Endosteal anchoring device for urging a ligament against a bone surface

An endosteal anchoring device for urging a ligament graft against a bone surface comprising an anchoring body, a member for resisting slippage of the anchoring body into the periphery of a bone tunnel under ligament tension, a member for avoiding puncturing, piercing or tearing of cross-fibers of the ligament graft and a member for urging the ligament graft flush against the inner surface of the bone tunnel for accelerated healing.

BACKGROUND 
1. The Field of the Invention 
This invention relates to orthopedic surgical procedures and, more 
particularly, to surgical devices involved in replacing, reconstructing or 
securing synthetic or biological connective tissue to a bone surface, such 
as, for example, attaching and maintaining a replacement anterior cruciate 
ligament (ACL) against a bone. 
2. The Background Art 
The knee joint is one of the strongest joints in the body because of the 
powerful ligaments which bind the femur and tibia together. Although the 
knee is vulnerable to injury as a result of the incongruence and proximity 
of its articular surfaces, the knee joint provides impressive stability 
due to the arrangement and interacting strength of its ligaments, muscles 
and tendons. 
To a layman, the operation of the human knee resembles the actions of a 
hinge joint. However, in reality, the knee joint provides complicated 
mechanical movements and maneuverability far more complex than a simple 
hinge mechanism in regards to the rotation and gliding motions that may 
occur at the joint. In addition, the motions of flexing and extending the 
knee (and, in certain positions, the slight rotation inward and outward of 
the knee), require a very detailed structural configuration to facilitate 
the associated, refined mechanical movements of the knee joint. 
Structurally, the knee joint comprises two discs of protective cartilage 
called menisci which partially cover the surfaces of the femur and the 
tibia. The menisci operate to reduce the friction and impact loading 
between the femur and the tibia during movement of the knee. The knee is 
also partly surrounded by a fibrous capsule lined with a synovial membrane 
which secrets a lubricating fluid. Strong ligaments on each side of the 
knee joint provide support to the joint and limit the side-to-side motion 
and joint opening of the knee. Fluid filled sacs called bursas are located 
above and below the patella (kneecap) and behind the knee providing a 
means of cushioning the kneecap upon impact and helping with joint 
lubrication. Moreover, the quadriceps run along the front of the thigh to 
straighten the knee, while the hamstring muscles run along the back of the 
thigh to bend the knee. 
Two intra-articular ligaments of considerable strength, situated in the 
middle of the joint, are known as the cruciate ligaments. These ligaments 
are referred to as "cruciate ligaments" because they cross each other 
somewhat like the lines of the letter "X". The anterior and posterior 
cruciate ligaments receive their names in respect to the positioning of 
their attachment to the tibia. The primary function of the anterior 
cruciate ligament (ACL) is to provide a means for limiting hyperextension 
of the knee and preventing the backward sliding of the femur on the tibia 
plateau. The ACL also assists in limiting any medial rotation of the knee 
joint when the foot is solidly on the ground and the leg fixed in 
position. Conversely, the posterior cruciate ligament (PCL) primarily 
provides a means for preventing hyperflexion of the knee and preventing 
the femur from sliding forward on the superior tibial surface when the 
knee is flexed. Although the structure of the knee provides one of the 
strongest joints of the body, the knee is usually one of the most 
frequently injured joints. Athletes and persons who perform tasks 
requiring a great deal of body rotation are the most susceptible to 
serious ligament stressing and tearing at the knee joint. Consequently, 
the growing number of ligament injuries has given rise to considerable 
innovative activity within the area of orthopedic medicine in an effort to 
create surgical procedures and devices for replacing and reconstructing 
torn or dislocated ligaments. 
Typically the surgical procedures for ligament replacement and 
reconstruction involve tissues being grafted from one part of the body 
(autograft) to the original attachment sites of a torn or dislocated 
ligament. Once the ligament graft has been transplanted, it is then 
attached to the natural fixation sites of damaged ligament. For example, 
the replacement of an anterior cruciate ligament (ACL) may involve 
transplanting a portion of the patellar tendon to the attachment sites of 
the original ACL to assist in the reconstruction of the ACL in the knee 
joint. 
The expectations of prior art orthopedic procedures typically relate to 
reconstructing or replacing natural ligaments so as to enable the 
recipient to return to his or her full range of activity in as short a 
period of time as possible. To that end, medical researchers have 
attempted to duplicate the relative parameters of strength, flexibility, 
and recovery found in natural ligaments of the body. Unfortunately, many 
of the prior art methods of reconstructing and replacing damaged ligaments 
have generally proven inadequate for immediately restoring full strength 
and stability to the involved joint. Furthermore, there has long been a 
problem of effectively fastening a ligament to a bone surface for the 
duration of a ligament's healing process, which process involves the 
ligament graft growing to an adjoining bone mass to restore mobility to 
the injured joint of an orthopedic patient. 
Early ligament replacement procedures traditionally comprised extensive 
incisions and openings in the knee to attach a replacement ligament to 
bone surfaces at the fixation sites of the natural ligament. The ends of a 
grafted ligament were typically secured to exterior bone surfaces by 
driving stainless steel staples through or across the ligament and into 
the adjacent bone mass. The legs of the staples are generally adapted for 
piercing and penetrating tissue and bone mass, while maintaining a 
ligament at a specified connection site. Other various types of tissue 
fastening devices, such as channel clamps, were also designed by those 
skilled in the art. The channel clamps normally differed from the 
abovementioned staple arrangement in that the channel clamp fixation 
devices comprise a plurality of components which do not require clinching 
in the conventional manner, as when setting a staple into a bone surface. 
However, the use of stainless steel staples and other related fixation 
devices have a number of disadvantages. For example, piercing and 
puncturing of the ligament by the legs of the staples or other fixation 
devices may result in serious damage to the cross-fibers of the ligament 
or tissue. Such damage may cause weakening in the tensile strength of the 
ligament and result in tearing along the cross-fibers of the ligament 
under normal physical stress. When puncturing or tearing of cross-fibers 
occurs, the time required for the ligament to heal increases, which in 
turn results in a significant extension in the amount of time required to 
rehabilitate the knee joint before allowing the patient to return to 
normal daily activities. 
