U.S. patent application number 13/530239 was filed with the patent office on 2013-01-03 for polymer femoral trial component.
Invention is credited to Thomas E. Wogoman.
Application Number | 20130006378 13/530239 |
Document ID | / |
Family ID | 46458231 |
Filed Date | 2013-01-03 |
United States Patent
Application |
20130006378 |
Kind Code |
A1 |
Wogoman; Thomas E. |
January 3, 2013 |
POLYMER FEMORAL TRIAL COMPONENT
Abstract
An orthopedic surgical instrument including a femoral trial
component configured to be coupled to a surgically-prepared distal
end of a patient's femur. The femoral trial component has a
fixation side configured to engage a posterior aspect of the
surgically-prepared distal femur.
Inventors: |
Wogoman; Thomas E.; (Warsaw,
IN) |
Family ID: |
46458231 |
Appl. No.: |
13/530239 |
Filed: |
June 22, 2012 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
61503237 |
Jun 30, 2011 |
|
|
|
Current U.S.
Class: |
623/20.35 |
Current CPC
Class: |
A61F 2/46 20130101; A61F
2002/30845 20130101; A61F 2/3859 20130101; A61F 2/28 20130101; A61F
2/4684 20130101 |
Class at
Publication: |
623/20.35 |
International
Class: |
A61F 2/38 20060101
A61F002/38 |
Claims
1. An orthopedic surgical instrument, comprising: a polymeric
femoral trial component configured to be coupled to a
surgically-prepared distal end of a patient's femur, the femoral
trial component comprising (i) an articular side comprising a
posterior femoral condyle surface, (ii) a fixation side that is
opposite the articular side, the fixation side comprising a
plurality of ribs that extend in a direction away from the
articular side so as to define a plurality of pockets therebetween,
each rib having an outer surface, and the outer surfaces of the
ribs defining a posterior fixation surface that extends generally
in the superior/inferior direction and is configured to match the
surgically-prepared distal end of the patient's femur, and (iii) a
plurality of teeth extending from the posterior fixation surface in
a direction away from the articular side, each tooth of the
plurality of teeth having a pointed tip that defines a longitudinal
axis of the tooth extending in the medial/lateral direction.
2. The orthopedic surgical instrument of claim 1, wherein each
tooth of the plurality of teeth has a triangular cross-section.
3. The orthopedic surgical instrument of claim 1, wherein the
plurality of teeth include at least four teeth.
4. The orthopedic surgical instrument of claim 1, wherein the
polymeric femoral trial component is formed as a molded integral
component.
5. The orthopedic surgical instrument of claim 1, wherein the outer
surfaces of a number of the plurality of ribs further define (i) a
distal fixation surface extending generally in the
anterior/posterior direction, and (ii) a posterior-chamfer fixation
surface extending superiorly and posteriorly from the distal
fixation surface to the posterior fixation surface.
6. The orthopedic surgical instrument of claim 5, wherein a second
plurality of pockets are defined in each of the distal fixation
surface and the posterior-chamfer fixation surface between the
plurality of ribs.
7. The orthopedic surgical instrument of claim 5, wherein the
femoral trial component has an aperture defined in the distal
fixation surface, the aperture extending from the fixation side to
the articular side.
8. The orthopedic surgical instrument of claim 1, wherein the
femoral trial component further includes: a lateral posterior
condyle including the articular side and the fixation side that is
opposite the articular side, and a medial posterior condyle
including (i) a second articular side comprising a second posterior
femoral condyle surface, (ii) a second fixation side that is
opposite the second articular side, the second fixation side
comprising a second plurality of ribs that extend in a direction
away from the second articular side so as to define a second
plurality of pockets therebetween, each rib having an outer surface
and the outer surfaces of the ribs defining a second posterior
fixation surface that extends generally in the superior/inferior
direction and is configured to match the surgically-prepared distal
end of the patient's femur, and (iii) a second plurality of teeth
extending from the posterior fixation surface in a direction away
from the second articular side.
9. The orthopedic surgical instrument of claim 1, wherein the
femoral trial component further has a medial side and a lateral
side, the medial side having at least one notch defined therein
extending from the fixation side to the articular side, and the
lateral side having at least one notch defined therein extending
from the fixation side to the articular side.
