Note: Descriptions are shown in the official language in which they were submitted.
WO90/08S10 P~T/US90/00651
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SCREW and DRIVER
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FIELD OF _HE INVENTION
The present invention relates to screw and driver
assemblies, and more particularly to surgical screw :;
and driver assemblies designed so t~la~ the driver is
releasab1y couplable to the screw.
BACKGROUND OF_THE INVENTION
In certain situations, it is desirable that a ` :~
screw be both rotationall~ as well as axially
releasably coupla~le with a drivex. For instance, in
limited-access work applications, e.g., in
arthroscopic or other "closed" surgeries~,~where a
scxew is to b~ insarted into a ho}e which is~not
readily accessible, i~ is advantageous to aXially
coup~e the screw with the driver be~ore inserting the
screw into the surgical sit~ Such~axial coupling is
15~ beneficial where the screw implantation site is ~: :
accessiblei e.g. where the screw is inserted:in;a
downwardly:facing hole.
With:such screw:and driver combinations, the screw
is ~Sirst attached to the driver and~then the driver is
manipulated until the~screw ~ontacts the implan~ation
site, wher~upon thQ:driYer is rotated until the screw
is:~ul~y implant~ed.~ Than~ the dri~er is ~isengaged
fr~m~the sarew~by~pulling it axially away from the ~ r ',
uch~screw~:;and~dri~er:~combinati~ons:~are~known:in :~
th~ art~ s illustrated by U.S.~:~Pat~nt:Nos. 2,32~,3~8,
2,511~,05~ 2,775,913,~3~:,463,~209, 3~,695j321, and
WO 9iD~O~10 PCr/US90/006$1 ,(
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3, 88g, ~44 . Known screw and driver combinations
typically ~;uf~r from one or more problems which limit
their utility and acceptance in certain situations.
For instance, known screw and drivex assemblies when
designed to provide sufficient axially locking
engagement can be difficult to operate, inasmuch as
the driver must be inserted with an un~cceptably large
axial ~orce to overcome the frictional interference
between screw and driver. With some screw and driver
combinations, the rotational enyagement between the
screw and driver is not sufficiently positive, i.e.,
there often is an unacceptably large ~mount o~ play
between the screw and driver. Other screw and driver
combinations (1) tend to be relatively expensive to
produce due to the relatively compIex shapes of the
screw and driver and (~) can permit ~ome axial wobble
between screw and drivert i.eO, the:combination is not
designed to ensure the driver is always perfectly
co-axially aligned with the screw.
ARY OF THE INVENTION
An object of the present invention is to provide a
screw and driver co~ ination dasign~d la) to provide
positiY~ rotational engagement between screw and ~ ;
driv~r, (b) to parmit ~he driver to be securely
atta~hable to the screw so that the driver is
restrained ~rom moving axially relati~e to the screw ~ i
while at the same time permitting ~he driver to be ,~
relative~y easily attachable to and~de~chable from
th~ screw, and (c)~ to ensurs ~he screw and driver when
engag~d remain co-axially aligned with~one another.
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WO90J08510 2~ ~s ~ PCT/~S90/00651
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Another object of the present invention is to
provide a screw and driver combination achieving the
foregoin~ objects which is adapted for use with a ~:
"K-wire" or other guide wire insertion system.
These and other objects are achieved by a screw
and driver combination comprising a screw and a driver
designed to rotatably drive the screw. The latter is
preferably, although not necessarily, threaded along
its entire length, comprises an axial bore of circular
cross section which is open to the top~end of the
screw and a counterbore of polygonal, preferably
hexagonal, cross-section which is also open to the top
end of the screw.
The driver comprises an elongate shaft ~erminating
in a radially-compressible cylindrical front portion.
The latter is sized and configured s~ ~ha~ when the
front portion is inserted through the~counterbore into
.
the axial bore of the screwr:the front~portion will : ;
;compress radially. When the front~portion is fully
i.nserted, it snugly engages the wall of the axial bore
with a minor spring-biased~in~erference, whereby the ~ ;
driv~r is re~easably~coupled in an~axial sense, to the
scr~iw.
:The driver also comprises an elongate intermediate~
portion having a polygonal, pref~rably~hexagonal,~
crvss-section with the cross-sectional configuration
and dimension:of the intermediate~;portion being:
subs~antially equal ~o the cross-s~e~tional :
con~iguration and dimension:o~ ~he:~counter~ore of the ;.
screw. The inter~ediate por~ion is attached to the ~ ~ .
rear~end of`the front portion and the front end of ~he ~:
WOg~/08~10 PCT/US90/00~5~
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shaft, Thus, when the front portion is inserted in
the axial bore of the screw and the intermediate ,`
portion is inserted in the counterbore, by rotating
the shaft rotational drive is transmitted, via the
engagement of the intermediate portion and the
counterbore, to the screw.
.
BRIEF DESCRIPTIC)N OF THE DRAWINGS
For a fuller understanding of the nature and
objects of the preæent invention, reference should be
made to the following detailed description which is
to be considered together~with the accompanying
drawing~
Fig, 1 is a sid~ elevation view, partially broken
away, of the screw o~ the present invention;
Fig. 2 is an end view of the screw taken alony
line 2-2 in Fig. 1; .
