U.S. patent application number 14/635056 was filed with the patent office on 2017-07-06 for implant fixation device.
The applicant listed for this patent is Biomet Manufacturing, LLC. Invention is credited to Kirk J. BAILEY, Mark A. BOLLINGER, Jason D. MERIDEW, Jon C. SERBOUSEK, W. Jason SLONE, John R. WHITE.
Application Number | 20170189189 14/635056 |
Document ID | / |
Family ID | 48903586 |
Filed Date | 2017-07-06 |
United States Patent
Application |
20170189189 |
Kind Code |
A9 |
MERIDEW; Jason D. ; et
al. |
July 6, 2017 |
Implant Fixation Device
Abstract
Disclosed is an orthopedic implant that includes an anchor, a
bore, and a compressible and expandable mesh. The anchor is
configured to secure the implant at an implantation site and
defines a longitudinal axis. The bore is defined by the anchor and
extends along the longitudinal axis. The compressible and
expandable mesh is aligned along the longitudinal axis and defines
a plurality of openings. The mesh is configured to compress along
the longitudinal axis and expand from the longitudinal axis to
engage surrounding bone or tissue at the implantation site to
secure the implant at the implantation site.
Inventors: |
MERIDEW; Jason D.; (Warsaw,
IN) ; WHITE; John R.; (Winona Lake, IN) ;
BOLLINGER; Mark A.; (Fort Wayne, IN) ; SLONE; W.
Jason; (Silver Lake, IN) ; BAILEY; Kirk J.;
(Rochester, IN) ; SERBOUSEK; Jon C.; (Winona Lake,
IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Biomet Manufacturing, LLC |
Warsaw |
IN |
US |
|
|
Prior
Publication: |
|
Document Identifier |
Publication Date |
|
US 20150238319 A1 |
August 27, 2015 |
|
|
Family ID: |
48903586 |
Appl. No.: |
14/635056 |
Filed: |
March 2, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13761345 |
Feb 7, 2013 |
8968415 |
|
|
14635056 |
|
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|
|
61595832 |
Feb 7, 2012 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61F 2/34 20130101; A61F
2002/30579 20130101; A61F 2002/3403 20130101; A61F 2002/30884
20130101; A61F 2002/3429 20130101; A61F 2/3601 20130101; A61F
2002/30565 20130101; A61F 2002/3241 20130101; A61F 2002/30332
20130101; A61F 2002/3631 20130101; A61F 2/30749 20130101; A61F
2002/30378 20130101; A61F 2/367 20130101; A61F 2002/30841 20130101;
A61F 2/4609 20130101; A61F 2/30734 20130101; A61F 2002/30507
20130101; A61F 2002/4629 20130101 |
International
Class: |
A61F 2/36 20060101
A61F002/36; A61F 2/34 20060101 A61F002/34; A61F 2/30 20060101
A61F002/30 |
Claims
1. An orthopedic implant comprising: a curved outer surface; a
concave surface opposite to the curved outer surface, an axis of
the implant extends through an axial center of the concave surface;
and a retention component configured to compress along the axis and
expand from the axis to engage surrounding bone or tissue at an
implantation site to secure the implant at the implantation
site.
2. The orthopedic implant of claim 1, wherein the retention
component includes a plurality of flexible fins that are configured
to first compress during implantation into the implantation site
and then expand into the surrounding bone at the implantation
site.
3. The orthopedic implant of claim 1, wherein a threaded bore is
defined through the concave articulation surface; wherein the
threaded bore is configured to cooperate with a threaded tip of a
compressor device including a flange; and wherein rotation of the
threaded tip when the threaded tip is in cooperation with the
threaded bore and the flange contacts an implant surface between
the bone engaging outer surface and the concave articulation
surface, compresses the implant along the axis, compresses the mesh
along the axis, and expands the mesh radially outward from the
axis.
4. The orthopedic implant of claim 3, wherein the implant includes
an acetabular cup implant including at least one of a flared
surface or a conical surface at the equator of the implant.
5. The orthopedic implant of claim 1, wherein the concave surface
is configured to cooperate with a femoral implant to replace a hip
joint.
6. The orthopedic implant of claim 1, wherein the retention
component includes a compressible and expandable mesh aligned along
the axis and defining a plurality of openings, the mesh is
configured to compress along the axis and expand from the axis to
engage surrounding tissue at the implantation site to secure the
implant at the implantation site.
7. The orthopedic implant of claim 6, wherein the mesh is included
in the anchor and arranged between a first solid anchor portion and
a second solid anchor portion.
8. The orthopedic implant of claim 1, wherein the retention
component is configured substantially at a rim of the implant.
9. An orthopedic implant comprising: a base including a first side
and a second side opposite to the first side: an anchor extending
from the first side of the base; a connector extending from the
second side of the base; and a resiliently compressible mesh
component included in the base portion or attached to the
connector, the mesh component is configured to retain the implant
at an implant site.
10. The orthopedic implant of claim 9, wherein the implant is a
femoral neck implant and the connector includes resilient
components that apply compressive force to surrounding bone.
11. The orthopedic implant of claim 9, wherein the implant is a
distal femoral implant.
12. An orthopedic implant comprising: a cup component including: a
hemispherical bone engaging outer surface; a concave articulation
surface opposite to the bone engaging surface, an axis of the cup
component extends through an axial center of the concave
articulation surface; and a plurality of concave biasing surfaces
spaced apart about an equator of the hemispherical bone engaging
surface; and a retention component including: a retention ring; and
a plurality of retention barbs extending from the retention ring
and spaced apart about the retention ring; wherein upon compression
of the retention component onto the cup component such that the
retention barbs contact the biasing surfaces, the retention barbs
are forced outward from the axis to engage surrounding bone or
tissue at an implantation site to secure the implant at the
implantation site.
13. The orthopedic implant of claim 12, wherein the implant is an
acetabular cup implant.
14. The orthopedic implant of claim 12, wherein the biasing
surfaces and the retention barbs are spaced apart at similar
intervals.
15. The orthopedic implant of claim 12, wherein each barb includes
an outer surface and an inner surface that is opposite to the outer
surface; and wherein the outer surface defines at least one first
notch therein and the inner surface defines at least one second
notch therein, the first notch is larger than the second notch.
16. The orthopedic implant of claim 12, further comprising a
threaded bore at the axis.
17. The orthopedic implant of claim 16, wherein the threaded bore
is configured to cooperate with a threaded tip of a compressor
device including a flange; and wherein rotation of the threaded tip
when the threaded tip is in cooperation with the threaded bore
compresses the retention ring against the cup component to expand
the retention barbs outward from the axis.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. patent application
Ser. No. 13/761,345 filed on Feb. 7, 2013, now U.S. Pat. No.