10. The orthopedic surgical instrument of claim 9, wherein the
medial side includes two notches, and the lateral side includes two
notches.
11. An orthopedic surgical instrument, comprising: a polymeric
femoral trial component configured to be coupled to a
surgically-prepared distal end of a patient's femur, the femoral
trial component comprising (i) an articular side comprising a
posterior femoral condyle surface, (ii) a fixation side that is
opposite the articular side, the fixation side comprising a planar
posterior fixation surface that extends generally in the
superior/inferior direction and is configured to match the
surgically-prepared distal end of the patient's femur, and (iii) a
plurality of teeth extending from the planar posterior fixation
surface in a direction away from the articular side, each tooth
having a pointed tip that defines a longitudinal axis of the tooth
extending in the medial/lateral direction.
12. The orthopedic surgical instrument of claim 11, wherein the
femoral trial component further has a medial side and a lateral
side, the medial side having at least one notch defined therein
extending from the fixation side to the articular side, and the
lateral side having at least one notch defined therein extending
from the fixation side to the articular side.
13. The orthopedic surgical instrument of claim 12, wherein the
medial side includes two notches, and the lateral side includes two
notches.
14. The orthopedic surgical instrument of claim 13, wherein a
plurality of pockets are defined in the planar posterior fixation
surface between the plurality of teeth.
15. An orthopedic surgical instrument, comprising: a polymeric
femoral trial component configured to be coupled to a
surgically-prepared distal end of a patient's femur, the femoral
trial component comprising (i) a medial side, (ii) a lateral side,
(iii) an articular side comprising a posterior femoral condyle
surface, and (iv) a fixation side that is opposite the articular
side, the fixation side being configured to engage a posterior
aspect of the surgically-prepared distal femur, wherein (i) a first
notch extending from the fixation side to the articular side is
defined in the medial side, and (ii) a second notch extending from
the fixation side to the articular side is defined in the lateral
side.
16. The orthopedic surgical instrument of claim 15, wherein (i) the
fixation side comprises a plurality of ribs, each rib having an
outer surface and the outer surfaces defining a posterior fixation
surface extending generally in the superior/inferior direction that
is configured to match the surgically-prepared distal end of the
patient's femur, and (ii) a plurality of teeth extend from the
posterior fixation surface in a direction away from the articular
side.
17. The orthopedic surgical instrument of claim 16, wherein the
plurality of teeth includes at least four teeth.
18. The orthopedic surgical instrument of claim 16, wherein each
tooth of the plurality of teeth has a pointed tip that defines a
longitudinal axis of the tooth extending in the medial/lateral
direction.
19. The orthopedic surgical instrument of claim 15, wherein the
femoral trial component is formed as a molded integral
component.
20. The orthopedic surgical instrument of claim 16, wherein each
tooth of the plurality of teeth has a triangular cross-section.
Description
[0001] This application claims priority under 35 U.S.C..sctn.119 to
U.S. Patent Application No. 61/503,237, which was filed on Jun. 30,
2011 and is incorporated herein by reference.
TECHNICAL FIELD
[0002] The present disclosure relates generally to orthopedic
surgical instruments and, more particularly, to surgical
instruments used on a patient's femur.
BACKGROUND
[0003] Joint arthroplasty is a well-known surgical procedure by
which a diseased and/or damaged natural joint is replaced by a
prosthetic joint. A typical knee prosthesis includes a tibial tray,
a femoral component, and a polymer insert or bearing positioned
between the tibial tray and the femoral component. Femoral
components are designed to be attached to a surgically-prepared
distal end of a patient's femur. Tibial trays are designed to be
attached to a surgically-prepared proximal end of a patient's
tibia.
[0004] To facilitate the replacement of the natural joint with the
knee prosthesis, orthopedic surgeons use a variety of orthopedic
surgical instruments such as, for example, prosthetic trial
components, cutting blocks, drill guides, milling guides, and other
surgical instruments. Prosthetic trial components, such as, for
example, a femoral trial component and a tibial bearing trial
component, are used to size and select the components of the knee
prosthesis that will replace the patient's natural joint. A
procedure that utilizes the trial components to size and select the
components of the knee prosthesis is often referred to as a trial
reduction.
