RELATED APPLICATIONSThis application is a continuation of application Ser. No. 08/210,653, filed Mar. 10, 1994, now abandoned, which is a continuation of Ser. No. 07/965,069, filed Oct. 22, 1992, now abandoned, which is a continuation of Ser. No. 07/604,094, filed Oct. 29, 1990, now abandoned, which is a continuation of Ser. No. 07/279,978, filed Dec. 5, 1988, now abandoned.
BACKGROUNDMenisci are large comma shaped cartilaginous pads interposed between the large bone ends of the knee joint. At present, the majority of meniscal tears are treated by resection of the meniscus via a formal incision (open method), or by a removal of just the torn portion of the meniscus via an arthroscopic procedure (closed), with the latter being of ever increasing popularity.
It has become apparent that all meniscal tears need not be removed, but rather that they can be repaired and salvaged by suturing. The problem thus far, however, has been that the method of repair by suturing requires that both sides of the meniscus be accessible, thereby necessitating either two surgical incisions and approaches or the use of the arhtroscope in lieu of one of those incisions. The arthroscope is a hollow, slender viewing rod, much like a small telescope, which can be used to view the interior of a joint. The use of an arthroscope requires a very small incision and it is possible to perform some limited types of surgery entirely with the arthroscope alone. However, this has not proven to be useful for meniscal repair.
At the present time, meniscal repair is performed in the following manner. An arthroscope is introduced through a small opening from the front of the knee joint (anteriorly) and the torn meniscus is visualized. A second small opening is also made anteriorly and a feeler device is introduced to probe the tear. These tears all occur toward the back of the knee joint (posteriorly). This is most unfortunate since this is the location of the great blood vessels and nerves of the leg. In order to repair the meniscus, therefore, one must, with significant risk, make an ample incision and surgical approach so as to expose the back of the knee joint in the region of the meniscus to be repaired. But even then there is precious little working room, and since the needles used to sew the meniscus back in place must be quite long, as they can only be passed from front to back as otherwise there would be no reliable way to tie the ends within the joint, they may cause innocent and vital structures to be either penetrated or entrapped and subsequently damaged. Hollow metal guards have been used to help direct the paths of the needles used to limit the possibility of such damage.
Therefore, there is a great need for a means of achieving a meniscal repair wherein the procedure is wholly arthroscopic, can be performed anteriorly alone, and does not require the use of an additional posterior incision.
Rivet-like tabs, sometimes referred to having a penetration head, projecting flexible members and a wide rear portion have been used for attaching carpeting to a main frame of an automobile. Such devices are typically hammered directly through the carpet into a hole pre-formed in the car body. Such devices are relatively large and have no application in a surgical procedure.
SUMMARY OF THE INVENTIONThe present invention comprises a small rivet-like member in the form of a shaft having flexible projection fins extending axially from the shaft, such projections preventing withdrawal of the rivet. A penetration head is located at the front of the shaft, and the rear of the shaft has a widened portion, in the form of a disc and means for removably engaging a driver member.
In use, the driver member is inserted into an opening in the rear end of the shaft and the penetration head of the rivet is then pushed through both sides of the meniscus to be healed, until the two pieces are trapped between the fins surrounding the head and the widened portion at the rear of the shaft. The flexible rearwardly angled projection fins prevent withdrawal of the shaft through the introduction hole. The driver member is then removed from the rear opening. Additional rivets are employed, depending on the size of the tear in the meniscus. The two pieces of meniscus are thus held in place by the rivet. The rivet remains in the body and is totally biodegradable and reabsorbable.
The present invention is safer than prior devices because it does not require a second incision, that incision usually being quite major, and since it can be deployed through the small portal already present to perform the diagnostic portion of the arthroscopy, it is more efficient than prior art. Accordingly, it does not threaten the neurovascular structures which would be interposed between the open incision and the inside of the knee joint. Because of the ability of escape the extra incision, there is decreased chance of infection and decreased tissue damage. Because this device can be utilized without additional surgery, it is more efficient than the prior art. Also, because it is specifically designed to bring meniscal fragments back together, and the prior art simply utilizes sutures, it is also more effective than prior systems.