______, which claims the benefit of U.S. Provisional Application
No. 61/595,832, filed on Feb. 7, 2012. The entire disclosure of the
above application is incorporated herein by reference.
FIELD
[0002] The present disclosure relates to orthopedic implant
fixation devices, including expandable fixation devices.
BACKGROUND
[0003] This section provides background information related to the
present disclosure, which is not necessarily prior art.
[0004] To secure orthopedic implants to bone, various fixation
devices are often used, such as pins and screws. While current
fixation devices are suitable for their intended use, they are
subject to improvement.
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] The present teachings provide for an orthopedic implant that
includes an anchor, a bore, and a compressible and expandable mesh.
The anchor is configured to secure the implant at an implantation
site and defines a longitudinal axis. The bore is defined by the
anchor and extends along the longitudinal axis. The compressible
and expandable mesh is aligned along the longitudinal axis and
defines a plurality of openings. The mesh is configured to compress
along the longitudinal axis and expand from the longitudinal axis
to engage surrounding bone or tissue at the implantation site to
secure the implant at the implantation site.
[0007] The present teachings further provide for an orthopedic
implant that includes a hemispherical bone engaging outer surface,
a concave articulation surface, and a retention component. The
concave articulation surface is opposite to the bone engaging
surface. An axis of the implant extends through an axial center of
the concave articulation surface. The retention component is at an
exterior of the implant and is configured to compress along the
axis and expand from the axis to engage surrounding bone or tissue
at an implantation site to secure the implant at the implantation
site.
[0008] The present teachings still further provide for an
orthopedic implant including a base, an anchor, a connector, and a
resiliently compressible mesh portion. The base includes a first
side and a second side that is opposite to the first side. The
anchor extends from the first side of the base. The connector
extends from the second side of the base. The resiliently
compressible mesh component is included in the base portion or
attached to the connector. The mesh component is configured to
retain the implant at an implantation site.
[0009] The present teachings also provide for an orthopedic implant
that includes a cup component and a retention component. The cup
component includes a hemispherical bone engaging outer surface, a
concave articulation surface, and a plurality of concave biasing
surfaces. The concave articulation surface is opposite to the bone
engaging surface. The axis of the cup component extends through an
axial center of the concave articulation surface. The plurality of
concave biasing surfaces are spaced apart about an equator of the
hemispherical bone engaging surface. The retention component
includes a retention ring and a plurality of retention barbs that
extend from the retention ring and are spaced apart about the
retention ring. Upon compression of the retention component onto
the cup component such that the retention barbs contact the biasing
surfaces, the retention barbs are forced outward from the axis to
engage surrounding bone or tissue at an implantation site to secure
the implant at the implantation site.
[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 a side view of an implant according to the present
teachings;
[0013] FIG. 1A is a close-up sectional view of interaction between
a fastener and a bore of the implant of FIG. 1;
[0014] FIG. 2 is a perspective view of the implant of FIG. 1;
[0015] FIG. 3 is a cross-sectional view taken along line 3-3 of
FIG. 1;
[0016] FIG. 4 is a perspective view of the implant of FIG. 1 in
cooperation with a driver;
[0017] FIG. 5 is a side-view of the implant of FIG. 1 in a
compressed position;
[0018] FIG. 6 is a perspective view of the implant of FIG. 1 in
cooperation with a compression tool;
[0019] FIG. 7 illustrates the implant of FIG. 1 implanted in a
femur bone;
[0020] FIG. 8 is an exploded view of another implant according to
the present teachings;
[0021] FIG. 8A is a cross-sectional view taken along line 8A-8A of
FIG. 8;
[0022] FIG. 9 is a side view of the implant of FIG. 8;
[0023] FIG. 9A is a close-up sectional view of interaction between
a fastener and a receptacle of the implant of FIG. 9;
[0024] FIG. 10 is a side view of the implant of FIG. 9 in a
compressed position;
[0025] FIG. 11 is a side view of the implant of FIG. 9 moved to a
compressed position with a compression tool;
[0026] FIG. 12 illustrates the implant of FIG. 9 implanted in a
femur;
[0027] FIG. 13 is an exploded view of another implant according to
the present teachings;
[0028] FIG. 14 is a side view of the implant of FIG. 13;
[0029] FIG. 15 is a cross-sectional view taken along line 15-15 of
FIG. 15;
[0030] FIG. 16 is a side view of the implant of FIG. 13 in a
compressed position;
[0031] FIG. 17 is a side view of the implant of FIG. 13 moved to a
compressed position with a compression tool;
[0032] FIG. 18 illustrates the implant of FIG. 13 implanted in a
femur;
[0033] FIGS. 18A-18C illustrate implantation of the implant of FIG.
13 in the femur;
[0034] FIG. 19 is a disassembled view of another implant according
to the present teachings;
[0035] FIG. 20 is a cross-sectional view taken along line 20-20 of
FIG. 19;
[0036] FIG. 21 is a side view of a sleeve compression tool;
[0037] FIG. 22 is a side view of the implant of FIG. 19 in an
uncompressed position in a femur bone;
[0038] FIG. 23 is a side view of the implant of FIG. 19 in a
compressed position and anchored in a femur;
[0039] FIG. 24 is a side view of the implant of FIG. 19 anchored in
a femur with a distal femoral implant secured thereto;
[0040] FIG. 25 is a side view of the implant of FIG. 19 anchored in
a femur with a distal femoral implant secured thereto, the distal
femoral implant including a compressible mesh portion;
[0041] FIG. 26 is a perspective view of another implant according
to the present teachings;
[0042] FIG. 27A is a perspective view of an additional implant
according to the present teachings in an uncompressed position, the
implant configured as an acetabular cup implant;
[0043] FIG. 27B is a perspective view of the implant of FIG. 27A,
the implant in a compressed position;
[0044] FIG. 28 is a perspective view of the implant of FIG. 27A and
a cup compressor;
[0045] FIG. 29 illustrates the implant of FIG. 27A implanted in a
pelvis;
[0046] FIG. 30A is a perspective view of another implant according
to the present teachings;
[0047] FIG. 30B is a perspective view of a further implant of the
present teachings;
[0048] FIG. 31 is an exploded view of an another implant according
to the present teachings;
[0049] FIG. 32 is another view of the implant of FIG. 31;
[0050] FIG. 33 is a sectional view illustrating assembly of the
implant of FIG. 31;
[0051] FIG. 34 is a sectional view illustrating the implant of FIG.
