~ackground of the Invention
Field: This invention pertains to endoscopes in
general and to arthroscopes in particular. Specifically, it
provides such an instrument in a configuration ideal for use
in arthroscopy.
State of the Art: Endoscopy is the art of examining
the interior of a body cavity or hollow organ by the use of
a slender tubular telescopic instrument called an "endoscope".
Endoscopes have been in common use since the early twentieth
century. These instruments include a lens system, which may
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i
1130~6S
be conventiollal glass lenses ~itllin a rigid tul)e, air sp lces
bet~ een glass rods sllaped to configurate t]le entrapl)ed air
.poekets as lenses, optieal glass fibers combined ~'ith COlI-
ventional lenses, or other means; and a lighting system, which
may be a direet ill.wnination system (e.gO, a tungsten light
bulb) but is more often fiber light (light transferred from
an external source t]lrough optical glass fil~ers)O Encloscopes
also eommonly contain an irrigation system for introducing
fluids, typieally normal saline solution, to the regioll being
~o examinedO These s~ stems are all eontained witllin a eylinclrieal
tubular housing, usually called a "slleath", ~hich may be flexi-
ble, but is more often ri~id. The cross-seetional eonfiguratio
of the sheath normal~ its longitudinal axis (that is, as vie-~ed
from the distal end of tlle endoscopc) is traditionally circularO
Examples of moderll en(loseopes are diselosed l~y U.SO
Patents Nos 3,525,332; 3,599,630; 3,608,547; 3,730,632;
3,744,906; 3,818,902; 3,819,267; and 3,889,662.
Endoseopes h~ve bcen used Eor artl~roscol)ic cxamina-
tions for several decades Tllc clcvclopmcnt of artlll~oscor)y
ao and instrumellts adopted Eor art:llroseopie e~camirlatiolls (artllro-
seopes) is clescribe~l in tlle mono~-r;ll~ll "Artllroseol)y o:C tlle
~nee", Robert l\~o Jaekson alld I)avid JO l)a~l~ly, ~lo~lern Ortllopedie
~5OIlograp]ls ~ 1976 Grune ~, Str ltton, IneO, J~e~ YorkO l:rom the
monograph, it is apparellt that tlle prillcip ll objeetive sought
in developillg art]~roseopes has been to reduce their diameter
eompared to earlier endoscopes. All of the compollellts eon-
ventional to an endoseope, namely an optic~l system, a lighting
system, an irrigation system, and often an~ strument ehannel,
are eontained l~ithin a usual-ly rigid cylindrical sheatll of -~
3O approximately eireular cross-sectionO llle l~atallabe 22 shown
in I~IGo 2-5 of t]le monograph utilizes a slleatll slig]ltly oval
in cross-section to aecol;unodate t~o erescentic bundles of
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1~30765
light fibers for illumination. The grouping of the light fibers
in this fashion is to avoid the penumbra typically present
in the center of the visual field.
Examination of the knee joint, or other joints,
imposes certain restrictions on procedures not normally en-
countered with other endoscopic examinations. For example,
a persistent problem in arthroscopy has been maintaining ade-
quate sterility. A circular cross-section is appropriate for
introduction into the orifices of the genitourinary and gastro-
intestinal tracts or for puncturing the abdominal wall, but
the introduction of conventional round arthroscopes to the
knee joint tends to be traumatic because of the limited spacing
between bones. Conventional arthroscopes of small cross-section
are susceptible of breakage if the knee is fle~ed or if too
much force is applied in efforts to distract the joint using
the arthroscope as a lever or fulcrum. In the past, less
delicate arthroscopes have necessarily been constructed within
sheaths of greater diameter.
Summary of the Invention
The arthroscope of this invention departs substan-
tially from the structural concepts traditional to endoscopes.
