Method of securing a graft using a graft fixation device

Information

  • Patent Grant
  • 6436110
  • Patent Number
    6,436,110
  • Date Filed
    Monday, February 26, 2001
    23 years ago
  • Date Issued
    Tuesday, August 20, 2002
    22 years ago
Abstract
A graft fixation device combination. The device is useful for affixing a tissue graft to a bone or other body surface. The combination has a fixation device having two implantation members connected by a connecting member. The connecting member has at least one lateral wing member extending therefrom. The implantation members have longitudinal passageways therethrough. The combination also has an insertion member in engagement with the distal end of each implantation member.
Description




TECHNICAL FIELD




The field of art to which this invention relates is surgical fastening devices, in particular, surgical fastening devices for fixating tissue grafts to bone.




BACKGROUND OF THE INVENTION




The medical technology associated with tissue engineering has advanced at a rapid pace. In particular, it is now known to harvest cells from the human body, for example, chondrocytes and fibrochrondrocytes from the knee joint. These autologous cells are then cultured in a laboratory environment on a bioabsorbable matrix. The matrix will typically have a shape substantially similar to the tissue section which needs to be replaced. After a sufficient period of time in an appropriate culture medium at the proper environmental conditions, the harvested cells will grow on the matrix to form an implantable section of tissue having substantially the same physical configuration as the section of tissue which needs to be replaced in the patient. Such a tissue-engineered construct, consisting of cells on the matrix (or, alternatively, consisting of a matrix alone without cells), is then affixed to the bone site using conventionally known surgical fasteners including sutures, periosteal coverings, or fibrin glue.




The advantages of tissue engineering are many, not the least of which is, for example, that it is now possible to replace cartilage with living cartilage tissue. In addition, the likelihood of rejection of the tissue implant is minimized since the cartilage tissue which has been grown in-vitro is identical to the autologous cartilage of the patient.




Although existing matrix fixation devices are adequate for their intended use, there are also some disadvantages attendant with their use. First of all these fixation devices are generic in the sense that they are not specifically designed for matrix fixation to bone or soft tissue, but can be used for a variety of surgical procedures. Other disadvantages include the difficulty in using many of these devices in a minimally invasive arthroscopic procedure. Additional disadvantages include the difficulty and surgical challenge of harvesting a piece of periosteum for use as a periosteal flap, the significant patient morbidity associated with such harvesting, and the difficulty in suturing such a thin, compliant material to surrounding tissue.




Accordingly, there is a need in this art for novel fixation devices that will effectively affix a matrix of tissue-engineered tissue to a bone or other anchoring site so that the tissue may continue to grow and regenerate in the patient's body.




DISCLOSURE OF THE INVENTION




Therefore, it is an object of the present invention to provide a fixation device that effectively fixates a tissue-engineered matrix to a bone or other anchoring site, thereby enabling the implanted matrix to remain in place while the tissue continues to grow and regenerate.




It is a further object of the present invention to provide such a device for fixating a matrix to a bone site which is easily installed using an arthroscopic procedure or an open procedure.




It is yet a further object of the present invention to provide such a device for fixating a matrix to a bone site which does not require sutures or suture knot tying.




It is still yet a further object of the present invention to provide a surgical method for fixating a matrix utilizing such a device in a location within a patient's body.




Accordingly, a graft fixation device is disclosed. The graft fixation device has first and second implantation members. The members are elongated and preferably have a cylindrical configuration. The members also have distal ends, proximal ends, and longitudinal axes. There are longitudinal passages extending through the entire length of each implantation member. The members have outer surfaces. The implantation members are connected to each other by a rod member having first and second ends and a central section. The first end of the rod member extends from the proximal end of the first implantation member and the second end of the rod member extends from the proximal end of the second implantation member. The rod member is preferably relatively rigid and may be configured to have a variety of geometric shapes, for example, an inverted “U” shape. However, the rod member may also be flexible. The rod member maintains the implantation members at a relatively fixed distance from each other. The central section of the rod member is designed to engage a section of a tissue-engineered matrix implant. In a preferred embodiment, the implantation members have a series of ridges extending out from the outer surfaces of the implantation members to assist in preventing withdrawal from a bone site or other anchoring site after the implantation members are implanted into previously-created bore holes.




Yet another aspect of the present invention is a method of using the graft fixation device of the present invention to affix a matrix containing tissue-engineered tissue to a bone.




Still yet another aspect of the present invention is a graft fixation device combination which is the combination of a fixation device and an insertion device. The fixation device has a first implantation member. The implantation member has a longitudinal axis, a proximal end, a distal end, an outer surface, and a longitudinal passage therethrough. The fixation device also has a second implantation member. The second implantation member has a longitudinal axis, a proximal end, a distal end, an outer surface, and a longitudinal passage therethrough. Each implantation member has a proximal annular face on its proximal end surrounding the longitudinal passages. There is a connecting member connecting the first and second implantation members. The connecting member has a central section, a first end extending from the first implantation member and a second end extending from the second implantation member. There are a pair of insertion devices. Each insertion device is a member having a proximal end, a distal tapered end and a longitudinal passage therethrough. The distal end of each implantation member is in engagement with the proximal end of an insertion device. Optionally an insertion device is mounted to the distal end of an implantation member.




