U.S. patent application number 12/788961 was filed with the patent office on 2010-12-02 for knee prosthesis.
This patent application is currently assigned to Biomet Manufacturing Corp.. Invention is credited to James G. Lancaster, Robert Metzger.
Application Number | 20100305710 12/788961 |
Document ID | / |
Family ID | 43221109 |
Filed Date | 2010-12-02 |
United States Patent
Application |
20100305710 |
Kind Code |
A1 |
Metzger; Robert ; et
al. |
December 2, 2010 |
Knee Prosthesis
Abstract
A knee joint prosthesis assembly can include a femoral component
that has a medial and a lateral condyle portion connected by a
patellar track portion. The femoral component can form an opening
between the medial and lateral condyles. A tibial component can
have a medial portion that includes a first engagement structure
and a lateral portion that includes a second engagement structure.
A medial bearing can have a third engagement structure formed
thereon that selectively engages the first engagement structure. A
lateral bearing separately formed and independent from the medial
bearing can have a fourth engagement structure formed thereon that
selectively engages the second engagement structure.
Inventors: |
Metzger; Robert; (Wakarusa,
IN) ; Lancaster; James G.; (Winona Lake, IN) |
Correspondence
Address: |
HARNESS, DICKEY & PIERCE, P.L.C.
P.O. BOX 828
BLOOMFIELD HILLS
MI
48303
US
|
Assignee: |
Biomet Manufacturing Corp.
Warsaw
IN
|
Family ID: |
43221109 |
Appl. No.: |
12/788961 |
Filed: |
May 27, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61181938 |
May 28, 2009 |
|
|
|
Current U.S.
Class: |
623/20.31 |
Current CPC
Class: |
A61F 2/3868 20130101;
A61F 2002/30462 20130101; A61F 2220/0075 20130101; A61F 2002/30708
20130101; A61F 2/3886 20130101; A61F 2/3836 20130101 |
Class at
Publication: |
623/20.31 |
International
Class: |
A61F 2/38 20060101
A61F002/38 |
Claims
1. A knee joint prosthesis assembly comprising: a femoral component
having a medial and a lateral condyle portion connected by a
patellar track portion, the femoral component forming an opening
between the medial and lateral condyles; a unitary tibial component
having a medial portion that includes a first engagement structure
and a lateral portion that includes a second engagement structure;
a medial bearing having a third engagement structure formed thereon
that selectively engages the first engagement structure; and a
lateral bearing separately formed and independent from the medial
bearing and having a fourth engagement structure formed thereon
that selectively engages the second engagement structure.
2. The knee joint prosthesis of claim 1 wherein the medial and
lateral condyles of the femoral component are configured to
articulate along complementary bearing surfaces of the medial and
lateral bearings.
3. The knee joint prosthesis of claim 2 wherein the medial and
lateral bearings are both configured to be fixed relative to the
tibial component.
4. The knee joint prosthesis of claim 2 wherein one of the medial
and lateral bearings is fixed relative to the tibial component and
the other of the medial and lateral bearings is a mobile bearing
component wherein at least a portion of the mobile bearing is
configured to slidably advance along an opposing surface of the
tibial component.
5. The knee joint prosthesis of claim 2 wherein both of the medial
and lateral bearings are mobile bearing components that have
respective portions that slidably advance along an opposing surface
of the tibial component.
6. The knee joint prosthesis of claim 4 wherein a condyle portion
of the medial and lateral condyle portions that articulates on the
mobile bearing component has a spherical, convex articulation
surface.
7. The knee joint prosthesis of claim 4 wherein the mobile bearing
component includes a fixed portion having the third or fourth
engagement structure that is configured to statically engage the
tibial component and a mobile bearing portion that is configured to
slidably advance along the opposing surface of the tibial
component.
8. The knee joint prosthesis of claim 7 wherein the fixed portion
defines a pocket that receives and confines the mobile bearing
portion therewithin.
9. The knee joint prosthesis of claim 8 wherein the mobile bearing
portion is formed of a polymeric material and includes a metallic
layer of material disposed around a perimeter thereof.
10. The knee joint prosthesis of claim 1, further comprising: a
locking bar that selectively locates between the tibial component
and the medial and lateral bearings, the locking bar cooperating
with the first, second, third and fourth engagement structures and
securing the medial and lateral bearings to the tibial
component.
11. The knee joint prosthesis of claim 1 wherein the tibial
component is U-shaped and is adapted to accommodate an anterior
cruciate ligament.
12. The knee joint prosthesis of claim 1 wherein the tibial
component has an inferiorly extending stem.
13. The knee joint prosthesis of claim 1, further comprising a
plurality of fixed and mobile medial bearings and a plurality of
separate fixed and mobile lateral bearings, wherein the plurality
of medial and lateral bearings have distinct thicknesses in a
superior/inferior direction.