Fig. 3 is a side elevation of the~dri~er of the
pre~sent invention;
~ ig. 4 is an enlarged view of the ~ront portion of
the driver illustrated in Fig. 3;
Fig. 5 is an enlarged cross-sectional view:taken ..
alon~ line 5-5 in Fig. 4;~
Fig~ 6 is a cro~s-sectional view of the driver
taken along line 6-6 in Fig. 5,
Fig! 7 is an~enI~arged side elevation view nf an . .
alternativa version~of the front portion~of~the
drit~er;
Fig~ 8 is an enlarged cross-sécti~onal view
o~ the:~ro~t por~ion illustrated~in~Fig. 7 taken
along line 8~8 in Fig~ 7; ~
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Fig. 9 is a cross~sectional view of the front
portion illustrated in Fig. 8 taken along line 9-9 in
Fig. 8;
Fig 10 is a plan view showing the screw of the
present invention inserted into a gap between a bone
plug and the wall of the hole in the bone in which th~
bone plug is inserted;
Fig. 11 is a side elevation, partially broken
away, of the screw of the f irst alternative embodiment
of the present invention;
Fig. 12 i~ a side elevatlon of the driver of the
first alternative embodiment of the present invention;
Flg. 13 is a schematic side elevation view showing
th~ screw and drivex of the first alternative
embodiment, the material in which ~he screw of the
first alternative embodiment is to be implanted, and
the guide wire used with the screw and driver of the
first alternative embodiment;
Fig. 14 is a side elevation, taken in cross
seation, of the front portion o~ one version of the
driver of the second alternative embodime~t;
Fig.~ 15 is a side elevation of~he driver o~ the
second alternative embodiment; and
Fig. 16 is a ~ide elevation, taken in cross
s~ction, of the front portion of anoth r ~ersion of
th~drlver of the second alternative embodiment..
:In:tha drawing~., lik~ referen~e numerals refer to : ~.
ike~parts.
~ ~ .
~ eferring to Fiqs.~ 3,~the present inve~tion is a
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WO90/~510 P~TJUS90/00~51 ~:
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screw and driver oombination consisting o~ screw 20 and
driver 50.
Screw 20 comprises an elongate shaft having a flat
back end 22 and a pointed front end 24. Screw 20 is
preferably cylindrical along the majority of its
length, with the front portion of the screw tapering
down to pointed front end 24. Thus, screw 20
preferably does not comprise a distinct head having a
diameter which is greater than the diameter of the
~haft of the screw. Alternatively, where the
application so requires, a head (not shown) may be
attached to back end 22.
Screw 20 is threaded along the entire length of
its outside surface. The`specific thread pitch will,
of course, vary with application and screw size,
although for a screw designed ~or use i~ arthroscopic
or other cIo~ed surgeries and having a length of about
one~inch (l") a thread pitch of about O.llO
inches/thread is satis~actory.
Screw 20 comprises a blind axial bore 26 which is
open to back end 22.: Axial bore 26 has a ciraular :~
cross-section, wi~h:the diameter o~ the axial bore
pre~erably being equal to roughly one-third the
outside diameter ~f screw 20. The length of axial bore 7 ' ''
~6 is preferably egual to about two-thirds the:overall
lengthlo~ screw~20.
Grew 20 also comprises~a blind c~unterbore 2~
which ls co-axia1~with axial ~ore 26 and i5 open to }
back end~22. Counter~ore 28~has a polygonal, , ~-
pre~erably hexagonal~ cro~s-section wi~h the result
that the:~sounterbor~:~comprises~a plura1ity o~ ~lat
:~
WO90/08510 PCT/US9~/00651 1 ~
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elongate adjoining faces 28'. Counterbore 2~ is
dimensioned so that the diame~er of a circle contacting
simultaneously all of the flat faces ~8' of the
counterbore is at least as large as the diameter of '~
axial bore 26, and in mosk ~ases is larger than the
diameter of axial bore 26. As a result of this
dimensioning, a seat 30 is fo~med at~the base of
counterbore 2a. The;length of counterbore 28 relative
to the portion of axial bore 26 having a circular cross
section may vary based on known design parameters,~ i
although in an exemplary screw 20 the~portion of bore
26 having a circular cross section is~approximately
one-and-a-half times as long as counter~ore~28.~A
tapered reoesses 29 is~preferably provi~ed at the mouth
of counterbQre 28.
As used~hereina~fter, bore 26 shall;refer~to the
portlon o~bore 2& having a~circular cross section,
iOe. th~ portion o~ bore;26;~be~ween sea~t 30 and the '' ','
blind~end of~the bore,~unless~speci~ically mentioned
otherwise.
Turning now to~Figs~ 3~-5, drxver 50~comprises~a ~ r
handle 52~and~an elongate~shaft 54~attached to the'~
front;~end~of the handl~e.~ Where screw~20~nd driver 50
ar~ ~intended to'be~ùsed;in~closed~surgeries,~the
outside~diame~er o~ shaft 54' must~be ~elected,so t,hat~
thè ~lat~er' can ~e ~reely inserted~into and removed
rQm a; con~entiona~}~cannula. ~The~length~of shaft 54
wil~,~-,o~ourse;~ var~,w~ith~,~appl~ication.~
` ' The~front~end~ ~ shaft~54~tap~rs~ a~reduoed
dia~eter~ nte ~ediaté~partion~56.~ ~The~latter~has~a
polygona~ cross-section, the spe~ polygonal :shape~
W090/0~;10 Pcr/lJsso/
of which corresponds to the polygonal configuration of
the cross-section of counterbore 2~ in the screw 20
with which the driver 50 is adapted for use. For
instance, if counterbore 28 has a hexagonal
cross-sectiona~ con~iguration, then intermediate
poxtion 56 also has a hexagonal cross-section.
