural acetabulum are diseased or damaged. Often, however, only the natural femoral head of a patient is diseased or damaged. In such circumstances, in order to be bone sparing which is advantageous in hip surgical procedures, a hip hemiarthroplasty surgical procedure is commonly used. In a hip hemiarthroplasty surgical procedure, the proximal portion of a femur is replaced with a suitable prosthetic implant that articulates directly with a patient's natural acetabulum.
In a hip hemiarthroplasty procedure, two types of femoral prostheses are typically used. One type is a bipolar prosthesis. In general, a bipolar hip prosthesis includes an acetabular shell component having an external surface that articulates with a patient's natural acetabulum. The bipolar prosthesis also includes a bearing component that comprises an internal surface that articulates with a spherical head member of a prosthetic femoral component.
The other type of prosthesis is often referred to as a unipolar endoprosthesis in which the prosthetic femoral component includes a spherical head member that is large enough to articulate directly with the natural acetabulum.
The present disclosure relates to a bipolar hip prosthesis. In the prior art, there are many femoral head components and many acetabular shell components that can be used together to create a bipolar hip joint. During surgery, the femoral head component may be implanted into the femur in a first procedure. The acetabular shell component may be inserted into the natural acetabulum in a second procedure. The femoral head component may then be joined to the acetabular shell component in a third procedure.
One concern of all such prior art devices is how to set the femoral head component in the bearing component of the bipolar prosthesis so that the femoral head component does not become displaced from the bearing component during normal activity. It is a great complication when a bipolar hip prosthesis becomes displaced after insertion. In a displacement, the spherical head of the femoral component becomes dissociated from the bearing component. Such a dissociation most typically occurs as the result of an abnormal twisting of the leg or after a trauma, such as a fall.
In the prior art, various locking mechanisms have been used to lock the femoral head component in place within the bearing component of the bipolar prosthesis and prevent the femoral head component from becoming displaced. Such prior art is exemplified by U.S. Pat. No. 4,798,610 to Averill et al., entitled Prosthetic Implant Device. The Averill et al. patent is itself an improvement of U.S. Pat. No. 4,241,463 (Khovaylo). In the Averill et al. patent, the femoral head component is mechanically prevented from dislocating from the bearing component by a free floating locking ring. The bearing component comprises a recess that is partially defined by a circumferential lip, wherein the ring is located within the recess and contacts the lip thereby preventing dislocation of the femoral head component from the bearing component. The ring itself comprises an inner surface that has an arcuate cross-sectional shape for contacting the spherical femoral head component when that component is urged downwardly against the ring by downward forces tending to disengage the femoral head component from the bearing component.
In order to solve the problems associated with displacement of the femoral head component from the bearing component of the bipolar prosthesis, devices have been developed that allow a displaced femoral head component to be reset into a bearing component without intrusive surgery. One such bipolar hip prosthesis is shown in U.S. Pat. No. 6,206,929 to Ochoa et al., entitled Bipolar Hip Prosthesis With Locking Head. In the Ochoa et al. patent, flexible locking elements hold the femoral head component within the bearing and shell components. During trauma, the femoral head component may be pulled out of the bipolar prosthesis. However, the femoral head component can be set back into the bearing component of the bipolar prosthesis without surgery, provided the flexible locking elements were not damaged by the removal of the femoral head component. Unfortunately, during different traumas, damage may sometimes occur to the locking elements. If damage to the locking elements does occur, then intrusive surgery may be required to either replace various parts of the bipolar prosthesis, such as the bearing component, or to assemble the acetabular shell component and the bearing component back onto the femoral head component.
The features and advantages of the disclosure will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by the practice of the disclosure without undue experimentation. The features and advantages of the disclosure may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims.
The features and advantages of the disclosure will become apparent from a consideration of the subsequent detailed description presented in connection with the accompanying drawings in which:
For the purposes of promoting an understanding of the principles in accordance with the disclosure, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the disclosure is thereby intended. Any alterations and further modifications of the inventive features illustrated herein, and any additional applications of the principles of the disclosure as illustrated herein, which would normally occur to one skilled in the relevant art and having possession of this disclosure, are to be considered within the scope of the disclosure claimed.
