Prosthesis (i.e. – artificial body members) – parts thereof – or ai – Implantable prosthesis – Ligament or tendon
Reexamination Certificate
1997-02-18
2001-05-15
Milano, Michael J. (Department: 3738)
Prosthesis (i.e., artificial body members), parts thereof, or ai
Implantable prosthesis
Ligament or tendon
C623S016110, C606S075000, C606S075000
Reexamination Certificate
active
06231606
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to an apparatus and method for securing a graft to bone.
Reconstruction of the anterior cruciate ligament (ACL) generally involves the placement of a tendon graft through a tibial tunnel and securing the graft at one end to the femur and at the other end to the tibia. It is known to secure the graft to the tibia using staples, a bicortical screw and a fastening washer having spikes for penetration into the bone, or a suture attached to a fixation post embedded into the bone.
SUMMARY OF THE INVENTION
A graft anchor for securing a graft to bone includes an anchor member for placement in bone tissue. The anchor member defines an opening. An inner member is insertably securable into the anchor member opening. A fastener is configured such that insertion and securing of the inner member into the anchor member opening results in a holding force being applied to the graft.
In particular embodiments of the invention, the anchor member is of limited length to maintain its distal end within the bone and the opening is a threaded axial bore. The inner member includes external threads for mating with the axial bore threads and a smooth shank proximal of the external threads. The anchor member includes external, threads; the threads are preferably self-tapping. The axial bore of the anchor member includes a distal drive opening for receiving a drive tool, and the inner member includes a proximal drive opening for receiving a drive tool. The distal and proximal drive openings are preferably hexagonally shaped. The fastener includes a channel for containing the graft, a guide defining the channel, a fastener body with protrusions extending from the fastener body for penetrating bone tissue, and a reinforcing member contained within the fastener body. The fastener body has a strength less than the reinforcing member. The fastener includes a through bore and a lip surrounding the through bore which separates the graft from the through bore. The fastener body has a generally circular shape which may include two flat sides.
According to another aspect of the invention, a method of securing a graft to bone includes the steps of placing an anchor member into the bone, positioning a fastener such that a portion of the graft lies between the fastener and the bone, inserting and securing an inner member into the anchor member, the insertion forcing the fastener into the bone to secure the graft by squeezing the graft between the fastener and the bone.
In particular embodiments of the invention, the method includes drilling a counterbore in the tunnel perpendicular to a central axis of the tunnel, and drilling a hole perpendicular to the central axis of the tunnel and centered within the counterbore. Placement of the anchor member into the bone is by screwing the anchor member into the hole. The anchor member is self-tapped into the hole. The anchor member is of limited length such that placement of the anchor member into the bone results in a distal end of the anchor member being maintained within the bone. The portion of the graft that lies between the fastener and the bone is contained within a protective channel defined by the fastener.
Advantages of the invention include the low profile presented by the graft anchor because of its placement in a counterbore. The placement of the graft anchor within a counterbore creates a tortuous path for the graft to follow which produces stronger initial fixation of the graft to the bone because of the increased surface area between the graft and the bone. The placement of the graft anchor within the bone tunnel eliminates any protrusion of the graft anchor from the surface of the bone. The fastener lip shields the graft from possible damage from the act of inserting the screw into the anchor member. The smooth shank of the inner member does not cut the graft. The containment of the graft substantially within the fastener channels causes the graft to lie flat against the bone increasing the area of contact between the graft and the bone which increases the ability of the graft to heal back to the bone. The anchor member has a larger outer diameter than conventional bone anchors which increases the pull out strength of the graft anchor.
