Note: Descriptions are shown in the official language in which they were submitted.
CA 02483116 2004-09-29
METHOD AND INSTRUMENTS FOR POSITIONINCr NUMERAL
COMPONENT DURING SHOULDER ART HROPLASTY
z The present invention relates generally to obtaining the proper
2 position of a prosthetic implant, and more specifically to devices and
methods
3 used for achieving the proper axial position and retroversion of a stemmed
4 Numeral component during shoulder arthroplasty, as well as to properly
s positioning a Numeral stem provisional, which is inserted on a trial basis
during
6 the operation, prior to inserting the permanent stemmed Numeral component.
BACKGROUND OF THE INVENTION
Shoulder fractures are not uncommon, especially among senior
9 citizens with osteoporosis. In certain instances, shoulder replacement
surgery is
to necessary. One type of fracture that commonly requires shoulder replacement
1 i surgery is called a four-part fracture. Such a fracture is characterized
by the
12 shoulder being broken into four parts -- the lesser tuberosity, the greater
13 tuberosity, the Numeral head, and the Numeral shaft.
14 During a shoulder replacement operation (also known as shoulder
Zs arthroplasty surgery), a canal found within the Numeral shaft is used for
i6 receiving the Numeral component of the. shoulder prosthesis. If necessary,
in
i7 order to better accommodate the Numeral component, the canal may be
m enlarged using known methods. The Numeral component of the prosthesis
19 typically includes a stem and a head, which is a partial sphere that
replaces the
2o fractured Numeral head. The stem and the head may be two separate
2t components, or they may be a single component. Regardless of whether the
22 Numeral component is a single part or two parts, a collar is formed between
the
1
CA 02483116 2004-09-29
1 stern and the head. Between this collar and the fracture line on the
proximal
2 end of the humerus, the fractured lesser and greater tuberosities are
normally
3 anchored around the stern of the Numeral component, as closely as possible
to
4 their original positions.
s Before implanting the permanent stemmed Numeral component., a
6 temporary component, often called a Numeral stem provisional, is temporarily
inserted into the humerus to determine the proper placement of the stemmed
s Numeral component. Proper positioning of the f nal stemmed Numeral
9 component is very important. Improper positioning can result in a range of
to problems from -mild discomfort to severe pain, as well as a lack of proper
range
t 1 of motion, depending upon the degree and type of improper positioning.
12 Accordingly, it is important that the Numeral stem provisional be properly
i3 positioned, and that such proper position can be reliably replicated when
14 implanting the final stemmed Numeral component. Th~.e two key areas of
proper
Is positioning are the stemmed component's axial position and its
retroversion.
i6 Currently, several devices are available to assist in properly
m positioning the stemmed Numeral component within the humerus. For example,
is Tornier~ markets a system under the Aequalis~ name that includes a jig that
9 uses a portion of the anatomy for referencing the position of the Numeral
2o implant. However, this jig is relatively large and bulky, and it is
difficult to
21 perform a range of motion analysis with the jig :in place. Other smaller
22 systems, such as the DePuy~ GlobalTM Fx System also include a positioning
23 jig. Although the jig of the CrlobalTM Fx System allows for better range of
24 motion analysis than the Tornier~ system; the GlobalTM Fx System still
2s includes a somewhat large positioning jig, which could benefit from being
25 changed to a more low profile system. Thus, an improved system for properly
2~ positioning the stemmed Numeral companent is desired.
2
CA 02483116 2004-09-29
i BRIEF SUMMARY OF THE INVE'.~TTION
2 The present invention relates to a set of tools and accessories used
3 fox properly positioning a stemmed Numeral component, and/or a Numeral stem
4 provisional, within a canal in the humerus. The set of tools and accessories
s includes one or more fin clamps that are configured to be temporarily
attached
6 to a fin on the Numeral component or the provisional; a ruler that is
configured
to be attached to the arm of the fin clamp, a fixation pin and pin driver
s configured to be used with the other tools for marking a position on the
g humerus; and one or more sleeves that are configured to slide over the stems
of
to the Numeral stem provisional to maintain it in the desired position.
More specifically, the present invention. includes a fin clamp for
12 positioning a stemmed Numeral component, or a hvmeral stem provisional,
i3 within a humerus during shoulder arthroplasty, where; the fin clamp
includes a
~4 head and an arm connected to the head. The head is configured to be seated
is between a proximal end of the humerus and a distal side of a collar of the
i5 stemmed Numeral component or the Numeral stem provisional, such that the
m head separates the proximal end of the hurnerus from the distal side of the
is collar by a predetermined distance. Preferably, the head includes an
attachment
~9 arrangement to attach the fin clamp to a fin that e.~tends radially
outwardly
20 from the stem of the Numeral component or the provisional.
21 The present invention also includes a system of fin clamps for
22 positioning a stemmed Numeral component, or a Numeral stem provisional,.
23 within a humerus during shoulder arthroplasty, where the system of fin
clamps
24 includes a .plurality of fin clamps. The system of fin clamps preferably
includes
2s at least two fin clamps, and more preferably includes three fin clamps. The
i~rst
26 one of the plurality of fin clamps is configured anf. arranged to separate
the
2~ proximal end of the right humerus from the distal side of the collar by a
first
2s predetermined distance and to separate the proximal end of the left humerus
29 from the distal side of the collar by a second predletermined distance.
'The
3o second one of the plurality of fin clamps is configured and arranged to
separate
3
3
CA 02483116 2004-09-29
1 the proximal end of the right humerus from the distal side of the collar by
the
2 second predetermined distance and to separate the proximal end of the left
3 humerus from the distal side of the collar by the first; predetermined
distance,
4 where the first predetermined distance is different from the second
s predetermined distance. The third one of the pharality of fin clamps is
6 configured and arranged to separate the proximal end of either the right
humerus or the left humerus from the distal side of the collar by a third
s predetermined distance, where the third predetermined distance is different
9 from both the first predetermined distance and the second predetermined
distance.
11 The present invention also relates to a method for positioning a
~2 stemmed Numeral component within a humerus during shoulder arthroplasty.