To alleviate the disadvantages of cross-fiber damage exhibited by staples 
and other related fixation devices that puncture the body of the ligament, 
improvements in the types of surgical devices and techniques were 
developed by those skilled in the art. For example, one such technique 
involves drilling a hole through a bone to form a channel wherein an 
anchoring device may be inserted with a ligament graft attached thereto. 
Typically, the ligament is maintained at a fixation site in the bone 
channel by passing a suture through one end of the ligament graft and 
thereafter attaching the other end of the suture to an anchoring device 
positioned at the face of the opening of the channel in the bone mass. 
However, problems materialize when trying to secure the threads of the 
suture to the anchoring device when a physician is working in restricted 
or confined areas. As a result, combination drilling devices operably 
coupled to suture anchors were designed for dealing with ligament 
placement problems in areas of restricted maneuverability. 
After a period of time, significant disadvantages emerged wherein a number 
of the ligament grafts retained in bone mass by the combination 
drilling/anchor devices began to rupture and tear at their fixation sites 
around the area where the ligament was in direct contact with the sharp 
outer edges of the opening of the channel formed in the bone. For example, 
as replacement ligaments tolerate the stress and strain associated with 
normal physical activity, the ligament generally begins to fatigue when 
wearing against the sharp outer edges of a bone channel opening. This form 
of fatigue typically causes significant damage to the ligament by tearing 
or cutting into ligament cross-fibers, thus, weakening the connection of 
the replacement ligament at its reattachment site. Consequently, after a 
period of time, cross-fiber fatigue, commonly known as "sun-dial" wear, 
may further result in dislocating the replacement ligament from its 
original fixation site. 
Because of the significant disadvantages associated with "sun-dial" wear or 
fatigue on replacement ligaments, improved surgical procedures were 
developed offering arthroscopic-assisted techniques typically including 
the formation of passages or tunnels through bone mass, wherein natural or 
synthetic ligaments may be inserted. After the ligament graft has been 
inserted into the bone tunnel, a ligament anchoring device is generally 
used to connect one end of a ligament to the exterior of the bone mass. 
The anchoring means generally requires that the replacement ligament end 
or ends be advanced beyond the bone tunnel, with each ligament end being 
bent and secured onto the exterior surface of the bone. Nevertheless, 
unfavorable disadvantages of ligament bending was observed by those 
skilled in the art as typically resulting in a force concentration at the 
location of the ligament bend generally causing the cross-fibers of the 
ligament to weaken, potentially subjecting the ligament to the possibility 
of further tearing or rupturing, as in the case of ligament sundial wear. 
In response to the problems associated with maintaining a replacement 
ligament graft at a fixation site, additional devices and techniques were 
developed offering means whereby a ligament may be retained within a bone 
tunnel by an endosteal fixation device, such as, for example, an 
interference screw. The threads of the interference screw are typically 
bored into the bone tunnel for recessed engagement with the attached bone 
and one end of the ligament graft, while maintaining the ligament at a 
fixation site within the bone tunnel. Unfortunately, puncturing, piercing 
and possible tearing generally results to the cross-fibers of the ligament 
when the ligament is in direct engagement with the sharp threads of the 
interference screw. In addition, the interference screw typically requires 
a ligament replacement graft to be attached to its original bone. 
During flexion or extension of the ligament, tension loads tend to act 
against the fixation site of the ligament generally causing strain on the 
ligament against its fixation site. Under such strain, the facing of the 
threads of the interference screw generally effect a pinching or piercing 
of the ligament which may cause tearing or dislocation of the replacement 
ligament under the stress associated with normal physical activities. 
Consequently, when a grafted ligament suffers cross-fiber damage due to 
puncturing, piercing or tearing, the healing period for the ligament 
dramatically increases, thereby in effect, increasing the rehabilitation 
time for the patient to recover. 
One of the preferred methods employed by a number of skilled physicians 
when repairing torn or dislocated ligaments involves the harvesting of an 
autograft patella tendon bone block for incorporation into a femoral 
socket. Although the use of a patella tendon bone block provides a number 
of advantages, especially when dealing with fixation of the replacement 
ligament, the harvesting of a patella bone block typically results in 
extensive morbidity to the knee joint, requiring a considerable amount of 
time for the knee joint to heal, before a patient can resume any normal 
physical activity. 
As illustrated by the foregoing summary, efforts are continuously being 
made to improve the graft types, surgical methods and devices used in 
replacing and reconstructing torn or dislocated ligaments so as to make 
the process more efficient and effective. However, significant 
disadvantages remain with all the presently known devices and methods 
offered by the prior art. 
BRIEF SUMMARY AND OBJECTS OF THE INVENTION 
In view of the foregoing, it is a primary object of the present invention 
to provide an endosteal anchoring device for urging a ligament against a 
bone surface without piercing, puncturing or tearing the cross-fibers of 
the ligament. 
Another object of the present invention is to provide an endosteal 
anchoring device and endoscopic technique for urging a ligament against a 
bone surface minimizing the possibility of sun-dial wear on the 
replacement ligament. 
It is also an object of the present invention to provide an endosteal 
anchoring device for urging a ligament against a bone surface which is 
capable of retaining a ligament at a fixation site within a bone tunnel, 
while restricting the anchor member from slippage under the stress and 
strain of normal physical activity. 
It is an other object of the present invention to provide an endosteal 
anchoring device for urging a ligament against a bone surface while 
dispensing a desired amount of surface area compression on the ligament 
graft allowing collateral circulation into the tissue for promotion of the 
ligament healing to the bone. 