OBJECTS OF THE PRESENT INVENTIONIt is an object of the present invention to provide for a device for arthroscopic meniscal repair which is safer, not requiring additional operational procedures.
It is another object of the present invention to provide for a device for arthroscopic meniscal repair which is more efficient, being able to be inserted quickly, and with a minimum of trauma.
It is another object of the present invention to provide for a device for arthroscopic meniscal repair which is more effective and simpler to use.
It is another object of the present invention to provide a device which can be used generally to attach soft tissue to bone.
These and other objects of the present invention will he apparent from a review of the following specification and the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGSFIG. 1 is a perspective view of the rivet of the present invention and a partial view of the driver.
FIG. 2 is a perspective view of the human knee joint showing the rivet of the present invention being passed through the meniscus and capsule.
FIG. 3 is a partial sectional side view of the present invention showing the rivet of the present invention in the deployed position.
FIG. 4 is a partial sectional side view of the present invention taken along lines4-4 ofFIG. 2.
FIG. 5 is a perspective view of an alternative embodiment of the present invention.
FIG. 6 is an expanded view of the driver of the alternative embodiment within the rivet.
FIG. 7 is an expanded view of the driver and rivet of the alternative embodiment within the meniscus.
FIG. 8 is a side sectional view of the alternative embodiment of the rivet with the driver removed.
FIG. 9 is a third alternative embodiment, in the form of a screw.
FIG. 10 is a forth alternative embodiment in the form of a screw.
DETAILED DESCRIPTION OF THE PRESENT INVENTIONReferring toFIGS. 1-4, the preferred embodiment of the present invention is shown. Therivet10 consists of atubular shaft12 having a cone shaped penetration head at one end. A series ofaxial projections16 extend from the shaft, spaced apart from one another. Theprojections16 are slightly sloped away from theprojection head14. Theprojections16 extend only about one half the length of theshaft12. A widened portion, in the form of a widecircular disc18, is formed at therear end20 ofshaft12. Thedisc18 is circular in shape and is beveled around itscircumference22.
Therear end20 of theshaft12 has a depression24 in the form of a sphere. The depression24 is designed to engage acomplementary projection32 at the end ofdriver30. Theprojection32 has a slightly smaller diameter than the depression24 in the rear20 of therivet10. Theprojection32 of thedriver30 fits within the depression24 in the same manner that toy pop beads engage one another.
The use of therivet10 in operation is shown inFIGS. 2-4. Therivet10 is attached to thedriver30 by having therivet engaging projection32 of thedriver30 pressed within the depression24 in therivet10. Therivet10 is then pushed through the meniscus M on one side of the tear T and through the other side of the tear T in the meniscus M. The meniscus is compressed between the fine16 surrounding thetip14 and thedisc18, pushing the tear T together. After insertion of therivet10 in the meniscus, thedriver30 is pulled rearward, disengaging theprojection32 from the depression24 in the rear20 of therivet10 due to the fact that theprojections16 prevent the withdrawal of therivet10. As shown inFIG. 3,additional rivets10 may be inserted until the entire tear T is held together.
Therivet10 is made of a soft flexible plastic which is biodegradable and totally absorbable within the body, such as polyglycolic acid or carbon composite, or any similarly biodegradable, bioabsorbable and otherwise biologically safe material. Thedisc18, as shown inFIG. 4, is sufficiently flexible so as to be able to conform to the angle of the meniscus M.
Referring toFIG. 5, an alternative embodiment of the invention is disclosed which is easier to drive through the meniscus. The rivet100 comprises ashaft112 having ahead portion114 in the shape of a truncated cone. A series ofprojections116 extend substantially radially from the from the upper half of theshaft112 and slightly to the rear to prevent withdrawal of the rivet after insertion. The rear120 of the rivet100 has a wideneddisc118. The rivet100 is hollow along its central axis creating apassageway124 through the entire length of the rivet100.