13 The method includes the steps of inserting the stemmed Numeral component,
14 with a fin clamp attached, into a canal located in the humerus at an
estimated
rs position and seating the Numeral component at an intended position by
making
16 contact between the distal side of the fin clamp and the proximal end of
the
m humerus, whereby the collar of the Numeral component is seated at a certain
I s predetermined distance from the proximal end of the hurnerus. If desired,
the
19 fin clamp may be attached to the stemmed hume;ral component after the
2o component has been inserted into the Numeral canal, instead of attaching it
21 prior to insertion into the Numeral canal. Preferably, the inserting step
and the
22 seating step are each performed twice, once for a hurr~eral stem
provisional and
23 once for the stemmed Numeral component. Optionally, the method may include
24 a step of attaching a sleeve upon the stem of the hume;ral stem provisional
prior
2s to -the inserting step, where the sleeve helps to secure the Numeral stem
26 provisional in position within the Numeral canal.
22 In addition, the present invention also relates to a method for
2s temporarily securing a Numeral stem provisional within a humerus during
29 shoulder arthroplasty. The methad includes the steps of attaching a sleeve
to a
3o stem of the Numeral stem provisional and inserting the Numeral stem
4
CA 02483116 2004-09-29
i provisional, with the sleeve attached thereto, into a canal located within a
2 proximal portion of the humerus. After determining that the Numeral stem
3 provisional is properly sized and positioned, the Numeral stem provisional
and
4 the sleeve are removed, and a permanent Numeral component is implanted in
the same location and orientation as the Numeral stem provisional previously
6 removed. In order to mark and recreate the position of the provisional when
~ implanting the permanent Numeral component, a ruler and a fixation pin may
be
s used.
Also included as part of the present invention is a system of
to Numeral stem provisionals and at least one sleeve, which are intended to be
n used during shoulder arthroplasty. The system includes a plurality of
Numeral
12 stem provisionals each including a stem and at least one sleeve configured
to fit
13 upon the stem of each Numeral stem provisional. Tl~e sleeve aids in
securely
14 seating the associated humenal stem provisional within a canal located
within a
Is proximal portion of a humerus.
16 The present invention also relates to a ruler fox use in positioning
m a stemmed Numeral component, or a Numeral stem provisional; withird a
1 s humerus during shoulder arthroplasty. The ruler preferably includes a
scale
19 with incremental marks indicting distance from a zero point; and a securing
2o assembly for securing the ruler to another device: used for positioning a
21 stemmed Numeral component, or a Numeral stem provisional, within a humerus
22 during shoulder arthroplasty.
23 Finally, the present invention also relates to a system that
24 includes a fixation pin and a driver used for inserting the fixation pin
into a
2s bone for marking the orientation of a provisional prosthesis in, order to
2~ duplicate proper orientation for the final prosthesis" The system
preferably
2~ includes a fixation pin with a threaded portion near a first end and a
portion of
2s non-circular cross-section near a second end thereof; and a driver that
includes
29 a first end portion and a second end portion. The first end portion
preferably
3o includes an axially extending aperture with a portion thereof that is of a
non-
5
CA 02483116 2004-09-29
I circular cross-section that corresponds to the non-circular cross-section of
the
2 fixation pin. The second end portion of the driver is preferably configured
to
3 either accept a T-handle (for manual rotation} or to be attached to a drill
(for
4 mechanized rotation}.
s BRIEF DESCRIPTION OF THE DRAWINGS
Preferred embodiments of the present invention are described
~ herein with reference to the drawings wherein:
s Figure 1 is a view of a fractured humerus, with a stemmed
9 Numeral component and head inserted into a :canal within the humerus;
1o Figure 2 is a view showing the fin clamp and a sleeve for
~ 1 positioning a Numeral stem provisional within a canal :in the humerus;
12 Figure 3 is a perspective view of a sleeve that is intended to be
13 used to maintain the pasition of a Numeral stem provisional within the
Numeral
14 canal;
Is Figure 4 is a perspective view of one type of fin clamp, shown
16 from the top and front side;
m Figure ~ is a different perspective view of the fin clamp of Figure
~ s 4, shown from the bottom and rear side;
n9 Figure 6 is a top view of the fm clamp of Figure 4;
20 Figure 7 is a front view of the fin clamp. of Figure 4 attached to a
21 Numeral stem provisional, and including a scale to show the zero point;
22 Figure 8 is a view similar to Figure 2, except this figure shows the
23 two version pins used to test the range of motion;
24 Figure 9 is another view similar to Figure, 2, except this figure
2s shows the ruler in place, and the driver being used to insert a fixation
pin into
26 the bone;
2~ Figure 10 is a perspective view of the ruler of Figure 9;
6
CA 02483116 2004-09-29
1 Figure 11 is a perspective view of the .fixation pin and driver of
2 Figure 9, except instead of including a portion of the drill, this figure
includes a
3 T-handle;
Figure 12 is a view of the end of the fixation pin, with an
enlarged view of one of the screw threads;
Figure 12A is an enlarged view taken within circle 12A of Figure
~ 12;
s Figure 13 is cut-away view of the end of the driver into which the
9 fixation pin is inserted;
to Figure 14 is a front view of the fin clamp of the earlier figures,
n which creates the same predetermined distance whether used for the right
12 humerus or the left humerus;
13 Figure 15 is ac front view of a second fin clamp, which creates
la different predetermined disl:ances far the right humerus and the left
humerus;
I s and
16 Figure 16 is a front view of a thixd fin clamp, which creates
17 different predetermined distances for the right humerus and the left
humerus
i s that are reversed from those of the in clamp shown in Figure 15.
19 DETAILED DESCRIPTION OF THE I~1VENTION
20 The present invention relates to a system of components used for
21 properly positioning the stemmed Numeral component of a shoulder
prosthesis,
z2 and/or to positioning the Numeral stemmed provisional, as well as to the
methods of using those positioning components. The system includes one or
24 more fin clamps, version pins, a specially configured ruler, one or more
sleeves
2s designed to be attached to the Numeral stemmed provisional, a fixation pin
and
26 a driver for the fixation pin.