14. A method of implanting a knee prosthesis, the method
comprising: providing a kit of tibial trays, medial bearings and
lateral bearings, the tibial trays including a bicruciate retaining
tray and a posterior cruciate retaining tray, the medial and
lateral bearings including a plurality of fixed and mobile medial
and lateral bearings; accessing a patient's proximal tibia and
distal femur; assessing the proximal and distal femur and at least
one of an anterior cruciate ligament and posterior cruciate
ligament; selecting one of a bicruciate retaining or posterior
cruciate retaining tibial tray from the kit based on the assessing;
securing the selected tibial tray to the proximal tibia;
determining whether a fixed or mobile bearing is desired for a
medial and lateral side of the selected tibial tray based on the
assessing; intraoperatively and independently selecting a medial
and a lateral bearing from the kit of bearings; and securing the
selected medial and lateral bearings to the selected tibial
tray.
15. The method of claim 14 wherein selecting the tibial tray
comprises selecting the bicruciate retaining tray having a U-shaped
slot and wherein securing the bicruciate tibial tray comprises
locating an anterior cruciate ligament through the U-shaped
slot.
16. The method of claim 14 wherein securing the selected medial and
lateral bearings comprises aligning respective engagement
structures on the selected tibial tray with complementary
engagement structures formed on the medial and lateral bearings
and, further comprising: slidably advancing a locking bar into
contact with the respective engagement structures on the tray and
the complementary engagement structures on the medial and lateral
bearings.
17. A knee joint prosthesis assembly comprising: a unitary tibial
component having a medial portion that includes a first engagement
structure and a lateral portion that includes a second engagement
structure; a medial bearing having a third engagement structure
formed thereon that selectively engages the first engagement
structure; a lateral bearing separately formed and independent from
the medial bearing and having a fourth engagement structure formed
thereon that selectively engages the second engagement structure;
and a locking bar that selectively locates between the tibial
component and the medial and lateral bearings, the locking bar
cooperating with the first, second, third and fourth engagement
structures and securing the medial and lateral bearings to the
tibial component.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit and priority of
61/181,938, filed May 28, 2009. The entire disclosure of the above
application are incorporated herein by reference.
FIELD
[0002] The present disclosure relates to a knee joint prosthesis
including a tibial tray component having independent and
selectively attachable bearings including fixed and mobile bearings
that can be secured to medial and lateral sides of the tibial tray
according to the needs of a particular patient.
BACKGROUND
[0003] This section provides background information related to the
present disclosure which is not necessarily prior art.
[0004] A knee joint prosthesis can generally comprise a femoral
component and a tibial component. The femoral component and the
tibial component can be designed to be surgically attached to the
distal end of the femur and the proximal end of the tibia,
respectively. The femoral component can further be designed to
cooperate with the tibial component in simulating the articulating
motion of an anatomical knee joint. In many examples, the tibial
component can further include a bearing component that includes
articulation surfaces on the medial and lateral side for
cooperating with a medial and lateral condyle portion of the
femoral component. In some examples, the bearing component can be
fixed relative to the tibial component. In other examples, the
bearing component can be a mobile bearing component that has at
least a portion that can move relative to the tibial component
during articulation of the femoral component.
SUMMARY
[0005] This section provides a general summary of the disclosure,
and is not a comprehensive disclosure of its full scope or all of
its features.
[0006] A knee joint prosthesis assembly can include a femoral
component that has a medial and a lateral condyle portion connected
by a patellar track portion. The femoral component can form an
opening between the medial and lateral condyles. A tibial component
can have a medial portion that includes a first engagement
structure and a lateral portion that includes a second engagement
structure. A medial bearing can have a third engagement structure
formed thereon that selectively engages the first engagement
structure. A lateral bearing separately formed and independent from
the medial bearing can have a fourth engagement structure formed
thereon that selectively engages the second engagement
structure.
[0007] According to additional features, the medial and lateral
condyles of the femoral component can be configured to articulate
along complementary bearing surfaces of the medial and lateral
bearings. The medial and lateral bearings can both be configured to
be fixed relative to the tibial component. According to other
features, one of the medial and lateral bearings can be fixed
relative to the tibial component and the other of the medial and
lateral bearings can be a mobile bearing component. In other
configurations, both of the medial and lateral bearings can be
mobile bearing components that have respective portions that
slidably advance along an opposing surface of the tibial component.
One of the medial and lateral condyle portions that articulates on
the mobile bearing component can have a spherical, convex
articulations surface.