It is to be understood that this disclosure is not limited to the particular configurations, process steps, and materials disclosed herein as such configurations, process steps, and materials may vary somewhat. It is also to be understood that the terminology employed herein is used for the purpose of describing particular embodiments only and is not intended to be limiting since the scope of the present disclosure will be limited only by the appended claims and equivalents thereof.
The publications and other reference materials referred to herein to describe the background of the disclosure, and to provide additional detail regarding its practice, are hereby incorporated by reference herein in their entireties, with the following exception: In the event that any portion of said reference materials is inconsistent with this application, this application supercedes said reference materials. The reference materials discussed herein are provided solely for their disclosure prior to the filing date of the present application. Nothing herein is to be construed as a suggestion or admission that the inventors are not entitled to antedate such disclosure by virtue of prior disclosure, or to distinguish the present disclosure from the subject matter disclosed in the reference materials.
It must be noted that, as used in this specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise.
In describing and claiming the subject matter of the present disclosure, the following terminology will be used in accordance with the definitions set out below.
As used herein, the terms “comprising,” “including,” “containing,” “characterized by,” and grammatical equivalents thereof are inclusive or open-ended terms that do not exclude additional, unrecited elements or method steps.
As used herein, the term “proximal” shall refer broadly to the concept of a nearest portion. For example, “proximal” may anatomically refer to an area or point of reference that is nearer another point, such as an origin, a point of attachment, or the midline of the body.
As used herein, the term “distal” shall refer broadly to the concept of a furthest portion, or shall generally refer to the opposite of proximal. For example, “distal” may anatomically refer to an area or point of reference that is located far from another point of reference, such as an origin, a point of attachment, or the midline of the body.
Applicants have discovered that the effectiveness of a bipolar hip prosthesis may be increased by utilizing the concepts and principles set forth in the present disclosure, and particularly by utilizing a uniquely designed free floating ring in conjunction with a modular bipolar prosthesis comprised of an acetabular shell component and a bearing component. Additionally, the efficiency in inserting a prosthetic femoral head component into a corresponding bearing component of the bipolar prosthesis may be enhanced by utilizing the uniquely designed free floating ring and bearing component of the present disclosure.
It should be noted that in the figures similar features and elements of a bipolar hip prosthesis of the present disclosure will be identified using the same reference numerals in the various embodiments with the only exception being the first digit of the two or three digit reference numeral indicating a different embodiment.
Further, it should be noted that any dimensions contained in the figures are for exemplary purposes only, and are in no way intended to limit the scope of the present disclosure. Rather, such dimensions have been retained in the drawings for purposes of disclosure and illustration only. One of ordinary skill in the art will appreciate that the dimensions contained in the figures may be changed or modified without departing from the spirit or scope of the principles of the present disclosure.
Referring specifically to
The acetabular shell component 20 may be a substantially semi-spherical member and may comprise an outer surface 22 and an inner surface 24. It will be appreciated that the shell component 20 may be configured and dimensioned to articulate with the natural acetabulum of the hip bone. More specifically, the outer surface 22 of the shell component 20 may be configured and dimensioned to articulate directly with the acetabulum of the hip bone. Such articulation between the outer surface 22 of the shell component 20 and the acetabulum of the hip bone may constitute the first articulation of the bipolar prosthesis 10.
The inner surface 24 of the shell component 20 may be dome shaped and may define an inner semi-spherical cavity 26 for receiving the bearing component 40 therein.
It will be appreciated that the shell component 20 may be manufactured from any suitable biocompatible material, including metal, such as titanium, stainless steel, cobalt-chromium-molybdenum alloy, titanium-aluminum vanadium alloy or other suitable metallic alloys, or non-metallic biocompatible materials such as carbon-fiber, ceramic, bio-resorbable materials or if desired any suitable high strength plastic such as an ultra high molecular weight polyethylene that is capable of functioning as an articulating surface with the acetabulum. It will be appreciated by those skilled in the art that other biocompatible materials, whether now known or later discovered, may be utilized by the present disclosure, and said biocompatible materials are intended to fall within the scope of the present disclosure.
