Femoral component of a knee prosthesis having an angled cement pocket
09724202 · 2017-08-08
Assignee
Inventors
- Christel M. Wagner (Plymouth, IN, US)
- Joseph G. Wyss (Fort Wayne, IN, US)
- David S. Barrett (Awbridge, GB)
Cpc classification
A61F2002/30772
HUMAN NECESSITIES
A61F2002/4631
HUMAN NECESSITIES
A61F2/3836
HUMAN NECESSITIES
A61F2/3886
HUMAN NECESSITIES
A61F2002/30878
HUMAN NECESSITIES
A61F2002/30884
HUMAN NECESSITIES
International classification
Abstract
An implantable orthopedic knee prosthesis includes a component that is configured to be coupled to a surgically-prepared bone. A fixation side of the component includes a fixation surface that has an angled cement pocket formed therein.
Claims
1. An implantable orthopaedic knee prosthesis, comprising: a femoral component configured to be coupled to a surgically-prepared distal femur, the femoral component having (i) an articular side comprising a posterior femoral condyle surface, and (ii) a fixation side that is opposite the articular side, the fixation side comprising a fixation surface, wherein, when viewed in the sagittal plane, the fixation surface comprises (i) a peripheral rim, (ii) an angled bottom wall spaced apart posteriorly from the peripheral rim, and (iii) a superior wall extending posteriorly from the peripheral rim to the angled bottom wall, wherein the superior wall extends between a pair of sidewalls that extend inferiorly and superiorly on a medial side and a lateral side of the fixation surface, and the superior wall, the angled bottom wall, and the pair of sidewalls collectively define a cement pocket, and wherein, when viewed in the sagittal plane, (i) an imaginary plane defined by the peripheral rim forms an acute angle with an imaginary plane defined by the angled bottom wall such that the cement pocket is deeper at its inferior end than at its superior end, and (ii) the cement pocket has a depth at its superior end that is greater than zero millimeters.
2. The implantable orthopaedic knee prosthesis of claim 1, wherein, when viewed sagittally, an inferior end of each sidewall is wider than a corresponding superior end.
3. The implantable orthopaedic knee prosthesis of claim 1, wherein the fixation surface is a posterior fixation surface.
4. The implantable orthopaedic knee prosthesis of claim 1, wherein the fixation surface is a posterior chamfer fixation surface.
5. The implantable orthopaedic knee prosthesis of claim 1, wherein the articular side comprises a posterior lateral femoral condyle surface.
6. The implantable orthopaedic knee prosthesis of claim 1, wherein the articular side comprises a posterior medial femoral condyle surface.
7. An implantable orthopaedic knee prosthesis, comprising: a tibial tray configured to be coupled to a surgically-prepared proximal tibia, a bearing coupled to the tibial tray, the bearing having a medial articular surface and a lateral articular surface, and a femoral component configured to be coupled to a surgically-prepared distal femur, the femoral component having (i) a lateral condyle surface configured to articulate with the lateral articular surface of the bearing and a medial condyle configured to articulate with the medial articular surface of the bearing, (ii) a lateral fixation surface opposite the lateral condyle surface, and (iii) a medial fixation surface opposite the medial condyle surface, wherein, when viewed in the sagittal plane, the medial fixation surface comprises (i) a medial peripheral rim, (ii) a medial angled bottom wall spaced apart posteriorly from the medial peripheral rim, and (iii) a medial superior wall extending posteriorly from the medial peripheral rim to the medial angled bottom wall, wherein the medial superior wall extends between a pair of medial sidewalls that extend inferiorly and superiorly on a medial side and a lateral side of the medial fixation surface, and the medial superior wall, the medial angled bottom wall, and the pair of medial sidewalls collectively define a medial cement pocket, wherein, when viewed in the sagittal plane, an imaginary plane defined by the medial peripheral rim forms an acute angle with an imaginary plane defined by the medial angled bottom wall such that the medial cement pocket is deeper at its inferior end than at its superior end, and (ii) the medial cement pocket has a depth at its superior end that is greater than zero millimeters, wherein, when viewed in the sagittal plane, the lateral fixation surface comprises (i) a lateral peripheral rim, (ii) a lateral angled bottom wall spaced apart posteriorly from the lateral peripheral rim, and (iii) a lateral superior wall extending posteriorly from the lateral peripheral rim to the lateral angled bottom wall, wherein the lateral superior wall extends between a pair of lateral sidewalls that extend inferiorly and superiorly on a medial side and a lateral side of the lateral fixation surface, and the lateral superior wall, the lateral angled bottom wall, and the pair of lateral sidewalls collectively define a lateral cement pocket, and wherein, when viewed in the sagittal plane, an imaginary plane defined by the lateral peripheral rim forms an acute angle with an imaginary plane defined by the lateral angled bottom wall such that the lateral cement pocket is deeper at its inferior end than at its superior end, and (ii) the lateral cement pocket has a depth at its superior end that is greater than zero millimeters.