[0008] According to other features, the mobile bearing component
can include a fixed portion that has the third or fourth engagement
structure that is configured to statically engage the tibial
component and a mobile bearing portion that is configured to
slidably advance along the opposing surface of the tibial
component. The fixed portion can define a pocket that receives and
confines the mobile bearing portion therewithin. The mobile bearing
portion can be formed of a polymeric material and can include a
metallic layer of material disposed around a perimeter thereof. A
locking bar can be provided that selectively locates between the
tibial component and the medial and lateral bearings. The locking
bar can cooperate with the first, second, third and fourth
engagement structures and can secure the medial and lateral
bearings to the tibial component.
[0009] A method of implanting a knee prosthesis can include
providing a kit of tibial trays, medial bearings and lateral
bearings. The tibial trays can include a bicruciate retaining tray
and a posterior cruciate retaining tray. The medial and lateral
bearings can include a plurality of fixed and mobile medial and
lateral bearings. The patient's proximal tibia and distal femur can
be accessed. The proximal and distal femur and at least one of an
anterior cruciate ligament and posterior cruciate ligament can be
assessed. A bicruciate retaining or posterior cruciate retaining
tibial tray can be selected from the kit based on the assessing.
The selected tibial tray can be secured to the proximal tibia. The
desirability of a fixed or mobile bearing can be determined for the
medial and lateral sides of the selected tibial tray based on the
assessing. The medial and lateral bearings can be intraoperatively
and independently selected from the kit. The selected medial and
lateral bearings can be secured to the selected tibial tray.
[0010] Further areas of applicability will become apparent from the
description provided herein. The description and specific examples
in this summary are intended for purposes of illustration only and
are not intended to limit the scope of the present disclosure.
DRAWINGS
[0011] The drawings described herein are for illustrative purposes
only of selected embodiments and not all possible implementations,
and are not intended to limit the scope of the present
disclosure.
[0012] FIG. 1 is an anterior perspective view of a knee prosthesis
assembly according to one example of the present teachings;
[0013] FIG. 2 is a posterior perspective view of the knee
prosthesis of FIG. 1;
[0014] FIG. 3 is a lateral perspective view of a femoral component
of the knee prosthesis of FIG. 1;
[0015] FIG. 4 is a superior perspective view of a tibial tray of
the knee prosthesis of FIG. 1;
[0016] FIG. 5 is an inferior perspective view of the tibial tray of
FIG. 4;
[0017] FIG. 6 is a perspective view of a mobile bearing of the knee
prosthesis of FIG. 1;
[0018] FIG. 7 is a perspective view of a fixed bearing of the knee
prosthesis of FIG. 1;
[0019] FIG. 8 is a perspective view of a locking bar associated
with the fixed bearing of a knee prosthesis of FIG. 1;
[0020] FIG. 9 is a partially exploded posterior view of a knee
prosthesis constructed in accordance to additional features of the
present teachings;
[0021] FIG. 10 is a posterior perspective view of the knee
prosthesis of FIG. 9;
[0022] FIG. 11 is an anterior perspective view of a tibial tray and
fixed bearing portion of the knee prosthesis of FIG. 10;
[0023] FIG. 12 is a perspective view of a mobile bearing that
slidably cooperates within a pocket formed on the fixed bearing of
FIG. 11;
[0024] FIG. 13 is an anterior perspective view of a knee prosthesis
assembly according to another example of the present teachings that
incorporates a mobile bearing component that is selectively
attachable to a medial side of a tibial tray and a fixed bearing
component that is selectively attachable to a lateral side of the
tibial tray;
[0025] FIG. 14 is an anterior superior exploded perspective view of
the knee prosthesis assembly of FIG. 13;
[0026] FIG. 15 is an anterior inferior exploded perspective view of
the knee prosthesis assembly of FIG. 13;
[0027] FIG. 16 is a perspective view of a mobile bearing
incorporating a metal sleeve according to various features;
[0028] FIG. 17 is an anterior perspective view of a tibial tray
constructed in accordance to additional features and incorporating
a pair of fixed bearings that are selectively locked to the tibial
tray with a locking bar;
[0029] FIG. 18 is an anterior superior exploded perspective view of
the tibial tray assembly of FIG. 17;
[0030] FIG. 19 is an anterior inferior exploded perspective view of
the tibial tray assembly of FIG. 17;
[0031] FIG. 20 is an anterior perspective view of a tibial tray
constructed in accordance to additional features of the present
teachings; and
[0032] FIG. 21 is a kit having a plurality of tibial trays, medial
bearings and lateral bearings according to the present
teachings.
[0033] Corresponding reference numerals indicate corresponding
parts throughout the several views of the drawings.
DETAILED DESCRIPTION
[0034] Example embodiments will now be described more fully with
reference to the accompanying drawings.
[0035] With initial reference to FIGS. 1 and 2, a knee prosthesis
assembly constructed in accordance to one example of the present
teachings is shown and generally identified at reference numeral
10. The knee prosthesis assembly 10 can generally include a femoral
component 12, a tibial tray 14, a medial floating or mobile bearing
16 and a lateral fixed bearing 18. As will be described, the knee
prosthesis assembly 10 can be used when it is desirable to retain
or reconstruct an anterior cruciate ligament (ACL) and/or a
posterior cruciate ligament (PCL).
