Prosthesis (i.e. – artificial body members) – parts thereof – or ai – Implantable prosthesis – Ligament or tendon
Reexamination Certificate
1999-01-29
2001-02-20
Isabella, David J. (Department: 3738)
Prosthesis (i.e., artificial body members), parts thereof, or ai
Implantable prosthesis
Ligament or tendon
C623S013140
Reexamination Certificate
active
06190411
ABSTRACT:
The invention relates to a fixing element for connecting a ligament to a bone part of a human or animal, comprising:
a hollow, substantially cylindrical element fixable in the continuous opening in the bone part, and
an engaging element for the ligament anchorable in the cylindrical element at least at two mutually differing axial positions.
When a ligament is damaged, for instance a hamstring is torn (ligament rupture) it is possible to arrange a new ligament surgically (plastic ligament). For such a new ligament can be used ligament material removed from another location in the body, but plastic material (plastic ligament) can also be employed for this purpose. The fixing of the ligament can take place for instance by means of a screw with toothed ring, staples, a bone plug, a toothed plug and so on. Fixing by means of a bone plug entails a continuous opening being arranged in a bone part through which the ligament for fixing is placed, The bone segment coming from the bone part and used for making the continuous opening is subsequently placed in the ligament such that the ligament is clamped fixedly in the continuous opening by the bone segment or bone plug. All these fixing methods are frequently used singly or in combination.
Drawbacks of the existing fixing method are that it is difficult to bring the ligament to, and hold it at, the correct tension. The consequence hereof is reduced function, pain and a sensation of instability. A drawback which applies particularly to a ligament manufactured from a ligament material removed from another location in the body (homologous) is that a ligament operatively arranged at the correct tension can slacken in the course of time whereby instability once again increases. A drawback to plastic ligament material is that this has a finite life-span so that it generally breaks after a number of years. The ligament will then have to be replaced and this is only possible by means of another major operation.
FR-A-2 663 837 describes a fixing element for connecting a ligament to a bone part. The fixing element comprises a hollow cylindrical element, which is fixable in a continous opening in the bone part and an engaging element for anchoring the ligament in the cylindrical element. The engaging element comprises a screw for displacing the engaging element in the cylindrical element.
The object of the present invention is to fix a ligament to a bone part such that it is very simple to hold the ligament to or vary tension respectively to replace a fixed ligament with another.
The present invention provides for this purpose a fixing element which is characterized in that the inner wall of the cylindrical element is provided with a profile for co-action with and axial positioning of the engaging element for the ligament.
See further page 2, line 14: “The outer wall ...” placed and this is only possible by means of another major operation.
The object of the present invention is to fix a ligament to a bone part such that it is very simple to hold the ligament to or vary tension respectively to replace a fixed ligament with another.
The present invention provides for this purpose a fixing element for connecting a ligament to a bone part of a human or animal, comprising:
a hollow, substantially cylindrical element fixable in the continuous opening in the bone part, and
an engaging element for the ligament anchorable in the cylindrical element at least at two mutually differing axial positions. The outer wall of the cylindrical element is preferably provided with a profile for a stable anchoring thereof in the bone part. The cylindrical element forms the engaging option for the engaging element which is connected to the ligament. The engaging element is connectable in relatively simple manner to the cylindrical element whereby displacement of the engaging element relative to the cylindrical element is comparatively simple to realize or whereby it in possible to release an engaging element with ligament fixed thereto from the cylindrical element and to replace it with a new ligament likewise provided with an engaging element, irrespective of the ligament type. It will be apparent that it is of great importance herein that the cylindrical element be rigidly connected to the bone part. The operative technique to be used does not differ greatly from the usual technique. For a simple connection between the cylindrical element and the engaging element the inner wall of the cylindrical element is preferably provided with a profile for co-action with the engaging element for the ligament. This internal profile can more preferably be formed by internal screw thread. For a simple and good coupling of the engaging element to the cylindrical element the outer side of the engaging element is preferably also provided with a profile for co-action with the inner side of the cylindrical element. This profile is preferably also formed by a screw thread. Readjustment of the ligament tension can take place for instance using a limited surgical operation such as for instance with an incision under local anaesthetic. In a preferred embodiment it is possible to provide the fixing element with adjusting means controllable from a distance. Herein can be envisaged for instance micromotors or induction principles. The tension on the ligament can then be adjusted “in the field” using a remote control or on a production line or while the patient is connected up to a knee laxity measuring apparatus. Other solutions are also conceivable in this respect, such as for instance temperature-sensitive materials or adjusting means controllable by means of a moving magnetic field.
Owing to the construction with the hollow cylindrical element which is permanently anchorable in the bone, the actions required for a possible revision are very limited and the revision time can be markedly reduced compared with the revision time for an existing ligament anchoring. The revision can be performed arthroscopically.
On at least one side of the cylindrical element the inner side preferably transposes smoothly into the end wall of the cylindrical element. When the cylindrical element is placed in the bone part such that the smooth transition of the inner side into the end wall forms the side along which the ligament is carried into the cylindrical element, excessive wear of the ligament resulting from contact with a sharp edge can be prevented.
The engaging element is preferably provided with means for clamping the ligament. Clamping of the ligament has the advantage that the ligament material is hereby not damaged, or hardly so, and that the ligament length required for a particular operation remains as limited as possible. The engaging element can be used irrespective of the type of implant (homologous, plastic ligament or combination).
In a preferred embodiment the engaging element comprises a continuous opening in which a clamping element is anchorable for clamping the ligament. Such a clamping construction is very reliable and moreover simple in use.
In another preferred embodiment the engaging element is connectable to the cylindrical element with interposing of a resilient element. By means of such a resilient connection the ligament tension can be held constant despite for instance stretching of the ligament material occurring in the course of time. Another advantage is that peak loads on the ligament can be at least partially absorbed by the resilient element, whereby damage to a ligament will occur less quickly.
In yet another preferred embodiment the engaging element is provided on the side remote from the ligament with at least one recess and/or projecting part for engagement of adjusting means for altering the position of the engaging element relative to the cylindrical element. By means of this provision it becomes possible to vary the tension on the ligament post-operatively using a very small incision. By inserting an adjusting means, for instance in the form of a spanner, into the incision such that it co-acts with the recess and/or projecting part it becomes possible to alter the p
Isabella David J.
Webb Ziesenheim & Logsdon Orkin & Hanson, P.C.
LandOfFree
Fixing element and ligament fixed with fixing element does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Fixing element and ligament fixed with fixing element, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Fixing element and ligament fixed with fixing element will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2612532