Furthermore, intermediate portion 56 is-dimensioned to
be freely slidably insertable into and ~emovable from
counterbore 28. At the same time~ intermediate
port.ion 56 is dimensioned so that when it is inserted
in counterbore 28 it positively engages the sidewall
of the counter~ore so t~at rotational dr.ive can be
tran~mitted from intermediate portion 56 to screw 20
with minimal lost motion.
As noted above, intermediate portion 56 has a
reduced outside diameter relative to~sha*t 54.
Intermediate poxtion 5~ joins shaft:54 with a smoothly
tapering radius portion 580 Preferably, although not
n~c~ssarily, the polygonal cross-~ction~of
in~rmediate portion 56 is carxied through tapering
radius poxtion 58 and terminates at the :junction of
the radius portion with shaft 54. The len~gth vf
intermediata portlon 56r as measured~between the fron~ s
end:60 of the intermediate~portion and:front end
of radius portion 58, is roughly equàl to;the length,
of couhterbore 28.;~
Driver 50 further comprises~an~elongate,
radial:ly compressible ~ront portion~66~having a
central portion ~$~and a radial~ly-project~ing tip
portioin 70,~ Central p~rtion 68~is cylindrical in
ex~erior configuratioll when not~: in ~ the t::Qmpressed
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WOg~/0~510 PCT/US90/00651 ~.
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state, and is attached at its rear end 72 to front end
60 of intermediate portion 56 so that the axes of ' ..
elongation of front portion 66 and intermediate .
portion 56 are co-axial. The diameter of the central
portion 68 is l~ss than the diameter of a circle ,:
circumscribin~ intermediate portion 56, with the
result that a shoulder 69 tFig. ~) is for~ed at the
junction of the central portion and:the interme~iAte
portio~. Preferably, front portion 66 is slightly,
e.g. 0.05", shorter than bore 2fi. , .`'
Tip portion 70 is co-axial and integral with
central portion 68, and is positioned~adjacent front : ;.
end~74 o~ front portion 66. Tip portio~ 70 has a
generally cylindrical exterior configuration, with the :
outside diameter o~ the:tip portion~being slightly .',
greater than (i.e.~ o.noos - O.OOlS inches) the diame~er
o~:axial bore ~ in screw~20~wh:en the tip portion is
not ln the compressed sta:te.~ Tip portion 70 tapers
radially inwardly (a)~at~its front :end~to intersect
front~;en~'74~ and (b)~at'its rear:end to:intersect '~
cen~ral: pcrtion 68.
"
Front portion 66~further~comprises an axial~ bore ~0
which~xtands:along~the entire:length of th~ront
~ port~ion.~The inside diameter ~f~axial bore 80 is
,~' : roughly half the outside diameter o central port~on
Front portion~66~al~s~in~1udes three slots 82 : ':~
xte~ding~along`the~length~o~;;the~front~portion~and:~
ing~axia~l bore~8~o~wit~h~i ou~side~surfa~e o~ the
nt~portion~ :Ea¢h~slot~8~2;~;ls a~ularIy space~about :~
the~circumference~'ot front~end:~74~so ~s to~be spaSed
WOgO/08510 PCT/US90/006~
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120 from the two adjacent slots, whereby front
portion 66 is divided into three equally-sized
elongate segments 84a, 84b and 84c.
. Preferably, although not necessarily, as best seen
in Fig. 6, the length of the radially-outermost
portion of each slot 82 is about equal to the length
of axial bore 80, while the length of the
radially-innermost por~ion of each slot 8~ is about
equal to two-thirds the length of axial bore 80. The
wall of front portion 66 in which slots 82 are
provided tapers along a gradual radius be~ween the
radially~innermost and radially-outermost portions of
the~ slots, as illustrated at 85 in Fig.~ 6.
Alternatively, the radially-innermost and radially-
~utermost portions of each slot 82 may be the same
length or may be related in length by a ralationship
of other than two-thirds to one. The width of slots
82~ is approximately equal to one quarter the diameter
:of axial bore 80.
As described in greater detail hereina~ter, axial
bore 8p and slo~s 82 are provided:to allow front
portion 66 to be compressed radially inwardly. When a
radia1ly compressive~force~is applied to front portion
66, segments 84a, 84b and 84c will move toward one 7
another. The diam~ter! of axial bore ~O,~jthe o;utside
diameter of tip portion 70 when in~the uncompressed
state, and the:width and~number o~slots::8~i are
selected:~so:~hat tip.por~io~ 70:wil1 snugly engage the
wall;~o~ axial~bore 2~6~with a~minor:spring interference ~ ~ :
it~when~insert~d~i~ bore 26. In this:compre~sed
state,:the front ends of.se~ments:84a~, 84b and 84c are
WOgO/0851~ PCT/US90/0~651
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driven toward one another so that the width of the
fror~t ends of slots 82 is reduced somewhat.