[0036] The respective components of the knee prosthesis assembly 10
can be patient specific, such that each component can be
constructed for optimal features for a given patient. For example,
the bone interface margins of the femoral component 12 and tibial
tray 14 can be patient specific for optimized bone coverage. In
addition, the overall size, such as anterior-posterior dimensions
and bone cut geometry can be determined and used for manufacturing
the components of the knee prosthesis assembly 10. Moreover, some
articulation features can be determined and used as criteria for
forming the components of the knee prosthesis assembly 10. In sum,
each of the components of the knee prosthesis assembly 10 can be a
patient-specific implant, a semi-custom implant or an off-the-shelf
or standard production implant. A custom-made implant is a
patient-specific, one-of-a-kind implant specifically made for a
particular patient, and consequently there is no inventory
associated with such implant. Standard or off-the shelf implants
are available and stocked in a number of sizes, typically six or
more, and a number of configurations or types, including bilateral
or unilateral implants, constrained, semi-constrained, mobile, etc.
Because of the variety of sizes and configurations that are kept in
stock to be accommodated by different patients, a large inventory
of standard implants is created, and several molds for each type
and size of implant may be used. Semi-custom implants can provide
an intermediate solution between custom-made and off-the-shelf
implants. Semi-custom implants reduce the size of inventory and
molds required for production, while allowing some degree of
patient-specific customization. Additional description of
patient-specific implants and semi-custom implants and their
implementations may be found in copending patent application Ser.
No. 12/103,824, filed Apr. 16, 2008 and entitled: Method and
Apparatus for Manufacturing an Implant, the disclosure of which is
hereby incorporated by reference.
[0037] With additional reference to FIG. 3, the femoral component
12 will now be described in greater detail. The femoral component
12 can generally comprise a cruciate retaining prosthesis and
includes various portions to replace or mimic the distal femur. The
femoral component 12 can include a medial condyle portion 20 and a
lateral condyle portion 22. The condyle portions 20 and 22 can
replace the medial and lateral condyles of a distal femur. The
medial and lateral condyle portions 20 and 22 can interconnect and
be formed as a single piece with a patellar track portion 26. The
patellar track portion 26 can allow for articulation of a patella,
either natural or prosthetic patella, once the femoral component 12
is implanted onto the distal femur. The medial and lateral condyle
portions 20 and 22 and the patellar track portion 26 can generally
define an exterior portion of the femoral component 12. The femoral
component 12 can define an opening or passage 30 between the medial
and lateral condyle portions 20 and 22. As can be appreciated, the
passage 30 can accommodate, and provide clearance for a host ACL
and/or PCL or a reconstructed ACL and/or PCL. The medial condyle
portion 20 can include a spherical contact surface that is convex
in an anterior/posterior direction and a medial/lateral
direction.
[0038] The femoral component 12 can include a bone contacting or
inferior surface 34 (FIG. 2). The inferior surface 34 can include
an anterior surface 36 that can be substantially flat and formed
generally parallel to a pair of posterior surfaces 38a and 38b. A
pair of intermediate surfaces 40a and 40b are provided generally at
an intermediate portion of the inferior surface 34. A pair of
angled anterior transition surfaces 42a and 42b generally connect
the anterior surface 36 with the intermediate surfaces 40a and 40b.
Similarly, a pair of angled posterior transition surfaces 44a and
44b are provided between the respective posterior surfaces 38a and
38b and the intermediate surfaces 40a and 40b. In one example, a
threaded boss 50a and 50b can be provided on each of the
intermediate surfaces 40a and 40b, respectively. Similarly, a
threaded boss 52a and 52b can be provided on the posterior surfaces
38a and 38b, respectively. The bosses 50a, 50b, 52a and 52b can be
optionally used to threadably couple with various augments (not
specifically shown) as necessary. The femoral component 12 can be
formed as a unitary structure and cast of a biocompatible high
strength alloy, such as cobalt-chromium-molybdenum alloy or similar
suitable material. All surfaces, which do not contact the femur,
can be highly polished to provide smooth articulating bearing
surfaces. The interior surface 34 of the femoral component 12 can
be roughened or uneven or include porous material to allow bone
ingrowth or attachment with bone cement. Other features of the
femoral component 10 can include those associated with the
Oxford.RTM. Partial Knee marketed by Biomet, Inc.