2~ Figure 1 shows one example of a stemmed Numeral component
zs 10 inserted within a humerus that has suffered a classic four-part
fracture. In a
29 four part fracture, bone has fractured into the following four parts -- the
lesser
CA 02483116 2004-09-29
1 tuberosity 14, the greater tuberosity 16, the Numeral shaft 18, and the
Numeral
2 head (not shown). During shoulder arthroplasty, the stemmed Numeral
3 component 10, including a Numeral head 20 (wlcich may be a separate
4 component or may be integrally formed with the Numeral component), is
s implanted into a canal that is naturally found in the Numeral shaft 18 (if
necessary, the Numeral canal may be enlarged), and the lesser and greater
tuberosities (14 and 16) are refitted and secured around the stemmed Numeral
s component 10 in locations as close as possible to their original anatomical
9 positions. It should be noted that although the present specification shows
and
Io describes only one example of a type of stemmed Numeral component and
11 provisional, it is contemplated that the present invention could also be
applied
12 to stemmed Numeral components and provisionals of many different
13 configurations.
14 In order for the shoulder prosthesis to mimic the original range of
1s motion of the shoulder joint, it is very important for all of the
components of
16 the prosthesis to be properly positioned. The present invention relates to
1~ positioning the stemmed Numeral component, as well as to positioning a
1g Numeral stem provisional, the stem of which is configured to match the
19 permanent stemmed Numeral component. As known in the art, the Numeral
20 stem provisional is temporarily placed in position in t:he Numeral canal
prior to
21 permanently positioning the permanent stemmed Numeral component.
22 Turning now to Figure 2, one example of a Numeral stem
23 provisional 22 is shown inserted into a canal within. a left Numeral shaft
18.
24 Since the provisional itself and the process of enlarging the Numeral canal
(if
2s necessary) are not part of this invention, and also since different types
of
26 provisionals and several prior art methods of enlarging the Numeral canal
are
2~ known, these aspects will riot be discussed in detail, except as necessary
for
2s understanding the present invention. Further, for ease of description, the
z9 implants, tools and procedures shown and described will normally only be
3o described for use with the left shoulder. However, o:ne of ordinary skill
in the
8
CA 02483116 2004-09-29
art can easily apply and modify, where necessary, the implants, tools and
2 procedures for use with the right shoulder. As can be seen in Figure 2, the
3 Numeral stem provisional 22 in this example includes a stem 24, a collar 26,
~ and four fins that extend radially outwardly of the sl:err -- a medial fm
2~, a
s lateral fin 30, an anterior fin 32, and a posterior fin 33 (shown in Figure
1) that
6 is a mirror image of the anterior fin 32. The collar 26 of the provisional
22 has
a proximal side 34 and a distal side 36.
s Seated upon the stem 24 is a sleeve 25, which is preferably made
9 of foam or other compressible material. The sleeve :~5 serves to maintain
the
Io Numeral stem provisional 22 in position during intraoperative assessment of
its
1 ~ axial height and version. In other words, because the ;>tem provisional 22
is not
~2 cemented or otherwise rigidly held in place, it may move from the intended
i3 position. However, by attaching the sleeve 25 to the stem 24 prior to
insertion
14 of both into the canal located within the Numeral shaft 18; the position of
the
is provisional 22 is maintained. Although the sleeve 25 helps to maintain the
15 provisional 22 in position, the addition of the sleeve 25 to the stem 24 of
the
m provisional 22 does iiot create such a tight fit that the provisional cannot
be
i 8 moved at all. Thus, even with the sleeve 25 in place, the position of the
19 provisional 22 can be adjusted, if necessary. However, the sleeve 25
provides a
2o tight enough fit within the Numeral canal to'prevent unintended movement of
2I the provisional 22 within the canal.
22 Turning ~ now to Figure 3, a perspective view of a preferred
23 embodiment of the sleeve 25 is shown. Basically, the sleeve 25 is
cylindrical in
24 shape; and is preferably made of foam or other similar material.
Preferably, the
2s sleeve 25 is manufactured by stamping multiple hollow cylindrical-shaped
26 sleeves from a flat sheet of foam (i.e., by axialldr stamping the sleeves).
2~ Alternatively, the sleeve 2S may be manufactured by rolling a flat,
rectangular
2s piece of foam into the hollow cylindrical shape shown, with the rolled
edges
29 being glued or otherwise affixed together along an axial line 39. Other
methods
30 of fabrication are also contemplated, such as injection molding, in which
case
9
CA 02483116 2004-09-29
1 the cylindrical shape can be directly formed. In order to provide better
gripping
2 upon the stem, as well as to make the sleeve suitable for use with stems of
3 different diameters, four slits 40 are provided to run axially along the
sleeve's
4. inner periphery 42. The slits 40 are preferably between 1 mrn and 2mm in
s depth, although other depths are also contemplated. Although four slits are
6 shown in this example, a different number of slits may also be used, or the
slits
may be omitted entirely, if desired.
s The sleeve 25 also preferably includes a tether 44 that is attached
9 via a hole 46 formed within a sidewall of the sleeve 25. In most cases, the
1o tether will not be used because the sleeve 25 will remain attached to the
stem
i 1 24 of the provisional 22 when the provisional is removed from the Numeral
12 canal. However, if the sleeve somehow slips off of the provisional 22; 'the
13 tether 44 may be used to pull the sleeve 25 out of the Numeral canal. Thus,
the
14 tether should be long enough to extend out of the Numeral canal, with
sufficient
Is length for gripping. For example, in the preferred embodiment, the tether
16 extends from the hole 46 about eight inches. Of course, the length of the
tether
m may be varied to be longer or horter~ if desired.
