US3915169A

US3915169A - Surgical knife having malleable shank

Info

Publication number: US3915169A
Application number: US523693A
Authority: US
Inventors: George Mcguire
Original assignee: Individual
Current assignee: Individual
Priority date: 1974-11-14
Filing date: 1974-11-14
Publication date: 1975-10-28
Anticipated expiration: 1992-10-28

Abstract

A surgical knife for removing meniscus from human knee joints or the like and adjacent the concave surfaces of the tibia, for example. The knife has a malleable shank portion which can be shaped by the surgeon as surgery progresses so that the blade at the end of the shank can be directed accurately in the desired path of the incision without damaging the articular cartilage, veins, nerves or arteries. The surgical knife also includes a hinge in the shank portion which permits the sharp blade to be turned in the desired location within the incision, and this actuation is accomplished by a mechanism in the handle of the knife and under full and accurate control of the surgeon.

Description

[ Oct. 28, 1975 1 SURGICAL KNIFE HAVING MALLEABLE SHANK [76] Inventor: George McGuire, Rte. 3, Orange Lane, DePere, Wis. 54115 22 Filed: Nov. 14, 1974 211 Appl. No.: 523,693

[52] US. Cl. 128/305; 30/321; 30/356 [51] Int. Cl. A61B 17/32 [58] Field of Search 128/305; 30/320, 321, 356

- [56] References Cited UNITED STATES PATENTS 2,029,495 2/1936 Lowe 128/305 3,221,744 12/1965 Stryker 128/305 3,252,210 5/1966 Bowden 29/213 E UX 3,832,771 9/1974 Morgan 30/320 X FOREIGN PATENTS OR APPLICATIONS 663,074 7/1938 Germany 128/305 373,517 1/1964 Switzerland 128/305 OTHER PUBLICATIONS Leggiadro, A Flexible Meniscotomy Knife, IN Jour.

of Bone and Joint Surgery, 40A 933-934, 1958.

Primary ExaminerChanning L. Pace Attorney, Agent, or Firm.lames E. Nilles [57] ABSTRACT A surgical knife for removing meniscus from human knee joints or the like and adjacent the concave surfaces of the tibia, for example. The knife has a malleable shank portion which can be shaped by the surgeon as surgery progresses so that the blade at the end of the shank can be directed accurately in the desired path of the incision without damaging the articular cartilage, veins, nerves or arteries. The surgical knife also includes a hinge in the shank portion which permits the sharp blade to be turned in the desired location within the incision, and this actuation is accomplished by a mechanism in the handle of the knife and under full and accurate control of the surgeon.

14 Claims, 13 Drawing Figures US. Patent Oct. 28, 1975 Sheet 1 of 3 US. Patent Oct. 28, 1975 Sheet2of3 3,915,169

US. Patent Oct. 28, 1975' Sheet3of3 3,915,169

\E a X FIG. 9 57 //AC 12 m MC 33 Ac BACKGROUND OF THE INVENTION The present invention pertains to surgical knives of the type, for example, for the removal of the meniscus SUMMARY OF THE INVENTION The present invention provides a surgical knive having a malleable shank which may be shaped by the surcartilage, commonly'referred'to as meniscus in the knee joint in case of damage or disease of the structure,

such as the torn cartilage? of the athlete. This surgical procedure is usually done from the front of the knee through a relatively small incision, the size of the incision being limited in its extent by the adjacent supporting ligaments which may not be cut. As a result, it is possible for the surgeon to see only the front portion of the meniscus cartilage and he must remove the back portion as a blind procedure. A surgical knife must be passed into the back of the knee beyond the vision of the surgeon and the entire meniscus cartilage excised.

In the event the knife is passed too far forwardly, a portion of the meniscus cartilage remains and that may require a second operation for its removal. On the other hand, if the knife passes too far to the back of the knee, the main vessels to the lower leg may be severed and if not repaired, the patient may lose his foot and lower leg. In addition to the above problems, this surgical procedure must be accomplished without in any way scratching the articular cartilage which covers the femur and the tibia and which is so soft that it may be marred by a fingernail, it cannot repair itself, and the fissure may initiate an ultimate breakdown of the entire surface. This is known as traumatic arthritis.

The above surgical procedure is further complicated by the fact that when the knife is near the termination of the excision at the back part of the meniscus, it should then be turned towards the front of the knee so as to sever that part of the meniscus located and attached at the rear of the knee, but this is not possible with any prior art knives of which I am aware. One conventional means for severing this meniscus cartilage at the back part of the knee is to make another small incision through the back of the knee joint, but this is undesirable and increases the amount of permanent damage to the ligaments, increases the patients pain and lengthens the time of recovery.