31 assembled;
[0052] FIG. 35 illustrates the implant of FIG. 31 implanted in a
pelvis;
[0053] FIG. 36 is a side view of another implant according to the
present teachings; and
[0054] FIG. 37 is a top view of the implant of FIG. 36.
[0055] Corresponding reference numerals indicate corresponding
parts throughout the several views of the drawings.
DETAILED DESCRIPTION
[0056] Example embodiments will now be described more fully with
reference to the accompanying drawings.
[0057] With initial reference to FIGS. 1-5, an orthopedic implant
according to the present teachings is illustrated at reference
numeral 10. The implant 10 generally includes a base 12, a
connector or coupler 14, and an anchor or stem 16. The base 12 is
between the connector 14 and the stem 16.
[0058] The base 12 generally includes a first surface 18, a second
surface 20 that is opposite to the first surface 18, and a side
surface 22 that is between the first surface 18 and the second
surface 20. The base 12 defines an aperture 24 at the first surface
18. The aperture 24 is aligned with, and provides access to, a
counterbore 26 defined by the base 12. The aperture 24 and the
counterbore 26 are generally at an axial center of the base 12,
which is aligned with a longitudinal axis A of the stem. As
illustrated in FIG. 2 for example, the side surface 22 generally
defines an oval shape and the second surface 20 generally defines a
concave shape. The base 12 can define any other suitable shape to
correspond to an opposing surface that contacts or is near the
implant 10 when implanted.
[0059] The connector 14 extends from the first surface 18 of the
base 12. As illustrated, the connector 14 is offset from the center
of the first surface 18 and the longitudinal axis A. The connector
14 includes a base end 28 at the first surface 18 and a tip end 30
that is opposite to the base end 28. A sidewall 32 extends between
the base end 28 and the tip end 30. The sidewall 32 is tapered from
the base end 28 to the tip end 30 such that the sidewall 32 has a
smaller diameter at the tip end 30 than the base end 28, thereby
providing the connector 14 with a male Morse taper surface. The
connector 14 can be integral with the base 12 or mounted to the
base 12 in any suitable manner, such as with a weld. The connector
14 can be any suitable connector for connecting another implant
component to the connector 14, such as a femoral head 34 (FIG. 7).
The connector 14 may also be aligned with the longitudinal axis A
or positioned at any other suitable location of the first surface
18.
[0060] The stem 16 generally includes a base end 36 at the second
surface 20 of the base 12 and a tip end 38 that is opposite to the
base end 36. A cylindrical sidewall 40 extends between the base end
36 and the tip end 38. The base end 36 of the stem 16 can be
integral with the base 12 or mounted to the base 12 in any suitable
manner, such as with a weld. The stem 16 defines a bore 42 that
extends along the longitudinal axis A from the counterbore 26 to
the tip end 38. The bore 42 is generally cylindrical, as
illustrated in FIG. 3 for example.
[0061] The stem 16 further includes a compressible mesh portion 44,
which is between a first stem portion 46 and a second stem portion
48. The first stem portion 46 is between the base end 36 and the
compressible mesh portion 44. The second stem portion 48 is between
the compressible mesh portion 44 and the tip end 38. The first stem
portion 46 and the second stem portion 48 are generally
non-compressible. As in the illustrated example, the compressible
mesh portion 44 extends from a point about half-way between the
base end 36 and the tip end 38 to a point about three-quarters
between the base end 36 and the tip end 38. However, the mesh
portion 44 can be at any suitable position between the base end 36
and the tip end 38 and be of any suitable length.
[0062] The compressible mesh portion 44 includes a first end 50
that abuts the first stem portion 46 and a second end 52 that abuts
the second stem portion 48. The first end 50 of the mesh portion 44
can be secured to the first stem portion 46 and the second end 52
can be secured to the second stem portion 48 in any suitable
manner, such as with a weld. The first stem portion 46, the second
stem portion 48, and compressible mesh portion 44 can also be
unitary or monolithic, and thus formed from a single metallic
portion, as further described herein.
[0063] At the compressible mesh portion 44, the sidewall 40 defines
a plurality of openings 54. At the first stem portion 46 and the
second stem portion 48 the sidewall 40 is generally solid. The
openings 54 can be of any suitable shape and size to permit
compression of the mesh portion 44 along the longitudinal axis A
and expansion of the mesh portion 44 away from the longitudinal
axis A in a direction generally perpendicular to the longitudinal
axis A (as further described herein and illustrated in FIG. 5). For
example, the openings 54 can be in the form of a lattice structure
with generally uniform and adjacent diamond-shaped openings of any
suitable size, such as from about 0.25 mm to about 5.0 mm, such as
about 1.0 mm. The openings 54 can also be generally spaced apart
slots extending generally parallel to the longitudinal axis A and
spaced apart at any suitable distance, such as from about 0.10 mm
to about 1.0 mm, such as about 0.5 mm, and can be of any suitable
size, such as from about 0.25 mm to about 5.0 mm, such as about 1.0
mm or about 2.0 mm.
[0064] The mesh portion 44 can also define openings 54 of any other
suitable size and shape, such as circular, hexagonal, octagonal,
parallelogram, or rhombus shaped openings. The shape can be
selected depending on the degree of retention force or grip desired
between the mesh portion 44 and, for example, surrounding bone. For
example, upon compression of the mesh portion 44, diamond shaped
openings will have sharper edges to more securely engage
surrounding bone as compared to, for example, circular openings.
Hexagonal and octagonal shaped openings will often provide greater
retention force when compressed to engage bone than circular
openings, but less than diamond shaped openings.
[0065] The openings 54 defined by the mesh portion 44 can be formed
in any suitable manner using any suitable manufacturing device
and/or technique, such as wire electrical discharge machining,
laser cutting, furnace brazing, fusion bonding, EOS laser
sintering, and rapid metal prototyping. For example, the openings
54 can be formed using wire electrical discharge machining to cut
completely through a wall of the stem 16 to define the openings 54
therein. Further or alternatively, lattice material defining the
openings 54 can be connected, such as by welding, between the first
stem portion 46 and the second stem portion 48. The compressible
mesh portion 44 can include any suitable material, such as a
suitable biocompatible metal or polymer.
[0066] At the second stem portion 48, the bore 42 includes a
plurality of internal threads 56. The threads 56 can extend from
the tip end 38 to nearly the compressible mesh portion 44.
[0067] A fastener 60 is seated in the bore 42. The fastener 60
includes a head 62 and a shaft 66, which includes external fastener
threads 68 at a distal end 70. In the uncompressed position of
FIGS. 1, 1A, 2, and 4, the shaft 66 is positioned such that the
anchor head 62 is seated within the counterbore 26, the shaft 66
extends through a majority of the stem 16, and the first few
fastener threads 68 at the distal end 70 engage the threads 56 of
the bore 42 that are closest to the mesh portion 44. The head 62
includes a coupler 72 configured to mate with a suitable device for
rotating the fastener 60, such as a driver 80.