1 s The tether 44 is preferably made of suture or other strong thread,
19 and is preferably a looped thread that has a knot 48 near the looped end
49. To
2o secure the tether 44 to the sleeve 25, the looped end 49 is passed through
the-
2i hole 46 until it extends out through the end of the sleeve 25. Then the
free end
22 50 and the knot 48 are passed through the looped en.d 49, and the free end
is
23 pulled to tighten the tether. Of course, other methods of attaching the
tether to
24 the sleeve are also contemplated:
25 Preferably, the sleeve 25 will be available in a variety of sizes
26 because there are a variety of sizes of Numeral stem provisionals. Thus,
for
2~ example, there may be a different sized sleeve for each different size of
2s Numeral stem provisional. ~lowever, in order to redu<;e the number of
different
29 sizes of sleeves that need to be stocked, each sleeve can preferably be
3o configured to be used with several differently sized provisionals. For
example,
CA 02483116 2004-09-29
i if humeral stem provisionals are available in thirteen different sizes, only
four
2 different sizes of sleeves are preferably needed, with each sleeve being
able to
3 fit three or four differently sized provisionals. The following chart
provides a
4 helpful example of how the sleeves can be sized:
INTERIOR
EXTERIOR INTERIOR DIAMETER OF STEM
DIAMETER OF DIAMETER OF SLEE~dE DIAMETER OF
SLEEVE SLEEVE (INCLUI?ING PROVISIONAL
TWO SLITS)
I2 mm ~ mm 8 mrn 6 mm - 8 mm
16 mm ~ mm 11 mm 9 mm - 11 mm
20 mm 12 mm 15 mm 12 tnm - 14
mm
24 mm I 6 mm 20 mm ~ 15 mm - 18
mm
s As indicated in the chart above for thirteen different provisional
6 sizes with stem diameters between 6mm and l8mm (in lmm increments), only
four different sleeves are needed because a 6mm interior diameter sleeve fits
8 provisionals with stems of diameters between 6mm and 8mm; a 9mm interior
9 diameter sleeve fits stems between 9mm and l lmm; a l2mrri interior diameter
1 o sleeve fits stems between l2mm and l4mm, and ~. 16mm sleeve fits stems
i 1 between 15 and 18mm. One reason that the sleeves can be used with
12 provisionals of different sizes is that the four slits 40 allow the inner
diameter
13 of the sleeves to slightly adjust to accommodate the dlifferent diaW eter
stems of
t4 provisionals of different si~;es. As shown in the chart, a sleeve with a
l2mm
Is exterior diameter has an interior diameter of 6mm (in the area without any
m slits), but it has an interior diameter of 8mm in the area with two of the
slits
m because each slit is I mm in depth (thereby the diarr~eter is increased by
2mm
i s because the two slits face each other). Likewise, the slits in the l6mm
exterior
11
CA 02483116 2004-09-29
1 diameter sleeve are also each preferably 1 mm in depth. The slits in the
20mm
2 exterior diameter sleeve are each preferably l .5mm in depth, and the slits
in the
3 24mm exterior diameter shaft are each preferably 2mm in depth. Additionally,
4 the axial length of all of the sleeves can be the same:. For example, the
axial
s length of each sleeve is preferably between 20 and 40mm. Of course, the
6 dimensions mentioned above, and in other parts of thus specification, are
only
~ examples of suitable dimensions, and other appropriate dimensions can be
s determined by those of ordinary skill in the art.
For ease of identification to distinguish the differently sized
to sleeves from one another, each of the sizes can be made of a different
color, if
n desired. Accordingly, since there are four different sizes of sleeves in the
12 example above, four different colors of foam would be used to produce the
13 sleeves. However, since the most likely instances of confusion arise
between
14 sleeves that are only slightly larger or slightly smaller than each other,
it may
Is only be necessary to use two different colors, alternating between the two
16 colors as the sleeves increase in size. For example for a set of four
sleeves of
7 exterior diameters of l2mm; l6mm, 20mm and 24m.m, the l2mm and 20mm
1 s sleeves could be of a first color, and the l6mm and 24 mm sleeves could be
of a
9 second color that is different from the first color. Such a system works
because
2o it is unlikely that someone would be confused between the 12 and 20mm
2i sleeves or between the 16 and 24mm sleeves. By only using two colors
instead
22 of four, manufacturing costs are reduced.
23 Turning back to Figure 2, another important aspect of the present
24 invention will be described -- fin clamp 60. Fin clamp 60 is preferably
made
zs of stainless steel or other metal, but other materials, such as plastic,
may also be
26 used. As described more fully bel~w, the fin clamp 60 is used to properly
2~ position the stemmed Numeral component (and the Numeral stem provisional)
2s with regard to both its axial height and its retroversion. Axial height
29 positioning will be discussed first. Figure '7 shows one example of a fin
clamp
30 60 attached to a stemmed Numeral component 10, which is shown alongside a
12
CA 02483116 2004-09-29
~ measurement scale. In the preferred embodiment, the zero point of the scale
is
2 taken as the point where the center axis of the stem 24 meets the distal
side 36
3 of the collar 26. This zero pointy and the rest of the numbering scale, is
the
~. same one currently used on other tools and templates in the
Bigliani/Flatow~
Shoulder Arthroplasty System, manufactured by Zi.mmer Ine. of Warsaw,
6 Indiana. However, it is not necessary to use the same scale as the
7 Bigliani/Flatow~ System, and other measurement sy;~tems and/or zero points
s may be used instead of those described.
Analysis has shown that in most fracture situations, the distal side
to 36 of the provisional's collar 26 should be spaced a certain distance from
the
~ i proximal surface 38 of the Numeral shaft 18. (Of course, since the
relevant
12 portions of the provisional are sized and shaped identically to those of
the
13 permanent stemmed Numeral component, the collar of the permanent
4. component, as well as the other portions of the permanent component, should
~s be positioned identically to those of the provisional.) More specifically,
in
6 most average sized adults, it has been found that in four-part fracture
scenarios,
7 the fractured joint is best rebuilt by positioning the stemmed Numeral
is component so that there is l8mm of space separating the distal. side 34 of
the
9 collar 26 (at the anterior fin) from the proximal surface 38 of the Numeral
shaft
20 18. However, in certain cases, the appropriate spacing is either slightly
Less or
21 slightly greater. than l8mm. Far example, certain situations requixe a
lSxnm
22 space and other cases require 2lmm of space. Accordingly, as described
23 below, the preferred embodiment of the invention 'includes a set of fin
clamps
24 that are configured to provide spacing of the following predetermined
2s distances: lSmm, l8mm, and 2lmm, in order to obtain the proper spacing in a
25 variety of different situations. However, the invention is not limited to
these
27 sizes.
2s First, fin clamp 6d, which provides l8mm spacing, will be
29 described. The fm clamp 60 is configured to be attached to the anterior fm
32
0 of the Numeral stem provisional 22, as shown in the exploded view of Figure
2.
13
CA 02483116 2004-09-29
I Likewise, because the stemmed Numeral component 10 has essentially the same
2 configuration as the provisional 22, the fin clamp 60 is also configured to
be
3 attached to the anterior f n of the stemmed Numeral component in the same
a. manner as attached to the provisional.