SUMMARY
[0005] According to one aspect of the disclosure, an orthopedic
surgical instrument includes a polymeric femoral trial component
configured to be coupled to a surgically-prepared distal end of a
patient's femur. The femoral trial component includes an articular
side having a posterior femoral condyle surface and a fixation side
that is opposite the articular side. The fixation side has a
plurality of ribs that extend in a direction away from the
articular side so as to define a plurality of pockets therebetween.
Each rib has an outer surface, and the outer surfaces of the ribs
define a posterior fixation surface that extends generally in the
superior/inferior direction and is configured to match the
surgically-prepared distal end of the patient's femur. The femoral
trial component also includes a plurality of teeth extending from
the posterior fixation surface in a direction away from the
articular side. Each tooth of the plurality of teeth has a pointed
tip that defines a longitudinal axis of the tooth extending in the
medial/lateral direction.
[0006] In some embodiments, each tooth of the plurality of teeth
may have a triangular cross-section. In some embodiments, the
plurality of teeth may include at least four teeth.
[0007] Additionally, in some embodiments, the polymeric femoral
trial component may be formed as a molded integral component. In
some embodiments, the outer surfaces of a number of the plurality
of ribs may further define a distal fixation surface extending
generally in the anterior/posterior direction and a
posterior-chamfer fixation surface extending superiorly and
posteriorly from the distal fixation surface to the posterior
fixation surface.
[0008] In some embodiments, a second plurality of pockets may be
defined in each of the distal fixation surface and the
posterior-chamfer fixation surface between the plurality of ribs.
In some embodiments, the femoral trial component may have an
aperture defined in the distal fixation surface, and the aperture
may extend from the fixation side to the articular side.
[0009] Additionally, in some embodiments, the femoral trial
component may further include a lateral posterior condyle including
the articular side and the fixation side that is opposite the
articular side, and a medial posterior condyle. The medial
posterior condyle may include a second articular side including a
second posterior femoral condyle surface and a second fixation side
that is opposite the second articular side. The second fixation
side may have a second plurality of ribs that extend in a direction
away from the second articular side so as to define a second
plurality of pockets therebetween. Each rib may have an outer
surface and the outer surfaces of the ribs may define a second
posterior fixation surface that extends generally in the
superior/inferior direction and is configured to match the
surgically-prepared distal end of the patient's femur. The medial
posterior condyle may also include a second plurality of teeth
extending from the posterior fixation surface in a direction away
from the second articular side.
[0010] In some embodiments, the femoral trial component may further
have a medial side and a lateral side. The medial side may have at
least one notch defined therein extending from the fixation side to
the articular side, and the lateral side may have at least one
notch defined therein extending from the fixation side to the
articular side.
[0011] In some embodiments, the medial side may include two
notches, and the lateral side may include two notches.
[0012] According to another aspect, an orthopedic surgical
instrument includes a polymeric femoral trial component configured
to be coupled to a surgically-prepared distal end of a patient's
femur. The femoral trial component includes an articular side
having a posterior femoral condyle surface and a fixation side that
is opposite the articular side. The fixation side has a planar
posterior fixation surface that extends generally in the
superior/inferior direction and is configured to match the
surgically-prepared distal end of the patient's femur. A plurality
of teeth extend from the planar posterior fixation surface in a
direction away from the articular side. Each tooth has a pointed
tip that defines a longitudinal axis of the tooth extending in the
medial/lateral direction.
[0013] In some embodiments, a plurality of pockets may be defined
in the planar posterior fixation surface between the plurality of
teeth.
[0014] According to another aspect, an orthopedic surgical
instrument includes a polymeric femoral trial component configured
to be coupled to a surgically-prepared distal end of a patient's
femur. The femoral trial component has a medial side, a lateral
side, an articular side including a posterior femoral condyle
surface, and a fixation side that is opposite the articular side.