REFERENCES:
patent: D. 368777 (1996-04-01), Goble et al.
patent: D. 374286 (1996-10-01), Goble et al.
patent: D. 374482 (1996-10-01), Goble et al.
patent: D. 375791 (1996-11-01), Goble et al.
patent: 4013071 (1977-03-01), Rosenberg
patent: 4246660 (1981-01-01), Wevers
patent: 4259072 (1981-03-01), Hirabayashi et al.
patent: 4590928 (1986-05-01), Hunt et al.
patent: 4632100 (1986-12-01), Somer et al.
patent: 4632101 (1986-12-01), Freedland
patent: 4708132 (1987-11-01), Silvestrini
patent: 4716893 (1988-01-01), Fischer et al.
patent: 4721103 (1988-01-01), Freedland
patent: 4759765 (1988-07-01), Van Kampen
patent: 4793335 (1988-12-01), Frey et al.
patent: 4834752 (1989-05-01), Van Kampen
patent: 4870957 (1989-10-01), Goble et al.
patent: 4950271 (1990-08-01), Lewis et al.
patent: 4960420 (1990-10-01), Goble et al.
patent: 4988351 (1991-01-01), Paulos et al.
patent: 5013316 (1991-05-01), Goble et al.
patent: 5108431 (1992-04-01), Mansat et al.
patent: 5139499 (1992-08-01), Small et al.
patent: 5139520 (1992-08-01), Rosenberg
patent: 5152790 (1992-10-01), Rosenberg et al.
patent: 5167665 (1992-12-01), McKinney
patent: 5176682 (1993-01-01), Chow
patent: 5209756 (1993-05-01), Seedhom et al.
patent: 5269784 (1993-12-01), Mast
patent: 5306301 (1994-04-01), Graf et al.
patent: 5314427 (1994-05-01), Goble et al.
patent: 5352229 (1994-10-01), Goble et al.
patent: 5364400 (1994-11-01), Rego, Jr. et al.
patent: 5374269 (1994-12-01), Rosenberg
patent: 5376119 (1994-12-01), Zimmermann et al.
patent: 5380334 (1995-01-01), Torrie et al.
patent: 5423819 (1995-06-01), Small et al.
patent: 5425767 (1995-06-01), Steininger et al.
patent: 5501695 (1996-03-01), Anspach, Jr. et al.
patent: 5522843 (1996-06-01), Zang
patent: 5545165 (1996-08-01), Biederman et al.
patent: 5571184 (1996-11-01), DeSatnick
patent: 5718706 (1998-02-01), Roger
patent: 196 49 450 A1 (1998-06-01), None
patent: 0 279 129 B1 (1991-03-01), None
patent: 2 590 792 (1987-05-01), None
patent: 2 248 778 (1992-04-01), None
patent: 2 288 739 (1995-11-01), None
Robertson et al., “Soft Tissue Fixation to Bone”, The American Journal of Sports Medicine, 1986.
“Washerloc Tibial Fixation Device For Soft Tissue Grafts”, Arthotek, Inc., 1997.
Howell, “Why the Double-Looped Semitendinosus and Gracilis Graft . . . ”, pp. 1-9.
Innovasive Devices, Inc., “GeoFit Screw & Washer System”, 1997.
Brown et al., “Anterior Cruciate Ligament Injuries”, Traumatic Disorders of the Knee, Chapter 14, pp. 215-218, 238-254, 277-284.
Otero, M.D., et al., “A Comparison of th edoubled Semitendinosus/Gracilis and Central Third of the Patellar Tendon Autografts . . . ”, The Journal of Arthroscopic and Related Surgery, 9(2):143-148.
Rosenberg, M.D., et al., Techniques for ACL Reconstruction with Multi-Trac Drill Guide, Acufex Microsurgical, Inc., 1994.
PCT search report from corresponding PCT application PCT/US97/02260, mailed May 22, 1997.
Blough Rebecca A.
Brown, Jr. Charles H.
Ferragamo Michael C.
Graf Ben K.
Cuddihy Francis K.
Fish & Richardson P.C.
Milano Michael J.
Smith & Nephew Inc.
LandOfFree
Graft anchor does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Graft anchor, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Graft anchor will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2499955