It will be appreciated that the shell component 20 of the bipolar prosthesis 10 of the present disclosure may be utilized with many different bearing components 40, whether disclosed herein or otherwise without departing from the scope of the present disclosure. It will be appreciated that the features of the bearing component 20 of the present disclosure will be discussed herein below.
Referring now to
Each of the bearing component embodiments of the present disclosure may be manufactured from various biocompatible materials, including biocompatible polymeric materials such as polyethylene or ultra high molecular weight polyethylene, or biocompatible ceramic materials, or even biocompatible metallic materials without departing from the scope of the present disclosure.
It will be appreciated that the outer surface 142 of the bearing component 140 may form a substantially semi-spherical dome portion 148 that may extend from approximately an apex region 150 of the bearing component 140 to approximately a midline 152 of the bearing component 140. From the midline 152, the outer surface 142 may comprise a cylindrical surface 151 that may extend toward the opening 149 of the bearing cavity 147 and terminate at a rim 153 of the bearing component 140. The rim 153 of the bearing component 140 may circumferentially extend around the perimeter of the bearing component 140.
It will be appreciated that the shape of the rim 153 may comprise various shapes and forms. However, the rim 153 illustrated in
It is to be understood that the rim 153 may be defined with reference to the bearing component 140 oriented in the manner illustrated in
With the bearing component 140 positioned in the orientation of
The second laterally extending wall 153c may extend inwardly from a terminal end 153b1 of the first tapered wall 153b in a substantial lateral direction toward the inner surface 144 of the bearing component 140.
The second tapered wall 153d may extend downwardly and inwardly, or in other words may taper inwardly in a distal to proximal direction with respect to the midline 152, at an angle β from a terminal end 153c1 of the second laterally extending wall 153c. The second tapered wall 153d may comprise an angle β with respect to a line parallel to the longitudinal axis A-A of the bearing component 140 that may be between the range of about ten degrees to about fifty degrees (10°-50°), specifically between about twenty degrees and about forty degrees (20°-40°), and more specifically between about twenty-five degrees to about thirty-five degrees (25°-35°), and even more specifically about thirty degrees (30°).
Finally, the first longitudinal wall 153e may extend downwardly from a terminal end 153d1 of the second tapered wall 153d in a substantial longitudinal direction defining the remainder of the rim 153.
The inner surface 144 of the bearing component 140 may define the bearing cavity 147. As illustrated best in
The bearing component 140 may further comprise a recess 146, which may be formed as part of the inner surface 144 of the bearing component 140. The recess 146 may be an annular recess. The recess 146 may be positioned adjacent the bearing cavity 147 on one side and may form a first junction 154 therebetween. On the opposite side, the recess 146 may also be positioned adjacent the first longitudinal wall 153e of the rim 153 and may form a second junction 155 therebetween. In other words, the recess 146 may essentially be sandwiched between the bearing cavity 147 and the first longitudinal wall 153e of the rim 153.
The recess 146 may be defined on the inner surface 144 of the bearing component 140 by several distinct surfaces. Referring specifically to
Defining the recess 146 more specifically, the first surface 156 of the recess 146 may extend in a substantial laterally outward direction from the first junction 154 away from the inner surface 144. It will be appreciated that the first surface 156 may form the lowermost surface of the recess 146. The second surface 157 may extend from a terminal end 156a of the first surface 156 upwardly and inwardly in a sloping manner, or in other words the second surface 157 may taper inwardly in a proximal to distal direction with respect to the midline 152 of the bearing component 140 at an angle. It will be appreciated that the second surface 157 may comprise an angle π with respect to a line parallel to the longitudinal axis A-A of the bearing component 140 that may be between the range of about five degrees to about thirty degrees (5°-30°), specifically between about ten degrees and about twenty-five degrees (10°-25°), and more specifically between about twelve degrees to about twenty degrees (12°-20°), and even more specifically about fifteen to about sixteen degrees (15°-16°). The third surface 158 may extend in a substantial laterally inward direction from a terminal end 157a of the second surface 157. The third surface 158 may form the uppermost surface of the recess 146. It should be noted that the first and third surfaces 156 and 158, respectively, may each extend in a substantially lateral direction as defined herein.