The fixation side is configured to engage a posterior aspect of the
surgically-prepared distal femur. The polymeric femoral trial
component also includes a first notch extending from the fixation
side to the articular side that is defined in the medial side, and
a second notch extending from the fixation side to the articular
side that is defined in the lateral side.
[0015] In some embodiments, the fixation side may include a
plurality of ribs. Each rib may have an outer surface and the outer
surfaces may define a posterior fixation surface extending
generally in the superior/inferior direction that is configured to
match the surgically-prepared distal end of the patient's femur. A
plurality of teeth may extend from the posterior fixation surface
in a direction away from the articular side. In some embodiments,
the plurality of teeth may include at least four teeth.
[0016] Additionally, in some embodiments, each tooth of the
plurality of teeth may have a pointed tip that defines a
longitudinal axis of the tooth extending in the medial/lateral
direction. In some embodiments, the femoral trial component may be
formed as a molded integral component. In some embodiments, each
tooth of the plurality of teeth may have a triangular
cross-section.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The detailed description particularly refers to the
following figures, in which:
[0018] FIG. 1 is a perspective view of an orthopedic surgical
instrument assembly;
[0019] FIG. 2 is an exploded perspective view of the orthopedic
surgical instrument assembly of FIG. 1;
[0020] FIG. 3 is a perspective view of the femoral trial component
of the orthopedic surgical instrument assembly of FIG. 1;
[0021] FIG. 4 is a sagittal cross sectional view of the femoral
trial component of FIGS. 1-3;
[0022] FIG. 5 is a bottom plan view of the femoral trial component
of FIGS. 1-4;
[0023] FIG. 6 is a perspective view of the femoral trial component
of FIGS. 1-5 positioned on a surgically-prepared distal end of a
patient's femur;
[0024] FIG. 7 is a sagittal cross sectional view of the femoral
trial component of FIGS. 1-6 on the surgically-prepared distal end
of the patient's femur;
[0025] FIG. 8 is a perspective view of the orthopedic surgical
instrument assembly of FIG. 1 positioned on surgically-prepared
ends of the patient's femur and tibia with the patient's knee in
extension; and
[0026] FIG. 9 is a perspective view of the orthopedic surgical
instrument assembly of FIG. 8 with the patient's knee in
flexion.
DETAILED DESCRIPTION OF THE DRAWINGS
[0027] 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.
[0028] Terms representing anatomical references, such as anterior,
posterior, medial, lateral, superior, inferior, etcetera, may be
used throughout the specification in reference to the orthopedic
implants and surgical instruments described herein as well as in
reference to the patient's natural anatomy. Such terms have
well-understood meanings in both the study of anatomy and the field
of orthopedics. Use of such anatomical reference terms in the
written description and claims is intended to be consistent with
their well-understood meanings unless noted otherwise.
[0029] Referring to FIGS. 1-4, an orthopedic surgical instrument
assembly 10 is shown. The orthopedic surgical instrument assembly
10 has a number of trial components 12, including a femoral trial
14, a tibial base trial 16, and a tibial bearing trial 18. The
femoral trial 14 is configured to be secured to a
surgically-prepared end of a patient's distal femur 20 (see FIG.
6), whereas the tibial base trial 16 is configured to be secured to
a surgically-prepared end of a patient's proximal tibia 22 (see
FIG. 8).
[0030] As shown in FIG. 2, the tibial base trial 16 includes a
plate 30 having an opening 32 defined therein sized to receive a
base insert 34. The base insert 34 includes a body 36 having a
number of fixation pins 38 extending away from a lower surface 40
of the body 36. The base insert 34 also includes a post 42
extending away from an upper surface 44 of the body 36. It should
be appreciated that in other embodiments the fixation pins 38 may
be omitted from base insert 34 or additional fixation pins 38 may
be added.
