US4950271A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ligament graft apparatus and method
Assignee: University of Minnesota System
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Filing: 1989-02-06
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Granted: 1990-08-21
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Expires: 2009-02-06
Abstract
Abstract A knee reconstruction apparatus and method provides for controlling and adjusting the point of fixation of a ligament graft, for example a replacement for the anterior cruciate ligament, which permits precisely and repeatably adjusting the length of the ligament graft or graft components with the joint under a prescribed load prior to fixation. A fixture is fixed on the tibia and includes an adjustable clamp that holds a ligament graft anchored or held in the femur. The clamp can be moved for adjusting the length of the ligament graft, or individual segments of a composite ligament graft while the joint is under a prescribed load. The load carried by one or more individual graft components also can be measured prior to fixation to ensure that each of the segments of a composite ligament graft will carry the desired or selected load for a joint under a prescribed load.
Inventors
- 👤 Jack L. Lewis
- 👤 William D. Lew
- 👤 Curtis W. Kowalczyk
- 👤 Robert E. Hunter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 14:18
CPC Classifications
A; A61; A61F; A61F2/00; A61F2/02; A61F2/08; A61F2/0805; A61B; A61B90/00; A61B90/06
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
149 words
A method of replacing ligaments in a joint of a human body between first and second bone portions comprising the steps of: temporarily fixing a replacement ligament graft at a first attachment site relative to a first of said bone portions, in a provided tunnel; passing the replacement ligament graft into a tunnel in a second bone portion; changing the location where the replacement ligament graft exits the tunnel in the first bone portion while measuring length changes of the replacement ligament graft as reflected by total forces in the replacement ligament graft while under external load; and fixing the replacement ligament graft to the second bone portion at a second attachment site and fixing the location where the replacement ligament graft exits the tunnel in the first bone portion to minimize changes in length of such replacement ligament graft during a desired amount of flexion of the joint.
Claim 2
Independent Claim
149 words
A method of replacing ligaments in a joint of a human body between first and second bone portions comprising the steps of: temporarily fixing a replacement ligament graft at a first attachment site relative to a first of said bone portions, in a provided tunnel; passing the replacement ligament graft into a tunnel in a second bone portion; changing the location where the replacement ligament graft exits the tunnel in the first bone portion while measuring length changes of the replacement ligament graft as reflected by total forces in the replacement ligament graft while under external load; and fixing the replacement ligament graft to the second bone portion at a second attachment site and fixing the location where the replacement ligament graft exits the tunnel in the first bone portion to minimize changes in length of such replacement ligament graft during a desired amount of flexion of the joint.
Claim 3
Dependent Claim
35 words
The method of claim 1 including the further step of applying a load on the replacement ligament graft to a desired level prior to fixation of the replacement ligament graft to the second bone portion.
Claim 4
Dependent Claim
49 words
The method of claim 1 including the step of varying the length of the replacement ligament graft between the first and second attachment sites on the two bone portions so that force in the replacement ligament graft is substantially matching normal loading of a natural ligament for the joint.
Claim 5
Dependent Claim
48 words
The method of claim 1 including the step of using a multi-segment replacement ligament graft and determining the load carried in the individual replacement ligament graft segments as the length thereof is adjusted prior to fixation of the replacement ligament graft segments with the joint under external load.
Claim 6
Independent Claim
172 words
An apparatus for use in installing replacement ligament graft members of either single or multiple segments to a joint between first and second bone components comprising: a removable fixture mountable on a first bone component adjacent to a joint in which a ligament graft member is to be used for joining the two bone components; the fixture comprising a frame; means for removably mounting said frame on the first bone component, said means for removably mounting being separate from any means fixing the ligament graft member to a bone component; means on the frame for adjusting the length of a ligament graft relative to the frame with the joint under a prescribed load, said means for adjusting being positionable adjacent a ligament graft member path on the first bone segment; and means for coupling the means for adjusting to the ligament graft member whereby the length of the ligament graft member can be adjusted while the joint is under load prior to fixation of the ligament graft member to both bone components.
Claim 7
Independent Claim
172 words
An apparatus for use in installing replacement ligament graft members of either single or multiple segments to a joint between first and second bone components comprising: a removable fixture mountable on a first bone component adjacent to a joint in which a ligament graft member is to be used for joining the two bone components; the fixture comprising a frame; means for removably mounting said frame on the first bone component, said means for removably mounting being separate from any means fixing the ligament graft member to a bone component; means on the frame for adjusting the length of a ligament graft relative to the frame with the joint under a prescribed load, said means for adjusting being positionable adjacent a ligament graft member path on the first bone segment; and means for coupling the means for adjusting to the ligament graft member whereby the length of the ligament graft member can be adjusted while the joint is under load prior to fixation of the ligament graft member to both bone components.
Claim 8
Dependent Claim
33 words
The apparatus of claim 5 including force measuring means coupled to the means for adjusting to determine the tension in a ligament graft member as the length of such ligament graft is adjusted.
Claim 9
Dependent Claim
40 words
The apparatus as specified in claim 6 wherein said frame includes a load carrying member independent of the means for adjusting for permitting exerting an external load to the joint before the length of the ligament graft member is adjusted.