The instrument providcs the necessary components for examination
(lens system, light system and usually an irrigation system)
within a sheath housing having a cross-sectional configuration
(taken normal the major axis of the arthroscope) which is
neither circular nor oval, but is shaped as either a parallelogram
or a modified parallelogram with a pair of approximately
parallel longer sides and a pair of shorter sides which may
also, but need not be parallel. The aforedescribed cross-
sectional configuration is perceived by viewing the arthroscope
from its distal end. Of substantial importance is that the
spacing between the longer sides (referred to as the "thickness"
1~30765
of the instrumcnt) be as small as possible, haVi]lg d~lC rcgard
to the space requirements of tllC components ~ hin tl~c sheatl10
In a dia~nostic arthroscope, the component of lar~cst diamcter
is usually the lens systemO Tlle cross-sectional spacing bctl~een
the longest sides of the sheath need tllen be just sufficient
to accommodate tllis component~ Operating arthroscopes sometimes
require larger sheat}ls to accommodate an instrument channel
of greater diameter than t?le lens systemO
Tlle longer sides, l~hile ~enerally parallcl or approxi-
mately parallel, are desirably arcuate ~ith a radius of curva-
ture selected to appro~imately match the boncs of t]le jo;nt
undergoing examinationO In most instances, wllen the longer
sides are arcuate, one side l~all is concave and the other is
convex, altllough it is possible for those side ~alls to be
either mutually concave or convex~ The rac];us of cllrvature
selected will necessarily vary accorcling to tlle corlstl-llction
of the joint of interest~ size of the in-liviclual p~ticnt,
and other f~ctors~ In pr~ctice, ho~ever~ a raclius of clllvature
between about t~o and ~l~ollt tllrce ccntimeters is ~cllcrally
ao appropriate Eor large jo:i.nts stlcl~ ~S tllc kllcec, hil- all(l slloulclcr
joints O A raclials of .Ibollt 2~1/2 ccnt imcters is I;l cscllt:ly
regarded as ideal Cor an instr~ cllt ill~ctlclc(l ~or ~cner~l
purpose applicationsO
~ ltllougll the inst~ mcllts of tl~is invclltion a-re
purposely constructed as tllin as possible, tlle spacing between
tlle short sides of the cross section, (rcfcrrcd to as the
"~idth" of the instrument) may ~e relatively largeO That is,
consiclerable free~om of ~iiclth is perlnissible to accommodate
a number of structllral featurcs not available ~ith conventional
3~ arthroscopes~ By ~ay of illustrationt the ~iclth of t]le instru
ment may be enlarged to accommodate adclitional optic fibcrs,
if gleater brilliallce at the opercltional site is clcsiredO
~lis feature has al~plicatio]l in instrulncnts a~apte(] for p]~oto-
graplly or to incorporate tcac]~ing attacllmellts, for e~mple~
~or most applications, a~equate lighting is proviclc~ hcn
the cross-sectional area of the optic fibers in the sheath
approximately e~uals the cross-sectional area o~ tlle objective
lens. Freedom of width also permits adaption of the distal
end of the arthroscope as a retractor to move the synovium
or the fat pad asideO ~loreover, tlle instrulnellt cl-anllel may
be shaped to pass relatively ~ide instrull-ents, thercby o~vi-
~o ating one of the limitations lleretorore imposcd on the clcsignof surgical instruments used ~it]l arthroscol~esO
One of the inllerent dif~iculties of mastering arthro-
scopic techniques ll<as ~een the lac~ of ~Icytll plccel~tion provided
by conventional arthroscopes. The incrcased ~idtll l-ermitted
by the present invelltion o~fers t~o means for iml)ro~;nS on
this situatiollO First, deptll percel~tion an~l persl-ective at
the operative site is cnh~nccd by increasillg tl~c latcral spacillg
of tlle o~jective lens from tlle (listill tCl`min.ltiOIl Or tl~e ;n-
strument cllallnel. Tlle sur~eoll ~hus ol~crv~s tl-e ;nstrllmellt
ao approaclling tlle operative site at ~ln Inl~le rllller tl~ln dilectly
in his line o~ si~ht~ Secolld, it is ~ ill col~teml~latioll to
mount a secolld lens sys~cll~ tlle sl~c;ltll, thel~c~y l)ro-
viding true billocular ~isionO lit11er or ~o~ll of these e~pedi-
Cllts l~i11 Cllall1e Illally lmOl`C S~ 'COI~S ~0 l~c(ollle s~il]Cul at
arthroscopic sur~ery, and sl)ollld also perlnit tl~e ~e~e]opment
of more intricate ~i~gnostic and sulgic~l proce(lures.
Of p~ramoullt importal~ce, the l'tllinlless" of the
artl~roscopes of this invention permits more thorough e~amina-
tion of joints tiith greater accur~cyO Tlle potential for false
negati~e readi~?gs is greatly rcducedO (A "ncgati~e" rcading
mea]ls that nothin~ l~rong is o~ser~ed,) l~hen the arcuate shape
hcrci~lbefore dcscri~cd is incorl)or.lte(l, l~otll ~iagnostic and
1~30765
surgical procedures are further facilitated. The claimed
arthroscopes often can probe to the interior of a joint without
mechanically distracting the joint as in current practice.
The aforedescribed advantages are achieved with an
attendant reduction of trauma to the patient. First, the
soft tissues which must be penetrated to gain access to the
joint space suffer markedly reduced trauma through use of this
invention. Of even greater significance, from the standpoint
of present expreience in the art, the present invention causes
less trauma to the cartilage surface of the joint. In those
instances when the tip of the arthroscope is used as a fulcrum,
e.g., to pry open the back of a knee joint, the forces are
spread over a larger surface area, thereby avoiding damage
both to the cartilage and the instrument. The sheath of the
claimed arthroscopes may be thicker than is now conventional.