[0031] The tibial bearing trial 18 is configured to assist the
surgeon in selecting a prosthetic tibial bearing component of a
typical knee prosthesis. The tibial bearing trial 18 is a
multi-piece assembly that includes a bearing surface trial 46 and a
shim 48. The post 42 of the base insert 34 is received in an
opening 50 defined in the shim 48 and an opening (not shown)
defined in the lower surface of the bearing surface trial 46. The
bearing surface trial 46 includes a lateral articular surface 52
and a medial articular surface 54 positioned opposite the lower
surface. In the illustrative embodiment, the bearing surface trial
46 is embodied as a fixed bearing trial and is fixed relative to
the tibial base trial 16 (i.e., it is configured to not
substantially rotate or move in the anterior/posterior direction or
medial/lateral direction). In other embodiments, the bearing
surface trial 46 may be a mobile bearing trial configured to rotate
relative to the tibial base trial 16. As shown in the illustrative
embodiment, the tibial bearing trial 18 is a multi-piece assembly,
but it should be appreciated that in other embodiments the tibial
bearing trial 18 may be a single monolithic component. One example
of a tibial bearing trial 18 is shown and described in co-pending
U.S. Patent Application Ser. No. 61/503,300, entitled "TRIALING
SYSTEM FOR A KNEE PROSTHESIS AND METHOD OF USE" by Thomas E.
Wogoman et al. (Attorney Docket No. 265280-210420, DEP6286USPSP),
which is incorporated herein by reference.
[0032] The femoral trial 14 of the orthopedic surgical instrument
assembly 10 is configured to assist the surgeon in selecting a
femoral prosthetic component, which will emulate the configuration
of the patient's natural femoral condyles. As such, the femoral
trial 14 includes a lateral condyle surface 56 and a medial condyle
surface 58, which may be shaped (i.e., curved) in a manner that
approximates the condyles of the natural femur. The lateral condyle
surface 56 and the medial condyle surface 58 are spaced apart from
one another, thereby defining an intercondylar notch 60
therebetween. The articular surfaces 52, 54 of the tibial bearing
trial 18 are configured to rotate with the lateral condyle surface
56 and the medial condyle surface 58, respectively, of the femoral
trial 14.
[0033] As shown in FIG. 3, the lateral condyle surface 56 and the
medial condyle surface 58 are formed in an articular side 62 of the
femoral trial 14. A fixation side 64, which is the side of the
femoral trial 14 that contacts the surgically-prepared distal femur
of the patient, is opposite the articular side 62. The fixation
side 64 includes a plurality of ribs 66 that extend in a direction
away from the articular side 62. Each of the ribs 66 includes an
outer surface 68, and the outer surfaces 68 of the ribs 66
cooperate to define multiple surfaces of the fixation side 64.
Those surfaces, identified below as "fixation surfaces," mate or
match with planar surfaces surgically cut into the patient's femur,
as discussed in greater detail below.
[0034] Although the femoral trial 14 is illustratively shown as a
single integral or monolithic component, the trial 14 is
characterized herein by a number of "regions" or "structures." For
example, the anterior structure of the femoral trial 14 is referred
to herein as an anterior flange 70. Moving along the femoral trial
14 from an anterior to posterior, the anterior flange 70
transitions to an anterior-chamfer region 72, which transitions to
a distal condylar region 74. The distal condylar region 74
transitions to a posterior-chamfer region 76. A pair of femoral
condyles 78 forms the posterior structure of the femoral trial 14.
One of the femoral condyles 78 is medially positioned and the other
laterally positioned when the femoral trial 14 is attached to the
distal end of the patient's resected femur 20 depending on which
knee is being replaced.
[0035] The outer surfaces 68 of the ribs 66 of each of the
posterior femoral condyles 78 define a planar posterior fixation
surface 82 on the fixation side 64, with one of the posterior
fixation surfaces 82 being the lateral fixation surface and the
other medial fixation surface. Each posterior fixation surface 82
is positioned opposite a posterior condyle surface 84 on the
articulation side 60. As shown in FIG. 4, the posterior fixation
surfaces 82 and the posterior condyle surfaces 84 extend generally
in the superior/inferior direction.
[0036] The outer surfaces 68 of the ribs 66 of the distal condylar
region 74 define a pair of planar distal fixation surfaces 86 (one
being medially positioned, the other laterally positioned). Each of
the distal fixation surfaces 86 is opposite a distal condyle
surface 88. As shown in FIG. 3, the distal fixation surfaces 86
extend generally in the anterior/posterior direction.