Further, it is an object of the present invention to provide an endosteal 
anchoring device for urging a ligament against a bone surface which is 
easily adjustable during a surgical procedure so that proper tension, 
nearly duplicating the natural condition of the torn or dislocated 
ligament, can be sustained on the replacement ligament graft. 
It is a still further object of the present invention to provide an 
endosteal anchoring device and method for urging a ligament against a bone 
surface whereby a ligament graft may be retained flush against the surface 
of a bone tunnel to facilitate a decrease in the amount of healing time 
for the ligament graft, while substantially decreasing its morbidity rate. 
It is also a still further object of the present invention to provide an 
endosteal anchoring device and method for urging a ligament against a bone 
surface while simulating the fixation advantages associated with a patella 
tendon bone block, without incurring excessive morbidity to the knee 
joint. 
Consistent with the foregoing objects, and in accordance with the invention 
as embodied and broadly described herein, a permanent or bio-absorbable 
endosteal anchoring device for urging a replacement ligament against a 
bone surface is disclosed as comprising an anchoring body, a means for 
resisting slippage of the anchoring body within a bone tunnel under 
ligament tension, a means for avoiding puncturing, piercing or tearing of 
ligament cross-fibers, and a means for urging the ligament graft flush 
against the inner surface of the bone tunnel to accelerate the healing of 
the replacement ligament.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
It will be readily understood that the components of the present invention, 
as generally described and illustrated in the Figures herein, could be 
arranged and designed in a wide variety of different configurations. Thus, 
the following more detailed description of the preferred embodiments of 
the endosteal anchoring device and method of the present invention, as 
represented in FIGS. 1 through 10, is not intended to limit the scope of 
the invention, as claimed, but it is merely representative of the 
presently preferred embodiments of the invention. 
The presently preferred embodiments of the invention will be best 
understood by reference to the drawings, wherein like parts are designated 
by like numerals throughout. 
When reconstructing or replacing a torn or dislocated ligament, care should 
be taken to provide a means for connecting a ligament to its predetermined 
connection site and maintaining it firmly thereto. Generally, surgical 
procedures involve either the use of natural biological tissue grafts or 
prosthetic ligaments, simulated to mimic the parameters of strength, 
flexibility and positioning of the natural ligament it replaces. 
As shown in FIGS. 1 and 2, to accommodate a ligament graft 14 to a fixation 
site, the present invention offers a device for urging a ligament 14 
against the peripheral surface of a tunnel 12 formed within a bone 10, by 
implementing an endoscopic technique designed primarily for use with 
arthroscopic assistance. When reconstructing or replacing a torn or 
dislocated ligament, particularly the anterior cruciate ligament (ACL) of 
the knee, a bone tunnel 12 is generally formed in the femur and/or tibia 
for positioning the natural or synthetic ligament graft 14 therein. 
The preferred method provided by the present invention for replacing or 
reconstructing dislocated ligaments utilizes an endosteal anchor member 
16, formed of plastic, bone, stainless steel or any other suitable 
material. The endosteal anchor member 16 consists of a rigid anchor body 
23 having an upper ridge 22 and a lower ridge 24 displaying a groove 25 
integrally formed therebetween. Preferably, the endosteal anchoring device 
is manufactured from a material suitable for sterilization and human 
implantation, and comprised of either a permanent non-biodegradable 
material or a bio-degradable material capable of being absorbed by the 
body while maintaining the essential rigid qualities required to 
accommodate its anchoring functions. 
The upper ridge 22 and the lower ridge 24 of the endosteal anchor member 16 
extend slightly beyond the first end 20 of the anchor body 23. Oriented 
between the upper ridge 22 and the lower ridge 24 is an elongated groove 
25 having a semi-circular cross-sectional area wherein a ligament graft 14 
may be positioned. At the first end 20 of the anchor body 23, a 
curvilinear indentation is formed between the upper ridge 22 and the lower 
ridge 24 providing a front semi-circular facing for the elongated groove 
25. 
Preferably, the ligament graft 14 is encircled around the first end 20 of 
the endosteal anchor member 16 and positioned within the surface area of 
the front curvilinear facing of the groove 25. The ligament 14 may then be 
looped around the perimeter of the anchor body 23 and positioned within 
the linear cross-sectional area of the groove 25. The first end of the 
ligament graft 14 is preferably advanced back upon itself and fastened to 
a connection site on the body of the ligament 14 to approximate a looped 
configuration. 
The positioning of the ligament graft 14 within the surface area of the 
groove 25 provides a means of locking the ligament at a specified fixation 
site when the anchor body 23 is positioned within the periphery of the 
bone tunnel 12. Looping the ligament 14 around the first end 20 of the 
body 23 of the endosteal anchor member 16 and positioning the ligament 14 
within the cross-sectional area of the groove 25, provides a means whereby 
restricting excessive compression on the ligament 14 when the endosteal 
anchor member 16 is positioned within the periphery of the bone tunnel 12. 
By restricting the movement of the ligament 14 within the bone tunnel 12, 
bone ingrowth occurs more readily, rather than fibrous formations, which 
significantly decreases the healing time required for the replacement 
ligament. 
Preferably positioned and integrally formed along the upper exterior 
surface 17 of the anchor body 23 are multiple tapped grooves which provide 
a means for intersecting with the threads 32 of a threaded insertion 
member 28. Being substantially circular and preferably comprised of 
stainless steel or any other suitable material, the threaded insertion 
member 28 exhibits a first end 29, preferably formed with a bullet nose, 
and a second end 30. Spirally threaded from the first end 29 to the second 
end 30 of the threaded insertion member 28, the threads 32 provide a 
circular diameter which is substantially compatible with the tapped 
grooves in the upper surface 17 of the anchor body 23. Recessed within the 
second end 31 of the threaded insertion member 28 is a slot 31 wherein a 
complimentary turning device is inserted to aid in rotating the threaded 
insertion member 28 into the periphery of the bone tunnel 12 for 
communication with the upper exterior surface 17 of the endosteal anchor 
member 16. 