[0039] With reference now to FIGS. 1, 2, 4 and 5, the tibial tray
14 will now be described in greater detail. The tibial tray 14 can
include a generally U-shaped body having a medial portion 60 and a
lateral portion 62. A slot 64 can be formed in the tibial tray 14
generally between the medial and lateral portion 60 and 62. As with
the passage 30 of the femoral component, the slot 64 of the tibial
tray 14 can accommodate and provide a clearance for a host ACL
and/or PCL or a reconstructed ACL and/or PCL. During implantation,
the tibial tray 14 can be advanced posteriorly, such that the slot
64 can accommodate a host ACL and/or PCL. In instances where a
reconstructed ACL and/or PCL is used, a tray (and bearing) having a
passage can be utilized. One suitable configuration is further
described in commonly owned in U.S. Pat. No. 7,255,715; issued Aug.
14, 2007 and is hereby incorporated by reference. The tibial tray
14 can include an inferior bone engaging side 66 (FIG. 5) and a
superior bearing engaging side 68 (FIG. 4). The medial portion 60
of the superior bearing engaging side 68 can include a highly
polished tibial bearing surface 70. A rail 72 can extend in a
generally anterior/posterior direction adjacent to the highly
polished tibial bearing surface 70. The lateral portion 62 can
include engaging structure 78 provided on the superior bearing
engaging side 68. The engaging structure 78 can include a pair of
posts 80 and 82 integrally formed at an anterior edge thereof. A
retaining rail 84 can extend superiorly from a posterior edge of
the lateral portion 62. The posts 80 and 82 can both have an
anterior groove 86 and a posterior groove 88, respectively. The
retaining rail 84 can have a transverse groove 90 formed on an
inwardly facing surface. The tibial tray 14 can be generally
manufactured of cobalt-chromium-molybdenum alloy or other suitable
biocompatible material. A pair of fins 94 can extend from the
inferior bone engaging side 66. While fins 94 are shown operatively
associated with the tibial tray 14, other structures suitable for
engaging a proximal tibia can include pegs, posts or porous
material can additionally or alternatively be provided on the
inferior bone engaging side 66.
[0040] With reference to FIGS. 1, 2 and 6, the medial floating
bearing 16 will now be described in greater detail. The medial
floating bearing 16 has a substantially planar inferior bearing
surface 100 which slidably moves and articulates relative to the
highly polished tibial bearing surface 70. The medial floating
bearing 16 further includes a first bearing surface 102. The first
bearing surface 102 articulates with the medial condyle portion 20
of the femoral component 12. The medial floating bearing 16 can be
formed from a surgical grade, low friction, and low wearing
plastic, such as ultra high molecular weight polyethylene (UHMWPE)
or other suitable material.
[0041] With reference to FIGS. 1, 2 and 7, the lateral fixed
bearing 18 can include engaging structure 106 formed on an inferior
surface for coupling with the engaging structure 78 provided on the
lateral portion 62 of the tibial tray 14. The engaging structure
106 can generally include a posteriorly extending lip 110 and an
anterior groove 112. A locking bar 114 (FIG. 8) can be slidably
inserted through the anterior groove 112 to interlock between the
respective grooves 86 to capture the lateral fixed bearing 18 to
the lateral portion 62 of the tibial tray 14. The posteriorly
extending lip 110 can be nestingly received by the retaining rail
84. The lateral fixed bearing 18 can include a second bearing
surface 120. The second bearing surface 120 can articulate with the
lateral condyle portion 22 of the femoral component 12. The lateral
fixed bearing 18 can be formed from a surgical grade, low friction
and low wearing plastic, such as UHMWPE or other suitable
material.
[0042] During use, the medial and lateral condyle portions 20 and
22 of the femoral component 12 can articulate on the first and
second bearing surfaces 102 and 120 of the respective medial
floating bearing 16 and lateral fixed bearing 18. As can be
appreciated, the lateral fixed bearing 18 is static relative to the
tibial tray 14 during articulation of the femoral component 12. The
medial floating bearing 16 is free to slide along the highly
polished tibial bearing surface 70 of the medial portion 60 of the
tibial tray 14. The medial floating bearing 16 is bound on an
inboard side by the rail 72.
[0043] While the embodiment shown in the figures includes a
floating bearing provided on a medial side and a fixed bearing
provided on a lateral side, the location of these bearings can be
swapped. Similarly, both of the medial and lateral sides can be
formed with floating bearings or fixed bearings. Turning now to
FIGS. 9-11, a knee prosthesis assembly constructed in accordance to
additional features of the present teachings is shown and generally
identified at reference numeral 210. The knee prosthesis assembly
210 can generally include a femoral component 212, a tibial tray
214, a medial side having a mobile bearing component 216 and a
lateral side having a fixed bearing 220. The mobile bearing
component has a fixed portion 217 and a mobile bearing portion 218.