[0037] The distal condylar region 74 also includes a pair of
apertures or through-holes 90, one of which is positioned laterally
while the other is positioned medially. Each through-hole 90
extends from an opening 92 defined in one of the distal fixation
surfaces 86 to an opening 94 defined in the corresponding distal
condyle surface 88. Each through-hole 90 is sized to receive a
surgical drill, as described in greater detail below.
[0038] The posterior-chamfer region 76 of the femoral trial 14
includes a pair of planar posterior-chamfer fixation surfaces 96
defined by the outer surfaces 68 of the ribs 66, with one being
medially positioned and the other laterally positioned. The lateral
and medial posterior-chamfer fixation surfaces 96 extend superiorly
and posteriorly from their respective lateral and medial distal
fixation surfaces 86 to their respective posterior fixation
surfaces 82. Each of the posterior-chamfer fixation surfaces 96 is
positioned opposite a posterior-chamfer condyle surface 98.
[0039] Similarly, the anterior-chamfer region 72 includes a pair of
planar anterior-chamfer fixation surfaces 100. Each
anterior-chamfer fixation surface 100 is positioned opposite an
anterior-chamfer condyle surface 102. The anterior-chamfer fixation
surfaces 100 extend superiorly and anteriorly away from their
respective lateral and medial distal fixation surfaces 86 to a
planar anterior fixation surface 104 of the anterior flange 70. The
anterior fixation surface 104 is opposite an anterior condyle
surface 106, and, like the posterior fixation surfaces 82, the
anterior fixation surface 104 extends generally in the
superior/inferior direction.
[0040] The plurality of ribs 66 define a plurality of pockets 108
in each of the fixation surfaces 82, 86, 96, 100, and 104. In the
illustrative embodiment, the pockets 108 are separated such that
none of the pockets are in fluid communication with each other. It
should be appreciated that in other embodiments two or more pockets
may be in communication with one another such that a single,
continuous pocket is formed in the fixation side 72 of the femoral
trial 14. It will be appreciated that in other embodiments the
pockets 108 may be omitted from one or more of the fixation
surfaces.
[0041] The femoral trial 14 of the orthopedic surgical instrument
assembly 10 includes a plurality of teeth 110 that extend from each
of the posterior fixation surfaces 82 in a direction away from the
articular side 62. The teeth 110 are configured to engage or grip
the surgically-prepared distal end of the patient's femur 20 when
the femoral trial 14 is coupled thereto. The illustrative teeth 110
extend parallel to each other in the medial/lateral direction. It
should be appreciated that in other embodiments the teeth 110 may
be angled relative to each other or arranged in various patterns on
the posterior fixation surfaces 82. Additionally, one or more of
the teeth 110 may extend inferiorly/superiorly along the posterior
fixation surface 82 in addition to, or instead of, extending
medially/laterally as shown in FIGS. 3-4. It should also be
appreciated that in other embodiments one or more teeth may be
formed on any of the other surfaces 82, 86, 96, 100, and 104 of the
fixation side 64 of the femoral trial 14.
[0042] As shown in FIG. 4, each tooth 110 has a triangular cross
section when viewed in the sagittal plane. It should be appreciated
that in other embodiments the teeth 110 may have a square cross
section, rectangular cross section, dome-shaped cross section, or
any other cross section suitable to engage the surgically-prepared
distal end of the patient's femur 20. Additionally, while the teeth
110 have the same cross section in the illustrative embodiment, it
should be appreciated that in other embodiments each tooth 110 may
have a unique cross section.
[0043] Each tooth 110 has a body 112 including a base 114 fixed to
the posterior fixation surface 82 between one or more of the
pockets 108. The body 112 extends outwardly from the posterior
fixation surface 82 to a tip 116. The tip 116 defines a
longitudinal axis 122 of each tooth 110 extending in the
medial/lateral direction. The tip 116 of each body 112 is spaced
apart from the posterior fixation surface 82 such that each tooth
110 has a height 120. In the illustrative embodiment, the height
120 is approximately 0.38 millimeters. However, in other
embodiments, the height 120 may be greater than that shown in the
illustrative embodiment. Additionally, while each tooth 110 has the
same height 120 in the illustrative embodiment, it should be
appreciated that in other embodiments the height 120 of each tooth
110 may vary.