Thedriver130 associated with rivet100 comprises ahandle131 having ashaft132 terminating in asharp tip133. Theforward face135 of thehandle131 at the juncture of theshaft132 and thehandle131 is flat so as to conform to the flat shape of thedisc118, and has a diameter slightly larger than the diameter of thedisc118. The diameter of theshaft132 is slightly smaller than the inside diameter of thepassageway124.
Thetip133 of theshaft132 is tapered so as to have substantially the same angle as the angle of the cone of thehead114, thereby forming a smooth transition from thehead114 to thetip133.
The use of the rivet is best shown by reference toFIGS. 6 and 7. Theshaft132 is passed through thepassageway124 in the rivet100 until the rear120 of thedisc118 abuts theflat face135 of thehandle131. The length of theshaft132 is such that when the rivet100 is seated on theflat face135, thetip133 of theshaft132 is in position to form a smooth transition with thehead114 of the rivet100.
Theshaft132 of thedriver130 with the rivet100 in place is then pushed through the meniscus M until the tear T is compressed. The force on theface135 of thedriver130 causes thedisc118 to deform so as to conform to the surface of the meniscus, as shown inFIGS. 6 and 7. Thebeveled edges122 of thedisc118 and the projectingfins116 prevent dislodging the rivet100 from the meniscus M. Once the rivet100 is in the meniscus M, thedriver130 can easily be withdrawn and another rivet100 placed on the driver and the process repeated.
The dimensions ofrivet10 are as follows: The overall length of therivet10 is approximately 8 mm, theshaft12 of the rivet has an outside diameter of about 2 mm and the outside diameter of the rear disc member is about 2.5 mm.
Theprojection32 of thedriver30 is slightly smaller than approximately 2 mm in diameter so as to fit within in the depression24 in the rear of the rivet of about 2 mm. The length of thehandle30 is about 500 mm.
In the alternative embodiment of the present invention, thepassageway124 of the rivet100 is about 1.25 mm in diameter. Theshaft132 of thedriver130 is slightly smaller than the passageway of the rivet100 and the angle of thetip133 and thehead114 is approximately 30-45 degrees. Thetip133 of the spear extends about 4 mm beyond the truncated end of thehead114.
Referring toFIGS. 9 and 10, alternative embodiments of the present invention are shown, in which a biodegradable screw is used in place of the rivet. Although, screws have been used before for such an application, they have been metal screws that were not biodegradable or absorbable.
InFIG. 9 the device is in the form of ascrew200, havingthreads204 which extend about one half of the length of theshaft102 screw. The tear of the meniscus would be compressed between thehead206 of the screw and thethreads204. Thescrew200 is driven by an allen wrench opening208 in the head of thescrew200.
InFIG. 10, a rivet in the form of asheet metal screw300 is shown. Again the screw is driven by an allen wrench opening302 in thehead304 and the tear in the meniscus compressed between the threads of thescrew300 and thehead304 of thescrew300.
In both instances the screw ofFIGS. 9 and 10 are inserted into the meniscus and then left in place. Due to the biodegradable absorbable nature of the screws, no danger is posed from the screws disengaging from the patient.
While the present inventions have been described in the concept of repairing the meniscus of the patient, it is recognized that the devices may be used in other parts of the body to repair or attach soft tissue, such as that in the shoulder where soft tissue may be desired to be attached to the bone. In such a case, a hole is drilled through the bone and then the rivet, is driven or screwed into the slightly smaller opening in the bone. The tissue is pressed against the bone and the projections or threads hold the rivet in place. The tissue reattaches itself to the bone and the rivet, being biodegradable, dissolves.
It is recognized that these and other embodiments of the invention may be devised without departing from the scope of the present invention.