As shown in FIG. 2, recessed within the second end 21 of the anchor body 23 
is an opening 26 wherein a directional driver 33 may be inserted to 
position the endosteal anchor member 16 being operably coupled to a looped 
ligament 14 within the periphery of the bone tunnel 12. Preferably, the 
face of the opening 26 and the tip of the directional driver 33 are formed 
having a complimentary hexagonal shape. It will be readily appreciated, 
however, that other shapes or configurations of the opening 26 and the tip 
of the directional driver 33 are also possible. 
As illustrated in FIGS. 1 and 2, positioned along the lower surface 18 of 
the anchor body 23 and extending therefrom, are a plurality of projecting 
members 19 which provide a means of resisting slippage of the endosteal 
anchor member 16 within the bone tunnel 12 after being placed therein. The 
projecting members 19 of the anchor body 23 are herein illustrated as 
displaying a curvilinear shape, however, other shapes or configurations 
are readily possible. 
In practice, the ligament graft 14 is looped around the front facing of the 
groove 25 at the first end 20 of the endosteal anchor member 16, 
thereafter looped back within the cross-sectional area of the groove 25 
encircling the anchor body 23. The directional driver 33 may be inserted 
into the recessed opening 26 formed within the second end 21 of the anchor 
body 23 for positioning the anchor body 23 within the bone tunnel 12. The 
threaded insertion member 28 is then rotatably introduced along the tapped 
upper surface 17 of the anchor body 23 while self-tapping into the 
adjacent surface area of the bone tunnel 12. 
The combination of the threaded insertion member 28 and the features of the 
endosteal anchor member 16 provides a means of locking the ligament graft 
14 at a fixation site. In addition, the projecting members 19 which emerge 
from the lower surface 18 of the anchor body 23 provide a means for 
restricting slippage of the anchoring device within the bone tunnel 12 
under the ligament stress and strain associated with normal physical 
activity. 
Illustrated in FIGS. 3 and 4 is a second presently preferred embodiment of 
the endosteal anchoring device for urging a ligament against a bone 
surface consisting of an endosteal anchoring member 116, formed of 
plastic, bone, stainless steel or any other suitable material, comprising 
a substantially elongated anchor body 123. Preferably, the endosteal 
anchoring device is manufactured from a material suitable for 
sterilization and human implantation, and comprised of either a permanent 
non-biodegradable material or a bio-degradable material capable of being 
absorbed by the body while maintaining the essential rigid qualities 
required to accommodate its anchoring functions. 
The anchor body 123 exhibits an upper ridge 122 extending the linear length 
of the anchor body 123 from its first end 120 to its second end 121. 
Preferably, the anchor body 123 is tapered and gradually decreases in 
surface area from the upper ridge 122 to the lower surface 118. The 
surface area between the upper ridge 122 and the lower surface 118 on both 
sides of the tapered anchor body 123 provides a substantially curved 
cross-sectional area wherein a ligament graft 14 may be positioned. 
Integrally formed within the second end 121 of the anchor body 123 is an 
opening 26 wherein a directional driver 33 may be inserted to introduce 
and position the endosteal anchor member 116 within the bone tunnel 12 at 
a designated fixation site. Preferably, the opening 26 at the second end 
121 of the anchor body 123 and the insertion tip of the directional driver 
are formed having a complimentary hexagonal shape. However, it will be 
readily appreciated that other shapes or configurations are also possible. 
An alternative means for introducing the endosteal anchor member 116 into 
the bone tunnel 12 offered by the present embodiment may involve the 
utilization of a post member 34 extending parallel and slightly beyond the 
first end 120 of the anchor body 123. The projecting post 34 preferably 
resembles a small circular stock or projecting rod and provides a means 
for positioning the endosteal anchor member 116 against the ligament graft 
14 within a bone tunnel 12. At the distal end of the post 34 is an eyelet 
35 wherein the end of a suture 36 is introduced and passed therethrough. 
After attaching the suture 36 to the post member 34, the leading ends of 
the suture 36 are pulled through a channel 37 having a significantly 
reduced diameter in comparison to the diameter of the bone tunnel. 
Situated beyond the bone tunnel 12 and extending to the outer exterior 
surface of the bone 10, the channel 37 provides an opening through the 
bone mass 10 wherein the suture 36 being attached to the projecting post 
34 can be pulled to introduce the endosteal anchor member 116 into the 
inner surface area of the bone tunnel 12. When using a blind-end 
technique, the post 34 of the endosteal anchor member 216 provides a means 
whereby the anchor body 223 can be inserted into the bone tunnel 12 
without having to form a tunnel through the entire body of the bone 
exposing at least two openings. 
As shown in FIG. 3, a ligament graft 14 may be passed up and over the post 
member 34 at the first end 120 of the anchor body 123. Preferably, the 
ligament 14 is looped around the perimeter of the anchor body 123 and 
positioned within the tapered surface areas of the anchor body 123 
established beneath the cross-sectional area of the upper ridge 122. 
Integrally formed within the tapered sides of the anchor body 123 is at 
least one through-bore 38 forming an opening which extends transversely 
through the anchor body 123 from one side to the other. Preferably, a 
suture is inserted through the through-bore 38 and passed through the 
looped ligament graft 14 placed within the tapered surface area of the 
anchor body 123. Positioned between the first end 120 and second 121 end 
of the endosteal anchor member 116, the through-bore provides an opening 
wherein a suture may be passed to secure the ligament graft 14 to the 
endosteal anchor member 116. 
As best shown in FIG. 4, an alternative means for retaining the looped 
ligament graft within the tapered surface area of the anchor body 123, 
comprises a plurality of urging members 40 projecting substantially 
outward from the underside of the upper ridge 122 and along the upper 
surface area of the sides of the anchor body 123. Preferably aligned in 
rows or oriented in criss-cross patterns along the anchor body 123, the 
urging members 40 display rounded or angularly blunt tips 41 which engage 
and maintain the looped ligament graft within the tapered surface area of 
the anchor body 123 without piercing, puncturing or tearing the 
cross-fibers of the ligament. 