[0068] As illustrated in FIGS. 4 and 5 for example, the
compressible mesh portion 44 can be compressed by rotating the
fastener 60 with the driver 80. Rotation of the fastener 60 causes
the fastener 60 to cooperate with additional threads 56 of the bore
42. Because the fastener 60 is restricted from moving along the
longitudinal axis A due to cooperation between the head 62 and the
counterbore 26, the tip end 38 and the second stem portion 48 are
drawn or driven toward the base 12 to compress the mesh portion 44
between the first stem portion 46 and the second stem portion 48,
each of which are generally non-compressible. In addition to being
compressed, the mesh portion 44 expands outward from the
longitudinal axis A (FIG. 5).
[0069] With reference to FIG. 6, the implant 10 can be compressed
with a compression tool 90 if the fastener 60 is not included. The
compression tool 90 generally includes a handle 92, and a shaft 94
including a distal end 96. A plurality of tool threads 98 are at
the distal end 96. A flange 99 is positioned along the shaft 94
such that the flange 99 sits in the counterbore 26 of the implant
10 when the shaft 94 is inserted in the bore 42 of the implant 10,
and the first few tool threads 98 closest to the distal end 96
cooperate with the bore threads 56 that are closest to the
compressible mesh portion 44. To compress the mesh portion 44 and
force the mesh portion 44 to expand from the longitudinal axis A,
the compression tool 90 is rotated such that the tool threads 98
engage additional threads 56 of the bore 42, thereby drawing the
second stem portion 48 toward the first stem portion 46 and
compressing the mesh portion 44 therebetween.
[0070] With reference to FIG. 7 the implant 10 including the
fastener 60 is implanted in a femur 102 to anchor the prosthetic
femoral head 34. The implant 10 permits preservation of
substantially all of femoral neck 104 and can be secured in the
femur 102 without the need for other fastening mechanisms, such as
transverse pins inserted through the neck 104 or bone cement. To
implant the implant 10 in the femur 102, the natural head is
resected and the femur 102 is milled or reamed through the neck
104. The stem 16 is inserted through the neck 104 such that the
second surface 20 of the base 12 is seated on an anterior surface
106 of the neck 104.
[0071] To secure the implant 10 in the neck 104, the fastener 60 is
rotated with the driver 80 to compress and expand the compressible
mesh portion 44 as described above. The compressible mesh portion
44 expands from the longitudinal axis A to engage and extend into
sidewalls 108 of the milled portion of the neck 104. While
cooperation between the mesh portion 44 and the sidewalls 108 is
typically sufficient to retain the implant in the femur 102, bone
cement or other adhesives may be added to augment fixation. The
femoral head 34 includes a female Morse taper 109, which cooperates
with the male Morse taper connector 14 to secure the head 34 to the
implant 10. If the implant 10 does not include the fastener 60, it
is implanted in the same manner and the compression tool 90 can be
used to compress and expand the mesh portion 44 as described
herein. While the implant 10 is illustrated as a femoral implant,
the compressible mesh portion 44 can be included in an anchoring
stem of any other suitable type of implant to facilitate fixation
of the implant to bone or tissue.
[0072] With additional reference to FIGS. 8-10, another implant
according to the present teachings is illustrated at reference
numeral 110. The implant 110 generally includes a base 112, a
connector 114 mounted to a first surface 116 of the base 112, and
an anchor or stem 118 mounted to a second surface 120 of the base
112. The first surface 116 is opposite to the second surface 120
and a side surface 122 extends therebetween. The connector 114 is
substantially similar to the connector 14 of the implant 10, and
thus the description of the connector 14 also describes the
connector 114 of the implant 110.
[0073] The first and the second surfaces 116 and 120 are
illustrated as planar, but can be curved. The first surface 116
defines an aperture 124 at generally an axial center thereof.
Aligned with the aperture 124 is a counterbore 126, which is
defined within the base 112. The aperture 124 and the counterbore
126 are aligned along a longitudinal axis B of the stem 118 (FIG.
9). Extending from the second surface 120 are a plurality of
anti-rotational pins 128.
[0074] The stem 118 extends from the second surface 120 of the base
112. The stem 118 generally includes a base end 130 at the second
surface 120 of the base 112 and a tip end 132 that is opposite to
the base end 130. The base end 130 can be integral with the base
112 or secured thereto in any suitable manner, such as with a weld.
The stem 118 defines a bore 134 that is aligned with the aperture
124 and the counterbore 126 along the longitudinal axis B. The bore
134 extends from the counterbore 126 to the tip end 132.
[0075] At the tip end 132 the stem 118 includes a solid portion
136. The solid portion 136 includes a pair of recesses 138 at the
tip end 132. Between the solid portion 136 and the base 112 is a
mesh portion 140, which defines a plurality of openings 142. The
mesh portion 140 and the openings 142 are substantially similar to
the mesh portion 44 and the openings 54 respectively of the implant
10. Thus, the above description of the mesh portion 44 and the
openings 54 also describes the mesh portion 140 and the openings
142 respectively.
[0076] The bore 134 of the stem 118 is sized to house a plurality
of washers 144. Each washer 144 generally defines a cone shape with
an open tip 146. The washers 144 are arranged in multiple washer
pairs, 148a-148f for example, such that the open tips 146 oppose
one another. The washers 144 are configured to be compressible to
apply a spring force that holds the implant in bone, as well as to
potentially absorb forces applied to the base and act as dampers.
The washers 144 are aligned in the bore 134 such that the open tips
146 are aligned along the longitudinal axis B (FIG. 9). In place of
the washers 144 can be any suitable resilient component or
compliant material.
[0077] The washers 144 are retained within the stem 118 with an end
cap 150. The end cap 150 is generally annular and defines a
receptacle 152 including cap threads 154. A proximal surface 156 of
the end cap 150 includes tabs 158, which are sized to cooperate
with the recesses 138 of the solid portion 136.
[0078] To retain the end cap 150 against the tip end 132 of the
stem 118, a fastener 160 is used. The fastener 160 generally
includes a head 162, a shaft 164 with a distal end 166, and
fastener threads 168 at the distal end 166. The fastener 160 is
inserted into the bore 134 such that the head 162 is seated in the
counterbore 126 and abuts the nearest washer pair 148a. The shaft
164 extends through the open tips 146 of each of the washers 144,
and into the receptacle 152 such that a few fastener threads 168
nearest the distal end 166 initially engage a few of the cap
threads 154 nearest the proximal surface 156.
