U.S. patent number 3,750,652 [Application Number 05/121,276] was granted by the patent office on 1973-08-07 for knee retractor.
Invention is credited to John M. Sherwin.
United States Patent |
3,750,652 |
Sherwin |
August 7, 1973 |
KNEE RETRACTOR
Abstract
This disclosure relates to a surgical retractor for use by an
orthopedic surgeon for a controlled distraction of a knee joint
through an anterior incision. This retractor generally consists of
a pair of screw actuated retractor arms, the tips of which are
operatively embedded in the intercondylar region of the patient's
knee.
Inventors: |
Sherwin; John M. (Manchester,
NH) |
Family
ID: |
22395634 |
Appl.
No.: |
05/121,276 |
Filed: |
March 5, 1971 |
Current U.S.
Class: |
606/90; 600/219;
600/217 |
Current CPC
Class: |
A61B
17/025 (20130101); A61B 2017/0268 (20130101) |
Current International
Class: |
A61B
17/02 (20060101); A61b 001/32 () |
Field of
Search: |
;81/72,302
;128/17,18,19,20 ;294/97 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
catalog of the V. Mueller & Co., Chicago, Ill. 1938, p.
67..
|
Primary Examiner: Laudenslager; Lucie H.
Claims
Having thus described my invention, I claim:
1. A surgical retractor for use in knee joint distraction
comprising:
a. a cross-arm member;
b. a pair of non-planar generally bow-shaped retractor arms each
pivotally connected at its upper end thereof to a respective end of
said cross-arm member;
c. the lower end of each retractor arm having an elongated off-set
portion which is angularly outwardly disposed in a laterally
extending plane with respect to the upper end thereof, and
generally parallel to each other, each off-set portion being
juxtaposed the other in the normally closed retractor position;
and
d. actuating means operatively connected to said retractor arms for
opening and closing them.
2. The retractor set forth in claim 1 wherein each said off-set
portion carries adjacent its lower end a sharpened tip extending
outwardly in opposed relation to one another in a direction
substantially colinear with the travel of the retractor arms, as
they are opened, and adapted for insertion into the intercondylar
notch of the femur in the knee joint being distracted.
3. The retractor set forth in claim 2 wherein said actuating means
comprises;
a. screw means operatively carried by said cross-arm;
b. an actuating link supported on the end of said screw means;
and
c. laterally extendable lever arm members pivotally connecting said
actuating link with said retractor arms.
4. The retractor set forth in claim 3 wherein said screw means
comprises;
a. a threaded shaft; and
b. a thrust bearing interposed between the end of said threaded
shaft and the actuating link.
Description
This invention relates to a device useful in orthopaedic surgery,
and more particularly relates to a knee retractor which is employed
by a surgeon in operating on a patient's knee through an anterior
incision, as, for example, to perform a meniscectomy, or for the
posterior view of a knee joint to permit the removal of foreign
bodies, loose bodies, or the posterior horn of the meniscii.
Operating procedures for performing meniscectomy have not changed
in any substantial way for the last 30 years. Current state of the
art techniques for doing this kind of an operation call for an
anterior incision of some 1-1/2 to 2 inches in length, either
anteromedial or anterolateral depending on which side of the knee
joint the surgeon intends to do the surgery on. The incision is
made and the joint is approached in the usual way employing
conventional right-angle retractors to hold the incision open. In
performing a meniscectomy, special surgical scalpels are employed
to detach the anterior horn of the meniscus and these are then
passed around the outer limits of the meniscus detaching it from
its margins to the most posterior attachment possible within the
limitations of the incision. However, once the detaching reaches
approximately ninety degrees around to the side of the joint, the
surgeon is frustrated by the extremely tight fibular or tibial
collateral ligaments which hold the knee joint closed and laterally
intact. Thus, there is no view of the posterior horn of the
meniscus, nor is there any way of viewing any loose bodies in the
posterior aspect of the joint short of a second posterior incision.
Obviously, in order to complete the surgical excision, the surgeon
must see what he is doing, since manipulating the scalpel blindly,
that is, without a direct visual view, could easily sever any one
of several ligaments which hold the knee joint intact, and thus
cause severe and permanent patient damage. Accordingly, this
problem of non-visibility is currently solved by one of two major
methods. First, with the help of one or two surgical assistants,
the femur and tibia portions adjacent the knee are manually grasped
and forcibly levered so as to cause the knee joint to open
laterally, thus providing a direct view of the posterior aspect.