Preferably positioned and integrally formed along the upper exterior 
surface 117 of the anchor body 123 are multiple tapped grooves which 
provide a means for intersecting with the threads 32 of a threaded 
insertion member 28, as best illustrated in FIG. 3. Being substantially 
circular and preferably comprised of stainless steel or any other suitable 
material, the threaded insertion member 28 exhibits a first end 29, 
preferably formed with a bullet nose, and a second end 30. Recessed within 
the second end 31 of the threaded insertion member 28 is a slot 31 wherein 
a complimentary turning device is inserted to aid in rotating the threaded 
insertion member 28 into communication with the upper exterior surface 117 
of the endosteal anchor member 116 and the peripheral wall of the bone 
tunnel 12. Spirally threaded from its first end 29 to its second end 30, 
the threads 32 of the threaded insertion member 28 provide a diameter 
substantially compatible with the tapped grooves in the upper surface 17 
of the anchor body 23 and diameter of the bone tunnel 12, for positioning 
therebetween. 
As illustrated in FIG. 4, extending from the lower surface 118 of the 
anchor body 123 are a plurality of projecting members 119 spaced apart a 
substantially equal distance from one another. The projecting members 119 
of the anchor body 123 are herein illustrated as displaying a curvilinear 
shape, however, other shapes or configurations are readily possible. 
In practice, the leading end of the ligament graft 14 may be positioned 
beneath the upper ridge 122 and along one side of the tapered anchor body 
123, passed up and over the projecting post 34 located at the first end 
120 of the anchor body 123 and further looped around the other tapered 
side of the anchor body 123 while providing a means for limiting 
compression on the ligament 14 as the ligament 14 is locked at its 
fixation site within the bone tunnel 12. Consequently, by restricting the 
movement of the ligament 14 within the bone tunnel 12, bone ingrowth 
occurs rather than fibrous formations, which may significantly decrease 
the healing time required for the replacement ligament 14. 
When positioning the endosteal anchor member 116 within the bone tunnel 12, 
a directional driver may be inserted into the recessed opening 26 formed 
within the second end 121 of the anchor body 123, or a projecting post 34 
may be used in combination with a leading suture 36 passed through the 
eyelet 35 at the distal end of the post 34 to pull the anchor body 123 
into the bone tunnel 12 using a blind-end technique. Once the endosteal 
anchor member 116 is positioned within the bone tunnel 12, the threaded 
insertion member 28 is rotatably introduced along the tapped upper surface 
117 of the anchor body 123, wherein the threaded insertion member 28 
provides a means for self-tapping into the adjacent surface area of the 
bone tunnel 12. Accordingly, the combination of the threaded insertion 
member 28 and the features of the endosteal anchor member 116 provides a 
means of locking the ligament graft 14 at its fixation site. In concert, 
the projecting members 119 emerging from the lower surface 118 of the 
anchor body 123 provides a means for restricting slippage of the anchoring 
device within the bone tunnel 12. 
Shown in FIGS. 5 and 6 is a third presently preferred embodiment of the 
endosteal anchoring device for urging a ligament against a bone surface 
comprising an endosteal anchoring member 216, formed of plastic, bone, 
stainless steel or any other suitable material. The endosteal anchor 
member 216 consists of a substantially elongated cylindrical body 223 
having an upper exterior surface 217 and a wedge member 42 extending from 
a lower surface 218 of the anchor body 223. Preferably, the endosteal 
anchoring device is manufactured from a material suitable for 
sterilization and human implantation, and comprised of either a permanent 
non-biodegradable material or a bio-degradable material capable of being 
absorbed by the body while maintaining the essential rigid qualities 
required to accommodate its anchoring functions. 
Projecting substantially outward from the lower surface 218 of the anchor 
body 223, is an elongated wedge member 42 disposed in alignment with the 
anchor body 223 and extending the linear length of the endosteal anchor 
member 216 from a first end 220 to a second end 221. Preferably arranged 
in rows or oriented in criss-cross patterns, a plurality of urging members 
40 may be positioned along the lower exterior surface 218 of the anchor 
body 223, adjacent the peripheral sides of the elongated wedge member 42. 
While projecting substantially outward from the lower exterior surface 218 
of the anchor body 223, the urging members 40 display rounded or angularly 
blunt tips 41 which discourage piercing, puncturing or tearing of ligament 
cross-fibers, when the endosteal anchor member 216 is in direct engagement 
with the ligament graft 14. 
As shown in FIG. 5, extending parallel and slightly beyond the first end 
220 of the anchor body 223 protrudes a post member 34 resembling a small 
circular stock or projecting rod. The post member 34 provides a means for 
positioning the endosteal anchor member 216 within a bone tunnel 12 to 
retain a ligament graft 14 at its fixation site. Accordingly, an eyelet 35 
is provided in the distal end of the post member 34 wherethrough a suture 
36 may be introduced. After passing the suture 36 through the eyelet 35 of 
the post member 34 and securing it thereto, the suture 36 is drawn through 
a small channel 37 formed in the bone 10 that extends beyond the periphery 
of the bone tunnel 12 out to the exterior surface of the bone mass 10. 
When using a blind-end technique, the post 34 of the endosteal anchor 
member 216 provides a means whereby the anchor body 223 can be inserted 
into the bone tunnel 12 without having to form a tunnel through the entire 
body of the bone exposing at least two openings. 
In practice, one end of the ligament 14 may be introduced along either side 
of the elongated wedge member 42, passed up and over the projecting post 
34 which is located at the first end 220 of the anchor body 223, and 
further positioned along the opposing side of the wedge member 42. After 
encircling the perimeter of the anchor body 223, the leading end of the 
ligament 14 may be attached to the body of the ligament graft 14 by a 
suture, or some other conventional means, conforming the ligament into a 
loop configuration. 