Yet another aspect of the present invention is a graft fixation device. The graft fixation device has first and second implantation members. The members are elongated and preferably have a cylindrical configuration. The members also have distal ends, proximal ends, and longitudinal axes. There are longitudinal passages extending through the entire length of each implantation member. The members have outer surfaces. The implantation members are connected to each other by a rod member having first and second ends and a central section. The first end of the rod member extends from the proximal end of the first implantation member and the second end of the rod member extends from the proximal end of the second implantation member. The rod member is preferably relatively rigid and may be configured to have a variety of geometric shapes, for example, an inverted “U” shape. However, the rod member may also be flexible. The rod member maintains the implantation members at a relatively fixed distance from each other. Extending laterally outward from the rod member is at least one wing member. The central section of the rod member is designed to engage a section of a tissue-engineered matrix implant. The wing member facilitates such engagement. In a preferred embodiment, the implantation members have a series of ridges extending out from the outer surfaces of the implantation members to assist in preventing withdrawal from a bone site or other anchoring site after the implantation members are implanted into previously-created bore holes.




Yet another aspect of the present invention is a method of using the above-described graft fixation device having a laterally extending wing member to affix a matrix containing tissue-engineered tissue to a bone.




A further aspect of the present invention is a graft fixation device combination which is the combination of a fixation device and an insertion device. The fixation device has a first implantation member. The implantation member has a longitudinal axis, a proximal end, a distal end, an outer surface, and a longitudinal passage therethrough. The fixation device also has a second implantation member. The second implantation member has a longitudinal axis, a proximal end, a distal end, an outer surface, and a longitudinal passage therethrough. Each implantation member has a proximal annular face on its proximal end surrounding the longitudinal passages. There is a connecting rod member connecting the first and second implantation members. The connecting rod member has a central section, a first end extending from the first implantation member and a second end extending from the second implantation member. Extending laterally outward from the connecting member is at least one wing member. There are a pair of insertion devices. Each insertion device is a member having a proximal end, a distal tapered end and a longitudinal passage therethrough. The distal end of each implantation member is in engagement with the proximal end of an insertion device. Optionally an insertion device is mounted to the distal end of an implantation member.




Yet another aspect of the present invention is a method of using the above-described graft fixation device combination having a laterally extending wing member to affix a matrix containing tissue-engineered tissue to a bone.




These and other features and advantages of the present invention will become more apparent from the following description and accompanying drawings.











BRIEF DESCRIPTION OF THE DRAWINGS





FIG. 1

is a perspective view of a graft fixation device of the present invention.





FIG. 2

is a cross-sectional view of the graft fixation device of

FIG. 1

taken along view line


2





2


.





FIGS. 3-6

illustrate a surgical procedure for affixing a matrix to bone using the graft fixation device of the present invention.





FIG. 7

is an illustration of a graft fixation device of the present invention after the implantation members have been implanted in bore holes in bone illustrating the device affixing a matrix securely to the surface of a bone.





FIG. 8

is a cross-sectional view of the graft fixation device of

FIG. 7

implanted in bone, and taken along View Line


8





8


.





FIG. 9

is an alternative embodiment of a graft fixation device of the present invention having two connecting members.





FIG. 10

is a perspective view of an instrument useful for making bore holes in bone into which the implantable members of the graft fixation devices of the present invention may be emplaced.





FIG. 11

is a perspective view of an instrument useful for implanting the device of the present invention into bore holes made in bone.





FIG. 12

is a view of a tissue engineered matrix secured to a bone with several graft fixation devices of the present invention.





FIG. 13

is a perspective view of an alternate embodiment of a graft fixation device of the present invention.





FIG. 14

is a side view of the graft fixation device of FIG.


13


.





FIG. 15

is an end view of the graft fixation device of FIG.


14


.





FIG. 16

is a cross-sectional view of the graft fixation device of

FIG. 14

, taken along View-Line


16





16


.





FIG. 17

is a cross-sectional view of the tissue retention member of the graft fixation device of

FIG. 14

, taken along View-Line


17





17


.





FIG. 18

is a perspective view of an insertion member useful to insert a graft fixation member of the present invention.





FIG. 19

is an exploded perspective view of an insertion instrument, a graft fixation device, and two insertion members.





FIG. 20

is a side view of the distal end of the insertion instrument, a graft fixation device, and insertion members engaged in bone, prior to removal of the insertion device.





FIG. 21

is a cross-sectional view taken along View-Line


21





21


of

FIG. 20

of the prong of the insertion instrument, and a section of the retention member engaged in a longitudinal groove of the prong.





FIG. 22

is an exploded perspective view of the distal end of an insertion instrument of the present invention, illustrating a removable distal end assembly for creating bore holes in bone for receiving the fixation devices of the present invention, wherein the assembly has an end member and pins.





FIG. 23

is a cross-section of the assembly end member of

FIG. 22

, taken along View-Line


23


.





FIG. 24

is a perspective view of the assembly end of

FIG. 22

, completely assembled and ready for use.





FIG. 25

is a cross-sectional view of the end assembly of

FIG. 24

, taken along View-Line


25





25


.





FIG. 26

is an exploded perspective view of an insertion instrument of the present invention having a removable distal end assembly useful for inserting the graft retention members of the present invention into bore holes in a bone, having an end assembly member and two pins; when used with insertion members, the instrument can be used to emplace the fixation devices directly into bone without first forming bone bore holes.





FIG. 27

is a cross-sectional view of the end assembly member of FIG.


26


.





FIG. 28

is a perspective view of the distal end of the insertion instrument of

FIG. 26

, having the end assembly member and prongs fully assembled and mounted.





FIG. 29

is a cross-sectional view of the distal end of the insertion instrument of

FIG. 28

take along View-Line


29





29


.





FIG. 30

is a cross-sectional view of the instrument of

FIG. 29

taken along View-Line


30





30


.