Front portion 66 is made from a materiaI which can .
readily accommodate, without fatigue;o:r shear,
~epeated compression and release of segments 84a, 84b
and 84c. This material is also sufficiently:resilient
and has sufficient spring memory so that when segments
84a, 84b and 8:4c are radially compressed,~the segments
attain a radially-outwardly acting spring bias.~
Suitable materials having these properties include I ::.
stainless steel and titanium. ~ ::
Re~erring now to~Fi~s. 7-s,:in~an alternative
embodiment of front portion 66j four slots 82 are ~ ~
provided in the front portion. ~ach of:the slots 82 ~ r'
:is s`paced~Q from adjacent:~slots, a~s:~measured around ~ .` the~ciraumference of front end 74. ~ As such, front
portion:66 is divided:into four equally-sized,
; ~ , ,j
qlongate ~segments 84a,~84b~,:8~c and 8;4d, and each~slot
~82:~is::~diametri~all~ opposite a:twin~slot 82.~ Th~
radial~ly~innermost~as~well~-as~the radially:outermost .
portions: of slots 8~2~of~`the~alternative embodiment:o~
front~portion 66 extend substantially the entire
Iength ~f~:~ront~p0rtiOn~;6~6~unl~ike the~510ts of~ he ;~
mb~diment illustrated:in~Figs.:4~-6`~(where the ` : :~
radially-outermost:.portion o~ the~sIot~is :: ~
prefe~ably l:onger than th~ radially-innermost`portion : ::
o~ the~s}ot,~as~;indica~ed.~at`~5~in~Fi~ 6). ~
Fr~ p~rtion~66~comp~ises-a~air of~transverse
borès~9o~and~92~éxté~di`ng;~èn*irely~through the~
hickness~of~:cen~ral~portion:~;~6~ .Bc~re 90;~and~:92
extend n~mally~to~the~long axis:of:~ront~portion 66,
WO90/085tO PCT~US90/006
intersect the axial bore 80 at the inner end thereof
and are perpendicularly aligned with respe~t ~o one
another. Bore 90 is positioned so that its long axis
extends through one of the pairs of diametrically
opposed slots 82, and bore 92 is positioned so that
its long axis extends through the other of the pairs
of diametrically opposed slots 82~: T~e diameters of
bore 90 and 9? are identical and are somewhat greater
than the width of slots 82. Bores~90 and 92 are
provided to prevent the formation of stress fractures ~.
at the base o~ slots 82 which might reduce the
resiliency and spring memory of elongate portions 8~a,
84b, ~4c,~and 84d.
The outside diameter of tip portion 7 0 of the
four-slot version o~ front portion 66:is about 0.002-
0.00~: inches, preferably 0.003 inches, greater than
the inside diameter of bore 26 of screw 20. Thus, the
outside diamater o~ tip portion 70 of the four-slot
version of front portion:~66 is slightly greater than
~th~ outside diameter o~ the tip portion 70 of the
thr~e-slot version of fxont portion~:66. Tip portion ~ ;
of the four-slot version of front portion 66 has
his slightly larger diameter~because the provision of
our~slots 82, as:opposèd to:three::slots 82, permits
the four slot ve~sion~of front portion 66 to be~more
ea:sily~radially~compressed. As such, to achieve the
desired minor spring interference~fit between front : ' 1.
:portion 66;and counterbora~26, the outside~diameter of
tip~portion 70~of~:the~;four ~lot~version~of front ; ;
portion 66 ~is slightly enlarged. ~
WO~0/0~510 PCT/US90/00651
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EXAMPLE
An ~emplary screw and driver combination of the .:
present invention, designed for use in arthroscopic or
other closed surgeries, possesses the foll~wing
~pecific dimensions: :
Scréw 20
. _ _
overall length: l.18"
outside diameter (measured at radially outermos~
portion of threads): 0.276"
angle of pointed front portion: 30 with respect 1 :
to longitudinal axis (included angle of 60)
diameter of axial bore 26: '~Q.094S"
polygonal configuration of counterbore:
~hexagonal,: with di~metric distance between
para}lel~opposing faoes equal to 110.0945
thread pitch:~ .llO:inches/thread
length of counterbore 2~: 0.20'
length of axial bore 26: 0,4511 :
Drlver 50
overall length: 9.25"
length o~ shaft 54: 4.00" ~
diam~eter of shaft 54: .l87" :~ ;
ength o~ intermediate:portion::56~(excluding ~ .
radius por~ion ~8): 0.20'~
pbl~gonal configùration of intermediàte portion
56: hexagonal,~with diametric distancP between ~ .
any two~pa~alIel~opposing faces~equa} to: O.Og28 : 5
ngth of~ront portion:~6:6: O.:~o"
length of cen~ral:portion~8: 0~40"
diameter-of cen~ral portian ~:(in un~ompressed
~ .
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WO90/08510 PCT/US90/00651 ~
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state): 0.088"
diamet~r of tip portion (in uncompressed state):
0.0955"
length of slots 82
radially innermbst edge: 0.l20"
radially outermost edge: 0.200"
width o~ slots 82: O.OlO1'
number of slots 82: 3
The above-listed dimensions are onIy exemplary,
and may, of course, be varied depending upon the `~
desired application of the pres~nt screw and:driver
com~ination.
:
OPER~T~
Referring to Figs. l-lO, the screw and driver ~ `~
c~mbination of the present invention may be
a~5factQrily used, for example, in a surgical context
:to secure a bone plug lO0 (Fig. lO) in a hole 102
drilled:in a bone 104. As is:well known,~the diametar
o~ hole 102 is selected so that the co~ners of bone
plug lOO will contact:the wall of hole lO2. Typically, : :
a tendon~(not shown) or other tissue is attached~to
bone plug lOO before it~is inserted~:in hole 102.