The femoral component 212 can be constructed similar to the femoral
component 12 described below. The fixed bearing 220 can be
constructed similar to the lateral fixed bearing 18 described
above. The mobile bearing component 216 can provide articulation
that is fully conforming with the femoral component 212. The mobile
bearing portion 218 can be captured around its perimeter by a
pocket 222 formed by the fixed portion 217. In this way, the mobile
bearing portion 218 can have a reduced likelihood of becoming
dislocated relative to the fixed portion 217. While the mobile
bearing component 216 is shown generally associated with the
lateral side of the tibial tray 214, such a configuration can be
additionally or alternatively provided on the medial portion of the
tibial tray 214. In one example, the mobile bearing portion 218 can
be formed by polyethylene or polyetheretherketone (PEEK). As shown
in FIG. 11, the fixed portion 217 can have a pair of channels 226
formed thereon for guiding tabs 230 provided on the mobile bearing
portion 218 (FIG. 12). It will be appreciated that while the mobile
bearing component 216 has been described and shown incorporated on
a medial portion of the tibial tray 214, it can additionally or
alternatively be incorporated on a lateral portion of the tibial
tray 214. Likewise, while the fixed bearing 220 has been described
and shown incorporated on a lateral portion of the tibial tray 214,
it can additionally or alternatively be incorporated on a medial
portion of the tibial tray 214.
[0044] With reference now to FIGS. 13-16, a knee prosthesis
assembly 310 constructed in accordance to additional features of
the present teachings will be described. As with the other knee
prosthesis assemblies disclosed herein, the knee prosthesis
assembly 310 can be patient specific, such that each component can
be constructed for optimal features for a given patient. In this
regard, the knee prosthesis assembly 310 can generally include the
femoral component 12, a tibial tray 314, a mobile bearing component
316 and a fixed bearing component 318. As shown, the mobile bearing
component 316 is selectively secured to a medial portion 320 of the
tibial tray 314 and a fixed bearing component 318 selectively
secured to a lateral portion 322 of the tibial tray 314 for a left
knee. However, it will be appreciated by those skilled in the art
that a mobile bearing component 316 can be provided for both the
medial portion 320 and the lateral portion 322 of the tibial tray
314. Similarly, a fixed bearing component 318 can be provided for
both of the medial portion 320 and the lateral portion 322 of the
tibial tray 314. Likewise, the fixed bearing component 318 can
alternatively be provided only on the medial portion 320, while a
medial bearing component 316 can be provided only on a lateral
portion 322 of the tibial tray 314. In sum, any combination of
mobile and fixed bearing components can be available and
selectively secured to either of the medial or lateral portions 320
and 322 of the tibial tray 314.
[0045] The femoral component 12 can be generally formed similar to
the femoral component 12 described in detail above. Again, the
medial condyle portion 20 can have a spherical, convex articulation
surface that can cooperate with the mobile bearing components 316
as will be described herein. It is appreciated that a similar
spherical, convex articulation surface can be provided on the
lateral condyle portion 22 in the event that a mobile bearing
component is desired on the lateral portion 322 of the tibial tray
314.
[0046] The mobile bearing component 316 can generally include a
fixed portion 330 and a mobile bearing portion 332 (FIG. 14). The
fixed portion 330 can generally include a pocket 334 defined within
a surrounding wall 336. A superior surface 338 can be contoured to
cooperate with the profile of the medial condyle portion 20 of the
femoral component 12. An inferior surface 340 (FIG. 15) can have a
channel 342 that tapers generally anteriorly for locking with a
portion of the tibial tray 314 as further discussed herein. A rail
346 can be formed into the surrounding wall 336. A groove 348 can
be formed around a posterior edge of the fixed portion 330. The
fixed portion 330 can have an inner wall 349 that cooperates with
the U-shaped profile of the tibial tray 314 to accommodate a host
or reconstructed ACL.
[0047] The mobile bearing portion 332 can have an outer perimeter
surface 350 that substantially matches a profile of the surrounding
wall 336, however, is reduced in size so as to be stepped inwardly
relative to the surrounding wall 336 (see also FIG. 9) to allow
movement within the surrounding wall 336. Tabs 352 can extend in
generally the medial and lateral directions from an inferior
surface 354 of the mobile bearing portion 332. A superior
articulating surface 358 can substantially conform to the profile
of the medial condyle portion 20 of the femoral component 12. The
fixed portion 330 and the mobile bearing portion 332 can be formed
of UHMWPE or PEEK. According to additional features, a mobile
bearing portion 332' (FIG. 16) can have a metal layer or band 359
disposed around a perimeter. The metal layer 359 can preclude
polymer-polymer contact between the perimeter of the mobile bearing
portion 332' and the surrounding wall 336 of the fixed portion 330
to inhibit wear. As shown in FIG. 16, similar features are
identified with common reference numerals having a "prime"
suffix.