FIG. 31

illustrates a fixation device of the present member having an insertion member molded into the distal end of each implantation member.





FIG. 32

is a cross-sectional view of the fixation device of FIG.


31


.





FIG. 33

is a perspective view of an alternate embodiment of a graft fixation device of the present invention having laterally extending wing members.





FIG. 34

is a view of a matrix secured to a bone with several graft fixation members of FIG.


33


.





FIG. 35

is a perspective view of yet another alternate embodiment of a graft fixation device of the present invention having laterally extending wing members.





FIG. 36

is a view of a matrix secured to a bone with several graft fixation members of FIG.


35


.











DESCRIPTION OF THE PREFERRED EMBODIMENTS




The graft fixation devices of the present invention can be made from conventional bio-compatible materials, including absorbable and non-absorbable materials, as well as biodegradable materials. The non-absorbable materials which can be utilized include conventional biocompatible materials such as stainless steel, polyethylene, Teflon, Nitinol, non-absorbable polymers, other bio-compatible metals, ceramics, combinations thereof and the like. The absorbable materials which can be used to manufacture the graft fixation devices of the present invention will typically include those conventional bioabsorbable or bioresorbable materials known in this art which can be effectively molded or machined. The bio-absorbable and bio-resorbable materials include polylactic acid, polydioxanone, polycaprolactone, polyglycolic acid, polygalactic acid, other known biocompatible bioabsorbable and bioresorbable polymers, ceramics, composites, combinations thereof and the like and equivalents thereof.




Referring now to

FIGS. 1-2

, a preferred embodiment of a graft fixation device


10


of the present invention is illustrated. The graft fixation device


10


is seen to have implantation members


20


. The implantation members


20


are seen to be elongated members, preferably having a substantially cylindrical shape. The members


20


may have other geometric shapes including conical, pyramidal, polygonal, cubic, spherical, etc. The implantation members


20


are seen to have distal ends


22


and proximal ends


24


. Each implantation member


20


is seen to have an outer surface


28


and a longitudinal axis


29


. Each member


20


is also seen to have longitudinal passage


35


extending therethrough. The implantation members


20


are also seen to have optional frustoconical ends


30


, and proximal endface surfaces


32


. Although it is preferred that endface surfaces


32


be flat, endface surface


32


may also be angled, concave, convex, etc. Endface surface


32


is seen to have central circular opening


36


in communication with passage


35


. Preferably, central opening


36


will have a circular cross-section, but it may have other geometric cross-sections as well including elliptical, polygonal, square, rectangular, combinations thereof and the like. Members


20


are also seen to have distal end face surfaces


37


having circular openings


38


in communication with passages


35


. As shown with the optional frustoconical end


30


, the annular end face surface


37


is of de minimis thickness around opening


38


, however this thickness would increase in the absence of a frustoconical end. Also seen to extend out from the surface


28


of member


20


are a series of optional projections


40


having tissue engagement edges


44


. Without the projections


40


, the surface


28


of the member


20


will be smooth.




The device


10


is seen to have graft retention member


50


connecting the implantation members


20


. Retention member


50


is seen to be a rod-like member having first end


52


, second end


54


and central section


55


. First end


52


is seen to extend from proximal endface surface


32


of the first member


20


while end


54


is seen to extend up from the proximal endface surface


32


of the other member


20


. The ends


54


and


52


of retention member


50


may also if desired extend from or be mounted to any section of outer surface


28


. The connecting member


50


is seen to be preferably bent or shaped into three segments including top segment


55


and leg segments


56


. The top segment


55


is seen to be substantially perpendicular to the leg segments


56


. Although it is preferred that connecting member


50


have an inverted “U” configuration, the connecting member


50


may have other geometric configurations including semicircular, arced, curved, triangular, polygonal, U-shaped, and the like and combinations thereof. The ends


52


and


54


of connecting member


50


may be permanently affixed to the implantation members


20


, or may be removably attached thereto in a conventional manner. Member


50


may be rigid or flexible. Member


50


will have a sufficient surface area to effectively retain a tissue-engineered matrix in place on a bone or other body surface. Preferably, connecting member


50


will have a circular cross-section, but may have other geometric cross-sections as well including elliptical, polygonal, square, rectangular, combinations thereof and the like. Member


50


may be rigid or flexible, and may have a single filamentary structure or have multiple interconnected filaments or members.




Referring now to

FIGS. 3-8

, the use of the graft fixation devices


10


of the present invention in a surgical procedure is illustrated. Referring first to

FIG. 3

, the initial step, prior to the installation of a matrix containing a tissue-engineered tissue using a graft fixation device


10


of the present invention, is to drill or “tap” two bore holes


200


into a bone


210


, for example, subchondral bone in the knee joint. The bore holes


200


are seen to be cylindrical holes having a bottom


208


and an open top


202


and side walls


205


. Optionally, the bore holes may be bone tunnels with a continuous passage and no bottom, or an open bottom. It is particularly preferred to tap the holes in the bone by using an instrument


400


as illustrated in

FIG. 10

which has a proximal section conventionally referred to in this art as a “slap hammer” section. The term “tapping” or “tap” as used herein is defined to mean a procedure wherein the distal pointed prongs


420


extending from the distal end


415


of the shaft


405


of instrument


400


are located over a bone site, and the proximal end


410


of instrument


400


is tapped or hit with slidable hammer handle


450


(of the “slap hammer”), which slides on shaft


460


between proximal end


410


and proximal stop


470


, to form the bone bore holes


200


. The distal end


465


of shaft


460


is connected to proximal end


411


. Proximal stop


470


is mounted to proximal end


467


. Hammer handle


450


is seen to have grasping section


451


, collars


455


and longitudinal passage


457


. Those skilled in the art will appreciate that a similar pointed instrument may be used to “tap” in the bore holes into bone, that is, any instrument having a nail-like distal end. In addition, although not preferred, one bone bore hole at a time may be “tapped” in. If the surgeon decides to drill the bore holes into bone, any conventional surgical drilling apparatus may be used. After the bore holes


200


are formed into the bone


210


, the matrix


220


containing tissue-engineering tissue is placed upon the bone surface


201


by the surgeon as seen in FIG.