As used herein, the phrase “substantial lateral direction” may refer to a ninety degree (90°) angle with respect to the longitudinal axis A-A of the bearing component 140, or to an angle that is greater than ninety degrees, but not more than one-hundred and thirty-five degrees (135°), or to an angle that is less than ninety degrees, but not less than forty-five degrees (45°). In other words, a “substantial lateral direction” may refer to an angle between forty-five degrees (45°) and one-hundred and thirty-five degrees (135°) with respect to the longitudinal axis A-A of the bearing component 140.
It will be appreciated that the dashed lines 156b and 158b in
It will be appreciated that
Referring now to
The rim 253 of the bearing component 240 may be defined by five surfaces, similar to the rim 153 of the previous embodiment. However, the surfaces of the rim 253 may not be the same as the surfaces that define the previous rim 153 embodiment. As illustrated best in
The laterally extending wall 253a of the rim 253 may extend inwardly from a first terminal end 253a1 of the cylindrical surface 251 toward the inner surface 244 of the bearing component 240. It will be appreciated that a ledge 241 may be formed at or near the junction of the laterally extending wall 253a and the terminal end of the cylindrical surface 251. The ledge 241 may be used as part of a means for attaching the bearing component 240 to the shell component 20. For example, the ledge 241 may mate with a corresponding ledge formed in the shell component 20 to form an interference fit, thereby maintaining the bearing component 240 within the shell component 20.
The substantially cylindrical wall 253b of the rim 253 may extend upwardly from a second terminal end 253a2 of the laterally extending wall 253a. It will be appreciated that the wall 253b may be substantially cylindrical or the wall 253b may slope without departing from the scope of the present disclosure.
The curved or arcuate wall 253c may comprise a radius of curvature and may extend from a terminal end 253b1 of the substantially cylindrical wall 253b to the tapered wall 253d. In other words, the curved wall 253c may join the substantially cylindrical wall 253b and the tapered wall 253d together.
The tapered wall 253d may extend downwardly and inwardly, or in other words may taper inwardly in a distal to proximal direction with respect to the midline 252, from the curved wall 253c. The tapered wall 253d may comprise an angle θ with respect to a line parallel to the longitudinal axis A-A of the bearing component 240 that may be between the range of about ten degrees to about fifty degrees (10°-50°), specifically between about twenty degrees and about forty degrees (20°-40°), and more specifically between about twenty-five degrees to about thirty-five degrees (25°-35°), and even more specifically about thirty degrees (30°).
Finally, the longitudinal wall 253e may be substantially the same and unchanged with respect to the longitudinal wall 153e of the previous embodiment.
It will be appreciated that the recess 246 may be substantially similar to the recess 146 of the previous bearing component 140 embodiment. For example, the recess 246 may be an annular recess, and may be comprised of three surfaces, namely a first surface 256, a second surface 257 and a third surface 258, which may be similar to surfaces 156, 157, and 158. It should be noted that the first and third surfaces 256 and 258, respectively, may each extend in a substantially lateral direction as defined herein, and may include surfaces similar to 156b and 158b without departing from the scope or spirit of the present disclosure.
The second surface 257 may comprise an angle μ that may be substantially similar to the angle π of bearing component 140, and may be between the range of about five degrees to about thirty degrees (5°-30°), specifically between about ten degrees and about twenty-five degrees (10°-25°), and more specifically between about twelve degrees to about twenty degrees (12°-20°), and even more specifically about fifteen and about sixteen degrees (15°-16°).
Referring now to
For reference purposes, it will be appreciated that in
It will be appreciated that the rings 60 of the present disclosure may be manufactured from various biocompatible materials, including biocompatible polymeric materials such as polyethylene or ultra high molecular weight polyethylene, or other biocompatible materials that may be adapted for use as a ring as described herein, such as ceramic materials, or even biocompatible metallic materials, without departing from the scope of the present disclosure.