~ter the bone plug lOO has been inserted i~nto hole ~
lO~,. driver SO is manipulated relative to screw 20 so : :
that front portion 66 passes through~counterbore:28
into axia~:bore:26:o~scr~ew 20. Because ~h~ diameter of
tip po~tion 70 in~the~uncompresscd~state is~slightly
gr~ater than:the diame~er::of axial bore 26:of screw:20, ~ :
frcnt~:partion 66 must~bé~radially compressed somewhat ~;
:
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so t.hat the tip portion can be slidingly inserted into
bore 26. To this end, tip portion 70 is provided with
an inwar,dly tapering front end which coacts in cam-like
fashion with either (a~ tapering recess 29 at.the mouth
of counterbore 28 when bore 26 and counterbore 28 have
similar inside diameters or (b) the mouth of bore 26
(adjacent seat 30) when the inside diameter of bore 26
is greater than the inside diameter of bore 26. Thus,
when front portion 66 is urged into bore 26 this
cam-like coaction forces segments 84a, 84b and 84c or,
84a-84d in the case of the alternative embodiment
illustrated ln Figs. 7-9, ra~ially inwardly. This
radially inward compressio~ of front portion 66 ~.
penmits the latter to be inserted through counterbore
28 and into axial bore 26 with a sliding ~it. Because
front portion 66 is campres`sed slightly~when received
in axial bore 26, tip portion 7~ engages the axial
bore with a minor spring interference fit.
When front portion 66 i~ fully inserted in axial
bore 26 in screw 20, and the length of the straight,
non-tapering section o~ intermediate portion ~6 is
greater than or equal to the length of counterbore 28
in screw 20, driver shoulder 69 will engage screw seat `
30. When the length of :the straight, non-tapering
section of intermediate portion 5~ is less than the
length l of counterbore 28 j bac:k ` end 22 of screw 20
adj acent recess 2~ :will engage radially tapering .. -
portion SB of intermediate portion~56 when fro~t
portion 66 is:fulIy inserted in axial bore 26. In ).
either~ case, this engagement provides feedback tc, the
u~e~ :as to when the~ fron~ portion is fully inser~ed.
.
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WO90/08~10 PCT/US90/00651
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During the insertion of front portion 66, shaft 54
must be rotated so that ~he ~lat faces of intermediate
piortion 56 are parallel to respective flat faces of
counterbore 28 in screw 20. The oross-sectional
dimensions of intermediate portion 56 are slightly
less than the cross-sectional dimensions o~ screw
counterbore 28 so the intermediate portion oa~ be
inserted into the counterbore with an easy sliding
fit. The dimensions of intermediate portion 56
relative to the dimensions of counterbore 28 are also
selected so that rotational drive can be transmitted
from driver 50 to screw 20 with minimal loss of
energy.
The pointed ~ront end of screw 20 is then inserted
into one of the gaps 106 (Fig. 10) between ~one plug
lO0 and the wall of hole 102. Because screw 20 is
coupled with driver 50 as a result of th~ minor spring
interference fit between tip 70 and axial bore 26, the
scr~w may be directed to the opening of the gap 10
solely by appropriate manipulation of driver 50.
Whe~re screw 20 is being used in a closed surgery, the
screw and driver sha~t 54:may~be inserted as a unit
into an appropriately-positioned cannula, with the
~driver being manipulated based on informiation pro~ided
by th~ fiber optic or other viewing system used in i ~
conjun~tion wit~ the clos~d surgery until ~he pointed ~ :
~ront end of the screw is receiv~d in the opening of ' ~:
the gap 106.
Next, driver handle 52 is rotated, causing shaft -
54 and intermediate portion 56 to:rotate. The latter
has th~ 6ame polygonal conf iguration as and ~s
:: : :
::
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WO90/08510 PCT/US90/00651
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approximately the same size as counterbore 28 so that
when intermediate portion 56 is rotated i~ trànsmits
rotational drive to the wall of ~he counterbore and
hence to screw 20. As screw 20 is rotated, its outer
threaded surface engages bone plug 100 and the
adjacent portion of bone 104 and thereby pulls the
screw into the bone and bone plug. When screw 20 is
fully implanted it ac~s as a wedge~forcing bone plug
100 into tight frictional engagement with ~he wall of
hole 102. ~ :
After screw 20 has been fully inserted, driver 50
is separated from the screw by pulling the driver
axially away from the screw. Tip portion 70 resists
this axial pulling to some extent so as~to ensure the
screw and driver do not lnadvertently become:separa~ed
prior to completion of the implantation of the screw.
However, when a moderately forceful axial pulI is ~`
app1ied, the minor spring interference between tip ~ ~;
portion 70 and axial bore 26 is overcome and the .:
d~iver can be detached~ from the screw.
':
FIRST ~LTERNATIVE EMBODIMENT
: In arthroscopi~ and other closed surgeries, so
called "K" wire or other guide wire systems are used . t`
to deliver a surgical ~asten~r to an implantatlon
site. As is known, these ~ystems comprise a long wire~ , :
typically having a pointed end, which is inserted in~o ~-;
selecte~ tissue in the~surg~ical site. ~Surgical tools, ': -:
fasteners and other~devices:adapted~for use~with guide
wire-systems (and hence:compris;ing~an:axial bore
ex~ending entirely through~the device) are deIivered
WO9~/0~S10 PCT/US90/0~651 ~.
`; - . ,.;
.
~ ~i ' ` 7 18
,~
to the site in the tissue where the wire has heen
inserted by placing the device on the wire so the
latter extends thxough the axial bore of the device.
The device is then moved down the wire until it
reaches the tissue.
Referring now to Figs. 11-13, screw I20 and driver
150 of the alternative embodiment o~ the present
invention are virtually identical to screw 20 and
driver 50 of the first embodiment of the present
invention, except that axial bores are~provided
extending through the entire length of both the screw
120 and driver 1i50. By providing these axial bores,
screw 120 and driver lSO are adapted for use with a
guide wire:s~stem o~ the type described above.