Moreover, it is practical to contour and polish the sheath
exterior to avoid laceration of the cartilage surfaces.
_ ief Descriptionof the Drawings
In the drawings, which illustrate what is presently
regarded as the best mode for carrying out the invention:
FIG. 1 is a typical operating arthroscope of this
invention viewed from its distal end and showing the arrangement
of its components;
FIG. 2 is a similar view of a typical diagnostic
arthroscope of this invention;
FIG. 3 is a similar view of the arthroscope of FIG.
1 together with a series of prior art instruments drawn to
the same scale;
FIGS. 4 through 6 illustrate various joints with
an arthroscope of this invention in place; and
FIG. 7 is a binocular version of an operating arthro-
scope of this invention viewed from its distal end.
Description of the Illustrated Embodiments
The operating arthroscope illustrated by FIG. 1
1~307~;5
compriscs a l~ns s~stcm, thc ob~cctivc lens 11 of ~hicll isvisible rrom the distal end of t]le instrumcnt; an irrigation
system, inclucling the conduit 12; and an instrument channel
13; arrangcd ~ithin a rigid sheatll 14~ Thc intcrstitial sp~ces
bet~een the components ll, 12 and 13 and ~it]lin the sheath
14 are packed with light-transmitting optic fibers lSo
The artllroscope of FIGo 1 is constructed in generally
conventional fashioll except for the cross-sectional shapc of
the sheath 14 and the alrangcme]lt of tlle componcnts 11, 12,
/o 13 and 15 houscd within the she~t}l 14. As viewed from its
distal end, the cross-section of thc arthroscope may be con-
sidered as llaving a minor axi.s, rcl~resented by line 20, which
intersects i.t.s geomctric ccntcr 21; and a major axis, repre-
sented by the line 22~ normal thc minor axis 21 at the center
21 The distal en(ls of instrumcllts ~itll regular cross-scctions
will be ~i.sected into ~o congrucllt parts by tlle minor axis
20. as shownO
Thc slleatll 14 is o~ rig;(l, c.g., stainlcss stccl,
constructlon, alld inclllclcs tl~o rc11t:ivcly l03lg s;~lc l~alls 31,
ao 32 and two relativcly sl~ort sidc ~alls 33, 3~. 'I'hc sidc ~alls
31, 32 ~ ich intersect t.l-c m.inor a~is 20 arc ap~ ox;lllcltely
~ parallel Iclcal:Ly, tllcsc si.dc ~lls 31., 32 ;Irc ar~ tc~ .lS
S)IO~n, to apl)rox:illl;ltcly m.lt~.ll tl~c ~lrracc contours of tllc bones
in a joi.ntO In the illllstl~ltc(l illSt.;lllCC, tllC raclills of cllrva-
ture R is ~ppro~ ately 2.5 cclltilllctcrs, sidc ~all 31 is concave
and side ~all 32 is convc~. T]lc short sidc ~.alls 33, 34 may
also ~e apl~ro~imately parallel, as sho~ , and are ideally
as short as possible; usually just long CnOU~ll to provide the
minilllum spacing rc(luircd bet~een tlle side ~alls 31 and 32 to
~0 contain tl-c largest systcm housecl in the sheath 14 Ctlle instru-
me3lt cllallllcl 13,~ FIGo 1; or tl~e lense systeln 41~ I IG~ 2~
The ~idtll (that is, thc spaci3lg of tllc si~c ~alls
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33 and 34), of tlle instr~)c]lt is sc1ccted to ]~rovi(~e ade(luate
cross-sectional area or the irrigation systcm C~ater channels
12, FIG~ 1 and 42~ ~IGo 2) dcsire~; the lig}~ting s~stcm ~optica1
fibers 15, FIG~ 1 and 45, ~IGo 2); and any otl-er systems w}lich
may be inc1uded l~rithin the slleath~
` For applications requiring greater strength, the
corners 50 connecting side ~alls, e~g~, 32 and 33, may be
structurally reinforccd~ e~g., by thickening the sheath as
sho~rn 51~ The lenses 11, 41 are shol~rn contained l~ithin rigid
~o tubes 50~ e~g " of structura1 ~lastic or meta10 The various
chanJIels 12, 13, 42 are ty~ica11y defined ~y similar rigid
tubes or conduit 51~
I,X~ll'LE I
The ol)erating artllroscope illllstrated by Fl~. 1 may
be constructed ~itllin a s]leath 1~ mcasuri]lg ~l~out 3-1/2 by
about 7 mi11imeters in cross section to hollse a lens s!~stem
witll a 2,5 mm objective lense 11, a 3 m]n instrulnellt c1~al1ne1
13, a gellerous ~ater cha]lllel 12, all(l a]lll)le ol-tieal il-crs 15.