Referring specifically to
The ring 160 may comprise elastic characteristics by virtue of the material from which it may be manufactured and may also comprise shape memory. Accordingly, the ring 160 may be expanded or contracted, due in part to the gap or slit 170 and the elastic material from which the ring 160 may be manufactured, when an external force is applied thereto. After the force has been released or removed from the ring 160, the ring 160 may return back to its original shape, configuration and orientation due to the elastic nature and shape memory of the ring 160.
The ring 160 may comprise a recess or slot 172 that may be formed within the outer surface 164 (illustrated best in
The ring 160 of the present disclosure comprises a unique shape that aids in the insertion process of the femoral head component 82. For reference purposes, it will be appreciated that the femoral head component 82 may enter into the center 161 of the ring 160 from the top surface 166 and may move downward through the center 161 of the ring 160 during the insertion process. The shape of the ring 160 may function to aid in the insertion and retention of the femoral head component 82.
Specifically referring to
With respect to the outer surface 164, the first outer surface 164a may taper or slope from a terminal end 166a of the top surface 166 downwardly and outwardly. In other words, the first outer surface 164a may taper or slope outwardly in a distal to proximal direction with respect to the midline 152 of the bearing component 140 when the ring 160 is located in the recess 146 thereof. It will be appreciated that the taper or slope of the first outer surface 164a may comprise an angle λ with respect to the top surface 166 that may fall within a range of angles between about ninety degrees to about one-hundred twenty degrees (90°-120°), specifically between about ninety-five degrees to about one-hundred fifteen degrees (95°-115°), and more specifically about one-hundred degrees to about one-hundred ten degrees (100°-110°).
The second outer surface 164b may extend from a terminal end 164a1 of the first outer surface 164 and may taper or slope downwardly and inwardly. In other words, the second outer surface 164b may taper or slope inwardly in a distal to proximal direction with respect to the midline 152 of the bearing component 140 when the ring 160 is located in the recess 146 thereof. It will be appreciated that the taper or slope of the second outer surface 164b may comprise an angle φ with respect to the bottom surface 168 that may fall within a range of angles between about fifteen degrees to about seventy degrees (15°-70°), specifically between about twenty-five degrees to about sixty degrees (25°-60°), and more specifically about forty degrees to about forty-five degrees (40°-45°).
With respect to the inner surface 162, the third inner surface 162c may taper or slope from a terminal end 168a of the bottom surface 168 inwardly and upwardly. In other words, the third inner surface 162c may taper or slope inwardly in a proximal to distal direction with respect to the midline 152 of the bearing component 140 when the ring 160 is located in the recess 146 thereof. It will be appreciated that the taper or slope of the third inner surface 162c may comprise an angle γ with respect to the first inner surface 162a that may fall within a range of angles between about fifteen degrees to about seventy degrees (15°-70°), specifically between about twenty-five degrees to about sixty degrees (25°-60°), and more specifically about forty degrees to about forty-five degrees (40°-45°).
The second inner surface 162b of the ring 160 may taper or slope from a terminal end 162c1 inwardly and upwardly. In other words, the second inner surface 162b may taper or slope inwardly in a proximal to distal direction with respect to the midline 152 of the bearing component 140 when the ring 160 is located in the recess 146 thereof. It will be appreciated that the taper or slope of the second inner surface 162b may comprise an angle κ with respect to the first inner surface 162a that may fall within a range of angles between about one-hundred eighty degrees to about two-hundred ten degrees (180°-210°), specifically between about one-hundred ninety degrees to about two-hundred degrees (190°-200°), and more specifically about one-hundred ninety-four degrees to about one-hundred ninety-six degrees (194°-196°).
The first inner surface 162a may extend upwardly in a substantially longitudinal direction from a terminal end 162b1 of the second inner surface 162b. The first inner surface 162a may join or terminate at a second terminal end 166b of the top surface 166, thereby forming or completing the outer shape of the ring 160.
It will be appreciated that once the femoral head component 82 is inserted into the bearing cavity 147 of the bearing component 140, the femoral head component 82 may contact or bear against the second inner surface 162b of the ring 160. Further, after the femoral head component 82 has been fully installed and seated in the bearing cavity 147, the top surface 166 of the ring 160 may contact the third surface 158, which may also be the uppermost surface, of the recess 146 of the bearing component 140, thereby retaining the femoral head component 82 within the bearing cavity 147 of the bipolar prosthesis 10.