4


. Next, the graft fixation device


10


is mounted on to the insertion instrument


250


. Insertion instrument


250


, as illustrated in

FIG. 11

, is seen to be an elongated rod


260


having a proximal end


262


and a distal end


264


. Mounted to the distal end


264


of the rod


260


is the depth stop


290


. The depth stop


290


is seen to be a substantially rectangular member which is mounted perpendicular to the longitudinal axis


251


of the rod


260


. Depth stop


290


is seen to have bottom


292


. Extending distally from the bottom


292


of plate member


290


is a pair of parallel, spaced-apart, mounting prongs


270


. The mounting prongs


270


are seen to be substantially rod-like members having distal pointed tips


277


and proximal ends


272


. The prongs


270


are seen to have first section


273


and distal section


275


. Section


273


is seen to have a greater cross-sectional dimension than distal section


275


such that the entire section


275


is insertable into passages


35


of members


20


, while proximal section


273


is not insertable therein. Instrument


250


is also seen to have a “slap hammer section” consisting of proximal shaft


300


extending from proximal end


262


, slidable hammer handle


320


(the “slap hammer”) which is slidable upon shaft


300


between proximal end


262


, and proximal stop


330


. Hammer handle member


320


is seen to have grasping section


325


, end collars


327


and longitudinal passage


329


. The graft fixation device


10


is mounted to the insertion instrument


250


by sliding the implantation members


20


onto the prongs


270


such that the distal sections


275


of members


270


are engaged within the longitudinal passages


35


of members


20


and distal points


277


protrude beyond the end of distal endface surfaces


37


. Then, as seen in

FIGS. 5 and 6

, the instrument


250


is manipulated such that the graft fixation device


10


is inserted through matrix


220


and into bone


210


by moving the implantation members


20


mounted on prongs


270


into the bore holes


200


such that the members


20


are engaged in the bore holes


200


, and such that the tissue engagement section


55


of the retention member


50


engages the matrix


220


such that the matrix


220


is firmly engaged against the surface


201


of the bone


210


. If desired, holes may be cut into matrix


220


prior to insertion of device


10


. Then, as seen in

FIG. 7

, the insertion instrument


250


is withdrawn proximally causing the prongs


270


to be withdrawn from the passages


35


of the implantation members


20


, thereby leaving the graft fixation device


10


engaged in the bone bore holes, and causing the matrix


220


to be maintained in engagement with the surface


201


of bone


210


. The “slap hammer” section of instrument


250


may assist in removal of the prongs. A cross-sectional view illustrating the device


10


engaged in bone


210


while maintaining the matrix


220


on bone surface


201


is seen in FIG.


8


.





FIG. 12

illustrates a matrix


220


mounted to bone surface


201


of bone


210


having multiple fixation devices of the present invention installed to secure the matrix


220


. The number, anatomical location and orientation of fixation devices


10


necessary to provide sufficiently effective fixation will vary with the size and type of implant or matrix, the type of tissue, the age of the patient, the size of the patient's defect, the size of the fixation devices, the material of construction of the fixation devices, the load on the tissue at the repair site, etc.




Those skilled in the art will appreciate that the size of the fixation devices of the present invention will vary in accordance with a number of variables including the specific design of the device, the materials of construction, the specific application for the devices, the type of surgical procedure, etc. Similarly, the size of the matrices fixated with these devices will similarly vary. The Figures which are part of this specification are merely schematic and illustrative of the device and method of the present invention; the actual dimensions of the devices and matrices may vary in practice.




The following example is illustrative of the principles and practice of the present invention although not limited thereto.




EXAMPLE




Six sheep were prepared for a surgical procedure using standard aseptic surgical techniques including the use of fully sterilized instruments and equipment, and conventional anesthesia procedures and protocols. The surgeon then created 7 mm diameter chondral (full thickness cartilage) defects on a weight-bearing area of the medial femoral condyle and in the trochlear groove in the right stifle (knee) in each of the six skeletally mature sheep. Defects were created using a specialized drill with a depth-stop to prevent subchondral bone exposure or penetration. The base surfaces of all the defects were then microfractured with a specialized micropick tool to provide access for cellular migration. The subjects were then separated into three groups of two subjects each:




Group 1: defect filled with a collagen matrix, fixed with the graft fixation device of the present invention.




Group 2: defect filled with a collagen matrix, fixed with 9-0 absorbable Vicryl™ suture (interrupted stitch technique, approximately 12 strands per matrix).




Group 3: unfilled defect (control group).




Both defects in a given stifle received the same treatment or served as controls.