[0044] The femoral trial 14 also includes a pair of sidewalls 124,
126 that extend between the articular side 62 and the fixation side
64, with one sidewall being medially positioned and the other
laterally positioned depending on which knee is being replaced. As
shown in FIG. 5, each of the sidewalls 124, 126 has a pair of
notches 128, 130 defined therein. The notch 128 extends between the
articular side 62 and the fixation side 64 of the distal condylar
region 74 and has a base surface 132 that connects the distal
fixation surface 86 to the distal condyle surface 88. Similarly,
the notch 130 extends between the articular side 62 and the
fixation side 64 of the distal condylar region 74 and the
anterior-chamfer region 72. The notch 130 includes a base surface
134 that connects the distal fixation surface 86 to the distal
condyle surface 88, and a base surface 136 that connects the
anterior-chamfer fixation surface 100 and the anterior-chamfer
condyle surface 102. In the illustrative embodiment, the notches
128, 130 extend inwardly approximately 1.75 millimeters from the
sidewalls 124, 126, respectively, to the base surfaces 132, 134,
136.
[0045] The sidewalls 124, 126 define an outer edge 138 of the
femoral trial 14 corresponding to a standard femoral prosthetic
component size. The base surfaces 132, 134, 136 of the notches 128,
130 define another edge 140 of the femoral trial 14 corresponding
to a standard, but more narrow, femoral prosthetic component size.
As such, a single femoral trial 14 may be used to size multiple
femoral prosthetic component sizes. It should be appreciated that
in other embodiments one or more of the notches 128, 130 may be
omitted from the femoral trial 14. It should also be appreciated
that in other embodiments the position of the notches 128, 130
along the sidewalls 124, 126 may vary such that, for example, the
notches 130 are formed entirely in the distal condylar region
74.
[0046] The femoral trial 14 is constructed from a polymeric
material. In the illustrative embodiment, the polymeric material is
a fifty percent glass-reinforced nylon. Another polymeric material
that may be used is thirty percent glass-filled polyether ether
ketone (PEEK) or polyethylene, such as ultrahigh molecular weight
polyethylene (UHMWPE), although other biocompatible polymers may be
used. The tibial bearing trial 18 may be constructed from a
material, such as, for example, any of the polymeric materials
described above, which permits smooth articulation between the
tibial bearing trial 18 and the femoral trial 14. The tibial base
trial 16 and the base insert 34 may be constructed from a
biocompatible metal, such as a cobalt chrome alloy; other
materials, such as ceramics, may also be used.
[0047] Referring now to FIGS. 6-9, the orthopedic surgical
instrument assembly 10 is shown in use with the patient's bony
anatomy. As shown in FIG. 6, a surgically-prepared distal end 200
of the patient's femur 20 includes a resected medial condyle 202
and a resected lateral condyle 204. In use, the surgeon positions
the femoral trial 14 over the distal end 200 of the patient's femur
20. An impactor assembly 206 may be used to impact the femoral
trial 14 into the distal end 200.
[0048] To do so, an engagement end 208 of the impactor assembly 206
is positioned in contact with the articular side 62 of the femoral
trial 14, and force is applied to the impactor assembly 206 until
the fixation side 64 of the femoral trial 14 contacts the resected
medial condyle 202 and the resected lateral condyle 204. Once the
femoral trial 14 is properly positioned on the distal end 200 of
the patient's femur 20, the surgeon may remove the impactor
assembly 206. It should be appreciated that in other embodiments
the surgeon may position the femoral trial 14 on the distal end 200
of the patient's femur 20 by hand without using the impactor
assembly 206.
[0049] When the femoral trial 14 is positioned on the distal end
200 of the patient's femur 20, the sidewalls 124, 126 indicate
where the outer edge of the standard femoral prosthetic component
would be located on the resected medial condyle 202 and the
resected lateral condyle 204. Conversely, the base surfaces 132,
134, 136 of the notches 128, 130 in the femoral trial 14 indicate
where the outer edge of the narrow femoral prosthetic component
would be located. If the sidewalls 124, 126 extend beyond the
resected medial condyle 202 and the resected lateral condyle 204 of
the distal end 200 of the patient's femur 20, the surgeon may
select the narrow femoral prosthetic component for
implantation.