8. The implantable orthopaedic knee prosthesis of claim 7, wherein, when viewed sagittally, an inferior end of each medial sidewall of the medial fixation surface is wider than its corresponding superior end.
9. The implantable orthopaedic knee prosthesis of claim 7, wherein, when viewed sagittally, an inferior end of each lateral sidewall of the lateral fixation surface is wider than its corresponding superior end.
10. An implantable orthopaedic knee prosthesis, comprising: a femoral component configured to be coupled to a surgically-prepared distal femur, the femoral component having (i) an articular side comprising a femoral condyle surface, and (ii) a fixation side that is opposite the articular side, the fixation side comprising a fixation surface, wherein the fixation surface has a cement pocket formed therein, the cement pocket is deeper at its inferior end than at its superior end, wherein the cement pocket is partially defined by an angled bottom wall that extends from the inferior end to the superior end and a superior wall extending posteriorly from a peripheral rim to the angled bottom wall, the superior wall extending between a pair of sidewalls that extend inferiorly and superiorly on a medial side and a lateral side of the fixation surface, and the cement pocket has a depth at the superior wall that is greater than zero millimeters, wherein, when viewed sagittally, an imaginary plane defined by the peripheral rim forms an acute angle with an imaginary plane defined by the angled bottom wall.
11. The implantable orthopaedic knee prosthesis of claim 10, wherein: the fixation surface comprises a posterior fixation surface having a posterior cement pocket formed therein.
12. The implantable orthopaedic prosthesis of claim 10, wherein the fixation surface is a posterior fixation surface.
13. The implantable orthopaedic prosthesis of claim 10, wherein the fixation surface is a posterior chamfer fixation surface.
14. The implantable orthopaedic knee prosthesis of claim 10, wherein the femoral component comprises a unicompartmental femoral component.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The detailed description particularly refers to the following figures, in which:
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DETAILED DESCRIPTION OF THE DRAWINGS
(14) 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.
(15) Terms representing anatomical references, such as anterior, posterior, medial, lateral, superior, inferior, etcetera, may be used throughout this disclosure in reference to both the orthopaedic implants described herein and a 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 specification and claims is intended to be consistent with their well-understood meanings unless noted otherwise.
(16) Referring now to
(17) The tibial tray 14 includes a platform 18 having a fixation member, such as an elongated stem 20, extending away from its lower surface. The bearing 16 includes a stem 22 (see
(18) The bearing 16 includes a lateral articular surface 26 and a medial articular surface 28. The articular surfaces 26, 28 are configured to articulate with a lateral condyle surface 30 and a medial condyle surface 32, respectively, of the femoral component 12. Specifically, the femoral component 12 is configured to emulate the configuration of the patient's natural femoral condyles, and, as such, the lateral condyle surface 30 and the medial condyle surface 32 are configured (e.g., curved) in a manner which mimics the condyles of the natural femur. The lateral condyle surface 30 and the medial condyle surface 32 are spaced apart from one another thereby defining an intercondylar notch therebetween.
(19) The components of the knee prosthesis 10 that engage the natural bone, such as the femoral component 12 and the tibial tray 14, may be constructed with a biocompatible metal, such as a cobalt chrome alloy, although other materials, such as ceramics, may also be used. The bone engaging surfaces of these components may be textured to facilitate cementing the component to the bone. Such surfaces may also be porous coated to promote bone ingrowth for permanent fixation.
(20) The bearing 16 may be constructed with a material that allows for smooth articulation between the bearing 16 and the femoral component 12, such as a polymeric material. One such polymeric material is polyethylene such as ultrahigh molecular weight polyethylene (UHMWPE), although other biocompatible polymers may be used.
(21) Although the femoral component 12 is herein illustratively described as a monolithic component, it is characterized by a number of “regions” or “structures”. For example, the anterior structure of the femoral component 12 is referred to as an anterior flange 34. The anterior flange 34 transitions to an anterior chamfer region 36, which, in turn, transitions to a distal condylar region 38. The distal condylar region 38 transitions to a posterior chamfer region 40. A pair of posterior femoral condyles 42 form the posterior structure of the femoral component 12.