The ring 160 may be configured and dimensioned to be movable within the recess 146 of the bearing component 140. As such, the ring 160 may be smaller than the corresponding recess 146 such that a specific, limited and known amount of play between the ring 160 and the recess 146 may be present. The shape of the ring 160 and the corresponding recess 146 allow the ring 160 to move into the wider portion of the recess 146 when an external force is applied thereto, thereby allowing the ring 160 to expand. Such expansion of the ring 160 may allow the overall inner diameter of the center 161 of ring 160 to increase, thereby allowing passage of the femoral head component 82, which has a larger diameter than the ring 160 when the ring 160 is in its natural, unbiased position or orientation.
Referring now to
It will be appreciated that angles λ and φ of the first and second outer surfaces 264a and 264b, respectively, of the ring 260 may be substantially the same as the corresponding surfaces of the ring 160. However, a difference between the ring 260 of the present embodiment and the ring 160, may include a change in the shape of the bottom surface 268 and the inner surface 262 of the ring 260.
Specifically, the bottom surface 268 of the ring 260 may comprise a curved or arcuate corner 268a, which has a radius of curvature. The corner 268a may further act as a junction between the bottom surface 268 and a third inner surface 262c. The corner 268a radius may provide a lead in surface along with the third inner surface 262c that may allow the femoral head 82 to more easily locate the femoral head 82 within ring 260. The corner 268a radius may also function to center the femoral head component 82 as it is lead into the inner surface 262 of the ring 260. Accordingly, the femoral head component 82 may be positioned within the ring 260 such that the femoral head component 82 may contact the third inner surface 262c and may slide down said third inner surface 262c until the femoral head component 82 reaches a position of stability.
It will be appreciated that the inner surface 262 of the ring 260 may comprise several changes with respect to the inner surface 162 of the ring 160. The first inner surface 262a may be shorter than the corresponding first inner surface 162a, and may taper or slope from a second terminal end 266b of the upper surface 266 instead of extending longitudinally from the second terminal end 166b as does the first inner surface 162a. It will be appreciated that the taper or slope of the first inner surface 262a may comprise an angle ε formed with respect to the second inner surface 262b that may fall within a range of angles between about ten degrees to about fifty degrees (10°-50°), specifically between about twenty degrees and about forty degrees (20°-40°), and more specifically between about twenty-five degrees to about thirty-five degrees (25°-35°), and even more specifically about thirty degrees (30°).
The second inner surface 262b may extend downwardly in a substantially longitudinal direction from a terminal end 262a1 of the first inner surface 262a, instead of tapering or sloping at an angle from the terminal end 162b1 as does the second inner surface 162b.
The third inner surface 262c may be elongated with respect to the third inner surface 162c and may taper or slope from a terminal end 262b1 of the second inner surface 262b. It will be appreciated that the taper or slope of the third inner surface 262c may comprise an angle γ formed with respect to the second inner surface 262b that may fall within a range of angles between about one-hundred forty degrees to about one-hundred eighty degrees (140°-180°), specifically between about one-hundred fifty degrees and about one-hundred seventy degrees (150°-170°), and more specifically between about one-hundred fifty-five degrees to about one-hundred sixty-five degrees (155°-165°).
The elongated third inner surface 262c allows for a greater potential for contact between the femoral head component 82 and the third inner surface 262c of the ring 260 when the femoral head component 82 may be fully seated and secured within the bearing component 240.
It will be understood that the inner surfaces 162 and 262 of the respective rings 160 and 260 may be straight, linear surfaces when viewed in cross-section. However, many of the surfaces may be modified to comprise other shapes beside straight, linear surfaces. Despite the foregoing, the third inner surfaces 162c and 262c of the rings 160 and 260 may be straight, linear surfaces in cross-section, and as such are, therefore, not arcuate or curved surfaces in cross-section.