[0050] The resected medial condyle 202 and the resected lateral
condyle 204 of the patient's femur 20 include a number of resected
surfaces 210. As shown in FIG. 7, the resected surfaces 210 of each
condyle 202, 204 include a posterior planar surface 212, a distal
planar surface 214, and an anterior planar surface 216. The
resected surfaces 210 also include a posterior-chamfer planar
surface 218 that extends superiorly and posteriorly from the distal
planar surface 214 to the posterior planar surface 212 and an
anterior-chamfer planar surface 220 that extends superiorly and
anteriorly from the distal planar surface 214 to the anterior
planar surface 216.
[0051] When the femoral trial 14 is positioned on the distal end
200 of the patient's femur 20, the anterior fixation surface 104 of
the femoral trial 14 contacts the anterior planar surfaces 216 of
the patient's femur 20 and the distal fixation surfaces 86 of the
femoral trial 14 contacts the distal planar surfaces 214 of the
patient's femur 20. Similarly, posterior-chamfer fixation surface
96 of the femoral trial 14 contacts the posterior-chamfer planar
surface 218 of the patient's femur 20. The anterior-chamfer
fixation surfaces 98 of the femoral trial 14 contacts the
anterior-chamfer planar surfaces 220 of the patient's femur 20.
[0052] Further, the posterior fixation surfaces 82 of the femoral
trial 14 grip the posterior planar surfaces 212 of the patient's
femur 20 when the femoral trial 14 is positioned thereon. As shown
in FIG. 7, one or more of the teeth 110 of the lateral posterior
fixation surface 82 engages with, or grips, the posterior planar
surface 212 of the resected lateral condyle 204. The engagement of
the teeth 110 with the posterior planar surfaces 212 secures the
femoral trial 14 to the distal end 200 of the patient's femur
20.
[0053] In addition to positioning the femoral trial 14 on the
distal end 200 of the patient's femur 20, the surgeon may also
position the tibial base trial 16 on a surgically-prepared proximal
end 230 of the patient's tibia 22. When the surgical instrument
assembly 10 is fully installed, the tibial base trial 16 is secured
to the surgically-prepared proximal end 230 of the patient's tibia
22, as shown in FIG. 8. The tibial bearing trial 18, including the
bearing surface trial 46 and the shim 48, are positioned over the
post 42 of the base insert 34. The lateral condyle surface 56 of
the femoral trial 14 contacts the lateral articular surface 52 of
the tibial bearing trial 18, while the medial condyle surface 58
contacts the medial articular surface 54. The surgeon may then
evaluate the range of motion and stability of the knee with the
surgical instrument assembly 10.
[0054] As the range of motion is evaluated, the load on the femoral
trial 14 translates posteriorly as the knee is moved from extension
(see FIG. 8) to flexion (see FIG. 9). As the load moves
posteriorly, the force normal to the posterior condyle surfaces 84
of the femoral trial 14 increases, thereby causing the teeth 110 of
the posterior fixation surfaces 82 of the femoral trial 14 to
further engage, or grip, the posterior planar surfaces 212 of the
surgically-prepared distal end 200 of the patient's femur 20. The
engagement of one or more of the teeth 110 of the femoral trial 14
with the distal end 200 of the patient's femur 20 retains the
femoral trial 14 on the patient's femur 20. It should be
appreciated that in other embodiments screws or other fasteners may
be inserted through the through-holes 90 into the femur 20 to
provide additional fixation.
[0055] 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.
[0056] There are a plurality of advantages of the present
disclosure arising from the various features of the method,
apparatus, and system described herein. It will be noted that
alternative embodiments of the method, apparatus, and system of the
present disclosure may not include all of the features described
yet still benefit from at least some of the advantages of such
features. Those of ordinary skill in the art may readily devise
their own implementations of the method, apparatus, and system that
incorporate one or more of the features of the present invention
and fall within the spirit and scope of the present disclosure as
defined by the appended claims.
* * * * *