:~De~cribing screw 120 in greater detail, the latter i
has a cylindrical configuration, wi:th the pointed
~ront end of the screw terminating in a~lunt tip 123.
The exterior sur~ace:is threaded,~as described above
with~reference to screw 2:0. Screw 120 comprises an
axial bore 125 which~extends through the èntir~ length
of the~screw. :The:pointed front end of screw 120 is
blunted`~as a result~o~ the passage of bore 125~
therethrough,~ with the:area of blunt;~ip;123 being
equàl ~o the: area of th~::cross-sec~ion of bore 125.
5crcw 120 includes a:count~rbore~1~6 which is ;
co-axial with akial`bore~l25 and is open to rear end
~122 o~ the~ screw.~ Screw 120 further inclùd~s a
aounterbo~e 1:28:which is ~al60 co-axial;~with axial bore~
125~:and is open to rear end 122:o~ the:screw. A ~ :
tapered~r~cess 129~is provided in~rear end~122 at the
mouth:;of counterbore 1~8~
~,
WO90/08510 PCT/US90/00651 ~
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-19- . '~
. ~.
The length, diameter and cross-sectional con-
figuxation of counterbores 126 and 1~ are equal to
the length and diameter of bore 26 and counterbore 28,
respectively, of screw 20. The diame~er of axial bore ~.
125 is somewhat greater than the diameter of the guide
wire with which screw 120 and drivPr 150 are to be ~.
used, so that the screw can slide freely along the
wire. Thus, for example, for a guide wire having a
diameter of 0.035", axial bore 125 should have a
diameter of about 0.045'l. In any event, the diameter
o~ axial bore 125 is always less than or equal to the
diameter of counterbore 126.
Thus, in every detaill except for the provision of
axial bore 125 and the resultant blunt tip ~23, screw
120 is identical to screw 20. t
Referring to Fig. 12, driver 1~0 comprises a :-
ha~dle 152, an elongate shaft 154 attached to the
handle, an intermediate portion ~56 attached to the
~ont en~ of the el~ngate shaft, and a front portion ,-
166 attached to the front end of the in~ermediate
portion. An axial bore 1~0 extends through the entire
length of front portion 166. Elements 152-156, 166
and 180 are identical in length, diameter and
cross-sectional configuration to corresponding I .:
elements 52-56, 66 and B0 of driver 50. ! ~-
Drlver 150 differs from driver 50 only in tha~ ~he ~'
f~rm~r comprises a c~ntral axial bore lB5 extending
through the entire length o~ driver 150. Thus,
central bore 185 ex~ends through handle 152, shaft
154, intermediate porti~n 156 and front portion 16
Although axial bore 180~can be regarded às a
~.
.
WO90~8S10 PCT/US9~/00651
i. ... .
~"~ y~ -20-
.~ :
counterbore with respect to axial bore 185, in most
cases central ~ore 18~ and axial bore 180 will be
coextensive inasmuch as the diameter of central bore
1~5 is preferably identical to the diameter of axial
bore 180. The diameters of axial bore 1~0 and central
bore 185 are, of course, somewhat greater than the
diameter of the guide wire with which screw 120 and
driver 150 are to be used.
Thus, in every detail, except for the provision of
central bore 185, driver 150 is identical to driver
180.
Referring now to Figs. 10-13, screw 120 and driver
150 axe used in substantially the same:manner as screw
20 and driver 50 of the first embodiment, the only
difference being screw 120 and driver:150 are
delivered to the implantation site using a guide wire
system. Thus, prior to inserting screw 120 using
dri~er lS0, a long thin guide wire 200 i5 inserted
into th~ material 300, e.~., tiSsuQ such as bone,
l~gament, or tendon, into which screw 120 is to be
implanted. Thus, referring to Fig. 10, if screw 120
i5 to be implanted in gap 106 between~:bone plug 100
and the wall ~f hole:102, then guide wire ~00 is
inserted into~the bone~at the bottom of gap 106. If
screw 120 is to be inserted into the material 300 ~
surxounding a pil'ot hole~400 formed in material 300,
as il~lustrated in Fig. 13, then guide wir~ 200 is ~ ~ t~
nsertèd into pilot hole 400 so that it~penetrates ~`
into~the material a~ the base of the pilot:hole and is -
substantially coaxial with~respect~to the pilot hole.
;Guide wire 200 has~a diameter of~approximately
, ~ ,
W~gOJ08~10 PCT/US9~/0065~
~.
3 .
21- 1
0.035 inches and its leading tip 202 preferably :
penetrates tissue 300 to a depth of at least 0.75
inches. It is to be appreciated that the guide wire's
leading tip 202 is substantially pointed so that it
can more easily penetrate through into material 300. :~
Guide wire 20Q may be implanted simply by pushing it
into the tissue, or it may be mounted in a drilling
device (not shown) t~ facilitate entry~
In the event the ~uide wire 200 is inkended to be
simply pushed into material 300, a supporting cannula ~ -
of the sort well known in the art (not shown) may be
concentrically mounted around at least a portion of -~
the guid~ wire during insertion;so as to help maintain
the linear shape o~ the guide wire during penetration.
If such a supporting cannula i~ used, it is removed
~rom around the guide wire as soon as th~ guide wire
ha~ been properly positioned as shown in Fig. 13.