The placement of the ligament 14 around the first end 220 of the anchor 
body and against the sides of the wedge member 42 provides a means for 
limiting compression on the ligament 14 when locked at its fixation site 
within the bone tunnel 12. Consequently, by restricting the movement of 
the ligament 14 within the bone tunnel 12, bone ingrowth occurs, rather 
than fibrous formations, significantly decreasing the healing time 
required for the ligament graft 14. 
Preferably positioned and integrally formed along the upper exterior 
surface 217 of the anchor body 223 are multiple tapped grooves which 
provide a means for intersecting with the threads 32 of a threaded 
insertion member 28. Being substantially circular and preferably comprised 
of stainless steel or any other suitable material, the threaded insertion 
member 28 exhibits a first end 29, preferably formed with a bullet nose, 
and a second end 30. Recessed within the second end 221 of the threaded 
insertion member 28 is a slot 31 wherein a complimentary turning device or 
directional driver is inserted to aid in rotating the threaded insertion 
member 28 in communication with the upper exterior surface 217 of the 
endosteal anchor member 216 and the peripheral wall of the bone tunnel 12. 
Spirally threaded from its first end 29 to its second end 30, the threads 
32 of the threaded insertion member 28 provide a diameter substantially 
compatible with the tapped grooves in the upper surface 217 of the anchor 
body 223 and the bone tunnel 12, for positioning therebetween. 
As illustrated in FIGS. 5 and 6, an endosteal anchoring member 216 is 
inserted into a bone tunnel 12 and positioned against a ligament graft 14. 
A complimentary turning member is inserted into the slot 31 recessed in 
the second end 30 of the threaded insertion member 28 for rotating the 
threads 32 of the threaded insertion member 28 into the tapped grooves of 
the anchoring body 223, and for self-tapping the insertion member 28 into 
the inner surface of the bone tunnel 12. In concert, the features of the 
endosteal anchor member 216, the cooperating threaded member 28 and the 
wedge member 42 in concert with the urging members 40 provide a means for 
firmly locking a replacement ligament 14 flush against the inner surface 
of the bone tunnel 12. The force concentration of the endosteal anchor 
member 216 and the cooperating threaded member 28 provides a means for 
resisting slippage of the anchor body 223 from the periphery of the bone 
tunnel 12. 
Shown in FIGS. 7 and 8 is a fourth presently preferred embodiment of the 
endosteal anchoring system for urging a ligament against a bone surface 
comprising an endosteal anchoring device 316, formed of plastic, bone, 
stainless steel or any other suitable material, having at least two 
wedge-shaped components 43 and 44 which together comprise a substantially 
tubular body 323. Preferably, the endosteal anchoring device is 
manufactured from a material suitable for sterilization and human 
implantation, and comprised of either a permanent non-biodegradable 
material or a bio-degradable material capable of being absorbed by the 
body while maintaining the essential rigid qualities required to 
accommodate its anchoring functions. 
An inner surface 45 extending from a first end 320 to a second end 321 of 
the first component 43 is preferably formed with a plurality of 
interlocking ridges 46 projecting substantially outward from the exterior 
of the inner surface 45. The inner surface of the second component 44 may 
also display a plurality of interlocking ridges 46 which project 
substantially outward from its inner surface 45, but which are positioned 
in such a way, so as to be disposed at an opposing angle with the ridges 
46 of the first component 43. When the first and the second component are 
positioned in alignment with one another, the opposing surface areas of 
the ridges 46 of the first component 43 and the ridges 46 of the second 
component 44 become interlocked with one another forming the substantially 
tubular body 323 of the endosteal anchor member 316. The one-way movement 
of the first wedge-shaped component 43 along the interlocking ridges 46 of 
the second component 44 creates a considerable urging force which 
maintains the endosteal anchor device 316 in communication with the inner 
peripheral surface of a bone tunnel when placed therein. 
Integrally formed on each side of the first component 43 is a substantially 
semi-circular elongated groove 325. Extending from the first end 320 to 
the second end 321 of the anchor body 323, the elongated groove 325 
provides a recessed surface area along the sides of the endosteal anchor 
device 316 wherein a ligament can be positioned. Preferably, a ligament 
graft is maintained within the cross-sectional area of the groove 325 
located on one side of the first component 43, looped up and over a 
protruding post 34 located on the first end 320 of the endosteal anchor 
device 316, and further positioned within the cross-sectional area of the 
groove 325 located on the opposing sides of the first component 43. 
Preferably, the lead end of the ligament graft is advanced back upon 
itself, where the ligament may be sutured to a connection site on the body 
of the ligament while forming a loop configuration. 
The upper exterior surface 317 of the first wedge-shaped component 43 and 
the lower exterior surface 318 of the second wedge-shaped component 44 may 
be provided with a plurality of urging members 40 which project 
substantially outward therefrom. Preferably, the urging members 40 exhibit 
rounded or angularly blunt tips 41 on their distal ends to provide a means 
of resisting slippage of the endosteal anchor device 316 when positioned 
within a bone tunnel. The urging members 40 are arranged in rows or 
oriented in criss-cross patterns and provide constant pressure against the 
periphery of the bone tunnel to maintain the endosteal anchor member 316 
from slippage under normal ligament stress and strain. 
As best shown in FIG. 7, substantially parallel to the inner surface 45 of 
the second component 44, and embedded therein is a substantially elongated 
rectangular canal 48 extending from the first end 320 to the second end 
321 of the anchor body 323. The elongated canal 48 of the second component 
44 engages a complimentary raised key member 47 which protrudes 
substantially outward from the inner surface 45 of the first component 43. 
The raised key member 47 of the first component 43 and the elongated 
linear canal 48 of the second component 44 provide a means for guiding the 
two components 43 and 44 into combination when placed into the bone tunnel 
to form the endosteal anchor device 316. 