[0048] The fixed bearing component 318 can generally include a
superior surface 360 that substantially conforms to and provides a
surface contact with the profile of the lateral condyle portion 22
of the femoral component 12. A channel 362 can be formed along an
anterior inferior surface 364 and that generally tapers anteriorly.
A groove 368 can be formed around a posterior edge of the fixed
bearing component 318. The fixed bearing component 318 can have an
inner wall 369 that cooperates with the U-shaped profile of the
tibial tray 314 to accommodate a host or reconstructed ACL.
[0049] The tibial tray 314 can generally include a locating tab 370
formed on an anterior edge of the medial portion 320 and a locating
tab 372 formed on an anterior edge of the lateral portion 322. A
slot 374 can be defined through the tibial tray 314 between the
medial and lateral portions 320 and 322. The slot 374 can be
configured to accommodate and provide clearance for a host ACL
and/or PCL or a reconstructed ACL and/or PCL. A retaining rail 375
can be formed around a posterior edge of the medial portion 320.
The retaining rail 375 can include a lip 376 and a groove 378. A
retaining rail 380 can be formed around a posterior edge of the
lateral portion 322 of the tibial tray 314. The retaining rail 380
can generally include a lip 382 and a groove 384. An inferior
surface 386 of the tibial tray 314 can be generally smooth, but may
also incorporate a series of round grooved pegs. The inferior
surface 386 can be configured to be cemented or press-fit onto the
proximal tibia. The tibial tray 314 can be generally manufactured
of cobalt-chromium-molybdenum alloy or other suitable biocompatible
materials.
[0050] Attaching the mobile bearing component 316 to the medial
portion 320 of the tibial tray 314 will now be described according
to one example. At the outset, the surgeon can select a given
medial bearing component 316 from a plurality of medial bearing
components (see also kit 600, FIG. 21) that satisfies the desired
characteristics for a given patient, such as height, articulation,
etc. The mobile bearing portion 332 can be initially advanced into
the pocket 334 superiorly, such that the tabs 352 can generally
locate against the rail 346 formed on the fixed portion 330.
Concurrently or subsequently, the fixed portion 330 can be located
onto the medial portion 320 of the tibial tray 314 along with the
mobile bearing portion 332 in an assembly. Next, a surgeon can
slidably advance the mobile bearing component 316 in a directly
generally posteriorly such that the channel 342 is progressively
advanced around the locating tab 370 and the groove 348 of the
fixed portion 330 is located under the lip 376 of the retaining
rail 375 on the tibial tray 314. It will be appreciated that at
this point, the fixed portion 330 remains static relative to the
medial portion 320 of the tibial tray 314 while the mobile bearing
portion 332 is free to slidably advance around the medial portion
320 of the tibial tray 314 within the confines of the surrounding
wall 336 of the pocket 334. It can be appreciated that articulation
of the medial condyle portion 20 of the femoral component on the
superior articulating surface 358 of the mobile bearing portion 332
can influence the mobile bearing portion 332 to rotate and/or
slidably advance such as in an anterior/posterior direction along
the medial portion 320 around the pocket 334.
[0051] Connection of the fixed bearing component 318 to the lateral
portion 322 of the tibial tray 314 is similarly carried out.
Initially, the inferior surface 364 of the fixed bearing component
318 is located onto the lateral portion 322 of the tibial tray 314.
Next, the fixed bearing component 318 is slidably advanced
posteriorly, such that the channel 362 slidably accommodates the
locating tab 372 while the groove 368 locates under the lip 380.
The fixed bearing component 318 is adapted to be statically secured
relative to the lateral portion 322 of the tibial tray when
assembled.
[0052] With reference now to FIGS. 17-19, a tibial tray assembly
413 constructed in accordance to additional features of the present
teachings will be described. As with the other knee prosthesis
assemblies disclosed herein, the tibial tray assembly 413 can be
patient specific, such that each component can be constructed for
optimal features for a given patient. In this regard, the tibial
tray assembly 413 can include a tibial tray 414, a first bearing
component 416, a second bearing component 418 and a locking bar
420. As with the tibial tray 314 described above, the tibial tray
414 can be generally U-shaped and provides a slot 422 that can be
configured to accommodate and provide clearance for a host ACL
and/or PCL or a reconstructed ACL and/or PCL. Other examples of
attaching an artificial or natural ACL and/or PCL may be found in
"Knee Prosthesis Assembly with Ligament Link" Ser. No. (Attorney
Docket No. 5490-000809 and 5490-000809/US/01), filed concurrently
herewith. As with the other bearing components disclosed herein,
the first bearing component 416 and the second bearing component
418 are both independently formed and intraoperatively selected
according to the needs of a given patient. The first bearing
component 416 and the second bearing component 418 are generally
fixed bearing components, however, a mobile bearing component may
be similarly provided for either of the medial and/or lateral
sides. As will become appreciated from the following discussion,
the locking bar 420 can be used to selectively and intraoperatively
secure the respective first and second bearing components 416 and
418 to the tibial tray 414. The first bearing component 416 can
have a superior surface 424, an inferior surface 426 (FIG. 19)
having engagement grooves 427 and an anterior channel 428.