Prior art knives of the general type to which the present invention relates are shown in the U.S. Pat. No. 2,029,495 to Lowe, issued Feb. 5, 1936 and the U.S. Pat. No. 3,221,744 to Stryker of Dec. 7, 1965. Both of these knives utilized a rigid shank which was permanently curved at its outer end in an attempt to have the blade follow the desired path of incision around the convex portions of the knee joint. Knee joints of various people are of different sizes, for example, the joint of a man presents an arcuate path of much greater radius than the joint of a child. As a result these rigid construction prior art knives would either dig into the bone and articular cartilage of the joint or in some cases would damage the vessels and nerves at the rear region of the knee joint.

Furthermore, these knivesmust be razor-sharp for every operation because the meniscus cartilage, due to its micro-structure, cuts with ease with a sharp edge, but will not cut at all if the instrument is somewhat dull. Consequently, it is desirable in view of the limited use and cost considerations of these knives that the knife be of the disposable type, at least in part.

geon as the incision process progresses so that the cut ting edge of the blade. is properly directed along its intended path of incision without damage to adjacent parts-The knife provided by the present'invention permits the surgeon to have accurate control of the cutting edge of the blade even though it is located at a remote location in the knee joint or the like and out of vision of the surgeon; Another aspect of the invention relates to a surgical knife of the above type which has a hinged or articulated blade and which is under positive and accurate control of the surgeon even though the blade may be located remotely within the incision.

The knife provided by the present invention has a disposable portion including a malleable shank formed of low density polyethylene which can be formed into various shapes without breaking or returning to its original shape The blade and the means for actuating the hinged blade are imbedded by being molded in the polyethylene shank. The assembled shank thereby forms a disposable portion of the knife and insures that a sharp blade is provided for each operation at an en- .conomical cost. Forwardly extending probes are integrally formed with the shank portion and of polyethylene so as to shield the knife and aid it in properly following its intended path of incision. The polyethylene portion of the knife is soft and of low density and will not scratch or damage the parts of the body adjacent the incision. Furthermore, the polyethylene will not v ent invention will appear hereinafter as this disclosure progresses, reference being had to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is an elevational view of a knife made in accordance with the present invention, certain parts being shown in section, the sectional portion bein taken generally along the line 1-1 in FIG. 2;

FIG. 2 is a view of the knife shown in FIG. 1 and taken generally along the line 2-2 in FIG. 1;

FIG. 3 is a view of the core, blade, and tensioning means of the knife shown in FIGS. 1 and 2;

FIG. 4 is a view of the core, blade, and tensioning means and taken generally along the line 4-4 in FIG.

FIG. 5 is a view similar to a portion shown in FIG. 2, but showing the blade when the tensioning means has caused it to swing to a position approximately from FIG. 7 is an enlarged, fragmentary, perspective view of the blade and of the knife shown in FIGS. 1, 2 and FIG. 8 is a perspective, exploded view of the knife made in accordance with the present invention;

FIG. 9 is an elevational view in section of a human knee and with the knee bent at an angle of about 90;

FIG. 10 is a plan view of the tibia shown in FIG. 9, the view being taken generally along the line 10l0 in FIG. 9;

FIGS. 11 and 12 are views similar to FIG. 10 but showing the knife of the present invention in various positions while the incision is being made;

FIG. 13 is a view similar to FIG. 12 showing the position of the knife when its incision is completed and when the blade has been flexed to sever the meniscus.

DESCRIPTION OF A PREFERRED EMBODIMENT A knife made in accordance with the present invention is shown in FIGS. 1-8 inclusive and includes a handle portion 1 having a trigger 2 shiftably mounted thereon as being pivoted on the shaft 3. A thumb screw 4 extends through an arcuate slot 5 in the handle and is threadably engaged in the tapped hole 6 of the trigger. A hole 7 receives a tension member, such as a flexible wire 8 which is held captive in its proper position in the trigger by means of the thumb screw 4.

The knife also includes a shank 12 which is molded from malleable material, preferably soft, low density polyethylene. The shank 12 has a metal core 14 molded and extending therein and this core may be of stainless steel, brass or other metals. Also molded within the shank 12 is the tension means or wire 8. The rear end of the core 14 is inserted in a recess 15 in the handle and the rear end of the shank 12 is inserted in the recess 16 and abuts against the shoulder 17 formed in the handle. The shank is held in place by the wire which is held by the thumb screw and is also held by the clamp action of the two halves of the handle. The shank and its associated parts may thus be removed from the handle when the thumb screw 4 is loosened to free the end of the wire 8. It will be noted that the shank is generally formed with a cross sectional shape of a triangle having round corners.