This standard surgical procedure is more fully described in
Campbell's Operative Orthopaedics, 4th edition, page 798. This is a
less than desirable method of operating because of the substantial
stress imposed on the convex apex of the levered knee joint. A
second method used to approach the posterior aspect of the meniscus
is to make a second posterolateral or posteromedial incision. This,
of course, prolongs the operation and also complicates it in terms
of wound healing. Further, in many cases, it produces a painful
posterior incision.
The present invention overcomes these prior art disadvantages by
providing a generally bow shaped knee retractor having a pair of
screw activated articulating arms in which the terminal tip
portions open and close. In the closed position these tips are
inserted into the inter-condylar region between the femur and
tibia, and then opened so as to forcibly effect a distraction of
about one-eighth inch in the knee joint without imposing any
harmful stresses thereon. This distraction thus provides an
approach to the posterior aspect of the knee joint from an anterior
incision.
It is, accordingly, among the various objects of this invention to
provide a surgical instrument for distracting the knee joint during
a knee operation without imposing harmful stresses on the
joint.
It is further an object of this invention to provide a surgical
instrument for distracting a knee joint to avoid iatrogenic damage
to the joint as a result of blind posterior meniscotom
manipulation.
Another object of this invention is to provide a surgical knee
retractor instrument for use through an anterior incision thereby
providing a direct view of the posterior aspect of the patient's
knee joint.
An important feature of this knee retractor is that this single
instrument may be employed interchangeably for either an
antero-medial or anterolateral approach to either a right knee or a
left knee, thus doing away with the necessity of so-called "mirror
image" instruments.
A further feature of this invention is that the angular disposition
of the retractor arms serves to hold the incision open, thus doing
away with the necessity of using a skin, a subcutaneous tissue, and
joint capsule right angle retractors, while at the same time
performing its primary function of joint distraction.
These and other objects and features will become apparent from the
following description when taken in conjunction with the
accompanying drawings and photographs in which like numerals refer
to like parts in the different views.
FIG. 1 illustrates a front elevation view of the surgical knee
retractor;
FIG. 2 illustrates a side elevation view of the knee retractor in
FIG. 1;
FIG. 3 illustrates a top plan view of FIG. 1;
FIG. 4 illustrates a bottom plan view of FIG. 1;
FIG. 5 illustrates the knee retractor positioned in the
inter-condylar region of a distracted knee joint;
FIG. 6 illustrates a cross-sectioned view of the thrust bearing
joint taken on line 6--6 of FIG. 1; and
FIG. 7 illustrates a top plan view taken on line 7--7 of FIG.
1.
Referring now with greater particularity to the drawings, there is
shown in FIGS. 1 - 4 the knee retractor 10 fabricated of surgical
stainless steel or other suitable material. This knee retractor is
generally comprised of two non-planar generally bowered (within
included angle A of FIG. 2) retractors arms 11, 12 which are
adapted to pivotally open and close by the coaction of a thumbscrew
17 and lever arms 18, 19 and 20, 21, operatively connected
therewith. The non-planar bowed shape of the retractor arms is
characterized by the lower end portions of arms 11, 12 being
outwardly, i.e., angularly, disposed with respect to the upper ends
thereof as shown by angle A in FIG. 2. Each of these lower end
portions of arms 11, 12 is also inwardly bent or off-set toward
each other, as seen in FIG. 1, so as to be substantially justaposed
when the retractor is in a normally closed position. As shown in
FIGS. 1, 2 and 3 each of the retractor arms 11, 12 is pivotally
connected at its upper end thereof by a pin 16 into its respective
recess 13, 14 of cross-arm 15. Centrally located through cross-arm
15 between pins 16 is threaded aperture 22 adapted to receive
threaded shaft 23 carrying a knurled handle 24 at its upper end,
and being rotatably connected at its lower end to an actuating link
25 by a thrust bearing 26.
The thrust bearing connection between threaded shaft 23 and
actuating link 25 is shown in enlarged cross-sectional detail in
FIG. 6. As shown in this illustration, the end portion of threaded
shaft 23 is turned to a stem portion 27 of reduced diameter so as
to slip-fit through aperture 28 in link 25. The bottom end of stem
portion 27 is internally threaded to receive a typical machine
screw 29 which has a screw head 30 broad enough to extend beyond
the diameter of steam portion 27 and thus come into bearing
relation against the lower surface of stem 27 and preferably just
barely spaced apart from the surface of actuating link 25.