As shown in Figures 2, 4, 5 and 6, the fin clamp 60 includes a
5 head 62 and an arm 64. The head 62 is configured to be seated upon the
~ anterior fin 32 so that the head 62 is positioned between the proximal end
s surface 38 of the humerus 18 and the distal side 36 of the collar 26. In
this
9 embodiment, the head 62 separates the proximal end surface 3 8 of the
humerus
to from the distal side 36 of the collar 2b by l8mm. This embodiment of the
fin
n clamp 60 is called the "universal" fin clamp because it can be used in most
12 situations and because it can be used on either the left humerus (as shown
in
3 Figure 2) or on the right humerus, with the separation distance for each
side
14 being the same (l8mm). Other embodiments of the fin clamp, which will be
is described below, are also configured to be used on either the left humerus
or
t6 the right humerus, but in these other embodiments, the separation distances
are
m not the same for both sides.
t8 The head 62 includes a channel 66 (best seen in Figure 6) that is
19 configured to accept the anterior fin 32 of both the hmmeral stem
provisional 22
2o and the stemmed Numeral component 10. Preferably, the channel 66 is ~yust
21 slightly deeper than-the radial length of the anterior fi.n 32, and is
defined from
22 side-to-side between an endblock 67 and a wall 69. An attachment
23 arrangement that includes one or more setscrews is provided in order to
attach
24 the fin clamp 60 to the anterior fin 32: More specifically; the preferred
25 embodiment includes two threaded holes 68, 70 (best shown in Figure S) that
26 extend through the wall 69, and two setscrews 72, 74, with one setscrew
being
2~ seated in each threaded hole. If desired, only one setscrew may be provided
for
2s both holes, in which case the user simply inserts the single setscrew into
the
29 appropriate hole. Preferably, the setscrews include sharp pointed tips for
3o providing more secure attachment to the fin.
14
CA 02483116 2004-09-29
In order to attach the fin clamp 60 to the anterior fin 32, one of
2 the setscrews (72 or 74) is tightened so that it extends through the wall 69
and
3 makes contact with fin 32. Preferably, whichever setscrew is positioned on
the
a proximal side will be tightened because easier access is provided for that
one.
s Thus, if the fin clamp 60 is being used during left shoulder arthroplasty,
6 setscrew 74 is the proximal setscrew and it will be tightened, and if it is
being
used during right shoulder arthroplasty, setscrew 72 i;9 the proximal one, and
it
s will be tightened.
The fin clamp's head 62 includes two angled surfaces 76 and 78,
to as most clearly shown in Figures 2 and 4, which are symmetric to each other
i t and which correspond to the angle of the distal side 36 of the collar 26
of the
12 Numeral stem provisional 22 and the stemmed Numeral component 10 (shown
13 in Figure 7). Flat surfaces 80 and 82 are also included adjacent to the
angled
14 surfaces 76 and 78, respectively. These surfaces are configured in this
manner
Is so that the surgeon can easily tell that the fin clamp 60 is properly
positioned
n6 (and therefore the provisional 22 or the Numeral component 10 is also
properly
1~ positioned) by noting when one of the angled surfaces (76 or 78) contacts
the
I8 distal side 36 of the callar 26 and the opposite flat surface (either 82 or
80)
~9 contacts the proximal surface 38 of the Numeral shaft. More specific~.lly,
2o during left shoulder arthroplasty, proper axial positioning has been
obtained
2r when angled surface 78 contacts the distal side 36 of the collar 26 and the
flat
22 surface 82 contacts the proximal surface 3 8 of the Numeral shaft. If the
23 universal fin clamp 60 is positioned in this manner, the desired l8:mm
z4 separation is provided. For ease of description, the invention is being
described
2s and shown as applied to a left Numeral stem provisional only (as well as to
a
26 left stemmed Numeral component only). However, the universal fin clamf> 60
2~ can also be used with a right provisional or right hurneral component if
the. fm
2s clamp is flipped so that the opposite angled surface is the one making
contact
29 with the collar of the provisional (or Numeral component).
CA 02483116 2004-09-29
1 In order to facilitate obtaining the proper orientation of the fin
2 clamp 60, markings indical:ing the proper orientation of the fin clamp are
3 preferably provided. Different markings need to indicate the proper
orientation
4 for use during left shoulder arthroplasty and during right shoulder
arthroplasty,
s because the orientation of the fin clamp is not the same for each side. One
6 example of such markings is shown in Figure 7, which includes the markings
L 18 and R18. These markings indicate that this fin clamp provides 18mm
s separation distance, and they also show the proper orientations of the fin
clamp
9 when used on either the left shoulder or the right shoulder. More
specifically,
to in this example, when the .fin clamp is used during an operation on the
heft
n shoulder, the designation L18 is upright (as shown in Figure 7), and when
used
12 during an operation on the right shoulder, the designation Rl8 is upright.
Of
1~ course, other types of markings may alsa be used; or the markings may be
~4 omitted entirely, if desired.
is Turning now to Figures 15 and 16, two additional embodiments
16 of the fin clamp will be described. The fin clamps of Figures 15 and 16 are
m used for creating predetermined separation distances other than the l8mm
Is distance described above with regard to fin clamp ~0. Figure 15 shows fin
19 clamp 60' and Figure 16 shows fin clamp 60". Figure ~ 14, which shows the
2o first embodiment, fin clamp 60, has been provided i~a order to easily
compare
21 the configurations of fin clamps 60' and 60'' with-that of fin clamp 60.
Fin
22 clamps 60' and 60" axe essentially the same as fin clamp 60, except that
they
23 provide different separation distances than fin clamp 60. Additionally, fin
24 clamps 60' and 60" are not symmetric about their respective central axis,
as fin
2s clamp 60 is.
26 More specifically, fin clamp 60' of Figure 15 is configured to
2~ provide a separation distance of l5mm when used during left shoulder
2s arthroplasty, as designated by the marking "L15," and to provide a
separation
29 distance of 2lmm when used during right shoulder arthroplasty, as
designated
by the marking "R21" (which is nearly upside-down i.n Figure 15). As with the
16
CA 02483116 2004-09-29
t universal fin clamp 60, which has designations L18 and R18, the surgeon can
2 tell which direction the clamp should be oriented and the separation
distance
3 created by the clamp by looking at the designations L 15 and R21. More
4 specifically, with fin clamp 60', when this fin clamp is used during an
operation
s on the left shoulder; the designation L 1 S should he upright (and a 1 Smm
6 separation will be provided), and when used during an operation on the right
shoulder, the designation R21 should be upright (andl a 2lmm separation will
s be provided).