(22) As shown in
(23) Each of the fixation surfaces has a cement pocket formed therein. In particular, a posterior cement pocket 70 is formed in each of the posterior fixation surfaces 50, a posterior-chamfer cement pocket 72 is formed in each of the posterior-chamfer fixation surfaces 54, a distal cement pocket 74 is formed in each of the distal fixation surfaces 58, an anterior-chamfer cement pocket 76 is formed in each of the anterior-chamfer fixation surfaces 62, and an anterior cement pocket 78 is formed in the anterior fixation surface 66. In the illustrative embodiment described herein, the adjacent cement pockets are contiguous with one another such that a single, continuous cement pocket is formed in the fixation side 48 of the femoral component.
(24) Each of the cement pockets 70, 72, 74, 76, 78 is formed by a sidewall 80 that extends away from a mounting rim 82. As can be seen in
(25) The depth (D.sub.1) of each of the posterior-chamfer cement pocket 72, the distal cement pocket 74, the anterior-chamfer cement pocket 76, and the anterior cement pocket 78 is approximately equal. In the illustrative embodiment described herein, each of the cement pockets 72, 74, 76, and 78 is approximately 1 mm deep (i.e., D.sub.1=1 mm).
(26) The posterior cement pocket 70, on the other hand, is angled and, as a result, is deeper at its inferior end than on its superior end. In particular, as shown in
(27) Such an arrangement creates an angled bottom wall 84′. In particular, the bottom wall 84′ slopes anteriorly from its inferior end 86 to its superior end 88. This sloped arrangement is illustratively shown in the cross sectional view of
(28) During a surgical procedure to implant the femoral component 12 to the surgically-prepared distal end of the patient's femur, the cement pockets 70, 72, 74, 76, 78 are preloaded with bone cement. The femoral component 12 is then positioned on the patient's surgically-prepared distal femur, which has also been coated in bone cement. The angled arrangement of posterior cement pocket 70 hydraulically loads the bone cement within the cement pocket. This enhances containment of the bone cement and reduces the occurrences of cement plowing. The arrangement of the posterior cement pocket 70 also improves filling of the bone cement and pressurization which, in turn, leads to enhanced bonding of the femoral component 12 to the distal femur.
(29) Referring now to
(30) Such an arrangement creates an angled bottom wall 84″. In particular, the bottom wall 84″ of the anterior cement pocket 78 slopes posteriorly from its inferior end 106 to its superior end 108. This sloped arrangement is illustratively shown in
(31) During a surgical procedure to implant the femoral component 12 of
(32) It should be appreciated that although the embodiment of
(33) Referring now to
(34) Referring now to
(35) The tibial tray's inferior side 122 is opposite its superior side 120, and is the side of the tibial tray 14 that contacts the surgically-prepared proximal tibia of the patient. The elongated stem 20 extends inferiorly away from the tibial tray's inferior side 122. The tibial tray's inferior side 122 includes multiple surfaces that mate with planar surfaces surgically cut into the patient's proximal tibia. Specifically, as shown in
(36) The inferior fixation surface 124 has a cement pocket 126 formed therein. In the illustrative embodiment described herein, the tibial tray's fins 128 divide the cement pocket 126 into separate cement pockets at various locations along the tray's medial/lateral width. In particular, an anterior cement pocket 130 is positioned anteriorly of the tray's fins 128 with a posterior cement pocket 132 being positioned posteriorly of the tray's fins 128. However, since the fins 128 do not stretch to the medial and lateral edges of the tray 14, the cement pockets 130, 132 are contiguous with one another such that a single, continuous cement pocket 126 is formed in the inferior side 122 of the tibial tray 14. It should be appreciated; however, that the tibial tray 14 could be embodied with one or more separate cement pockets.
(37) Each of the cement pockets 126, 130, 132 is formed by a sidewall 140 that extends superiorly away from a mounting rim 142. As can be seen in
(38) The cement pocket 126 is angled and, as a result, deeper at its anterior end than on its posterior end. In particular, when viewed sagittally, such as in the cross sectional view of
(39) Such an arrangement creates an angled top wall 144. In particular, the top wall 144 slopes inferiorly from its anterior end 166 to its posterior end 168. This sloped arrangement is illustratively shown in the cross sectional views of
(40) During a surgical procedure to implant the tibial tray 14 to the surgically-prepared proximal end of the patient's tibia, the cement pocket 126 is preloaded with bone cement. The tibial tray 14 is then positioned on the patient's surgically-prepared proximal tibia, which has also been coated in bone cement. The angled arrangement of cement pocket 126 hydraulically loads the bone cement within the cement pocket. This enhances containment of the bone cement and reduces the occurrences of cement plowing. The arrangement of the cement pocket 126 also forces any excess bone cement out the anterior side of the tibial tray 14 where it can be readily wiped away or otherwise removed by the surgeon.
(41) Referring now to
(42) 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.
(43) 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.