For the two sheep in Group 1, after a defect had been created and microfractured, a punch tool


400


was used to create the two requisite bore holes in the subchondral bone to receive one graft fixation device of the present invention. Only one polydioxanone device (4 mm tip-to-tip distance) was used to attach each matrix. To create the bore holes, the punch tool was centered in the defect, oriented in the sagittal plane, and hit or “tapped” with a slap hammer repeatedly until it penetrated several millimeters into the subchondral bone. Next, a 7 mm diameter circular collagen matrix, saturated with saline, was placed in the defect and then blotted dry to remove excess saline. When the inserter tool


250


was loaded with the graft fixation device


10


of the present invention, the device and inserter tool were centered above the matrix and oriented in the sagittal plane. The surgeon then located the previously created bore holes by slowly advancing the distal tips of the inserter through the matrix. Once the surgeon located the holes with the inserter tips, a hammer was used to fully advance the inserter tool (and implantation members


20


of the fixation device


10


) through the matrix and into the subchondral bone. The inserter tool had a depth stop to prevent the implantation members


20


from being inserted too deeply, thereby assuring the proper placement of the implantation members through the matrix. The insertion was completed when the connecting retention member between the two implantation members initially started to compress the collagen matrix, thereby indicating secure fixation with the underlying subchondral bone. After the two defects in a given stifle had each been repaired with a matrix and fixation device, the stifle was closed and the sheep was allowed to recover. It was noted by the surgeon that it took approximately one minute to attach a matrix with a fixation device of the present invention (Group 1), versus approximately 15 minutes to attach a matrix with suture alone and the requisite suture manipulation and knot tying (Group 2).




Two weeks after the surgeries were completed, the knee joints were surgically opened for examination. Gross macroscopic assessment of the joints demonstrated that all four matrices held by the graft fixation device of the present invention were fully intact. However, all four matrices held by sutures alone were only partially intact with, on average, approximately 30% of the sutures broken on any given matrix.




Another embodiment of the fixation device of the present invention having multiple retention members is seen in FIG.


9


. The device


300


is seen to have a pair of implantation members


310


. The implantation members


310


are substantially cylindrical members having longitudinal axis


311


, distal ends


314


and proximal ends


312


. Each implantation member


310


is seen to have a longitudinal passage


320


. The members


310


are seen to have a distal frustoconical end


330


, outer surface


350


, and ridges


355


extending outward from surface


350


. The members


310


are seen to be connected by a pair of retention members


340


, having first and second ends


342


and


344


respectively.




Yet another embodiment of a fixation device of the present invention is illustrated in

FIGS. 13-17

. The graft fixation device


500


is seen to have implantation members


520


. The implantation members


520


are seen to be elongated members, preferably having a substantially cylindrical shape. The members


520


may have other geometric shapes including conical, pyramidal, polygonal, cubic, spherical, etc. The implantation members


520


are seen to have distal ends


522


and proximal ends


524


. Each implantation member


520


is seen to have an outer surface


528


and a longitudinal axis


529


. Each member


520


is also seen to have longitudinal passage


535


extending therethrough. The implantation members


520


are also seen to have optional frustoconical ends


530


, and proximal end face surfaces


532


. Although it is preferred that endface surfaces


532


be flat, endface surfaces


532


may also be angled, concave, convex, etc. Each endface surface


532


is seen to have central circular opening


536


in communication with passage


535


. Preferably, central opening


536


will have a circular cross-section, but it may have other geometric cross-sections as well including elliptical, polygonal, square, rectangular, combinations thereof and the like. Members


520


are also seen to have distal end face surfaces


537


having circular openings


538


in communication with passages


535


. Preferably, endface surfaces


537


have a sharp edge configuration, but may also have various widths with a rounded or flat configuration. As shown with the optional frustoconical end


530


, the annular end face surface


537


is of de minimis thickness around opening


538


, however this thickness would typically increase in the absence of a frustoconical end. However, although not preferred, even with a frustoconical, the end surface


537


could have various widths as previously mentioned. Also seen to extend out from the surface


528


of member


520


are a series of optional projections


540


having tissue engagement edges


544


. Without the projections


540


, the surface


528


of the member


520


will be smooth, however, it will be appreciated that surface


528


could be rough, or could have a variety of conventional projections such as cones, hemispheres, rods, hooks, etc., and the like and equivalents thereof.




The device


500


is seen to have graft retention member


550


connecting the implantation members


520


. Retention member


550


is seen to be a band-like member preferably having an oval cross-section. The retention member


550


is seen to have first end


552


, second end


554


and central section


555


. First end


552


is seen to extend up from proximal endface surface


532


of the first member


520


while end


554


is seen to extend up from the proximal endface surface


532


of the other member


520


. A section


557


of end


552


is seen to extend out from section


539


of surface


528


, while section


558


of second end


554


is also seen to extend out from a section


539


of surface


528


. The ends


554


and


552


of retention member


550


may if desired extend from or be mounted to any section of outer surface


528


. The connecting member


550


is seen to be preferably bent or shaped into three segments including top segment


555


and leg segments


556


. The top segment


555


is seen to an arc shaped member, and the leg segments


56


are seen to be preferably perpendicular to surfaces


532


. Although it is preferred that connecting member


550


have an inverted “U” configuration, the connecting member


50


may have other geometric configurations including semicircular, arced, curved, triangular, polygonal, V-shaped, and the like and combinations thereof. The ends


552


and


554


of connecting member


550


may be permanently affixed to the implantation members


520


, or may be removably attached thereto in a variety of conventional manners, for example, a ball and socket joint, a plug joint, etc. Member


550


may be rigid or flexible. Member


550


will have a sufficient surface area to effectively retain a tissue-engineered matrix in place on a bone or other body surface. Preferably, connecting member


550


will have an oval cross-section, but may have other geometric cross-sections as well including circular, elliptical, polygonal, square, rectangular, combinations thereof and the like. Member


550


may be rigid or flexible, and may have a single filamentary structure or have multiple interconnected filaments or members.