At the other end of the shank is located the metal blade 20 which has a sharpened front edge 21. The blade 20 is brazed, soldered, welded or otherwise rigidly secured to the metal core 14. This blade is preferably formed of spring steel so that it can flex and thus form a hinge joint in the shank. For this purpose, the shank is formed with a traverse notch 24 adjacent its front end so that it can flex to a desired angle, for example, to the position shown in FIG. 5, when the wire 8 is pulled in the direction of the arrow. The front of the blade and of the shank is also formed with a pair of transversely spaced and substantially parallel .probes 26 and 27 which extend from the end of the knife. These probes are formed integrally with the shank from the said malleable material such as low density polyethylene. It will be noted that the probes are located at each end of the blade so as to shield the latter as the knife is being used. These blunt probes shield the blade and prevent the knife from penetrating outside the joint and also serve to guide the meniscus into the blade, as will appear.

The blade 20 also has a hole 28 therein which receives the hooked end of the wire 8.

The present invention finds particular utility when operating on a knee joint, that is to say, in operating to remove the meniscus cartilage MC which has been damaged in the knee joint and which is located just above the concave surfaces of the tibia. As shown in FIGS. 9 to 13, the human joint of the knee includes the femur 31 and the tibia 32 having

concave surfaces

33 and 34. Both the femur and tibia are covered with articular cartilage AC which can be damaged. FIG. 9 shows the knee joint when viewed from the front and when it is flexed to a bent or angle. FIGS. 10 to 13 inclusive are top views of the tibia. It is at this front side 35 of the tibia that the surgeon makes the

initial incision

36 and 37 and through which incision the surgeon inserts the present knife. At the rear side of the leg, that is at the rear side of the knee joint are located an artery 40, a vein 41, and nerves 42. As shown in these figures, the meniscus cartilage MC has attached ends 47 and 48 located at the front of the knee and also attached ends 50 and 51 located at the rear side of the knee. The front ends of the meniscus cartilage can be readily served by the surgeon and by visual observation simply by inserting a conventional surgical knife through the opening formed by

incision

36 and 37. The meniscus cartilage MC also lies between the tibia and femur, as clearly shown in FIG. 9.

It is a difficult task however to sever the attached ends 50 and 51 which are located to the rear of the knee joint and out of vision of the surgeon and it is to this particular problem that the present invention is directed.

In order to sever the

ends

50 and 51 of the meniscus, the surgeon must insert his knife around the joint and along the track or path indicated generally by the dotted lines 55. This path is located adjacent the articular cartilage which covers the tibia and femur. The articular cartilage is extremely soft and can be marred and damaged by the slightest irritation such as a fingernail. This articular cartilage cannot repair itself and a fissure initially will cause breakdown in the surfaces, resulting in traumatic arthritis. Consequently, it is necessary that the surgeons knife does not damage or in any way abuse the articular cartilage by contact with it in case the blade is directed inwardly too far from its intended path of travel. On the other hand, the blade upon reaching the rear side of the knee, must not move outwardly so as to come in contact with the arteries, veins,

or nerves, by passing too far outwardly from the joint. 1

During the first portion of the knifes travel in the intended path 55, the incision is under the visual observation of the surgeon through the opening formed in the front side of the knee. However, as the knife passes the

ligaments

57 or 58 approximately half-way along the side of the knee, further fisual observation of its course of travel is precluded. Heretofore, the prior art knives used in such an operation would inadvertently either dig inwardly and into the articular cartilage of the joint or would extend outwardly at the rear end of the knee, thereby damaging the arteries, veins, or nerves.

The knives used in such an operation must therefore follow an arc of over and are confined to this path by the ligaments on the outside and the surfaces of the articular cartilage on the tibia and femur. The size of the knee obviously varies from patient to patient. Another problem is the fact that the meniscus cartilage at the rear of the knee must be severed at the proper location, that is to say, if the knife passes prematurely through the meniscus, a portion of the meniscus remains and may require a second operation for its removal. If however the knife passes the meniscus too far to the backside of the knee, the main vessels to the lower leg may be cut.

The knife provided by the present invention overcomes the above mentioned dangers and difficulties and permits the surgeon to shape the malleable shank of the knife as the surgical procedure progresses. In other words, the surgeon may periodically withdraw the shank from the incision which is being made and then bend or shape the malleable shank so as to cause it to conform to the intended path 55 of travel. During the passage of the knife in the joint, the

rounded probes

26 and 27 act to guide the blade end of the knife while the blade acts to sever the meniscus, thus forming the The various stages of such a surgical procedure are shown in FIGS. and 13. When the blade has reached the position shown approximately in FIG. 12, the surgeon begins to pull the trigger 2 to pull the tension means 8 thereby causing the blade to flex or turn, and then when the end of the blade continues to travel and reaches the position shown in FIG. 13, the flexing action of the knife edge has severed the attached ends 50 of the meniscus cartilage.