~lternatively, in the event guide wire 200 is intended
to be drilled into material 300, the guide wire's
l~ading tip 202 may also include a helical drilling
thread (not shown~ to facilitat~ penetration. If a -
drilling device is used to deploy guide wire 200, the
drilling device is de~ached from the guide wire as
soon as the guide wire has been properly positioned in
the manner shown in Fig. 13~
eerence shou1d be made to Fig~ 13 in
c:o~nectiorl with the following descrip~ion of-~he f
manner in whic:h sc:rew 12 0 and driver 1~0 are used with
,
~uide wire ~00. First, driver 150 i5 urged toward
scraw 120 so that driver ~ront portion 766 en~ers
cou~terbore 128 of screw 120. DriYe~ 150 is urged
~' ~
'.
W090/08S10 PCT/~S~0/006~1
-22-
.,~``'` ~ ^~ ;
toward screw 120 until the driver's intermediate .
portion 156 reaches the mouth oP counterbore 128. At
this juncture, driver 150 i5 rotated so that the flat
~aces o~ intermediate portion 156 line up with the
corresponding respective flat faces o~ counterbore 128 -~of screw 120. Th~reafter; driver 150 is urged toward
screw 120 causing interme~iate portion 156 of driver
150 to enter screw counterbore 12~ and driver front
portion 166 to enter screw counterbore 126. As
di~cussed above with respect to driver 50, when front
portion 166 is inserted into counterbore 1:26, front
portion 16~ is radially compressed slightly so that ~;
the ~ront portion 166 engages the wall of the
counterbore 126 with a minor spring:interference fit.
When front portion 166 of driver 150 is inserted
in screw 120 in this manner, by rotating driver 150,
:typically via handle 15~, rotational drive is
transmitted from driver I50 to the screw as a result of :
the positive rotational engagement beb~ween
intermediate portion 156 of driver 150 and~the wall o~
counterbore 128 of screw 1200 Additionally, screw 120
and driver 150 are releasably coupl~d in an~axial :~
sènse as ~ result of the minor spring inter~erence ~:::~ `~ :
~etWeen ~river fron~ p~rtion 166 and the wall of :
coun~erbore 126 of screw 12~
Nex~, screw i20~and driver 150 are l~oaded ::
oncentrically~onto~guide wire~200, with the ~crew9~
ront~tip 123:leading., s:o that the guide wixe passes ~ ?
through~the screw/s~axial bore 125 and~the driver's
cen~àl b~re 185. ~Screw 12~0 is then deIivered to
p:~lot h~le ~00 l:y mov:ing th~: c:oupl:~d~:æcrew and driYer ~ ~ ;
WO90/08S10 PCT/US9~/006
-2~,- ,
combination down guide wire 200 until tip 123 of screw
120 çontacts th~ portion~ o~ material 300 surrounding
the opening of the pilot hole, as illustrated in Fig.
13. Driver 150 is ~hen rotated, which in turn causes
screw 120 to rotate, whereby the screw thread on the
exterior of screw 1~0 engages material 300 and pulls
the screw into the material. Driver 150 is rotated
until the screw is eith~r partially or fully implanted
in material 300, as desired. Driver 150 is then
separated from screw 120 by pulling the driver away
from the screw with a force sufficient to overcome the
minor spring interference between driver front portion
166 and screw counterbore 126. After removing dri~er
150 f~om guide wire 200, the latter is withdrawn from
pilot hole 400 le~ving screw 120 firmly implanted in
material 300. This compl~tes the screw implantation .:
procedure usiny t~e screw and driver combination of
the alternativ~ embodiment.
Referring to Fi~. 10, a similar implantation
procedure is followed when æcrew l~O~is to be
implanted into gap 106 between bone plug lO0 and the
wall of hole 102 in bone 104~ the only differencP
being guide wire 200 i~ positioned in gap~106 instead
o~:in pilot hole 400. ~ :
SEC'OND ~ sTgRNA I!`t7E EMBOt:)IME~
Under certain circumstances it may ba desirable to ~i
~: f~rc~ elon~a~e ~sections:`:84a-84c or 84a~84d, as~:the
case may be; o~ front~portion 66~adially outwardly.
~ To achieve this function~,~a second~alternati~e
: : :e~bodiment of th~ pr~sent~invention is:provided
:: , :
W~90/08510 PCT/US9~/~0651 ~ ;
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..
--24-- `
consistin~ of drivi~r 250 illustrated in Figs. 14-16.
Driver 250 com~ris~s a handle 2~2`, an elongate shaft
254, an intermediate portion 256, and a front portion
266. The latter comprises a central portion 268, a
tip portion 270, and terminates at ~ront end 274.
Three or four slots 282 are provided extending along
the length of front portion 266 and coupling the
exterior surface of ~ront portion ~66 with axial bore
280 which runs the entire length of ~ront portion 266.
Elements 2S2, 254, 256, 266, ~68, 270, 274, 280, and
282 are identical in siæe, configuration and number~
as the case may be, respectively, to elements 52,:54,
56, 6~6,~ 68, 70, 74, 80, and 82 of driver 50
il`lust~ated in Figs. 3-9 and described above.
: Driver ~50 dif~ers from driver 50 in several :
respects. First, axial bore 280 is extended ` ~ :
rearwardly through intermediate portion 266,~shaft 254
~: and into at least the front portion;o~ handle;2520
` : Second,:an:elonga~e shaft 293 is disposed in axial
bore:28~0. ;The outside diameter of sha~t~293 is~
selectéd so that:th~e latter slides frèely inside axial
bore~280.~ Sha~t::293 termlnates in a blun~ end 294.