An embodiment of graft fixation device


500


having lateral wing members


580


is seen in

FIGS. 35 and 36

. Referring to

FIG. 35

, the device


500


is seen to have wing members


580


extending laterally from the central section


555


of the connecting member (or graft retention member)


550


. The wing members


580


are preferably elongated members having a distal end


584


and a proximal end


582


. Extending from the distal end


584


is a rounded nose section


590


. If desired nose section


590


may have other geometric configurations including conical, pyramidal, and the like, etc. The wing members


580


are seen to have outer surface


586


. As seen in

FIG. 35

, the wing members


580


are seen to have a circular cross-section, tapering from a maximum dimension at proximal end


582


. There is seen to be a transitions section


592


between the proximal end


582


and the top


555


of retention member


550


. If desired, the diameter may be constant along the length of the wing member


580


. The wing members


580


may have other cross-sectional configurations as well including oval, square, rectangular, triangular, polygonal, curved, combinations thereof and the like. The length of the wing members


580


is sufficient to provide effective retention of an implant graft. If desired, although not preferred, the wing members


580


may short or of medium length, rather than elongated. Similarly, the width or diameter of the wing members will vary to provide sufficiently effective graft retention. Although it is preferred to have two opposed wing members


580


extending laterally from the retention member


550


, a single wing member


580


may be used, or a plurality of wing members


580


may be used with device


500


. The retention devices


500


having wing members


580


are illustrated implanted in bone and securing a graft matrix implant in FIG.


36


. The method of implanting a device having wing members


580


is substantially similar, and having the same steps, to implanting a device


500


without wing members


580


as described and illustrated previously herein. As seen in

FIG. 36

, at least a portion of surface


586


engages the top of the matrix


220


on bone


210


.




Another aspect of the present invention is a distal insertion member (device) useful with the fixation devices of the present invention. As seen in

FIG. 18

, the insertion device


600


is seen to be a substantially cylindrical member having proximal end


610


and distal end


620


. Proximal end


610


is seen to have a flat end surface


612


. Frustoconical end section


630


is seen to extend distally from distal end


620


, although device


600


may have other configurations as well. If desired, distal end


620


can have any tapered or curved configuration, but it is preferred that it have a frustoconical end section extending therefrom. The frustoconical end section


630


is seen to have outer surface


632


and distal tip


640


. The member


600


is also seen to have exterior surface


650


. Extending through member


600


is the longitudinal passage


660


having first circular opening


665


in communication therewith, and second circular opening


667


in tip


640


in communication therewith. The insertion members


600


are used in combination with the fixation members of the present invention to engage the fixation member in bone simultaneously with tapping the bore holes into bone, thereby eliminating the need for a separate step to form the bore holes prior to inserting the fixation member.




Referring to

FIGS. 19-21

, the previously mentioned combination of an insertion member


600


and a fixation member


500


is illustrated. Initially, a fixation member


500


is mounted to prongs


700


extending from the distal end


415


of the shaft


405


of instrument


400


. Each prong


700


is seen to have first cylindrical section


710


extending from the distal end


415


of the shaft


405


. Each cylindrical section


710


is seen to have proximal end


711


and distal end


712


, and receiving grooves


715


. Extending from the distal end


712


of each first section


710


is the central pin section


720


. Central pin section


720


is seen to have proximal end


722


and distal end


724


. Extending distally from distal end


724


of central pin section


720


is the distal pin member


730


. Distal pin member


730


is seen to have proximal end


732


and distal pointed end


734


.




If desired, the insertion member


600


may be molded into or affixed to the distal end of an implantation member


520


, thereby forming a unitary structure as seen in FIG.


31


and FIG.


32


. In addition, the insertion member


600


may be mounted to the distal end of an implantation member


520


in a conventional manner by gluing, cementing, mechanical fastening, friction fit and the like and equivalents thereof.




The combination of a unitary implantation device


500


having wing members


580


as previously described and an insertion member


600


is illustrated in

FIGS. 33 and 34

. This combination with wing members


580


securing a matrix


220


to bone


210


is seen in FIG.


34


. If desired, although not shown, the insertion members


600


may be separate from the insertion device


500


having wing members


580


. The method of inserting this combination having wing members


580


is substantially identical to that described and illustrated herein.




The combination of the insertion members


600


and fixation members, such as fixation member


500


of the present invention, are used to affix a matrix to bone in the following manner. Initially, the implantation members


520


of a fixation device


500


are placed upon prongs


700


of an instrument


400


such that the leg members


556


are at least partially engaged in grooves


715


in first section


710


(see FIG.


21


), and, intermediate sections


720


of pin members


700


are engaged in passages


535


of implantation members


520


, while pin members


730


extend out from the distal ends of the implantation members


520


. Then, insertion members


600


are placed over the pin members


730


, such that the pin members


730


are engaged in passages


660


, and such that the pointed piercing ends


734


extend beyond the distal ends


640


of the insertion member


660


. Then, the tool


400


and the assembly consisting of fixation device


500


and insertion member


600


is placed over a tissue matrix


220


placed upon a bone


210


. The piercing points are then pressed through matrix


220


to contact the surface


211


of bone


210


. A slap-hammer section of instrument


400


is engaged to drive the piercing points


734


, insertion members


600


and implantation members


520


into the bone


210


as bore holes


200


are formed in the bone. The instrument


400


is then withdrawn proximately, thereby removing the intermediate sections


720


of prongs


700


from the implantation members


520


and the pin members


730


from the insertion members


600


, leaving the insertion members


600


and the implantation members


520


securely in the bone (as seen in FIG.