Parallel and slightly beyond the first end 320 of the first wedge-shaped 
component 43 extends a post member 34, resembling a small circular stock 
or projecting rod. The post member 34 provides a means for positioning the 
endosteal anchoring device 316 into a bone tunnel and for retaining a 
replacement ligament at its fixation site. An eyelet 35 may be provided in 
the distal end of the post member 34 wherethrough a suture may be 
introduced. Once the suture is passed through the eyelet 35 of the post 
member 34 and secured thereto, the suture is further introduced through a 
small channel formed through the bone, extending beyond the periphery of 
the bone tunnel and to the outer exterior surface area of the bone. Using 
a blind-end technique, the post 34 of the endosteal anchor device 316 
provides a means whereby the anchor body 323 can be inserted into the bone 
tunnel, without having to drill a tunnel having at least two openings 
formed in the bone. 
As shown in FIG. 8, at the second end 321 of the first wedge-shaped 
components 43 is a recessed slotted opening 26 wherein a directional 
driver may be inserted for positioning the first component 43 within the 
bone tunnel. It will readily be appreciated, however, that other shapes or 
configurations of the slotted opening 26 and the tip of the directional 
driver are readily possible. 
Preferably in practice, the second wedge-shaped component 44 is positioned 
within the bone tunnel, while a ligament is looped around the first 
wedge-shaped component 43 and positioned within the recessed area of the 
groove 325. The raised key member 47 of the first component 43 is aligned 
and integrally positioned within the elongated rectangular canal 48 of the 
second component 43 to be slideably engaged therein. As the surface of the 
ridges 46 of the inner surface 45 of the first component 43 slides along 
the surface of the ridges 46 of the inner surface 45 of the second 
component 44, both the first and second components 43 and 44 become 
interlocked, thereby providing an interactive means for securing the 
anchor device and the ligament within the bone tunnel. As the components 
43 and 44 become interlocked, the urging members 40, positioned on the 
upper exterior surface 317 and the lower exterior surface 318, provide a 
means of forced compression on the surface area of the bone tunnel while 
maintaining the looped ligament flush against the bone at a fixation site. 
Illustrated in FIGS. 9 and 10 is a fifth presently preferred embodiment of 
the endosteal anchoring device for urging a ligament against a bone 
surface comprising an endosteal anchor member 416, formed of plastic, 
bone, stainless steel or any other suitable material. The endosteal anchor 
member 416 consists of a substantially elongated cylindrical body 423 with 
at least two extending wings 52 projecting substantially outward and 
perpendicular to a first end 420 of the anchoring body 423. Preferably, 
the endosteal anchoring device is manufactured from a material suitable 
for sterilization and human implantation, and comprised of either a 
permanent non-biodegradable material or a bio-degradable material capable 
of being absorbed by the body while maintaining the essential rigid 
qualities required to accommodate its anchoring functions. 
The extending wings 52 of the endosteal anchor member 416 are preferably 
rectangular or disc-shaped and project substantially outward a distance 
greater than the diameter of the opening of a bone tunnel 12. It will 
readily be appreciated, however, that other shapes or configurations for 
the extending wings 52 are readily possible. As illustrated in FIG. 9, 
when the body 423 of the endosteal anchor member 416 is introduced into 
the bone tunnel 12, the extending wings 52 of the anchor body 423, being 
significantly greater in length and width than the diameter of the opening 
in the bone tunnel 12, engage the exterior surface area of the bone 10 
adjacent the bone tunnel opening. Consequently, the risk of the anchor 
body 423 slipping into the periphery of the bone tunnel 12 is minimized 
due to the counteracting forces provided by extending wings 52 acting 
against the surface area of the bone 10. 
Preferably, the exterior surface area of the anchor body 423 is 
substantially covered with a plurality of urging members 40 projecting 
substantially outward from the exterior surface. Aligned in rows or in 
criss-cross patterns, the urging members 40 exhibit rounded or angular 
blunt tips 41 to discourage piercing, puncturing, or tearing of the 
ligament cross-fibers as the ligament experiences the stress and strain of 
normal physical activity. 
Preferably formed in a looped configuration, the leading end of the 
ligament graft 14 is introduced along one side of the anchor body 423, 
passed up and over the surface area of the extending wings 52 of the 
endosteal anchor member 416, and further passed across the opposing side 
of the anchor body 423. In practice, the tips 41 of the urging members 40 
apply pressure against concentrated areas of the ligament graft 14 to 
retain the ligament 14 firmly at a fixation site. While the tips 41 of the 
urging members 40 maintain the ligament graft 14 flush against the inner 
surface of the bone tunnel 12, circulation to the transplanted ligament 
graft 14 is improved without damaging any cross-fibers of the ligament. 
As illustrated in FIG. 10, recessed between the extending wings 52 of the 
anchor body 416 is an opening 51, preferably tapped, projecting inwardly 
into an annular canal 50 extending the length of the cylindrical anchor 
body 423 from its first end 420 to its second end 421. The cross-sectional 
diameter of the canal 50 at the first end 420 of the endosteal anchor 
member 416 begins to taper radially, becoming progressively smaller 
towards the second end 421 of the anchor body 423, while preferably 
forming a slight inner conical cavity therein. 
A threaded insertion member 28, being substantially circular and preferably 
comprised of stainless steel or any other suitable material, may be 
introduced into the opening 51 at the first end 420 of the endosteal 
anchoring member 416. The first end 29 of the threaded insertion member 
28, preferably comprising a bullet nose, is introduced into the opening 51 
of the endosteal anchoring member 416 to be further rotatably inserted 
into the inner surface area of the annular canal 50. 
Spirally threaded from its first end 29 to its second end 30, the insertion 
member 28 has threads 32 displaying a diameter substantially compatible 
with the inner surface of the annular canal 50 formed within the anchor 
body 423. The second end 30 of the threaded insertion member 28 may be 
formed with a recessed slot 31 wherein a complimentary turning device may 
be inserted to aid in introducing the threaded insertion member 28 into 
the periphery of the annular canal 50. 