Interposed between the upper surface of actuating link 25 and the
shoulder or end portion of threaded shaft 23 is a thrust bearing 26
comprised of two annular retaining members 31, 32 separated by an
annular disc 45 of Delvin or other suitable plastic material having
the qualities of lubricity and non-wearing. In view of the
structural details of this connection, it can be seen that as
threaded shaft 23 is rotated, screw 29 will rotate with it and any
relative movement between parts will occur at the thrust bearing
and between screw head 30 and actuating link 25.
Actuating link 25 has two recesses at each end thereof 33, 34 and
35, 36 for receiving respectively an end portion of each lever arm
37, 38 and 39, 40 which is pivotally fastened thereto by pins 41.
The other end portions of each lever arm are pivotally connected to
their respective retractor arm by pins 42.
The lower end portions of retractor arms 11, 12 each have generally
beveled surface 43 which carries an outwardly disposed sharpened
tip portion 44 of 3 mm in length.
It should now be apparent in light of the foregoing description
that as thumb-screw 17 is rotated in a clockwise direction,
threaded shaft 23 will advance downwardly through cross-arm 15
exerting a laterally extending force component through each lever
arm 37, 38 and 39, 40 to the retractor arms 11, 12 thus causing
them to open.
In surgical use, the patient's leg is preferably supported so that
the knee is naturally bent at an angular disposition of
approximately 45.degree. or more. A conventional incision and
approach is made through the subcutaneous tissues and capsule of
the knee joint through the synoyium to the joint itself. As shown
in FIG. 5, the knee retractor is oriented so that the interior
angle A of FIG. 2 faces downward. The tips 44 at the end of the
retractor arms are placed deep in the intercondylar notch of the
femur 50 well away from any weight bearing surface superiorly and
inferiorly into the anterior aspect of the anterior cruciate
ligament 49 also a non-weight bearing portion of the tibia 51. Once
the retractor tips are in position, thumb-screw 17 may be rotated
thus spreading retractor arms 11, 12 apart with a force sufficient
to overcome the ligament forces tending to keep the knee joint in
its naturally approximated position, i.e., the tibia against the
femur. The tips 44 are designed with a generally sharpened conical
shape for the obvious reason of preventing any slippage. Though, as
can be seen from FIG. 6, these tips presumably indent the cartilage
in their respective areas of contact, they do not disrupt in any
way the weight bearing surface gliding features of the knee joint.
Distraction is carried out as far as possible until there is
sufficient resistance so that the retractor will open no further.
This will usually open the side of the knee joint being operated on
approximately one-eighth of an inch. This, of course, depends on
the health of the knee's collateral ligaments and in the usual
young knee, about one-eighth of an inch is the maximum opening.
This small distraction, however, is the crucial contribution of
this instrument. However, in a knee where collateral ligaments have
been destroyed, as, for example, in the injury O'Donahue's Triad,
where the medial collateral ligament, medial meniscus, and the
anterior cruciate ligament have all been torn, distraction of the
knee is possible up to one-half inch, and beyond that, distraction
is not necessary.
Use of the herein disclosed knee retractor results in an average
reduction in operating time of 25 percent since no extraordinary
surgical maneuvers are necessary to achieve opening of the
posterior aspect of the joint in order to assure removal of the
entire meniscus. A further desirable feature of this knee
retractor, particularly from a cosmetic point of view, is that its
use allows a minimal skin incision anteriorly only, and with the
reduced morbidity in wound healing, recovery time is substantially
reduced with limited ambulation occurring in normal cases within 3
days.
Thus, it should now be apparent in light of the foregoing
disclosure that as a result of the generally bowed shape, seen in
FIG. 2, coupled with the retractor arm off-set portions, shown in
FIG. 1, I have provided a useful surgical instrument which provides
means for a controlled knee joint distraction heretofore
unavailable.
The particular embodiment of the invention herein chosen for
illustration and description is exemplary only and it will,
accordingly, be understood that various changes in the details,
materials and arrangement of parts herein described and illustrated
may be made by those skilled in the art within the principles and
scope of the invention as expressed in the appended claims.
* * * * *