20


). This completes the affixation of the matrix


220


to the bone


210


using a single step, wherein the bore holes in the bone are formed simultaneously as insertion members


600


and fixation device


500


are emplaced in the bone.




It is particularly preferred to use conventional remote visualization surgical procedures when inserting the fixation devices of the present invention. For example, inserting a scope through a trocar cannula into the joint or body cavity, while insufflating the joint or body cavity.




The insertion members


600


will typically be made from a strong, hard, bioabsorbable material such that they can be driven into bone without fracturing or breaking. Examples of the types of materials which can be used to make the insertion member


600


include polylactic acid, polyglycolic acid, tricalcium phosphate, calcium phosphate, tetracalcium phosphate and hydroxyapatite, and any copolymers, mixtures or blends thereof. Although not preferred, it is possible to make the insertion members from a conventional biocompatible material which is not bioabsorbable or biodegradable, such as titanium, stainless steel, ceramics, Nitinol and the like and equivalents thereof. The insertion member


600


assists in forming the bore holes


200


while protecting the implantation members


520


.





FIGS. 22-23

illustrate a disposable distal end assembly


800


for an instrument


400


of the present invention. When using the disposable assembly


800


, it is preferable that the distal end


415


of the shaft


405


of instrument


400


have screw threads


418


, although other conventional detachable mounts may be used, for example a bayonet-type mount, locking levers and tabs, male and female mating sections, etc. As seen in

FIGS. 22-25

, the assembly


800


consists of housing


810


having proximal end


811


and distal end


817


. Housing


810


is seen to have hollow cavity


815


therein. Cavity


815


is seen to be in communication with proximal end opening


812


and distal end openings


820


. Member


810


is seen to have outer surface


822


. Outer surface


822


is preferably knurled to facilitate the grasping and turning of the housing


810


. Housing


810


is further seen to have distal end surface


825


. The outer surface


822


is seen to have a tapered section


823


that tapers toward end face


825


. Contained within cavity


815


, on inner surface


818


are the screw threads


819


. Assembly


800


is also seen to have driving pin members


830


. Each driving pin member


830


is seen to have proximal disk member


832


mounted to proximal end


831


, shaft section


834


and distal pointed end


838


. Surrounding each opening


820


on the interior of the member


810


are the annular recesses


840


. The assembly


800


is mounted to the distal end


415


of the instrument


400


in the following manner. The pins


830


are inserted into cavity


815


and through openings


820


such that the shafts


834


and distal piercing points


838


extend through end face


825


, and the disk members


832


are contained within the annular recesses


840


. Then, the housing


810


is mounted upon the threads of distal end


415


such that threads


418


engage mating threads


819


, and screwed further such that the proximal end surfaces


833


of the disk members


832


are in contact with the distal end face


416


of distal end


415


. After use in a surgical procedure, the assembly


800


is removed and discarded. A new sterile assembly


800


is utilized with a cleaned and sterilized instrument


400


for each new procedure.




Referring now to

FIGS. 26-30

, a disposable end assembly


900


for mounting to an insertion instrument


250


is illustrated. The insertion member


250


is seen to have distal end


264


, having endface


265


and screw threads


266


. The assembly


900


is seen to have housing


950


. Housing


950


has proximal end


952


and distal end


956


and exterior surface


954


. Extending from distal end


956


is the plate member


960


. Plate member


960


is seen to have distal surface


962


. The exterior surface


954


is seen to have optional knurling and distal tapered section


957


tapering into plate member


960


. Housing


950


is seen to have internal cavity


955


. Housing


950


is also seen to have proximal opening


951


in communication with cavity


955


and distal openings


970


also in communication therewith. Housing


950


is seen to have internal screw threads


959


extending from internal surface


958


. Also contained within the interior of housing


950


in the distal end


956


is the recessed groove


980


. Assembly


900


is mounted to the distal end


264


of instrument


250


in the following manner. Pins


910


are inserted through cavity


950


and openings


970


such that proximal members


922


are engaged in groove


980


. Sections


920


and


930


of pins


910


extend through openings


970


. Sections


920


are seen to have grooves


925


. Then, the housing


950


is screwed on to distal end


264


such that the threads


266


engage the mating internal threads


959


of housing


950


. The housing is tightened until the distal end surface


265


of the distal end


264


engages the top surfaces


923


of members


922


. After a surgical procedure, the assembly


900


is removed from instrument


250


and discarded. A new sterile assembly


900


is utilized with a cleaned and sterilized instrument


250


for each new procedure.




The fixation devices of the present invention and the combination of the fixation devices with insertion members, and methods of using such devices and combinations, of the present invention have many advantages. The advantages include providing a fast and routine way to fixate a matrix of tissue engineered tissue or other tissue. The fixation devices and combination, because they eliminate the need for suture knot tying, can be utilized in arthroscopic surgical procedures that require a minimum of surgical incisions and thus greatly reduce patient morbidity. In addition, the fixation devices and combination have been demonstrated to provide excellent matrix fixation without damaging the surrounding normal cartilaginous tissue, unlike the conventional fixation of chondral defect matrices with traditional suture that must be passed through (and thus damage) the surrounding tissue.




Although this invention has been shown and described with respect to detailed embodiments thereof, it will be understood by those skilled in the art that various changes in form and detail may be made without departing from the spirit and scope of the claimed invention.