The surgical knife provided by the present invention permits the surgeon to control the direction of travel of the blade during the entire path of the incision. The knife shank can be readily shaped for any particular size knee thus preventing damage to adjacent parts. The knife will not scratch the articular cartilage and it can be controlled so as to accurately cut the meniscus cartilage along the proper path and at its attached, rear end. The malleable shank can be readily shaped by the surgeon as the surgery progresses but it is rigid enough to enable it to direct sufficient force on the blade to cause the latter to cut the meniscus.

I claim:

1. A surgical knife comprising, a malleable shank having a metal core extending therein, a cutting blade on one end of said core and having a cutting edge adjacent one end of said knife, said knife also having a handle portion at the other end of said shank, said shank being shapable by hand to conform to the desired path of movement of said blade during surgery.

2. The knife set forth in claim 1 including a hinge formed in said shank for swingably mounting said blade.

3. The knife set forth in claim 2 further characterized in that said hinge is formed by a transverse notch in said shank which permits said core to bend.

4. The knife set forth in claim 1 including spaced and substantially parallel probes extending from said one end of said knife and formed integrally with said shank, said probes being located at each end of said blade so as to shield the latter.

5. The knife set forth in claim 1 further characterized in that said shank is molded of low density polyethylene.

6. A surgical knife comprising, a malleable shank formed of malleable material, said shank having a metal core extending therein, a steel blade fixed to one end of said core and having a cutting edge adjacent one end of said knife, a hinge formed in said shank for swingably mounting said blade, tension means connected to said blade and extending along said core for swinging said blade relative to said shank; said core, blade and tension means being encapsulated in said malleable material and being molded therein, said knife also having a handle portion at its other end and connected to the other end of said shank, and means on said handle portion for actuating said tension means to cause said blade to swing on said hinge, said shank being shapable by hand to conform to the desired path of movement of said blade during surgery.

7. The knife set forth in claim 6 further characterized in that said hin'ge is formed by a transverse notch in said shank which permits said core to bend.

8. The knife set forth in claim 6 including spaced and substantially parallel probes extending from said one end of said knife and formed integrally with said shank from said malleable material, said probes being located at each end of said blade so as to shield the latter.

9. The knife set forth in claim 6 further characterized in that said malleable material is low density polyethylene.

10. The knife'set forth in claim 6 further characterized in that said actuating means includes a shiftable trigger carried on said handle portion, said tension means comprises a flexible metal member which is rigidly attached to said trigger.

11. A surgical knife for removing meniscus in a human knee joint or the like, said knife comprising, a malleable shank formed of low density polyethylene, said shank having a metal core extending therein, a steel blade fixed to one end of said core and having a cutting edge adjacent one end of said knife, a transverse notch in said shank which forms a hinge and permits said core to bend for swingably mounting said blade, tension means connected to said blade and extending along said core for swinging said blade relative to said shank; said core, blade and tension means being encapsulated in said malleable material and being molded therein, said knife also having a handle portion at its other end and connected to the other end of said shank, and means on said handle portion for actuating said tension means to cause said blade to swing on said hinge, said shank being shapable by hand to conform to the desired path of movement of said blade during surgery.

12. The knife set forth in claim 11 including spaced and substantially parallel probes extending from said one end of said knife and formed integrally with said shank from polyethylene, said probes being located at each end of said blade so as to shield the latter.

13. The knife set forth in claim 11 further characterized in that said actuating means includes a shiftable trigger carried on said handle portion, said tension means comprises a flexible metal member which is rigidly attached to said trigger.

14. The knife set forth in claim 12 including spaced and substantially parallel probes extending from said one end of said knife and formed integrally with said 4 shank from said malleable material, said probes being located at each end of said blade so as to shield the latter.

Claims

7. The knife set forth in claim 6 further characterized in that said hinge is formed by a transverse notch in said shank which permits said core to bend.

10. The knife set forth in claim 6 further characterized in that said actuating means includes a shiftable trigger carried on said handle portion, said tension means comprises a flexible metal member which is rigidly attached to said trigger.

14. The knife set forth in claim 12 including spaced and substantially parallel probes extending from said one end of said knife and formed integrally with said shank from said malleable material, said probes being located at each end of said blade so as to shield the latter.