: Third:, the front;end:of:axial bore:~280 tapers:;
radially inwardly adjacent~ront~end 274 as indicated
: a~ 295.
F~urth~, à transverse~lot 296 is~provided in
handle 252~couplin~ axial~ bore 280 with the outside
sur~ace~of:~hè~:handl~
Fl~th,:a l~er:~297::~is~pivo~ally;mounted~in slot
2g6~Q~:~as~bè::tio~rotatabl~about~an axis~extending~
per~è~d:icular~to~:th~long~axis~of~shaft~254.~ one end ;~
WO90/08510 PCT~US90/00651 ~ .
; 5 ~
. .
,
of lever 2g7 is flexibly attached to the rear end of
sh~ft 293 and the other end of the lever projects out
of slot 2g6 away from the exterior surface of handle ~.
252. Lever 297 is mounted and attached in this
fashion so that by moving the protruding portion of
lever 297 l:oward front portion 266, shaft 293 is
c~used to move rearwardly in axial bore 280 away ~rom
front end 274 o~ front portion 266. Similarly, ~y
moving the protruding portion of lever 297 away from
front portion 266, shaft 293 is caused to mo~e
forwardly in axial bore 280:toward front end 274.
Shaft 293 is sixed so that when the protruding~portion
of lever 297 is mo~ed rearward of the vertical~
position, as seen in Fig~` I5, blunt end 2~4 of shaft
293 will cont~c~ the radially-inwardl~y tapering
portion 295 of: axial bore: 280. Further:rearward
mov~ment of lever 2~7 caus~s blunt end 294 to move
forward relative to tapering portion 295, whereby the
;~ blunt end coacts with the tapering~portion`in cam-like
fashion causing~front portion 2~6 to~expand r~dially.
Shaf~ 293 is also sized so that when lever 297 is ~ `
moved forward of the~vertical position, as seen in ~ig
15t blunt end 2g4~ o~ shaft 293 will not contact ` t .,
tapèring portion 295.~
These di~erences~between driver 2~50 and driv~r $0
exist for both ~he ~our~slo~ v~rsion (Fig. 14) and the ~ `
three sil:ot ver~,ion ~ ig~. 16:) of ~ront portion 266. . t;-J'
Optional~y,~axial~bore ~0:may be~xtended~ to the
rear~end o~`~handle 252~and::a ~ore~may b~ provided in
;shaft 293 so ~hat dr;iver ~50~can~be~used~with ~ guid~
wire:200 o~ the~ype:~described above~ and~illustrated
~ .
WO90/08510 . PCT/US90/00651 `~
!`
-26- ,
~ r~
in Fig. 13.
Driver 250'is adapted for use with screw ~O
described above, and functions in a similar manner to :
driver 50. The only difference in operation between
driver 250 and:driver 50 is that the ~or~er, after
being rotationally and axially:coupled to screw:20, is ~'`
actuated to cause front portion 2~6 to expand radially
and thereby securely axially couple the front portion ;~ ,,
with the wall of bore 2~ o~ screw~20. This'actuation
is effected by moving tha protruding portion of lever ; .. :
297 rearwardly so as to cause blunt end~29~ of sha~t
29~ to~muve forwardly and coact in cam-like fashion
with;tap;ering portion,295~ This aoaction causes front
portion~266 to :expand radially~
An:important advantage of the ~screw and driver
combination~of the~:~present-~invention~is th~at front: ;: :~
: : portion 66~(166,~2~66)~ is~de6igned~to~engage bore 26(~126)~
of screw 2~0(120) with~both;:~an~interference a~s well as a~
spring'~it. ~This mode~o~engageme~t is advantageous in
that~it~provides~ a s~ecùre~axial coùplin~:between s~rew
and~driver~and~ye~permits~the:driver~to:be withdrawn
from~the~,screw withoùt~the~neéd`;~to:~apply an
una~ceptably-~large~axial,;~f;orce:to the::~drivcr.
Addit~io~nally,~by~sizing~the~front~portion 66(166, 2~6) :~
and~bore ~26(126)~ so~that~they~engage~one anoth:er~with,
an~ln~irf~rence':~fi~ 'the:'ilim1tations associated~:with~a :~
solely~spring-biased engagemen~ e.g.~ loss of,~
res`il~iency'~ th use',~ e oid
e~ irst~àlter~at:lve~embodiment o~the present :
invention~hich is~desig~èd r~use~w a~guide wire
s~stem:is a~an~ag~ous'~ln that it ~facilita~is:quick
WO90/~851~ PCr/US90/00~51
~ `: 2 i ~ 7~
-27~
and easy axial alignment of the screw with the pilot
hol. This ease o~ alignment i-~ especially impor~ant
where the screw is to be inserted in a pilot hole
which is relatively inaccessible, e.g. a pilot
hole located deep in a arthroscopy site.
The second alternative embodiment of the present
in~ention is advantageous in that axially coupling
between ~crew and driver is achieved by interference
fit, spring bias and positive mechanical locking. By -
designing ths driver 250 to include these three means
for axially coupling the screw thereto,~ the material ;,
characteristic~ for driver ~50 become less critical
inasmuch as the spring memory characteristics of the
material are less important.
Since certain changes may be made in the
above-described screw and~driver without departing
from the scope of the invention hersin involved, it is
intended th~t all matter con~ained in the above
descripti~n or shown~in the~accompanying drawings
shall be interpreted in an illustrative and not in a
limiting sense~
.
?
: - : : ?`
