Prosthesis (i.e. – artificial body members) – parts thereof – or ai – Implantable prosthesis – Ligament or tendon
Reexamination Certificate
2001-05-24
2004-03-02
Isabella, David J. (Department: 3738)
Prosthesis (i.e., artificial body members), parts thereof, or ai
Implantable prosthesis
Ligament or tendon
C623S915000, C623S901000, C606S036000
Reexamination Certificate
active
06699286
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to surgical methods and apparatus in general, and more particularly to methods and apparatus for making an ACL repair.
BACKGROUND OF THE INVENTION
A ligament is a piece of fibrous tissue which connects one bone to another.
Ligaments are frequently damaged (e.g., detached or torn or ruptured, etc.) as the result of injury and/or accident. A damaged ligament can impede proper motion of a joint and cause pain.
Various procedures have been developed to repair or replace a damaged ligament. The specific procedures used depend on the particular ligament which is to be restored and the nature and extent of the damage.
One ligament which is frequently damaged as the result of injury and/or accident is the anterior cruciate ligament (ACL). Looking now at
FIG. 1
, an ACL
5
is shown extending between the top of the tibia
10
and the bottom of the femur
15
. A damaged ACL
5
can cause instability of the knee joint, further damage to other structures, and cause substantial pain and arthritis.
Numerous procedures have been developed to restore a damaged ACL through a graft ligament replacement. In general, these ACL replacement procedures involve drilling a bone tunnel
20
(
FIG. 2
) through tibia
10
and up into femur
15
. Then a graft ligament
25
, consisting of a harvested or artificial ligament or tendon, is passed through tibial tunnel
30
, across the interior of the joint, and up into the femoral tunnel
35
. Then a distal portion of graft ligament
25
is secured in femoral tunnel
35
and a proximal portion of graft ligament
25
is secured in tibial tunnel
30
.
There are currently a variety of ways to secure graft ligament
25
in a bone tunnel. One way is to use an interference screw
40
(FIG.
3
), such as the ARTHREX interference screw, to “directly” wedge graft ligament
25
against the side wall of bone tunnel
20
. Another way is to use a bearing structure and expansion screw
45
(FIG.
4
), such as the INNOVASIVE INTRAFIX system, to “indirectly” wedge graft ligament
25
against the side wall of the bone tunnel
20
. Still another way is to use a fastener device
50
(FIG.
5
), such as the INNOVASIVE LYNX system, to secure graft ligament
25
in bone tunnel
20
. Yet another way is to use an anchor
55
(FIG.
6
), such as the MITEK ligament anchor, to suspend graft ligament
25
within bone tunnel
20
. And another way is to use a suture suspension system
60
(FIG.
7
), such as the ACUFEX ENDOBUTTON system, to suspend graft ligament
25
in bone tunnel
20
. And still another way is to use a cross-pinning system
65
(FIG.
8
), such as the ARTHREX cross-pinning system, to suspend graft ligament
25
in bone tunnel
20
. And yet another way is to pass graft ligament
25
completely through bone tunnel
20
and affix graft ligament
25
to the outside of the bone with a screw and washer arrangement
70
(
FIG. 9
) or a staple (not shown).
Some of the aforementioned reconstruction techniques utilize a graft ligament which is harvested so as to include a portion of bone block, e.g., a patellar tendon including a portion of the patella. Others of the aforementioned reconstruction techniques utilize a graft ligament which is harvested so as to consist entirely of soft tissue, e.g., a harvested hamstring tendon.
In general, it is preferable to harvest graft ligaments consisting entirely of soft tissue, e.g., a hamstring tendon, since this involves less trauma to the donor site. However, graft ligaments consisting entirely of soft tissue are more difficult to biologically integrate into the host bone, due to the fact that two different types of tissue are involved, i.e., both tendon and bone. Such difficulties with biological integration can raise questions as to the adequacy and permanence of the ligament reconstruction. As a result, many ligament reconstructions are still effected using a graft ligament which includes a portion of bone block. While such “bone block” reconstructions generally result in more significant trauma to the donor site, they also simplify biological integration of the graft ligament into the host bone since, within a bone tunnel, bone heals to bone more readily than tendon heals to bone.
In addition to the foregoing, ligament reconstructions tend to be complex surgical procedures where a variety of factors must be carefully balanced in order to achieve the best possible results. More particularly, in order to optimize the ligament reconstruction and minimize trauma to the surrounding anatomy, it is generally necessary to position a sizable graft ligament at exactly the right location within the joint, taking care to minimize trauma to the host bones by making the smallest possible bone tunnels. More particularly, when creating the ligament reconstruction, it is generally important to use as much graft ligament material as possible, so as to (i) provide the highest possible graft strength along the length of the graft, whereby to prevent subsequent rupture, and (ii) provide an extensive supply of collagen material, whereby to facilitate effective integration of the graft ligament into the bone. At the same time, the physics of the knee joint dictate the location of the graft ligament and hence the location of the bone tunnels, and the particulars of the surrounding anatomy may effect graft ligament size and/or bone tunnel size. And in addition to the foregoing, it is also generally important to minimize the size of the bone tunnels. Minimizing the size of the bone tunnels is important, since (i) larger bone tunnels are more destructive of the host bone, (ii) larger bone tunnels are more difficult to revise later on in the event of graft failure, and (iii) larger bone tunnels have larger diameters and, since bony ingrowth commences from the periphery of the bone tunnel, may reduce the proportion of tendon experiencing bony ingrowth, thereby weakening graft fixation. Thus it will be seen that the relative sizing of the graft ligament and the bone tunnels is a delicate balance involving a range of factors.
In addition to all of the foregoing, there must also be sufficient clearance between the graft ligament and the walls of the bone tunnels to permit the graft ligament to be pushed and/or pulled into position within the bone tunnels. And to further complicate the matter, in many cases, the surgeon must also be able to position surgical instruments within the bone tunnels, alongside the/graft ligament. Thus, “real estate” becomes a very precious commodity in ligament reconstructions. In practice, in order to permit deployment of the graft ligament within the bone tunnel, the graft ligament must generally be sized so as to have a cross-sectional area at least somewhat less, and in some cases significantly less, than the cross-sectional area of the bone tunnels it is to be deployed in.
Unfortunately, there are at least three significant problems associated with “undersizing” the graft ligament relative to the bone tunnel. First, such undersizing tends to undermine biological integration of the graft ligament with the host bone. Second, it can allow some movement of the graft ligament to occur relative to the host bone. Such movement can further impede the aforementioned biological integration; in addition, it can also result in abrasion, and hence deterioration, of the graft ligament and/or the host bone. Third, undersizing of the graft ligament relative to the host bone tunnel can also permit the incursion of synovial fluid into the bone tunnel. Such synovial fluid incursion is believed to result in degradation of the bone tunnel and/or in degradation of the biological integration of the graft ligament into the host bone.
SUMMARY OF THE INVENTION
As a result, one object of the present invention is to provide an improved way of effecting a ligament reconstruction using graft ligaments consisting entirely of soft tissue, yet which facilitates effective biological integration of the graft ligament with the host bone.
Another object of the present invention is to provide a way to temporarily reduce th
Chattopadhyay Urmi
Isabella David J.
Pandiscio & Pandiscio
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