Claim 10
Dependent Claim
35 words
The apparatus of claim 5, said length adjusting means including a clamp for receiving a ligament graft member, and a screw threadable for moving the clamp to change the length of the ligament graft member.
Claim 11
Dependent Claim
24 words
The apparatus of claim 8 and guide pulley means for guiding a ligament graft member for aligning such ligament graft member with the clamp.
Claim 12
Dependent Claim
26 words
The apparatus of claim 9 and a load cell carrying forces from the screw to the clamp to measure loads carried on the ligament graft member.
Claim 13
Independent Claim
143 words
An apparatus for providing a guide for locating a ligament graft member relative to a first bone segment adjacent to a joint with a second bone segment for which said joint ligament graft member is to be used, said apparatus comprising: means for providing a first tunnel in the first bone segment through which a graft will extend; and plug means for mounting in said first tunnel comprising a plug having a central axis and a second tunnel through the plug extending substantially parallel to the central axis, the second tunnel being offset form the central axis, said second tunnel receiving a ligament graft member, and said plug being rotatable about its central axis to change the exit position of the ligament graft member received in the second tunnel in respect to a tunnel formed in a second bone segment forming the joint.
Claim 14
Independent Claim
143 words
An apparatus for providing a guide for locating a ligament graft member relative to a first bone segment adjacent to a joint with a second bone segment for which said joint ligament graft member is to be used, said apparatus comprising: means for providing a first tunnel in the first bone segment through which a graft will extend; and plug means for mounting in said first tunnel comprising a plug having a central axis and a second tunnel through the plug extending substantially parallel to the central axis, the second tunnel being offset form the central axis, said second tunnel receiving a ligament graft member, and said plug being rotatable about its central axis to change the exit position of the ligament graft member received in the second tunnel in respect to a tunnel formed in a second bone segment forming the joint.
Claim 15
Dependent Claim
57 words
The apparatus specified in claim 11 and means to clamp a ligament graft member passing through said second tunnel of said plug, and means to move the clamp to adjust the length of a ligament graft held therein when the opposite end of such a ligament graft member is retained in the second bone segment against movement.
Claim 16
Dependent Claim
24 words
The apparatus of claim 11 and means for securing the plug with the second tunnel in a selected rotational position about its central axis.
Claim 17
Independent Claim
141 words
An apparatus for use in installing ligament graft members to a joint between first and second bone components, said ligament graft member comprising a plurality of individual, elongated graft segments which share load carried by the graft member comprising: a fixture mountable on a first bone component adjacent to as joint in which a ligament graft member is to be used for joining the two bone components; the fixture comprising a frame; means for mounting said frame on the first bone component; a plurality of individual adjustable members on the frame for individually adjusting the length of each graft segment relative to the frame with the joint under a prescribed load, said adjustable members being positionable adjacent a ligament graft member path on the first bone segment; and means for coupling the individual adjustable members to the respective individual graft segments.
Claim 18
Independent Claim
141 words
An apparatus for use in installing ligament graft members to a joint between first and second bone components, said ligament graft member comprising a plurality of individual, elongated graft segments which share load carried by the graft member comprising: a fixture mountable on a first bone component adjacent to as joint in which a ligament graft member is to be used for joining the two bone components; the fixture comprising a frame; means for mounting said frame on the first bone component; a plurality of individual adjustable members on the frame for individually adjusting the length of each graft segment relative to the frame with the joint under a prescribed load, said adjustable members being positionable adjacent a ligament graft member path on the first bone segment; and means for coupling the individual adjustable members to the respective individual graft segments.
Claim 19
Independent Claim
151 words
An apparatus for use in installing ligament graft members of either single or multiple segments to a joint between first and second bone components comprising: a fixture mountable on a first bone component adjacent to a joint in which a ligament graft member is to be used for joining the two bone components; the fixture comprising a frame; means for mounting said frame on the first bone component; means for adjusting the length of a ligament graft member relative to the frame with the joint under a prescribed load, said means for adjusting comprising a clamp for receiving a ligament graft member and being positionable adjacent a ligament graft member path on the first bone segment and force generating means for moving the clamp relative to the frame; and a load cell carrying forces from the force generating means to the clamp to measure loads carried through the ligament graft member.
Claim 20
Independent Claim
151 words
An apparatus for use in installing ligament graft members of either single or multiple segments to a joint between first and second bone components comprising: a fixture mountable on a first bone component adjacent to a joint in which a ligament graft member is to be used for joining the two bone components; the fixture comprising a frame; means for mounting said frame on the first bone component; means for adjusting the length of a ligament graft member relative to the frame with the joint under a prescribed load, said means for adjusting comprising a clamp for receiving a ligament graft member and being positionable adjacent a ligament graft member path on the first bone segment and force generating means for moving the clamp relative to the frame; and a load cell carrying forces from the force generating means to the clamp to measure loads carried through the ligament graft member.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-08-20 | 1994-02-19 | 1994-08-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-08-20 | 1998-02-19 | 1998-08-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-08-20 | 2002-02-19 | 2002-08-21 | $7700.00 | Window Closed / Lapsed |