~X~II'J.l, II
ao The dia~]lostic instl~tlllent S]~O~ y ll~,. 2 lila)~ l)c
constructed ~rithi]l a slleatl~ ~ me.lsllrinl~ .al)l)ro~ l.ltely 2-l/2
by about 4 millillletersO 'I'lle tcns s~";tCII) in SIICII a]l i])stlnllllCllt
could have an objective ]ens ~ll as 1a~ C ;IS al-ollt 2.2 mm.
}'XA~ll'l,l I r I
,_ . _ , . . . _
I~IG. 3 com1~ares the rclative cross-scctiol1s of an
instrument 60 constructcd as shol~rn in l~ . 1 an(l dcscribed
in EX~lPLI, I ~itll a series 61, 62, 63 and 64 of conventiona1
instruments in cu`rrent use~ By l~ay of comparison, tlle cur-
rently used instrlJmcnt 61 (a l~'o1 ol~crating arthroscope) contains
~0 a 2~5 mm o~jcctive lens 71~ a 3 mm instrumcnt channe1
72 and a l~air o~ irrigation crlannels 73 ~itllin a circular
c~rlin~lrical sllcatll 7~ l)ac~ied ~ith sufficiellt optic i~er 75
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1130765
to providc a(lc(lu;lte illumirlltionO Ihc shcath 74 is 6c5 mm
in diameterQ Tl~e thickncss of thc instrumcnt of r;~A~II'LE I
is only slightly over half (about 54%) the diametcr of tllc
comparable IYolf instrument, ancl provides for better irrigation
at the operative site, ~he cross-scctional area of the in-
strument of EXA~lP~E I is also significantly Cmore tllan ~0~
smaller, thereby requiring a smaller puncture wound for in-
sertion
Tlle other instruments 62, 63, 64 illustrated by
/O FIG~ 3 have dlameters of 5, 2,5 and 2 2 mil]imeters, rcspec-
tively, but include neither instrllment nor irrigation channels~
T]icse instrllrnents include only lenses alld o~tical fiber lightillg
systems, and are useful for diagnostic ~plllications onlyO
~ IGSo 4~ 5 alld 6 illustrate tlle l~laccmellt of an
art]~roscope 60, constructcd as taug}lt by ~ample I, ~rithin
a ~lee jOillt, shoulder joint and hip joint, rcs~cctivclyO
The jOillts are shown in connection l~ith a rcfcrcnce circle
80~ Typical mature joints from tllc s~ e malc individual arc
illustratcd compclred to a refcrcncc circlc \~i th a l`~ldiUs of
aO approximately 2-1/2 CentilllCtCrSo 0f CoUrSC!, thc jOilltS o
various indivi(lllals (lifcr sOIllC~i]);lt ;11 si~e al~l confi~ tion.
NeVertlleleSs, clS may l~e scen froln ~llc ,lr;~ s, a sillgle ;Irthro-
scol~e oE stall(l<lrdi~cd dimens;oll Call lle used in all of thc
major jOillts of khe majority of tl~c l~ulllall l~ol~ulatioll.
lYitllin tolerable limits, the sockcts defincd ~y the
femur 81 and tibia 82 of tlle ~nee; thc scapull 83 and hu]nerus 84
of the slloulder; alld the femur 85, ilium 86 and pubis 87 of
the hip are generally similar in configuration in a given
individualO Accordingly, rclati~rely fe~ art]lroscopic instru
3~ ments constructed in accordaT-ce witl~ this in~tention are sufficicnt
or a coml)lete diagrlostic antl treatmcnt service of tl~cse jointsO
~ ltllougll tllis disclosure has becll dircctcd slecifi-
cally to arthroscol~cs an~ artlroscol~y, witll spcciic rcfercnce
1~30765
to certain illustrated embodiments, it is not intended to
thereby limit the scope of the appended claims. It is within
contemplation that the improvements disclosed and claimed
herein may be adapted to endoscopes of various types. It is
also contemplated that the teachings of this disclosure will
lead directly to the development of practical instruments
for the improved examination of smaller joints, such as those
of the hands or feet. In such instruments, certain design
changes, such as the desired radii of curvature for the arcuate
side walls of the sheath, are expected. It is also within
contemplation that the lens system be adapted to provide a
line of sight divergent from the central longitudinal axis
of the sheath. An arthroscope in a sheath shaped as in FIGS.
1 and 2, for example, may be provided with a lens system
presenting a line of sight canted about 20 toward the concave
surface.
The binocular version illustrated by FIG. 7 includes
a pair 91, 92 of lens systems.
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