[0079] With reference to FIG. 10, to compress the mesh portion 140,
thereby causing it to expand outward from the longitudinal axis B,
the fastener 160 is rotated using any suitable device, such as the
driver 80 illustrated in FIG. 4. Rotation of the fastener 160
causes the fastener threads 168 to engage additional cap threads
154 and extend through the receptacle 152 so that the fastener 160
extends through the end cap 150. Engagement between the head 162 of
the fastener 160 and the counterbore 126 prevents the fastener 160
from moving along the longitudinal axis B, which results in the end
cap 150 being pulled toward the base 112. As the end cap 150 is
pulled toward the base 112, the mesh portion 140 is compressed
between the end cap 150 and the base 112 along the longitudinal
axis B.
[0080] With additional reference to FIG. 11, the implant 110 can be
compressed with the compression tool 90 rather than the fastener
160. The compression tool 90 is initially positioned such that the
flange 99 is seated in the counterbore 126 and the tool threads 98
only partially engage the cap threads 154. As the compression tool
90 is rotated, the tool threads 98 cooperate with and engage
additional threads 154 of the end cap 150 to pull the end cap 150
toward the base 112. The mesh portion 140 is compressed between the
end cap 150 and the base 112, thus causing the mesh portion 140 to
expand outward from the longitudinal axis B. The compression tool
90 is rotated in an opposite direction to disengage the implant
110. The mesh portion 140 remains compressed after the compression
tool 90 is removed due to cooperation with surrounding bone and
properties of material included in the mesh portion 140.
[0081] With additional reference to FIG. 12, the implant 110
including the fastener 160 is implanted in the femur 102. The
implant 110 is implanted in the femur 102 in substantially the same
manner as the implant 10. Therefore, the above description of
implantation of the implant 10 also applies to the implant 110.
While the implant 110 is illustrated as a femoral implant, the mesh
portion 140 can be included in an anchoring stem of any other
suitable type of implant to facilitate fixation of the implant in
bone or tissue.
[0082] With reference to FIG. 13, another implant according to the
present teachings is illustrated at reference numeral 210. The
implant 210 includes various components that are substantially
similar to components of the implant 110, and thus are illustrated
with like reference numbers. For example, the implant 210 similarly
includes the base 112, the connector 114, the anchor or stem 118,
the washers 144 arranged in multiple washer pairs 148a-f in the
stem, the aperture 124, the counterbore 126, and the bore 134.
[0083] The fastener 160 is positioned such that the head 162 is
seated in the counterbore 126, the shaft 164 extends through the
bore 134, and the distal end 166 extends beyond the tip end 132.
The fastener 160 includes a flange 170 that abuts a shoulder 172 at
a distal end of the counterbore 126 to prevent the fastener 160
from passing through the counterbore 126 and the base 112. To
prevent the washers 144 from exiting the bore 134 at the tip end
132, a retention clip 174 is seated within the bore 134 distal to
the most distal washer 144. The retention clip 174 can be secured
within the bore 134 in any suitable manner. For example, the
retention clip 174 can be seated within an annular recess defined
within the bore 134.
[0084] Unlike the implant 110, the stem 118 of the implant 210 is
solid and does not include the mesh portion 140. The stem 118 of
the implant 210 can, however, include a mesh portion substantially
similar to the mesh portion 140 as well.
[0085] The implant 210 further includes an expandable anchor cap
220. The anchor cap 220 generally includes an anchor head portion
222 and an anchor body portion 224. The anchor cap 220 defines a
bore 226 that extends through the anchor head portion 222 and the
anchor body portion 224. The bore 226 is aligned with a
longitudinal axis C (FIG. 14) of the stem 118.
[0086] The head portion 222 generally includes a support sphere
228, which is connected to the anchor body portion 224 with a neck
230. At an end of the support sphere 228 opposite to the neck 230
is a boss 232. The anchor body portion 224 includes a solid base
234, a mesh portion 236, and a tip 238. Extending from the solid
base 234 toward the neck 230 are tabs 240, which are sized and
shaped to mate with the recesses 138 of the stem 118. The mesh
portion 236 is similar to the mesh portion 44 of the implant 10 and
the mesh portion 140 of the implant 110, and thus defines openings
242 that extend through the mesh portion 236 to the bore 226. The
descriptions of the mesh portions 44 and 140 also describe the mesh
portion 236. The tip 238 defines a concave outer shape and includes
anchor threads 244 in the bore 226.
[0087] As illustrated in FIG. 14 for example, the anchor cap 220 is
mounted spaced apart from the tip end 132 of the stem 118 with the
fastener 160, or any other suitable fastening device. The fastener
160 is positioned such that the head 162 is seated in the
counterbore 126 and the shaft 164 extends through the stem 118 and
into the anchor cap 220. FIG. 15 is a cross-sectional view showing
the fastener 160 extending through the mesh portion 236 of the
anchor cap 220. The fastener threads 168 at the distal end 166 of
the fastener 160 partially engage the anchor threads 244 of the
anchor cap 220 at the tip portion 238 in the uncompressed position
of FIG. 14.
[0088] With additional reference to FIG. 16, the mesh portion 236
of the anchor cap 220 is compressed by rotating the fastener 160 in
any suitable manner, such as by using the driver 80 of FIG. 4.
Rotation of the fastener 160 causes the fastener threads 168 to
engage additional anchor threads 244 of the anchor cap 220 and draw
the tip 238 toward the solid base 234, thereby compressing the mesh
portion 236 therebetween and causing the mesh portion 236 to expand
outward from the longitudinal axis C. The mesh portion 236 can be
compressed before or after the anchor cap 220 is coupled to the
anchor or stem 118, as further described herein.
[0089] With additional reference to FIG. 17, the mesh portion 236
of the anchor cap 220 can also be compressed with the compression
tool 90. The compression tool 90 is orientated such that flange 99
is seated in the counterbore 126 and the shaft 94 extends through
the stem 118 to engage the anchor cap 220. The shaft 94 extends
through the anchor cap 220 such that the tool threads 98 cooperate
with the anchor threads 244 at the tip 238 of the anchor cap 220.
Rotation of the tool 90 causes the tool threads 98 to engage
additional anchor threads 244 thereby pulling the anchor tip 238
toward the solid base 234 of the anchor cap 220 and compressing the
mesh portion 236 therebetween. The compression tool 90 is rotated
in an opposite direction to disengage the anchor cap 220. The mesh
portion 236 remains compressed after the compression tool 90 is
removed due to cooperation with surrounding bone and properties of
material included in the mesh portion 236.