Claims
  • 1. A method of mounting a matrix to tissue, comprising the steps of:providing a graft fixation device comprising the combination of: I. A fixation device comprising: a first implantation member, said implantation member having a longitudinal axis, a proximal end, a distal end, an outer surface, and a longitudinal passage therethrough; a second implantation member, said implantation member having a longitudinal axis, a proximal end, a distal end, an outer surface, and a longitudinal passage therethrough; a connecting member connecting the first and second implantation members, the connecting member having a central section, a first end extending from the first implantation member and a second end extending from the second implantation member; and, at least one wing member extending laterally from the connecting member; and, II. A pair of insertion members each insertion member, comprising: a member having a proximal end, a distal tapered end and a longitudinal passage therethrough, wherein the distal end of each implantation member is in engagement with the proximal end of an insertion member; mounting the combination to an insertion instrument having a pair of spaced apart prongs, said prongs having distal ends and distal tips extending therefrom, such that the prongs are contained within the passages of the implantation members, such that the distal tips of the prongs extend beyond the distal ends of the insertion members; placing a matrix onto the surface of the bone; and, inserting the implantation members and insertion members through the matrix and into the bone thereby forming bore holes while simultaneously emplacing the implantation members in the bone, thereby securing the matrix to the bone.
  • 2. The method of claim 1, wherein the implantation members have a series of ridges extending from the outer surfaces thereof.
  • 3. The method of claim 1, wherein the connecting member comprises a configuration having a central section and rod members, wherein the rod members are substantially parallel to the longitudinal axes of the implantation members, and the central section is substantially perpendicular to the rod members.
  • 4. The method of claim 1, wherein the connecting member has a semi-circular configuration.
  • 5. The method of claim 1, additionally comprising a frustoconical end extending from the distal end of the first implantation member and the distal end of the second implantation member.
  • 6. The method of claim 1, wherein the implantation members have a cylindrical configuration.
  • 7. The method of claim 1 wherein the insertion member comprises a bioabsorbable material selected from the group consisting of polylactic acid, polyglycolic acid, tricalcium phosphate, calcium phosphate, tetracalcium phosphate and hydroxyapatite, and copolymers, mixtures and blends thereof.
  • 8. The method of claim 1 wherein the insertion member comprises a biocompatible material selected from the group consisting of titanium, stainless steel, ceramic, and Nitinol.
  • 9. The method of claim 1 wherein the fixation device comprises a bioabsorbable polymer.
  • 10. The method of claim 1 wherein the fixation device comprises two opposed wing members extending from the connecting member.
  • 11. The device of claim 1 wherein the insertion members comprise a cylindrical shape having a distally extending frustoconical tip.
  • 12. A method of mounting a matrix to tissue, comprising the steps of:providing a fixation device comprising: a first implantation member, said implantation member having a longitudinal axis, a proximal end, a distal end, an outer surface, and a longitudinal passage therethrough; a second implantation member, said implantation member having a longitudinal axis, a proximal end, a distal end, an outer surface, and a longitudinal passage therethrough; a connecting member connecting the first and second implantation members, the connecting member having a central section, a first end extending from the first implantation member and a second end extending from the second implantation member; and, at least one wing member extending laterally from the connecting member; mounting the device to an insertion instrument having a pair of spaced apart prongs, said prongs having distal ends and distal tips extending therefrom, such that the prongs are contained within the passages of the implantation members; placing a matrix onto the surface of the bone; forming a pair of bore holes in the bone; and, and inserting the implantation members through the matrix and into the bone bore, thereby securing the matrix to the bone.
  • 13. The method of claim 12, wherein the implantation members have a series of ridges extending from the outer surfaces thereof.
  • 14. The method of claim 12, wherein the connecting member comprises a configuration having a central section and rod members, wherein the rod members are substantially parallel to the longitudinal axes of the implantation members, and the central section is substantially perpendicular to the rod members.
  • 15. The method of claim 12, wherein the connecting member has a semi-circular configuration.
  • 16. The method of claim 12, additionally comprising a frustoconical end extending from the distal end of the first implantation member and the distal end of the second implantation member.
  • 17. The method of claim 12, wherein the implantation members have a cylindrical configuration.
  • 18. The method of claim 12 wherein the fixation device comprises a bioabsorbable polymer.
  • 19. The method of claim 12 wherein the fixation device comprises two opposed wing members extending from the connecting member.
Parent Case Info

This is a Continuation-In-Part application of commonly-assigned, copending U.S. patent application Ser. No. 09/535,187 filed on Mar. 27, 2000 which is a Continuation-In-Part of commonly-assigned, patent application U.S. patent application Ser. No. 09/360,367 filed on Jul. 23, 1999, now U.S. Pat. No. 6,179,840 which are incorporated by reference.

US Referenced Citations (13)
Number Name Date Kind
4454875 Pratt et al. Jun 1984 A
4548202 Duncan Oct 1985 A
5269783 Sander Dec 1993 A
5352229 Goble et al. Oct 1994 A
5454814 Comte Oct 1995 A
5500000 Feagin et al. Mar 1996 A
5520700 Beyar et al. May 1996 A
5569252 Justin et al. Oct 1996 A
5643319 Green et al. Jul 1997 A
5647874 Hayhurst Jul 1997 A
5656492 Glowacki et al. Aug 1997 A
5658313 Thal Aug 1997 A
5702462 Oberlander Dec 1997 A
Foreign Referenced Citations (1)
Number Date Country
B1 0578425 Sep 1997 EP
Continuation in Parts (2)
Number Date Country
Parent 09/535187 Mar 2000 US
Child 09/793043 US
Parent 09/360367 Jul 1999 US
Child 09/535187 US