As described above, since the annular canal 50 is preferably tapered 
radially from the first end 420 to the second end 421 of the anchor body 
423, when the threaded insertion member 28 is introduced therein, the 
diameter of insertion member threads 32, remaining somewhat constant from 
its first end 29 to its second end 30, begins to enlarge the annular canal 
50 along a divisional split, disposed in alignment with the anchor body 
423. Preferably, the expansion of the annular canal 50 causes the anchor 
body 423 to extend outwardly against the inner surface of the bone tunnel 
12 concentrating an association therewith. Upon insertion of the threaded 
member 28 into the opening 51 of the annular canal 50, the extending wings 
52 of the endosteal anchoring member 416 also begin to expand while 
providing a means for retaining the anchor body 423 from further slippage 
into the bone tunnel 12. 
Although the endosteal anchoring device of the present invention may be 
used at any location in the body which requires the fixation of a ligament 
graft, it is preferably employed during an endoscopic technique used with 
arthroscopic assistance for replacement and reconstruction of an anterior 
cruciate ligament (ACL) of the knee, which in practice, appears to 
significantly decrease the level of morbidity of the ligament graft. The 
method or technique provided by the present invention allows for isometric 
placement of a variety of tissue graft types into tibial and femoral bone 
tunnels drilled under arthroscopic control. 
Preferably, the endoscopic technique is performed by first establishing 
anteromedial and anterolateral portals in the knee for diagnosis and 
operative arthroscopy. Once a diagnosis and the pathology of the knee has 
been adequately studied, the ACL reconstruction may be performed. 
A tissue or ligament graft (autograft or allograft) is harvested and 
prepared for attachment at the fixation site of the torn or dislocated 
ACL. The patellar tendon may be grafted to replace the ACL, however, other 
tendons, such as the Achilles tendon or hamstrings may be used to 
reconstruct and replace dislocated ligaments without incurring the serious 
disadvantages associated with a patella tendon bone block concerning 
morbidity to the knee joint. 
With an arthroscope in the anterolateral portal, the tibial anatomic site 
is studied and a guide pin inserted to mark the proposed site for the 
drilling of a tibial tunnel. Accordingly, the tibial tunnel is drilled by 
passing an endoscopic drill bit over the already inserted guide pin. 
When identifying a femoral attachment site, the isometric and mechanical 
behavior of the selected femoral attachment site for the ligament graft 
should be assessed prior to formation of the femoral tunnel, since changes 
in the placement of the replacement ligament will have significant effects 
on the behavior of the isometric properties of the ligament graft. Once 
the femoral attachment site is selected, the guide pin is further inserted 
and passed through the tibial tunnel while the knee is flexed at a 
substantially 90 degree angle, to mark the proposed fixation site on the 
femur for the ligament graft. An endoscopic drill bit is manually passed 
over the guide pin through the tibial tunnel, across the joint and into 
the femur to drill a femoral tunnel. 
Consequently, the guide pin is removed and the femoral tunnel irrigated 
wherein a small Beathe-type pin is placed. A suture is attached to the 
ends of the transplanted ligament graft and used to advance the graft 
through the tibial tunnel, across the joint and into the femoral tunnel. 
Once the graft is properly oriented in the tunnel, it is seated with 
tension on the guide suture until the bone-tendon junction is flush with 
the opening of the femoral tunnel. A blind-end technique, as discussed 
above in reference to the preferred embodiments of the endosteal anchoring 
device, may also be considered as a viable option when applying the 
arthroscopic-assisted and endoscopic techniques offered by the present 
invention. 
The ligament graft is maintained against the inner surface of the femoral 
bone tunnel at the fixation site of the natural ligament using one of the 
preferred embodiments of the endosteal anchoring device of the present 
invention. Preferably, the endosteal anchoring device and the threaded 
insertion member is manufactured from a material that is suitable for 
sterilization and human implantation, which may comprise a permanent 
material or a bio-degradable material capable of being absorbed by the 
body while maintaining sufficient rigid qualities to accommodate its 
prescribed functions. 
The body of the endosteal anchoring device is inserted and positioned 
within the bone tunnel, while the knee is flexed at a substantially 90 
degree angle, and under direct arthroscopic visualization. The endosteal 
anchoring device of the present invention, as discussed above, provides a 
means for resisting slippage of the anchoring body from its placement 
within the bone tunnel. 
The endosteal anchoring device of the present invention provides a means 
whereby a ligament graft may be looped around the body of the endosteal 
anchor member and retained within the cross-sectional area of an adjacent 
groove. The positioning of the ligament graft within the groove of the 
anchor member provides a means of locking the ligament at a fixation site, 
and restricts excessive ligament compression of the ligament against the 
surface of the bone tunnel. By restricting ligament movement within the 
bone tunnel, bone ingrowth occurs rather than fibrous formations, which 
significantly increases the healing rate of the replacement ligament. 
The endosteal anchoring device of the present invention also provides a 
plurality of urging members that extend substantially outward from the 
exterior surface of the anchoring body that provide a means for urging the 
ligament graft flush against the inner surface of the bone tunnel without 
piercing, puncturing or tearing the cross-fibers of the ligament. 
Moreover, after positioning the endosteal anchoring device against the 
ligament graft in the bone tunnel and after the proper tensioning of the 
ligament is achieved, the incisions are then closed and a sterile dressing 
applied thereto. 
While preferred embodiments of the endosteal anchoring device have been 
shown and described herein, the present invention may be embodied in other 
specific forms without departing from its spirit or essential 
characteristics. The described embodiments are to be considered in all 
respects only as illustrative, and not restrictive. The scope of the 
invention is, therefore, indicated by the appended claims, rather than by 
the foregoing description. All changes which come within the meaning and 
range of equivalency of the claims are to be embraced within their scope.