Fin clamp 6(1" of Figure 16 merely provides the opposite
- to configuration to that of clamp 60' of .Figure 15. 'thus, fin clamp 60"
c;an
i 1 provide a 2lmm separation distance during left shoulder arthroplasty, and
it can
~2 provide a l5mm separation during right shoulder arthroplasty. More
13 specifically, with fin clamp 60", when this fin clamp is used during an
14 operation on the Ieft shoulder, the designation L21 should be upright (and
a
is 2lmm separation will be provided), and when used during an operation on the
6 right shoulder, he designateon RI S should be upright: (and a l Smm
separation
1~ will be provided).
a s In order to allow the surgeon to be able to accommodate
19 situations where any one of the three different separation distances
(lSrrun,
20 l8mm and 2lmm) is to be provided, a system, or kit, that includes several
21 different fin clamps should be provided. More specifically, in the
preferred
22 embodiment of the kit or system, three different fin clamps are provided --
fin
23 clamp 60, fin clamp 60' and fin clamp 60". Accordin.gly, with the kit, the
most
24 commonly-desired separation distances can reliably be: obtained.
2s As mentioned above, in addition to obtaining the correct a~~ial
26 spacing, the present invention also provides a way to set the proper
retroversion
2~ of the humeral stem provisional and the stemmed hurrreral component.
Turning
2s now to Figure 8, the humeral stem provisional 22 is shown seated within a
29 canal in the left humerus 12, and the fin clamp 60 has been secured to the
o anterior fin by tightening the setscrew 74.
17
CA 02483116 2004-09-29
I The first step for obtaining the proper retroversion of the
2 provisional 22 and/or the Numeral component 10 relates to aligning the arm
64
3 with respect to the approximate position of the bicipital groove in an
intact
4 humerus (Figure 1 shows a bicipital groove 92), if clear evidence of the
groove
s is still available. If the bicipital groove cannot be located, the surgeon
may
6 simply estimate its position, and align arm 64 with that estimation, or
slightly
7 posterior to the estimated position of the groove.
s Figure 6 shows that the arm angle is preferably 55 degrees from
g the anterior fin 32 (and ~5 degrees from the axial stem of the Numeral
to component 10 and the provisional 22, when the fin clamp is attached
thereto).
t 1 Designing the arm 64 of the fin clamp 60 to be at the 55 degree angle to
align
12 with the bicipital groove has several advantages. The fracture line between
the
~3 lesser tuberosity 14 and the greater tuberosity 16 typically occurs either
in line
14 with, or slightly posterior to, the bicipital groove 92, as shown in the
Figure 1
is example. Because the 55 degree angle aligns the arrry64 of the fin clamp
with
16 this fracture line, the arm 64 does not interfere with the surgeon's task
of
m reorienting the tuberosities to confirm the position of the provisional 22
and/or
I g the Numeral component 10 while the fin clamp is attached to the
provisional or
19 the Numeral component. In addition, with the arrm 64 of the fin clamp
2o configured at this angle, the arm does not interfere with a range of motion
2r analysis. ..
22 The second step for obtaining the proper retroversion involves the
23 use of two version pins. In Figure 8, two version pins 84 and 86 are she>wn
24 inserted into two version pin holes 88, 90; respectively (the version pin
holes -
zs are also shown in Figure 4, without the version pins imser~ed therein).
Turning
26 now to Figure 6, version pin hole 88 is set to be 20 degrees from channel
66
2~ (which sets it at 20 degrees from the anterior fin 32 and 20 degrees from
the
2s axial stem of the Numeral component 10 and the provisional 22, when the fin
29 clamp is attached thereto). In a similar manner, version pin hole 90 is set
to be
30 40 degrees from channel 66 (and 40 degrees from the anterior fin and the
axial
18
CA 02483116 2004-09-29
1 stem of the numeral component 10 and the provisional 22, when the fin clamp
2 is attached thereto). When the two version pins 84 and 86 are seated within
'the
3 appropriate version pin holes 88 and 90, as shown in Figure 8, the
retroversion
4 of the provisional 22 or the numeral component 10 can be tested by extending
s the patient's arm to make sure that the patient's forearm is centered
between the .
version pins 88 and 90. To avoid confusion regarding the use of version iain
~ holes 88 and 90, it is desirable to have them marked with degree indications
s "20" and "40," as shown in Figure 4. However, such markings are . not
9 required. It should be noted that the 20 and 40 degree orientations of the
- - version pins and the 55 degree stem angle shown and described are intended
to
11 be used for guidance to obtain proper retroversion. In certain situations,
proper
12 retroversion, as discovered during a range of motion analysis, will differ
from
13 these guidelines.
14 Once the proper axial height and the version of the provisional 22
1s has been established, and the provisional is located in the desired
position, it is
16 useful to mark that position to facilitate the placement of the permanent
1~ stemmed numeral component 10 into the exact same position. The present
1 s invention includes the following tools for marking the position -- a
specially
19 configured ruler that can be attached to the arm of the fin clamp and a
fixation
o pin and pin driver for temporarily inserting the pin inti~ the humerus at a
desired -
21 location along the scale of the ruler.
22 , Figure 9 shows one example of a specially configured ruler 94
23 attached to the arm 64 of fin clamp 60, with fixation pin 96 being inserted
into
24 a slot (or elongated hole) 95 in the ruler via a pin driver 98 that is
attached to a
2s rotary drill 100. Preferably, the ruler 94, the fixation pin 96 and the
driver 98
26 axe all made of stainless steel, or other metal, although other materials
are also
2~ contemplated.
2s Briefly, in order to mark the location of the provisional, the ruler
29 94 is attached to the fin clamp's arm 64, and the fixation pin 96 is
temporarily
3o driven into the humerus 18 at a position within the ruler's slot 95, and
the
19
CA 02483116 2004-09-29
1 position of the pin with respect to the ruler is noted. Then, the
provisional 22,
2 the fin clamp 60 and the ruler 94 are removed, but the fixation pin 96
remains
3 in place in the humerus. The permanent stemmed Numeral component is
4 inserted into the humerus, and the fin clamp 60 and ruler 94 are attached
s thereto, as they were attached to the provisional. The: position of the
assembly
6 of the permanent stemmed Numeral component, the fin clamp and the ruler is
adjusted until the fixation pin is positioned at the same spot within the slot
on
s the ruler that was previously noted. Thus, by using the fin clamp, the ruler
and
9 the fixation pin (and pin driver) -- the version and height of the
provisional can
to be been duplicated for the permanent Numeral component.