[0090] The implant 210 can be implanted in substantially the same
manner as the implants 10 and 110. Thus the description of the
implantation of the implants 10 and 110 also describes implantation
of the implant 210. Unlike the implants 10 and 110, the anchor cap
220 includes the expandable mesh portion 236. Thus, once the
implant 210 is seated in the femur 102, the fastener 160 is rotated
to compress the mesh portion 236 thereby causing the mesh portion
236 to extend out from the longitudinal axis C and engage the
surrounding bone of the femur 102 to secure the implant 210 to the
femur 102. While the implant 210 is illustrated as a femoral
implant, the anchor cap 220 including the compressible and
expandable mesh portion 236 can be included in any other suitable
type of implant to facilitate fixation of the implant in bone or
tissue.
[0091] FIGS. 18A-18C illustrate an additional method for implanting
the implant 210. With initial reference to FIG. 18A, the anchor cap
220 is initially implanted within any suitable bone hole in any
suitable manner. For example, the anchor cap 220 can be implanted
within a bone hole formed at the neck 104 of the femur 102. With
additional reference to FIG. 18B, the mesh portion 236 is
compressed such that it extends outward and into the bone hole to
anchor the anchor cap 220 within the femur 102. The mesh portion
236 can be compressed in any suitable manner, such as with a tool
that engages the anchor threads 244 and draws the tip 238 and the
solid base 234 together.
[0092] As illustrated in FIG. 18C, the implanted anchor cap 220
serves as an anchor for the remainder of the implant 210. The stem
118 is inserted within the bone hole and the fastener 160 is
threaded into engagement with the anchor threads 244. A gap is
defined between the tip end 132 of the stem 118 and the solid base
234 of the anchor cap 220. The base 112 of the implant 110 is
seated against the anterior surface 106 of the femur 102, and the
pins 128 extending from the base 112 engage the anterior surface
106. As the fastener 160 is tightened, the fastener threads 168 of
the fastener 160 thread further into the anchor threads 244 thereby
drawing the remainder of the implant 210 toward the anchor cap 220,
which compresses the base 112 against the femur 102, thereby
facilitating healing and strengthening the femur bone 102.
[0093] An additional implant according to the present teachings is
illustrated in FIGS. 19 and 20 at reference numeral 310. The
implant 310 generally includes an anchor or sleeve 312 and a cap
314. The sleeve 312 generally includes a first end 316, a second
end 318 that is opposite to the first end 316, and a sidewall 320
that extends between the first end 316 and the second end 318. The
sidewall 320 is generally cylindrical, as illustrated in FIG. 20
for example. The sleeve 312 defines a bore 322 that extends through
the sleeve 312 from the first end 316 to the second end 318. A
longitudinal axis D of the sleeve 312 extends through an axial
center of the bore 322.
[0094] The sleeve 312 includes a first sleeve portion 324 at the
first end 316, a second sleeve portion 326 at the second end 318
and an intermediate portion 328 about half-way between the first
end 316 and the second end 318. The first sleeve portion 324, the
second sleeve portion 326, and the intermediate portion 328 are
generally solid and generally not compressible. At the second end
318 the second sleeve portion 326 defines a recess 329.
[0095] Between the intermediate portion 328 and the first sleeve
portion 324 is a first mesh portion 330. Between the intermediate
portion 328 and the second sleeve portion 326 is a second mesh
portion 332. Each of the first mesh portion 330 and the second mesh
portion 332 define a plurality of openings 334. The first mesh
portion 330 and the second mesh portion 332 are substantially
similar to the compressible mesh portion 44 of the implant 10, the
mesh portion 140 of the implant 110, and the mesh portion 236 of
the anchor cap 220. Thus, the description of the mesh portions 44,
140, and 236 also describe the first and the second mesh portions
330 and 332 of the sleeve 312.
[0096] The cap 314 includes a first surface 336 and a second
surface 338 that is opposite to the first surface 336. A side
surface 340 extends between the first surface 336 and the second
surface 338. The side surface 340 defines a generally cylindrical
outer shape of the cap 314. The cap 314 defines a cap bore 342
therein. The cap bore 342 includes internal cap threads 344. A pair
of flanges 346 extend from the first surface 336 and are sized and
shaped to be received in the recess 329.
[0097] With additional reference to FIG. 21, a sleeve compression
tool is illustrated at reference numeral 360. The tool 360
generally includes a handle 362, a shaft 364 that extends from the
handle 362 and includes a distal end 366, and tool threads 368 at
the distal end 366. Between the distal end 366 and the handle 362
is a flange 370. The sleeve compression tool 360 is operable to
couple the sleeve 312 and the cap 314 together and compress the
first and the second mesh portions 330 and 332, as described
herein.
[0098] With additional reference to FIG. 22, the implant 310 is
illustrated assembled and seated within an intramedullary canal 380
of the femur 102 at the isthmus 382 of the intramedullary canal
380. To implant the implant 310 in the intramedullary canal, the
sleeve 312 is mated with the sleeve compression tool 360 such that
flange 370 of the tool 360 mates with the first sleeve portion 324,
the shaft 364 extends through the bore 322 to the second end 318 of
the sleeve 312, and the tool threads 368 at the distal end 366
cooperate with the first few cap threads 344 of the cap 314 that
are nearest the flange 346 in order to hold the cap 314 at the
second end 318 of the sleeve 312.
[0099] As illustrated in FIG. 23 for example, with the implant 310
at the isthmus 382 of the intramedullary canal 380 the sleeve
compression tool 360 is rotated so that the tool threads 368 engage
additional cap threads 344 of the cap 314 and thus draw the cap 314
toward the first end 316 of the sleeve 312. As the cap 314 is drawn
toward the first end 316, the sleeve 312 is compressed between the
flange 370 and the cap 314. More specifically, the first mesh
portion 330 and the second mesh portion 332 each compress along the
longitudinal axis D and expand outward in a direction generally
perpendicular to the longitudinal axis D. As the first mesh portion
330 and the second mesh portion 332 expand outward from the
longitudinal axis D, the sidewall surfaces 320 thereof engage the
intramedullary canal 380 to secure the implant 310 in position.
After the first and second mesh portions 330 and 332 are
compressed, the sleeve compression tool 360 is rotated in an
opposite direction and removed. The intermediate portion 328 is
solid and does not expand or compress, which helps maintain the
bore 322 aligned with the longitudinal axis D and facilitates
cooperation between the bore 322 and another implant, as described
herein. The intermediate portion 328 can include a compressible and
expandable mesh portion as well.
