Procedure for verifying isometric ligament positioning

• US RE34,762 E
• Filed: 08/03/1993
• Issued: 10/18/1994
• Est. Priority Date: 09/19/1988
• Status: Expired due to Term

• Current Assignee: Goble E. Marlowe
• Original Assignee: Goble E. Marlowe, Somers W. Karl
• Inventors: Goble, E. Marlowe, Somers, W. Karl
• Primary Examiner(s): Pellegrino, Stephen C.
• Assistant Examiner(s): Lewis, William W.
• Application Number:
  US08/101,040
• Time in Patent Office: 441 Days
• Field of Search: 606/53, 606/66, 606/86, 606/87, 606/88, 606/96, 606/1, 623/13, 623/16, 623/20, 128/898
• US Class Current: 606/96
• CPC Class Codes: A61B 17/0401 Suture anchors, buttons or pledgets, i.e. means for attaching sutures to bone, cartilage or soft tissue; Instruments for applying or removing suture anchors A61B17/0642 takes precedence; fixation devices for tendons or ligaments A61F2/0811
• CPC Class Codes: A61B 17/8645 Headless screws, e.g. ligament interference screws
• CPC Class Codes: A61B 2017/044 with a threaded shaft, e.g. screws
• CPC Class Codes: A61B 2017/0458 Longitudinal through hole, e.g. suture blocked by a distal suture knot
• CPC Class Codes: A61B 2017/0496 for tensioning sutures
• CPC Class Codes: A61B 2090/064 for measuring force, pressure or mechanical tension
• CPC Class Codes: A61B 90/06 Measuring instruments not otherwise provided for
• CPC Class Codes: A61F 2/0805 Implements for inserting tendons or ligaments
• CPC Class Codes: A61F 2/0811 Fixation devices for tendons or ligaments
• CPC Class Codes: A61F 2002/0882 Anchor in or on top of a bone tunnel, i.e. a hole running through the entire bone
• CPC Class Codes: A61F 2240/008 Means for testing implantable prostheses

Abstract

For knee reconstruction surgery involving replacement of an anterior or posterior cruciate ligament the present invention is in a process of verifying isometric ligament positioning at the femoral and tibial points of origin that includes, as apparatus, an arrangement of a stud (19) with attached suture (24) to serve as a mock ligament for testing isometry. In practice, as for an anterior cruciate ligament replacement procedure, a surgeon, observing on a fluoroscopic monitor (17), forms a tibial tunnel (18) from a point medial to the tibial tuberosity that exits a test or proposed tibial point of ligament origin. The stud (19) is arranged for turning on a driver (20) that is then passed through that formed tunnel and the stud is turned into the test or proposed femoral point of ligament origin. The driver (20) is then pulled out of engagement with the stud (19) exposing the suture (24) that extends from that stud, which suture (24) is attached under tension to a tension isometer (25) and the knee (10) is flexed through its full range of motion. With an isometrically correct selection of the femoral and tibial ligament points of origin, the tension isometer (25) will show no more than a three (3) pound change in force and no more than a two (2) mm change in ligament length or distance between the two points of origin over a full range of knee (10) flexure.

Claims

1. A process to verify proper isometric ligament positioning in an arthroscopic surgical procedure on a human knee to replace the anterior or posterior cruciate ligament as performed by a surgeon viewing a fluoroscopic monitor, comprising the steps of, with a patient'"'"'s knee maintained appropriately forming a test passage from a point on the anterior medial portion of the tibia for an anterior cruciate ligament replacement or of the femur for a posterior cruciate ligament replacement, through the bone to intersect and pass through a first proposed or test ligament point of origin;

guiding an isometric testing stud means mounted to the end of a driver through the passage and turning it into the bone at a second proposed or test ligament point of origin on the femur for an anterior cruciate ligament replacement or on the tibia for a posterior cruciate ligament replacement;

pulling the driver out of engagement with the isometric testing stud means and withdrawing said driver out of said test passage exposing a suture means connected to the exposed end of said isometric testing stud means;

connecting, under tension, said exposed portion of said suture means to a tension isometer that will read a load condition on said suture;

flexing the knee through its full range of motion; and

observing the tension isometer during that knee flexure, where providing the proposed or test points of origin are isometrically correct, there will be no more than a three (3) pound change in tension on said suture means.

2. A process recited in claim 1, wherein through a full range of knee flexure there will be no more than a two (2) mm change in the suture means length or distance between the test points of origin for an isometrically correct selection of points of origin. .Iadd.

3. A process to verify proper isometric ligament positioning in an arthroscopic surgical procedure on a human knee to replace the anterior cruciate ligament, comprising the steps of:

positioning the knee in a bent attitude;

forming a straight test passage from a point on the anterior medial portion of the tibia through the tibia to intersect and pass through a first proposed ligament point of origin on the tibia;

guiding an isometric testing stud mounted in the end of a driver through the test passage and turning said isometric testing stud into the femur at a second proposed ligament point of origin on the femur;

disengaging the driver from the isometric testing stud and withdrawing said driver out of said test passage exposing a suture connected to the exposed end of said isometric testing stud, said suture extending outwardly through said test passage;

connecting said suture to a tension isometer that reflects a change in tension of a change in length of said suture;

flexing the knee through its full range of motion; and

observing the tension isometer during said knee flexure to confirm the correct isometric positioning of said suture based upon readings obtained from said tension isometer. .Iaddend. .Iadd.

4. The process as recited in claim 3 wherein during the step of observing the tension isometer to confirm the correct isometric position of the suture, there will be no more than a two millimeter change in length of said suture as the knee is flexed through its full range of motion. .Iaddend. .Iadd.5. The process as recited in claim 3 wherein during the step of observing the tension isometer to confirm the correct isometric position of the suture, there will be no more than a three pound change in tension on said suture as the knee is flexed through its full range of motion. .Iaddend. .Iadd.6. A process to verify proper isometric ligament positioning in an arthroscopic surgical procedure on a human knee to replace the posterior cruciate ligament, comprising the steps of:

positioning the knee in a bent attitude;

forming a straight test passage from a point on the anterior medial portion of the femur through the femur to intersect and pass through a first proposed ligament point of origin on the femur;

guiding an isometric testing stud mounted in the end of a driver through the test passage and turning said isometric testing stud into the tibia at a second proposed ligament point of origin on the tibia;

disengaging the driver from the isometric testing stud and withdrawing said driver out of said test passage exposing a suture connected to the exposed end of said isometric testing stud, said suture extending outwardly through said test passage;

connecting said suture to a tension isometer that reflects a change in tension or a change in length of said suture;

flexing the knee through its full range of motion; and

observing the tension isometer during said knee flexure to confirm the correct isometric positioning of said suture based upon readings obtained from said tension isometer. .Iaddend. .Iadd.7. The process as recited in claim 6 wherein during the step of observing the tension isometer to confirm the correct isometric position of the suture, there will be no more than a two millimeter change in length of said suture as the knee is flexed through its full range of motion. .Iaddend. .Iadd.8. The process ar recited in claim 6 wherein during the step observing the tension isometer to confirm the correct isometric position of the suture, there will be no more than a three pound change in tension on said suture as the knee is flexed through its full range of motion. .Iaddend.