1 ~ Details of the preferred embodiment of the ruler 94, the fixation
12 pin 96 and the pin driver 98 will be described next, while making reference
to
13 Figures 9-13. Figure 10 shows a perspective view of the preferred
embodiment
m of the ruler 94, which includes a securing assembly 1.02 and a main body
1.04
ns that has a scale 106 and the slot 95 mentioned above. The securing assembly
16 102, which is used to secure the ruler 94 to the arm 64 of the fin clamp 60
(as
m shown in Figure 9), preferably includes an opening 108, which allows the
ri:~ler
1 s to be slid upon the arm 64 of the fin clamp 60. Preferably, the opening
108 is
19 large enough to allow the arm 64 to slide through with ease, but not so
large
2o that the ruler is free to rotate about the arm. It is also desirable to
'configure the
21 opening 108 with flat upper and lower surfaces 112, 114, which, in
22 combination with the flat upper and lower surfaces 116, l 18 of the fin
clamp's
23 arm 64 (Figure 4), also prevent the ruler 94 from unduly rotating on the
arm 64.
24 The securing assembly 102 also includes a setscrew 110 that extends into a
2s threaded hole that goes into opening 108. By tightening the setscrew 110,
the
26 ruler 94 can be secured upon the arm 64. Preferably, 'the setscrew 110
includes
2~ a flat bottom, which provides better lateral stability for the ruler when
i1; is
2s attached to the arm. Although only a setscrew-based securing assembly 102
has
29 been shown and described, other mechanisms for securing the ruler to the
arm
3o are also contemplated:
CA 02483116 2004-09-29
1 As can be seen in Figure 10, the scale 106 includes a plurality of
2 incremental marks. Although not shown, periodic numerals may also be added
3 for ease of reference. It should be noted that the scale 106 is preferably
based
4 on the same scale with the same zero paint used for the fin clamp 60, which
s was shown and described while referring to Figure i'. Thus, in this
preferred
6 embodiment, the upper incremental mark 120 on the ruler 94 would be
designated as l5mm (and not zero) because when the ruler is properly secured
s upon the arm 64 of the fin clamp 60, the incremental mark 120 is located
l5mm
9 from the zero point on the numeral stem provisional (or the stemmed Numeral
io component). Optionally, a series -of peripheral ,grooves 122 may also be
11 provided on each side of the main body 104 at regular increments (such. as
12 every l Omm) in order to facilitate reading the scale.
13 Figure 11 shows an example of the preferred embodiment of the
14 pin 96 and the pin driver 98, as well as a T-handle 124 that can be
attached to
~s the pin driver for manually rotating the pin. If desired, the T-handle 124
can be
16 used in place of the rotary drill 100 mentioned earlier, if manual
insertion of the
1~ pin is desired. The end of the pin driver 98 is preferably configured to
accept
is either the T-handle 24 or the drill 100. In order to transfer rotation from
the; T-
t9 handle 124 or the drill 100 to the pin driver 98, one end 126 of the driver
2o preferably includes one or more flat'surfaces 128, and forms the male
portion of
21 a male/female connection, where the female portion is found on end I30 -of
the
22 T-handle 124 (of the drill 10), the interior periphery of which is shaped
to
23 correspond to end 126 of the pin driver 98, and included the same number of
24 flat surfaces as found on the driver. In the preferred embodiment, there
are:
2s three flat surfaces 128 on the male portion formed on the driver.
Accordingly,
26 there would also be three flat surfaces ~n the female portion formed on the
T-
2~ handle or drill. ~f course, cross-sectional shapes other than those
described
2s can also be used to transfer rotation from the T-handle (or drill) to the
pin
29 driver 98.
21
CA 02483116 2004-09-29
The other end of the driver 98, end 132, should also include
2 means for transferring rotary motion, but this time the rotary motion is
being
transferred from the pin driver 98 to the pin 96. Accordingly, the pin driver
and
the pin should include mating malelfemale portions of corresponding non
s circular cross-sections. In the preferred embodiment shown in Figure 11, a
flat
portion 134 is used to create a non-circular cross-section on the pin 96,
which
defines the male portion of the connection. As best shown in Figure 13, a
s corresponding flat portion 136 is created on the inner periphery of end 132
of
the driver 98, thereby creating a female portion with a corresponding non-
t.o circular cross-section. Although only one type of n.on-circular cross-
sectional
1 i shape is being shown and described, other non-circular cross-sectional
shapes
12 may also be used, as long as they allow the transfer of rotary motion
between
13 the driver and the pin.
14 For ease of manufacture, the flat portion I36 of the driver 98 may
Is be formed during a separate process after aperture 138 has been drilled. In
the
16 preferred embodiment, flat portion I36 is formed by depositing material,
such
m as the same metal used for driver 98, into a cavity 140 formed near end 132
of
i s the driver. In order to catch and shape the material, a mold is inserted
into
i9 aperture 138 to create the desired shape of the flat portion 136. Once the
2o material placed into cavity 140 has dried, the mold is removed and the.
outer -
21- periphery can be machined to create a smooth outer periphery. Drilling a .
.
22 circular aperture 138 and inserting a plug-of material in a cavity 140 is
easier,
23 and less costly, than directly attempting to machine an aperture with a
flat
24 surface.
2s To inform the surgeon of the location of the flat surface 136 on
26 the driver 98 so that the flat surface 134 of the pin can be properly
oriented to
2~ contact the flat surface 13G when the pin is inserted into the driver, a
line 140 or
2s other type of mark may be engraved or otherwise made on the outer periphery
29 of end 132 of the driver 98. In order to more tightly secure the pin 96
within
the driver 98, a C-ring 142 is preferably seated within a channel 144, as
shown
22
CA 02483116 2004-09-29
1 in Figure 13. The channel 144 is preferably formed in an area of the
aperture
2 138, of circular cross-section, that is between the location of the flat
surface
3 134 and end 132.