[0100] With additional reference to FIG. 24, the sleeve 312 is
illustrated as anchoring a distal femoral implant 410. The distal
femoral implant 410 is anchored to the sleeve 312 with a spindle
412 and a taper adaptor 414. The spindle 412 includes a spindle
base 416 with an anchor or spindle stem 418 extending from a first
side of the base 416 and a spindle male Morse taper surface
connector 420 extending from a second side of the base 416, which
is opposite to the first side. The spindle stem 418 includes
spindle threads 422 at a distal end 424 thereof. The taper adaptor
414 includes a female Morse taper surface 426 and a male Morse
taper surface 428, which are at opposite ends of the taper adaptor
414. The distal femoral implant 410 includes a female Morse taper
surface 430 and an aperture 432 configured to receive a screw
fastener 434.
[0101] To connect the spindle 412 to the sleeve 312, the spindle
stem 418 is inserted through the bore 322 and the distal end 424 is
threadably engaged with the cap threads 344 of the cap 314. The
spindle 412 is orientated and the spindle stem 418 is provided with
an appropriate length such that the spindle base 416 is at a distal
end 103 of the femur 102 when coupled with the sleeve 312. The
taper adaptor 414 is connected to the spindle 412 through
cooperation between the female Morse taper surface 426 and the
spindle male Morse taper surface connector 420. The distal femoral
implant 410 is connected to the taper adaptor 414 through
cooperation between the male Morse taper surface 428 and the female
Morse taper surface 430 of the distal femoral implant 410. The
fastener 434 can be used to further secure the distal femoral
implant 410 to the taper adaptor 414. In addition to securing the
distal femoral implant 410 to the femur 102, the sleeve 312 can be
used to secure any suitable implant to any suitable bone or
tissue.
[0102] With additional reference to FIG. 25, a body portion 440 of
the taper adaptor 414 can include a mesh portion 442 that defines a
plurality of openings 444. The mesh portion 442 is substantially
similar to the mesh portions 44, 140, 236, 330, and 332 described
herein, and thus the description of these mesh portions also
describes the mesh portion 442. In response to a shock force across
the assembly of FIG. 25, the mesh portion 442 compresses to absorb
the shock and act as a damper. The mesh portion 442 thus increases
patient comfort and reduces stress on the assembly of FIG. 25 to
prolong the life of the assembly.
[0103] With additional reference to FIG. 26, the implant 10 of
FIGS. 1-5 and 7 is illustrated with the base 12 including a mesh
portion 480 between the first surface 18 of the base 12 and the
second surface 20 of the base 12. The mesh portion 480 defines a
plurality of openings 482 in the base 12. The mesh portion 480 is
substantially similar to the mesh portions 44, 140, 236, 330, 332,
442 described herein, and thus the description of these mesh
portions also describes the mesh portion 480. The mesh portion 480
is compressible to dampen shock forces experienced by the implant
10. The mesh portion 480 thus reduces stress on the implant 10 and
the femoral head 34 connected thereto to prolong the life of the
implant 10 and increase patient comfort.
[0104] With additional reference to FIG. 27A, another implant
according to the present teachings is illustrated at reference
numeral 510. The implant 510 generally defines a cup or
hemispherical shape. The implant 510 includes a bone engaging
surface 512 and an articulation surface 514 that is opposite to the
bone engaging surface 512. The bone engaging surface 512 is
generally convex in relation to the articulation surface 514. The
articulation surface 514 is generally concave with respect to the
bone engaging surface 512. The implant 510 is thus generally
configured as an acetabular cup.
[0105] The articulation surface 514 defines a circular aperture 516
that provides an opening to a receptacle 518, which is also defined
by the articulation surface 514. The articulation surface 514
further defines a threaded bore 520 at an axial center thereof. A
longitudinal axis E extends through an axial center of the
articulation surface 514, the aperture 516, and the threaded bore
520. Surrounding the aperture 516 is a planar base surface 522.
[0106] The implant 510 further includes a generally ring shaped
mesh portion 530. The mesh portion 530 is proximate to both the
planar base surface 522 and an equator of the implant 510. The mesh
portion 530 defines openings 532 that extend entirely through the
mesh portion 530. The mesh portion 530 is substantially similar to
the mesh portions 44, 140, 236, 330, 332, 442, 480 described
herein, and thus the description of these mesh portions also
describes the mesh portion 530. As illustrated in FIG. 27B, the
mesh portion 530 can be compressed along the longitudinal axis E.
Such compression also causes expansion of the mesh portion 530 away
from the longitudinal axis E in a direction that is generally
perpendicular to the longitudinal axis E.
[0107] With additional reference to FIG. 28, the mesh portion 530
can be compressed using a suitable compression tool, such as the
cup compressor 550. The cup compressor 550 generally includes a
threaded tip 552, which extends from a flange 554. The flange 554
is connected to a handle 556 with a connector 558. To compress the
mesh portion 530, the threaded tip 552 is inserted within the
threaded bore 520 to bring the flange into contact with the planar
base surface 522. The handle 556 is rotated so that the threaded
tip 552 progressively threads into the threaded bore 520 and the
flange 554 applies force to the planar base surface 522, thereby
compressing the mesh portion 530. The handle 556 is rotated in an
opposite direction to disengage the implant 510. The mesh portion
530 remains compressed after the cup compressor 550 is removed due
to cooperation with surrounding bone and properties of material
included in the mesh portion 530.
[0108] With additional reference to FIG. 29, the implant 510 can be
implanted into an acetabulum 580 of a pelvis 582, for example. The
acetabulum 580 can be prepared in any suitable manner, such as by
milling or reaming. To affix the implant 510 at the acetabulum 580,
the implant 510 is mated with the cup compressor 550 as described
above and then seated within the prepared acetabulum 580. Rotation
of the handle 556 causes the threaded tip 552 to thread deeper
within the threaded bore 520 and compress the flange 554 against
the planar base surface 522, which thus compresses the mesh portion
530 along the longitudinal axis E. The mesh portion 530 also
expands outward from the longitudinal axis E to engage the
surrounding acetabulum 580 and secure the implant 510 therein.
Securing the implant 510 with the mesh portion 530 can make anchor
pins and screws unnecessary.
[0109] With additional reference to FIG. 30A, another implant
according to the present teachings is illustrated at reference
numeral 510'. The implant 510' is similar to the implant 510, and
thus like features are designated with the same reference numbers,
but include the prime (') symbol. The implant 510' further includes
a flared or conical lip portion 534 of the bone engaging surface
512'. The flared portion 534 abuts the mesh portion 530', extends
around the bone engaging surface 512' proximate to the equator of
the implant 510', and extends outward from the longitudinal axis E.