Similarly, the second bearing component 418 can include a superior
surface 430, an inferior surface 432 (FIG. 19) having engagement
grooves 433 and an anterior channel 434.
[0053] The tibial tray 414 can include a medial portion 436, a
lateral portion 438, posterior engagement tabs 440, an anterior
engagement bridge 442 and anterior engagement tabs 443. The
anterior engagement bridge 442 can include a track 444 formed
thereon. The anterior engagement bridge 442 can provide an
increased thickness to the tibial tray 414 at the connection
between the medial and lateral portion 436 and 438, respectively to
increase durability. A wall 446 can be formed on the anterior
engagement bridge 442 adjacent to the track 444. The tibial tray
414 can have inferiorly extending posts 450.
[0054] The locking bar 420 can generally include a body 454 having
a finger 456 extending therefrom. A catch 458 can be formed on a
terminal end of the finger 456. The locking bar 420 can be formed
of biocompatible metallic material, such as titanium for example.
The body 454 can further include a leading end 460 and a trailing
end 462.
[0055] Attaching the respective first and second bearing components
416 and 418 to the tibial tray 414 according to one example of the
present teachings will now be described. Once a surgeon has
selected a first and second bearing component 416 and 418 that
satisfies the given needs of a particular patient (see also kit
600, FIG. 21), they are independently located onto the medial and
lateral portions 436 and 438 of the tibial tray 414. In this
regard, the posterior engagement tabs 440 of the tibial tray 414
can locate into the respective engagement grooves 427 and 433 of
the first and second bearing components 416 and 418. In some
examples, the respective first and second bearing components 416
and 418 may be advanced posteriorly, such that the engagement tabs
440 can lock into the engagement grooves 427 and 433. Concurrently,
the anterior tabs 443 can locate into the anterior engagement
grooves 427 and 433 of the first and second bearing components 416
and 418. Next, a surgeon can slidably advance the leading end 460
of the locking bar 420 through the respective anterior channels 428
and 434 of the first and second bearing components 416 and 418.
Concurrently, a portion of the body 454 can locate along a
posterior side of the anterior engagement bridge 442 while the
finger 456 locates around an anterior side of the anterior
engagement bridge 442. The locking bar 420 can be further advanced
until the catch 458 on the finger 456 can locate around the wall
446 on the anterior engagement bridge 442.
[0056] With reference now to FIG. 20, another tibial tray 514
constructed in accordance to the present teachings is shown. The
tibial tray 514 generally includes an inferiorly extending stem
516. The tibial tray 514 can be a full tibial tray that can be
particularly suited for examples where a central slot (such as the
slot 422) for accommodating an ACL is not needed. The tibial tray
514 includes posterior engagement tabs 540 and an anterior
engagement bridge 542. Anterior locating tabs 543 can be formed on
the tray 514. The anterior engagement bridge 542 can include a
track 544. The tibial tray 514 can be configured to selectively and
intraoperatively secure independent medial and lateral bearings,
such as the bearings 416 and 418 disclosed herein.
[0057] Turning now to FIG. 21, a kit 600 is shown having a
collection of medial and lateral bearings that provide unique
articulations, sizes and thicknesses (i.e., D1, D2, D3, etc.) and
incorporate either a fixed or mobile configuration on the lateral
and medial sides. The kit 600 further includes the bicruciate
retaining tibial tray and the posterior cruciate retaining tray. As
disclosed herein, the kit can be particularly suited for allowing a
surgeon the opportunity to intraoperatively select a given medial
and/or lateral bearing component and tibial tray that is
particularly suited for a given patient. It is contemplated that
with the kit 600, a surgeon can also utilize the components during
a revision surgery where the level of constraint needs to be
increased. In this regard, a surgeon may only desire to change some
components while leaving others unchanged.
[0058] As used herein, the terms superior, superiorly, superior
direction are used to generally refer to the anatomical meaning,
such as higher in place or position or generally situated above.
Similarly, the terms inferior, inferiorly, inferior direction are
used to generally refer to the anatomical meaning, such as lower in
place or position or generally situated below.
[0059] The foregoing description of the embodiments has been
provided for purposes of illustration and description. It is not
intended to be exhaustive or to limit the disclosure. Individual
elements or features of a particular embodiment are generally not
limited to that particular embodiment, but, where applicable, are
interchangeable and can be used in a selected embodiment, even if
not specifically shown or described. The same may also be varied in
many ways. Such variations are not to be regarded as a departure
from the disclosure, and all such modifications are intended to be
included within the scope of the disclosure.
* * * * *