Turning now to Figures 11, 12, and 12A, the pointed end 146 of
s the pin 96 will be discussed. As mentioned earlier, the pin 196 is
temporarily
6 inserted into the humerus after the Numeral stem provisional has been
properly
positioned, in order to facilitate re-creation of that position for the
stemmed
s Numeral component. Accordingly, the pointed end 146 of the pin must be
9 configured so that it can be easily .inserted/removed to/from the bone, and
also
1o so that when it is inserted into the :bone, it remains securely in
position. The
r ~ preferred embodiment of the pointed end includes a knife edge tip 148 and
a
12 sharpened threaded portion 150.
~3 The knife edge tip 148 is used for cutting the initial pathway for
14 the remainder of end 146 of the pin 96 being inserted into the bone. The
knife
is edge tip 148 is preferably generally flat, and generally triangular-shaped.
The
16 two edges that converge to form the tip are preferably sharpened, so that
the tip
m can be easily inserted into the bone when the pin is rotated:
i s Figure 12A shows a magnified section of the sharpened threaded
19 portion 150, taken from within circle 12A of Figure 1:2, which shows a
trough
20 152 between two sections ef the thread in order to illustrate the preferred
21 confi-guration of the threaded portion. More specifically, Figure 12A shows
22 how a trailing edge portion 154 of the thread continues into a trough 152
and
23 how it further continues into the leading edge portion 156 of the next
section: of
24 thread. As shown in the figure, the leading edge :portions 156 are sloped,
2s preferably at approximately 35 degrees, to facilitate a~utting into the
bone. In
26 contrast, the trailing edge portions 154 are essentially normal to the axis
of the
2~ pin 96 (or they may be slightly sloped at approximately 3 degrees), which
helps
2s to prevent the pin from becoming dislodged from the bone.
29 To provide for better understanding of the present invention, the
o method of using the tools described above will be summarized, without the
23
CA 02483116 2004-09-29
detailed descriptions of the tools themselves already provided, while
referring
2 primarily to Figures 2, 8 and 9. After the Numeral canal has been prepared
and
3 the proper size of stemmed Numeral component has been selected, a Numeral
4 stem provisional 22 of the same size as the Numeral component is selected,
an
s appropriately sized sleeve 25 is attached to the provisional's stem 24, and
the
desired fin clamp is attached to the provisional. The provisi~nal 22 (with a~
fin
clamp and a sleeve attached) is inserted into the Numeral canal, and the
selected
fin clamp (60, 60' or 60") is used to properly position the provisional within
9 the Numeral canal. Although the appropriate fm clamp is preferably attached
to
io the provisional-prior to its insertion into the canal, the fin clamp may
also be
i 1 attached to the provisional after insertion into the. canal, if desired.
Attachment
i2 of the fin clamp to the provisional is accomplished by tightening the
setscrew
13 located on the proximal side (72 ar 74; 72' or 74'; 72" or 74"). The
appropriate
fin clamp is selected depending upon whether the operation relates to the left
is shoulder or the right shoulder, and whether the desired separation distance
m between the proximal end of the humerus 38 and the distal side 36 of the
collar
m 26 is intended to be l ~mm; l8min or 2lmm. Once the appropriate fin clamp
t s (60, 60' or 60 ") has been selected, the channel 66 is seated on the
anterior fm 3
19 of the provisional 22, as shown in Figure 8.
2o After the provisional (with f n clamp and sleeve attached) has
21 been inserted into the Numeral canal, it is rotated so-that the fin clamp's
arm 64
22 is either aligned with, or slightly posterior of, the bicipital groove 92
(Figure I j.
23 The axial position of the provisional 22 is adjusted by maintaining the
24 appropriate angled surface (76 or 78; 76' or 78'; 76'' or 78") flush with
the
2s distal side 36 of the collax 26, while the appropriate flat surface (82 or
80; 82'
26 or 80'; 82" or 80") is made to be approximately flush with the proximal
2~ surface 3 8 of the Numeral shaft.
28 In order to estimate the proper retroversion of the provisional,
29 version pins 84 and 86 (Figure 8) are. inserted into version pin holes 88
and 90,
3o and the patient's arm is extended so that the forearm sits between the
version
24
CA 02483116 2004-09-29
1 pins. A range of motion analysis is performed. .Any necessary adjustments to
2 the location of the provisional are then made. The version pins 84 and 86
are
3 then removed from the version pin holes 88 and 90, and the ruler 94 is
attached
to the arm 64 of the fin clamp; as shown in Figure 9, by tightening the
setscrew
s 110.
To mark the position of the provisional 22 before it is removed
from the Numeral canal, pin 96 is. driven into the bone by being rotated,
either
manually or with a drill, in a location within the slot 95 of the ruler. The
position of the pin within the slot is noted so that it can be recreated when
the
1 o stemmed Numeral component is being positioned.
1 ~ Next, the Numeral stem provisional 22, along with the fin clamp
12 and ruler, are removed. The open-ended slot 95 on the ruler 94 permits the
13 ruler to be lifted from the area without disturbing t~~e location of the
pin 96.
la. The stemmed Numeral component 10 is then inserted into the Numeral canal
in
is the position that the provisional previously occupied. The fin clamp is
attached
1 ~ to the Numeral stem component, and the axial location and retroversion are
m confirmed by inserting the version pins 84 and 86 and by making any
necessary
1s adjustments so that the forearm is between the pins: As an additional check
on
the position of the Numeral component, the ruler 94 is attached to the fm
2o clamp's arm 64; and the position of the alignment pin 96 with respect to
the
21 ruler is compared to the position noted earlier. Any necessary adjustments
are
22 made. Once the proper position of the stemmed Numeral component has been
23 obtained, it is cemented into place in the conventional manner, and the
bone
24 fragments are refitted using any one of the desired conventional
techniques:
2s The operation is then continued to completion using any desired technique.
26 While various embodiments of the present invention have been
2~ shown and described, it should be understood that other modifications,
2s substitutions and alternatives may be apparent to one of ordinary skill in
the art.
29 Such modifications, substitutions and alternatives can be made without
2S
CA 02483116 2004-09-29
1 departing from the spirit and scope of the invention, which should be
2 determined from the appended claims.
3 Various features of the invention are set forth in the appended
claims.
26