The mesh portion 530' extends along the longitudinal axis E from
the flared portion 534. The flared portion 534 provides an enlarged
base for the mesh portion 530', and thus the mesh portion 530' can
have a larger outer diameter than the mesh portion 530, thereby
allowing the mesh portion 530' to extend further into surrounding
bone, for example, to enhance fixation of the implant 510' at an
implant site. The implantation of the implant 510 described above
also applies to the implant 510'.
[0110] FIG. 30B illustrates another implant according to the
present teachings at reference numeral 510''. The implant 510'' is
similar to the implant 510, and thus like features are designated
with the same reference numbers, but include the double prime ('')
symbol. Unlike the implant 510, the mesh portion 530'' and the
planar base surface 522'' attached thereto of the implant 510'' are
modular with respect to the remainder of the implant 510''. The
implant 510'' includes a flange 536 and defines a seat 538 for the
modular mesh portion 530''. The mesh portion 530'' is positioned
over the flange 536 and positioned on the seat 538. Upon
compression of the mesh portion 530'', the mesh portion 530''
expands into surrounding bone and retains the implant 510'' at an
implant site. The implant 510'' can be compressed and implanted in
a manner similar to that described above with respect to the
implant 510, with the cup compressor 550 modified to accommodate
the rigid flange 536.
[0111] With additional reference to FIGS. 31-35, another implant
according to the present teachings is illustrated at reference
numeral 610. The implant 610 generally includes a cup component 612
and a retention component 614. The cup component 612 generally
defines a hemispherical shape. The cup component 612 includes a
bone engaging surface 616 and an articulation surface 618 that is
opposite to the bone engaging surface 616. The bone engaging
surface 616 is generally convex in relation to the articulation
surface 618. The articulation surface 618 is generally concave with
respect to the bone engaging surface 616. The implant 610 is thus
generally configured as an acetabular cup.
[0112] The articulation surface 618 defines a circular aperture 620
that provides an opening to a receptacle 622, which is also defined
by the articulation surface 618. The articulation surface 618
further defines a threaded bore 624 at an axial center thereof. A
longitudinal axis F extends through an axial center of the
articulation surface 618 and the threaded bore 624. Surrounding the
receptacle 622 is a planar base surface 625. At an exterior equator
626 of the cup component are a plurality of biasing surfaces 628,
which are spaced apart about the equator. The biasing surfaces 628
are curved away from the longitudinal axis F.
[0113] The retention component 614 generally includes a retention
ring 640 with a plurality of retention barbs 642. The retention
barbs 642 protrude from an undersurface 644 of the retention ring
640 and are spaced apart about the retention ring 640. The
retention barbs 642 include a pointed distal end 646 and a barb
body 648 between the undersurface 644 of the retention ring 640 and
the pointed distal end 646.
[0114] With reference to FIG. 33 for example, the barb body 648
includes an outer surface 650 and an inner surface 652. The outer
surface 650 includes a plurality of outer notches 654 therein. The
inner surface 652 includes a plurality of inner notches 656
therein. The outer notches 654 are larger than the inner notches
656 to facilitate bending of the retention barbs 642 away from the
longitudinal axis F, as illustrated in FIG. 34. The retention
component 614, including the retention barbs 642, can be made of
any suitable type of material, such as a suitable metallic,
fibrous, or polymeric component.
[0115] To assemble the implant 610, the retention barbs 642 are
aligned with the biasing surfaces 628 and the retention component
614 is forced onto the cup component 612 with, for example, the cup
compressor 550. In particular, the threaded tip 552 of the cup
compressor 550 is connected to the threaded bore 624. As the
threaded tip 552 is threaded deeper into the threaded bore 624, the
flange 554 presses the retention ring 640 against the cup component
612 such that the undersurface 644 of the retention component 614
contacts the planar base surface 625 of the cup component 612 and
the retention barbs 642 are forced into contact with the biasing
surfaces 628, as illustrated in FIGS. 32 and 33 for example.
Because the biasing surfaces 628 are curved outward from the
longitudinal axis F, the retention barbs 642 are forced outward
from the longitudinal axis F into an extended position, as
illustrated in FIG. 34 for example. Movement of the retention barbs
642 to the extended position of FIG. 34 is facilitated by the outer
notches 654 being larger than the inner notches 656, which results
in less resistance to bending of the retention barbs 642 at the
outer surface 650 thereof.
[0116] In the extended position of FIG. 34, the pointed distal ends
646 of each retention barb 642 extend into surrounding bone to
secure the implant 610 at a desired implant site. For example and
with reference to FIG. 35, the implant 610 can be implanted at an
acetabulum 580 of a pelvis 582. After the acetabulum 580 is
prepared, such as by reaming for example, the cup component 612 is
seated in the acetabulum and the retention component 614 is
compressed onto the cup component 612 using, for example, the cup
compressor 550. Compression of the retention component 614 onto the
cup component 612 causes the retention barbs 642 to extend into the
surrounding bone, as described above, to secure the implant 610 at
the acetabulum 580 without the need for bone cement.
[0117] With additional reference to FIGS. 36 and 37, another
implant according to the present teachings is illustrated at
reference numeral 710. The implant 710 generally includes a cup
component 712 and a retention component 714. The cup component 712
generally defines a hemispherical shape. The cup component 712
includes a bone engaging surface 716 and an articulation surface
718 that is opposite to the bone engaging surface 716. The bone
engaging surface 716 is generally convex in relation to the
articulation surface 718. The articulation surface 718 is generally
concave with respect to the bone engaging surface 716. The implant
710 is thus generally configured as an acetabular cup.
[0118] The retention component 714 includes a plurality of
retention fins 720 that extend outward from and extend around an
outer perimeter wall 722 of the implant 710. The retention fins 720
can be made of any suitable material, including the material of the
implant 710. For example, the fins 720 can be formed as a porous
metal construct added to the bone engaging surface 716 through
additive manufacturing. The porous metal construct can be similar
to the Regenerex.RTM. porous metal construct sold by Biomet, Inc.
and the additive manufacturing process can be similar to the
electron beam melting process sold by Arcam, AB.
[0119] The retention fins 720 are generally flexible. The fins 720
can flex between an extended position, in which the fins 720 extend
to a greatest extent outward from the outer wall of the implant
710, and a bent or engaged position, in which the fins 720 do not
extend the greatest extent outward from the outer wall. In the
extended position, which is illustrated in FIG. 37, the retention
fins 720 are configured to engage bone to retain the implant 710 at
an implantation site. During implantation, the implant 710 is
impacted into bone. As the implant 710 is impacted, the retention
fins 720 flex or bend inward to the bent or engaging position. The
fins 720, however are biased and subsequently extend outward to
engage surrounding bone after implantation to secure the implant
710 to the bone.
[0120] 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.
* * * * *