Referring now to
It will be appreciated that the point of convergence “C” is not specifically illustrated in
Referring now to the method of operation of the foregoing structural components of the bipolar prosthesis 10, no matter which embodiment of the bearing component 140 or 240 and the free floating ring 160 or 260 are used, the same basic method and operation of use of the bipolar prosthesis 10 may be employed. Specifically, insertion of the femoral head component 82 into the bipolar prosthesis 10 may be accomplished by pushing the femoral head component 82 against the top surface 166 or 266 of the ring 160 or 260, thereby forcing the ring 160 or 260 up into the recess 146 or 246 of the bearing component 140 or 240. As force is applied to the top surface 166 or 266, the outside surface 164 or 264 of the ring 160 or 260 may slide against the second surface 157 or 257 of the recess 146 or 246 thereby expanding the ring 160 or 260 within the recess 146 or 246.
When expansion of the ring 160 or 260 occurs, the diameter of the center 161 or 261 of the ring 160 or 260 enlarges such that the femoral head component 82 may be allowed to pass thereby. Thereafter, the ring 160 or 260 may slide within the recess 146 or 246 until the top surface 166 or 266 comes into contact with the third surface 158 or 258 of the recess 146 or 246, thereby capturing the femoral head component 82 and allowing the femoral head component 82 to settle into a position of stability within the ring. It is to be understood that the top surface 166 or 266 of the ring 160 or 260 may abut the third surface 158 or 258 of the recess 146 or 246 thereby retaining the ring within said recess 146 or 246.
It will be appreciated that the structure and apparatus disclosed herein is merely one example of a means for attaching the bearing component to the shell component, and it should be appreciated that any structure, apparatus or system for attaching the bearing component to the shell component which performs functions the same as, or equivalent to, those disclosed herein are intended to fall within the scope of a means for attaching the bearing component to the shell component, including those structures, apparatus or systems for attaching the bearing component to the shell component which are presently known, or which may become available in the future. Anything which functions the same as, or equivalently to, a means for attaching the bearing component to the shell component falls within the scope of this element.
Those having ordinary skill in the relevant art will appreciate the advantages provide by the features of the present disclosure. For example, it is a potential feature of the present disclosure to provide a modular bipolar prosthesis which is simple in design and manufacture. Another potential feature of the present disclosure is to provide such a bipolar prosthesis having a shell component, a bearing component, and a free floating ring, wherein a straight, linear portion in cross-section of the inner surface of the ring contacts the femoral head component. It is a further potential feature of the present disclosure, in accordance with one aspect thereof, to provide a uniquely shaped free floating ring for centering the femoral head component within the inner surface of the ring. Another potential feature of the present invention is to provide an inner ring surface and an outer ring surface that may comprise a point of convergence that may fall within a certain range of angles. It will be appreciated that there may be additional potential features of the present disclosure not mentioned in this portion of the disclosure, which nevertheless may be considered pertinent to the present disclosure.
In the foregoing Detailed Description, various features of the present disclosure have been grouped together and discussed in a single embodiment, while differences between embodiments have been discussed in isolation for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the disclosure requires more features than are expressly recited, whether in claims or otherwise. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the following claims are hereby incorporated into this Detailed Description of the Disclosure by this reference, with each claim standing on its own as a separate embodiment of the present disclosure.
It is to be understood that the above-described arrangements are only illustrative of the application of the principles of the present disclosure. Numerous modifications and alternative arrangements may be devised by those skilled in the art without departing from the spirit and scope of the present disclosure and the appended claims are intended to cover such modifications and arrangements. Thus, while the present disclosure has been shown in the drawings and described above with particularity and detail, it will be apparent to those of ordinary skill in the art that numerous modifications, including, but not limited to, variations in size, materials, shape, form, function and manner of operation, assembly and use may be made without departing from the principles and concepts set forth herein.
This application claims the benefit of U.S. Provisional Application No. 60/655,285, filed Feb. 22, 2005, which is hereby incorporated by reference herein in its entirety, including but not limited to those portions that specifically appear hereinafter, the incorporation by reference being made with the following exception: In the event that any portion of the above-referenced provisional application is inconsistent with this application, this application supercedes said above-referenced provisional application.
| Number | Date | Country | |
|---|---|---|---|
| 60655285 | Feb 2005 | US |
